THE SOUTH PACIFIC ISLAM) FISHERIES HEHSLETTER

- No. 10 Noumea, New Caledonia November 1 973

-.

C O N T E N T S

Edi tor ia l 1

Special Project on Outer Reef Artisanal Fishing 2

Special Project on Inshore Fisher ies Development 3 - 4

I n i t i a l Organizational Work f o r Fanning Penaeid Shrimps in St. Vincent's Bay (New ~ a l e d o n i a )

by Professor F. Doumenge 5 - 21 Deep-Water Fishing in some Islands of the

South-West Pac i f ic by P. Fourmanoir 22 - 26 The Development of Tuna and Skipjack Fishing i n French

Polynesia and Experience i n l ive-bait Techniques (Summarized by Professor Fe ~oumenge) 27 - 30

Exploratory Shrimp Trapping i n the Hawaiian Islands, by P. Struhsaker

and D. Aasted 31 - 34

Developing the Exploitation of Trcchus n i lo t i cus Stock on the T a h i t i Reefs (~uaimarized by Professor F. ~ o u m e n ~ e ) 35 - 36

Development of the "Turtle Project" i n French Polynesia (Summarized, by Prokessor F. ~ourcenge) 37 - 39

Catch Data, American Samoa Tuna Longline Fishery, 1972 40

Q Diary of forthcoming meetings 41

Issued by the South pac i f ic Islands Fisher ies Development Agency, a United Nations Development Programme (special Fund) project , with the Food and Agriculture Organization of the United Hations act ing a s Executing Agency and. the South Pacif ic Commission Co-operating Agency on behalf of the par t ic ipat ing Governments.

SOOTH PACIFIC ISLAiIDS FISHERIES DBTELOPMEHT AGENCY

Project Manager:

Project CO-Hager:

Address :

Cables :

Professor F. Doumenge

H r R.E. Baird.

c/o P.O. Box D5 N O r n A GEDEX New Caledonia

Professor Doumenge has now returned t o France, and this is the l a s t SPIFDA Newsletter. A s mentioned i n the Edi tor ia l of Newsletter no.9, S E wil l , a t the request of delegates t o the 6 t h Technical Heeting on Fisheries, continue t o produce a Newsletter which w i l l be dis t r ibuted t o the present recipients of the SPIEDA Newsletter.

Sometime i n 1974, the South Pacif ic C o d s s i o n ? r i l l have an offset p r in t ing press a t Headquarters i n Noumea. This w i l l undoubtedly improve the presentation of the Newsletter. We s incerely hope tha t the content w i l l l i v e up t o the improved presentation.

c

A t the South Pacif ic Commission conference i n Guam i n

e September, the SPC's Special Fisheries Projects (see pp. 2-3-4 f o r summaries) were approved i n t o t a l . These projects were made possible by special ~ 0 h X t a r y contributions from Australia and New Zealand., with supplementary funding made by France a t the conference.

Three of the papers i n this present Newsletter show the exci t ing poss ib i l i t i e s of f i she r i e s developments outside the reefs :

- Deep water Fishing, by P. Fourmanoir ;

- The Development of Tuna and Skipjack Fishing i n French Polynesia ;

- Exploratory Shrimp Trapping, by P. Struhsaker and D. Aasted.

The shrimp farming experiments show promise f o r the fu ture , but w i l l inevi tably be a high cost , advanced technology operation f o r some time. Farming of molluscs can add t o both protein and cash income i n many areas. Turtle farming has promise and the t ransplantat ion and "seeding" of Trochus i n Tahi t i , demonstrates t ha t the introduction of exotic species can so produce good economic returns.

R.H. Baird

2

SPECIAL PROJECT ON OOTER-EEEF ARTISAHAL FISHING

.. .

~ h e ' ~ r i i n a , & goal of f i she r i e s development programmes i n the south . ' , .

Pacif ic should be sa t i s f ac t ion of loca l f resh f i s h demand, thus providing,protein at reasonable cost . Surplus catches can be so ld t o foreign..markets as a source of foreign. exchange. I n i t i a l deyelop- men? :&a?% be based on indigenous crews working from re l a t i ve ly s n a i l craft.. The American Samoa. Dory Project . has demonstrated. the p ra t i ca l po ten t ia l of this approach. . .

It is proposed t h a t SPC undertake an a r t i s ana l experimental and demonstration f i sh ing project i n those terri tories which a re not able, at present, t o t e s t and develop t h e i r loca l f i she r i e s potential. The objectives of the project a r e t o assess t e r r i t o r i a l resources, determine and demonstrate successful f i sh ing techniques, prepare an economic investment prospectus, t r a i n a limited number of fishermen, and compare the cost effectiveness of two d i f fe ren t types of f i sh ing c r a f t . The, project w i l l . be- subs tan t ia l ly self-contained, , with

f o r . b o a t s , f i sh ing gear, re f r igera t ion and personnel'. . The two. boat. types will be the petrol-poi'rered 24 ' plywood ''Sanoan doryw ' . . ,

and-.an,a$uminium . . boat with d i e s e l power. A.:variety of f ishing, . . ..

teahniques...will be used. Personnel t r i l l include a Project Menager, , .. .,

master fisherman and, four volun'teers. Trainee crews. w i l l come from the t e r r i t o r i e s i n which the project operates.

SPECIAL PROJECT ON INSHOEE FISHERIES DEVELOPMEBT

( ~ e e f and lagoon)

Introduction

With the increase i n population of many of the Pacific is lands and with consequent increase i n pollution and i n f i sh ing pressure, i n many cases the is land populations can no longer maintain t h e i r f i s h requirements from lagoon sources, par t icu la r ly not i n areas close t o centres of population. T h i s is the reason f o r the SPC's emphasis on outer reef a r t i s ana l f i sh ing developments.

However, there s t i l l a r e many poss ib i l i t i e s f o r reef and lagoon f i sher ies developments.

Lobster (~anu l i ru s spp. ) - There i s some considerable body of evidence tha t commercially exploitable stocks of lobsters are found on the reefs of most Pacif ic islands. Remarkably l i t t l e is known of the v i t a l population parameters such as growth r a t e , mortali ty, stocks and i n consequence, optimum yield. Knowledge of a l l these i s required i n the long term i n order t o maintain maximum sustained yield.

However, i t i s known tha t there a r e many, a t present unexploited or under- exploited stocks. The main d i f f i c u l t y is t h a t of log is t ics . Widely scat tered archipelagos, with remote is lands with exploitable stocks of lobsters , are unable a t present t o market lobsters because of the i r regul- a r i t y of collection. One immediate, and f a i r l y inexpensive p a r t i a l solut ion of this problem would be l i v e storage a t i s land s i t e s . Live storage of lobsters i s practised extensively i n Central America, Europe and Africa of Panulirus spp. and also Homarus spp. i n H. America and Europe. There seems t o be no reason why Panulirus spp. should not a l so be successfully stored a l i ve on i s land s i t e s i n the Pacif ic . I f t h i s vere possible pending col lect ion f o r processing and marketing, i t could make a subs tan t ia l contribution t o the cash income of many remote i s land vi l lages .

Recornanclations have already been mde i n reports t o the Administrations of both the Br i t i sh Solomon Islands Protectorate and the TSev Hebrides, t ha t t h i s problem should be looked i n t o and guide l i nes have been given f o r the i n i t i a l approach. However, nei ther of these t e r r i t o r i e s has the resources of personnel t o conduct reasonable long-term experiments i n depth. A s the problem i s one common t o nearly a l l the t e r r i t o r i e s of the Pacif ic , who would a l l stand t o gain from a def in i t ive answer, it would be desirable f o r the Commission t o finance one or two years work i n t o the solut ion of this problem.

There is a t present a b ig demand a t a good price f o r Beche-de-mer. Many t e r r i t o r i e s a r e a t present exploi t ing this resource. A handbook prepared by the FAO Consultant t o SPIEDA, Mr. Sachithananthan, on Beche-de-mer i s suffer ing some considerable delays i n production due t o doubts about i den t i f i ca t ion of some species.

A s with lobs te rs , l i t t l e is known about growth r a t e s , stocks and recruitment. Iden t i f ica t ion of the main commercial species is frequently a problem f o r out islanders. The volunteer working on lobs te rs

, - .. . ~ . .

above would often be working on an area of Bsche-de-mer. He could, incidentally, begin to make a study of stocks and. methods of preservation (f ormalin injection) that would allow the main comnercial species. to. ,. . .

be preserved in a recognisable form and distributed , . for species identification. ~ .. . , . , . ~

,, ~,

. . ~ . . ,

~urt'le Fanning . . ,

. . . . . In are&.. where nesting turtles occur, turtle" fanning, by means of hatcheries and rearing has been shown to be a congenial and effective' operation a$ the village level, producing both protein.food and cash, a l e at the same time contributing substantially t o c6nservatiOn.. :, ,, : ,

of turtle stocks.

An investigation of the feasibility of this operation in one or two Pacific islands is considered a well worthwhile low costproject. A -

reasonably succes?ful farming operation could be used as a demonstration ~entre and asubst&tial industry could be built up in the Pacific area for turtleproducts., ~. ,

. . . Turtles have the advantage, like Sche-de-mer and possibly lobsterg, ,. ,

of be'ingableto be held in remote areas ei-raiting'collection for' .

processing and marketing without the need for high cost freezing

.. equipment. ~ , . . ~ .~ > , ... :

. . . .. . ~

. . . .

... ~. . . . . " . . . . . . . . . . ,

. . Ã

* ¥

. . . .. . . . . . , . . . . - ~ . .

. . . : . .

. . .

INITIAL ORGAHIZATIONAL UOHE FOR FAEi.IIliG PENAEID SHRIPlPS II'T ST. VIITCEI~TI" S BAY ( l ~ f CALZDOITIA)

by Professor Francois Doumenge Project Manager, SPIFDA

I. Natural population for stockinf the farm

A natural population is present, of which juveniles and young specimens that have not yet reached adult size keep to the mangrove channels and the mud-sand floor of the coastal strip. In order to stock the pond, live shrimps 2 to 5 gr in weight may be caught without any great difficulty by means of fixed nets ulucli act as traps. these fyke nets, called capet- chades, are used by fishermen in the lagoon and. salt-water pools along the French IIediterranean Coast. Capetchades, irliich consist of a barrier 50 or 100 m long leading into an enclosure surrounded by 5 trap nets, keep alive the fish and shell-fish which get into them. Setting up a complete oapet- chade using 6poles for the barrier and 7 for the enclosure and trap nets, takes about an hour. Once in position, the capetchade may be left in the same spot for one or tiro ireeks. The nets in the trap should be inspected twice a day - this involving in all between 15 and 20 minutes - so that specimens caught may be removed and the trap aets put back into position. The contents of the nets are spread out on net sacks placed in the bottom of the fishing boat. Live shrimps are immediately sorted by hand and put into a plastic tub full of sea water that is stirred and constantly changed. If more than 10 or 15 minutes are spent between the time the live shrimps are caught and their release into the rearing pond, a battery-operated portable oxygen-bubble generator should be used.

The shrimps are mixed with other shell-fish and fish, which also, are immediately sorted. All juveniles and young specinens not used are returned alive to the sea once sorting is completed by washing and rinsing the bags. With trained, staff on the job, this takes only a few minutes. The i-rhole thing can be managed by tuo persons, though it is most useful to have a third person on hand to speed up the manual processes. Hitherto, shrimp catches have consisted almost exclusively of Penaeus mersuensis (banana prawn), ~rhicliare very delicate, having to be handled with great care and swiftness if a high mortality rate is to be avoided. Ifhen the experiment was initiated, there was less than 2ff/o survival. Improved organization, with the benefits of daily training, then raised this figure to a very satisfactory 80 to 85$ survival. A capetchade set-up can easily provide 100 to 300 live shrimps per day; and this was the case in a season characterized by a pronounced drought which made it impossible for the nets to be used at a time when masses of shrimp concentrated on the coastal fringe following a period of heavy rain.

This suggests that if capetchades are used during the season uhen juveniles come together, they could provide daily several thousand subjects for farming, so that it irould be possible to fill a pond in about 10 days of intensive collection. Along ~rith the Penaeus mermimsis, there is also a natural population of a a e u s semisulcatus and Penaeus monodon, but up to now catches lmve been limited to a few specimens. Further, great numbers of Hetavenaeus monoceros are aixed up with the Penaeus mersuieasis, but at the juvenile stage it is difficult to distinguish betveen them.

6

11. Size-increase n-l stocl: used

Since August 1972 when the experimental pond was f i l l e d , some hundreds of shrimps fished with a ca s t net and weighing 1 t o 3 gr , isgre put i n to the "t: so tha t observations could be made of t h e i r behaviour, no food being introduced from outside.

These juveniles showed rapid growth and t h e i r average weight i n mid-December 1972, vhen they had been i n the pond f o r four months, was 12 g r i n the case of males, while the females varied i n ueight between 20 and '35 g r , de'oending on t h e i r sexual maturity. (see SPIFDA Heirsletter No. 7, December 1972, p. 9-12). Subsequently, the small number of specimens remaining continued t o grow, even though the s a l i n i t y leve l of the pond water remained constant a t about 40~,&,01ring t o the protracted and unusually bad drought experienced i n this par t o f Hew Caledonia.

I n March and i n the beginning of April 1973, Penaeus merflriensis introduced in to the pond 7 months before neighed 40 t o 55 gr , which made them ident ica l i n s i z e t o the large shrimp fished i n Australia.

Apart from the few hundred specimens introduced systematically in to t i e pond when i t was f i l l e d , other shrimpgot i n through the pumping system, despi te the f a c t t ha t the water uas introduced through a coke-filter. It was in te res t ing t o note t ha t the l a rva l or post-larval stages of Penaeus semisulcatus, Penaeus monodon and.&apenaeus monoceros entering the tank, developed t o the adul t stage equally a s well a s Penaeus meroriensis.

111. Harvesting of the pond-reared specimens of marketable s i z e

Wherever shrimps a r c found, whether i t is i n Japan, i n Europe o r i n the United States , one of the problems most d i f f i c u l t of solution l i e s i n harvesting, gradually, the t o t a l i t y of farmed individuals t ha t have at ta ined marketable s ize , while a t the same time endeavouring not t o endanger the animal l i f e of the pond a s a whole.

The most d ra s t i c method, which consis ts of draining the pond was adopted t o observe the e f f ec t s on animal. l i f e and to determine the problems tha t were l i k e l y t o come up. The experiment conducted on 18th and 19th April 1973 was f a r from conclusive and was i n f ac t ra ther unsuccessful. The shape of the pond and the f a c t t ha t there is too much mud on the bottom render t h i s procedure t o t a l l y unsuitable. Losses irere very high, the majority of big shrimps remaining buried i n the mud, where they died a f t e r a feu hours. 7

Another technique has been developed which appears t o be qui te sat isfactory. T h i s consis ts of using a large fixed pound net w i t h l a r g e meshes from 15 t o 35 mm square of the Mediterranean "guangui" type. This type of net is used i n the channels and s a l t water pools f i she r i e s along the French Mediterranean coast. The net is f ixed t y means of 3 poles, its vings and mouth opened t o face the d i r ec t ion from vhicli the punped water comes over the overflow-chute, the cod-end of the net being f ixed abreast of the "moine p6cheriet1, a concrete t rap, f i t t e d with s luices . The l e f t wing of the net i s f i x e d w i t h a stake t o the edge of the tank. Shrimps of marketable s ize , i .e. specimens weighing over 10 gr each, a r e retained i n the cod-end of the net. The r a t e of ' f ishing can be improved

by making the animals in the pond move around, by simultaneously pumping in filtered sea water and partially emptying out water near the bottom by removing a board from the sluices.

This is a simple and labor-saving system since harvesting of the live shrimps in the net can be carried out by a single person. To avoid the accumulation of too many specimens in the cod-end, collection of shrimps caught can be made every 4 or 5 hours. This harvesting method makes for top-quality produce. It has also made it possible to use the first reared specimens to try and build up a controlled breeding-stock.

IT. Transport of farm-reared and natural specimens to Tahiti, to set UD a controlled breeding centre

. The French Centre for Oceanic Management ( ~ ~ 0 ) has set up in Tahiti a very large laboratory ~rliich is to concentrate on experimental large-scale farming of Penaeides.

As natural populations of these species do not exist in the waters of French Polynesia, external sources had to be approached for specimens that could constitute an initial breeding-stock.

CIEXO approached the St Vincent's Bay Demonstration Centre, uhich is at present the only organization in the Pacific capable of supplying specimens to be used for breeding purposes follouing controlled grouth in a rearing pond.

It is especially satisfactory that the St Vincent's Bay Demons- tration Centre could be used in this venture as at present neither conditions nor equipment are suitable for carrying out controlled reproduction expe- riments.

five batches were sent by plane (one in December 1972, one in January 1973, two in February 1973 and one in +rch 1973). comprising about 200 shrimps in all from the rearing-pond population. The method of condition- ing consisted of lowering the water temperature and releasing oxygen into plastic or glass bottles. The method was gradually improved until the in-flight mortality rate was reduced from 75/80$ to only 25/3@;.

With a view to increasing the breeding-stock in Tahiti, two batches were sent on 18th and 25th Hay 1973, involving 462 shrimps from a natural habitat, 343 of which were found to be alive upon arrival. In the course of April 1973, another experiment was carried out involving the transport by sea in the "Coriolis" of 37 juvenile shrimps. Nine of these- reached Tahiti alive after 17 days on the ship.

Finally at a more recent date, 122 shrimps from natural stocks and 75 from the tank were sent by air on 23rd June and 10th Aug~~st respec- tively. A shipment of about 81 shrimps TTBS made on the 25th August 1975.

Very sa t i s fac tory growth-ratawere obtained i n Tahi t i with the use of a locally-produced food, based on a m i x t u ~ e trochus f l e s h (l'rochus n i lo t icus) and skipjack (~atsu~ronus 13elanis) meat, improved by the incor- poration of vitamins and minerals.

I n mid-July 1973, the following were "under observation i n the CHEXO laboratory i n Vairao ( ~ a h i t i ) from among the specimens transported from S t Vincent's Bay:

Penaeus mereuensis: 400 individuals between 4 and 9 g r i n weight plus some specimens weighing between 13 and 16 gr.

. . .; . , . . . . , C . , ? , " . . . , . 1 . . . , . . , , , . c J

~&tapehaebs monockrbs; about 35 males 'from 14 t o 12 g r i n

weight.

Penaeus semisulcatua: 5 individuals, including a female weighing 51 gr.

Penaeus mon&%: 1 male 75 g r i n weight.

20 males and 20 females of the species P. meratifinsis kept i n a f ib reg lass tank (500 l i t r e s ) a r e weighed regular ly t o determine the

growth 3 a t t e r n i n captivity.The other individuals a r e reared i n two tanks of 12 m , made of f l ex ib l e p l a s t i c sheeting.

The presence of mature females i n the l a s t batch t o a r r ive (25th ~ u g u s t ) , made it possible t o i n i t i a t e l a rva l and post-larval t e s t s i n t he beginning of September, with the technique normally practised i n a r t i f i c i a l hatcheries.

7. Stockina the rearine-'pond

The pond was drained f o r the first time i n mid-April 1973. Routine treatment was given, such a s ploughing the bottom when dry. The pond was ready for r e f i l l i n g by the 20th May 1973, 150 kg of phosphate& f e r t i l i z e r being added. The object of the current experiment i s t o study the behaviour and growth of Penaeid and Metapenaeid shrimps at a density of about one individual per m^.

This experiment i s expected to l a s t 6 o r 7 months and should, i f successful, make i t possible t o obtain i n mid-December 1973 a few hundred k i l o s of specimens having reached a sub-adult stage, very close t o being reproductive. I n i t i a l l y , between 25th May and 9th July, 5363 shrimps were placed i n the pond. This population came from catches made with two capetchades, placed very close to the farm, one on the muddy zone i n f ron t of the mangrove swamp shielding the wall of the dam, and the other a lso i n a mangrove swamp within a small adjoining bay, a t a distance of about 400 m. T h i s sor t of locat ion has made i t possible t o solve transportation and survival problems i n a sa t i s fac tory manner.

The juvenile sl ir lmpare mainly of the species Penaeus merfuensis (banana prawn). An analysis of the catches shows c l ea r ly hou p l en t i fu l they were, considering the l imited number of days vhen conditions were favourable. I n one s ingle day, 14th June, 687 specimens were collected; and the six best days (6th June, 10th June, 14th June, 18th June, 19th June and 30th ~ u n e ) between them accounted f o r over 4@ (2244) of t he shrimps collected. For the time being, i t is not possible t o cor re la te the catches made with the phases of the moon or t i d a l flow, aa too many external fac tors interfered with the e f f ec t s of natural conditions, f o r instance losses due t o the improper use of nets, y ie lds affected by the f a c t t ha t i t was not a t f i r s t possible t o inspect the ne ts regular ly or a s only one capetchade was a t t he time su i tab le f o r f ishing.

The breakdown of l i v e shrimps collected t o stock the pond was a s follows:

394 specimens from 25th t o 31st Bay 692 11 from 1 s t t o 7 th June

1 604 IT from.8th t o 14th June 1161 11 from 15th t o 21 st June 589 11 f rom 24th t o 30th June (l) 923 II from 1st to 9 th July.

(1) All shrimps caught from 22nd t o 23rd June were sent t o Tahit i . These a r e not mentioned i n this table.

A summary check was made on how the na tura l stock was made up, the s i ze s of shrimps i n cer ta in batches being measured before they were released in to the farming pond. The d is t r ibu t ion indicateethat the popu- l a t i o n of juveniles is f a i r l y homogeneous.

Of the shrimps concerned, 50 t o 7@-/ (overall average 62.5$), were in the 7 t o 8 cm size-bracket, 21% of the t o t a l col lected being more than 8 cm, and 16.$ l e s s than 7cm i n length.

Later on, i n ear ly July, two large batches of specimens which were found dead i n the pocket of the capetchade nets were measured f o r s i z e and preserved a s controls f o r checking the s t a t e of the na tura l stock upon completion of the f i r s t stocking period. There was hardly any difference between t h e i r s izes i n ear ly July and those recorded i n June, confirming the s t ruc ture of the population being fished.

. %of theshr imps coll&cted, 69.7% were i n c h e 7 t o 8 cm group, . . . . . . . ~

them 'being la rger and 20.$ smaller. '.'~ ... . . . . . . . ~. .... ' > ~. ' . : , .

, .

208 . .

Total . . 234. . . . --- . .

I n the case of these sample batches, the average weights were ' & & ~ e m i ~ & d ~ n 3rd July.:' 'The 234 721 g?, so '+hat'.&e '..

average weight was 3.08 gr. The 193shrimps-collec'fed o n 4 t h ' J u l y weighed 605 gr, giving an average weight of 3.15 gr per individual. . . . . . . . . . . . . . . . . . . . .: . . . , . . ,. . . . . . . .

I n connection with the f i r s t shipment of shrimps to the CMEXO laboratory i n Tahiti, a check wasmade on 10 th August 1.973. on. the. growth pat tern a f te r .%hey h a d been reared i n t h e pond for'-an average of. six weeks. 447 shrimps -were studied, representh* about -&..of t h e specimens introduced between 25th May and 9 July. A considerable increase i n s i ze could be noted, '-the 9-1 0 cm group being the most numerous (?C$ o r 31 2 i h i v i d u a l s ) against 7.2$ %hat were smaller (33) &d 22.8$ (102) l a rge r i n s i z e . This sample, check iaade it possible t o es tab l i sh a size/$eight r a t i o tha t can be used i n assessing the live-weight of shrimps stocked in the t a w .

Panaeus mer&&sis - batch of 10th Awust, 1 9 7 ' . . ,

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ~~ . . .

Total leneth i n ! centimetres. ' .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5.

. . . ~ . . 8.8 : . . . . ,. ..... , . . , - . . ,. ; . .

. . . . . . 10.2 ~ :., . . . . .

~. . .

. 1.1 .2 . ~. . ~. ... . . . ,

:?.

.l 2.4 . . . . . . . . . . . . . . ~. .

After sorting iias completed, it was possi'ole to classify 217 male specimens neighing 1,454 gr in all, with an average weight per individual of 6.7 gr, and 222 females with a total veight of 1 .g36 gr and an average individual weight of 8.17 gr. The average weight of this population, which appears to be evenly balanced, is thus 7.7 gr per shrimp. It may thus be assumed that on 9th August 1973 the pond must have contained about 40 kg of live-weight in shrimps, leaving all mortality factors out of the reckoning.

Adjustment of these figures taking into account natural mortality can only be made after harvesting. Up to the present moment, no accidental mortality has been noted.

VII. Rearing tank: hydroloeical characteristics and water displacement

The water supply to the tank consists of pumped sea water filtered throu h a coke ring about 80 cm thick. The rate of flow varies between 9 500 m and 800 m3 per hour, depending on tidal conditions and the power adjustment. Pumping initially carried out over a total of 10 hours between 25th and 30th May made it possible to cover the muddy bottom of the pond with a 30-40 cm layer of sea water. This ensured the disappearance of bacterial and planktonic flora and facilitated the onset of curing so that the bottom could be covered with algae. The sea water pumped in had a.

0 mean temperature of 23.5' and its salinity was 36 /oo.

Owing to a particularly bad drought (4 mm of rainfall between 25th Hay and 5th ~une) and heat that was quite unusual for that time of the year (the maximum air tenperature in the shade varied between 26 and 27'0 from 25th to 31st Hay and 29' and 30'0 betdeen 1st and 5th ~une) the water temperature in the tank: rose sharply to 27.4' on 5th June, the salinity shooting up to 41 .4g0/oo.

It should be pointed out that the first shrimps placed in pens during this period seemed to adjust perfectly to these extreme conditions.

From the 6th June onwards, after superficial ploughing of the area not covered by the water of the first pumping, pumping was resumed so as to bring the water-level in the tank to the mean mark, i.e. 1.40 metres in the "moine p8cheriet1, the effect of evaporation being compensated for. For a month, from 6th June to 5th July, pumpingiras carried out almost daily for 1 to 5 hours per day, depending on the tidal level and the effect of -

evaporation. In the course of these 30 days, pumping went on for a total of 60 hours, so that the salinity of thewater in the pond could gradually

C be brought down from over 41 /oo between 5th and 9th June to 40.19 /oo on 10th June, 39.2O/oo on 12th June, 38.4 /oo on 15th June, to hold steady between 38.5O/oo and 39.5O/oo from 16th to 28th June. It retui'ned to 38.40/00 on 29th June, 37.58O/oo on 4th July and 37.35O/oo on 5th July. W i n the period from 6th June to 4th July, drought conditions con- tinue 8 to be extreme and only 9.6 mm of rainfall uas recorded. The effect of a pronounced drop in air temperature (maximum between 24 and 260 and minimum between 1 2 and 150) soon made itself felt and the temperature in the pond dropped almost throughout this period to 2 0 and 23 C. On 5th July at 7.15 a.m., when the first period ofdrought came to an end, the sea temperature was 20.55 C and the salinity 35 /oo, while in the pond a tenpe- rature of 21 .2O0 was recorded, the salinity being 37.35 /oo.

. There followed, between 5 th and 20th July, a r e l a t i ve ly cold . (inax&mw temperature. between 21 and 2 4 ~ ) and rainy (1 50 I&) s p e l l which.

did.. a ce r t a in amount of damage. ' Following heavy r a i n on 7th, 8 t h and. 9 th ~ u l ~ , when over 90'mill of r a i n f a l l were recorded, s a l i n i t y i n the' tank f e l l , t o 32.1 0 /oo. Pumping was then. reduced t o a minimum jus t s o as t o mingLe the surface water and avoid s . t r ~ i f i c a t i o n . ~e tween . 5th and 20th ~ u l y , . water wag pumped i n only 5 times, f o r a t o t a l duration of 11 ohoks . A t ' .

7.1 5 a.m. on 17th July, the water i n the sea (33.39 /oo, 18 C) and that i n thepond (33.80/00 and 19.65 C) showed very s imi l a r character is t ics .

,

here was drought again between 21 st July and 20th August. . ( 3 mill of r a in fa l l ) , but there was lessevapora t ion a s the 'temperatures were lower (minimum usually between 10 and 1 5 0 and, maximum temperature betweep-24' and 26¡C) ~ 14 pumpings over a t o t a l period.. of . . ~ 30 . hours were. enough t o keep the temperature very c lose t o that of sea water (average 20°c) and the s a l i n i t y a l i t t l e higher ( a t 7.1 5 !.m. on 1 5th August, 34.8'/00 . . i n t he sea t o 36.00 /oo i n t he tank). -

On 20th and 21 st August, 15 mm of r a i n f a l l cooled the weather down sharply, s a l i n i t y dropping considerably. On 22nd August a t 8.00 a.m., the temperature i n the tank was 16.5 C and the s a l i n i t y 33.T0/oo.

. .. . . ,

From 22nd August t o 25th ~ e ~ t e m b e r , the weather remained cool and of ten cloudy, but r a i n f a l l continued, t o be low ( l e s s than.,15 &),and both the temperature and the s a l i n i t y of 'the pond gradually increased. 'The s a l i n i t y recorded on. 1 0 t h September was over 36O/oo and on 25th September

0 at 7.1.0 a~m., the readings taken i n the tank were 23'~. and 38.1 Loo. To. compensate f o r l o s s due t o evaporation and i n order t o maintain fa ixphysico- chemical s t a b i l i t y , i n the pond, pumping was effected f o r 14 hours between 22ndAugust and 9th September,, and 18 hours between 9th and 25th ' ~ e ~ t e m b e r . '

. . . .

On 22nd September a t 7.10 a.m., sea water i n t he v i c i n i t y o f the 0 pumping s t a t i on had a temperature of 18.5'~ and a s a l i n i t y o f . 35.3 /oo, while

0 0 the correspondingreadings f o r the pond water were 19.5 C and. 37 /oo. Between 25th and 30th September, a br ief wet s p e l l brought with i t 28 mm of r a i n f a l l ,

0 so . t h a t t h e s a l i n i t y was maintained below 37 /oo, but owing t o pers is tent windsand the f a c t t ha t day temperatures were between. 25' and 27 C , there was considerable .evaporation. . .

~. . ,

Thus, despite. cl imatic conditions t h a t were par t icu la r ly unfa- vourable. (long periods of drought interrupted-by a few days .of .very heavy ra in) , the e x i s t i n g f a c i l i t i e s and water-control methods practised proved. adequate i n maintaining ce r t a in hydrological charac te r i s t ics i n the . farming of Penaeid shrimps; and. there i s every likelihood of success .

. .

. . . . . .

. ,

~. . . , ,

, .

V I I I . Pond water-supply and fauna eauilibrium

Low density stocking enables the use of the natural productivity of the water channelled through a coke-fi l ter , during the pumping process.

It is worth noting that ,during the period under review (end of Hay 1973 to beginning of October 1973), onlh planktonic forms developed i n the pond, and, i n par t icular , t ha t there was no invasion of predatory crustacea o r f i sh , whereas during the period from September 1972 t o April 1973, eggs and larvae of numerous species passed through the f i l t e r and eventually developed in to approximately a thousand "blue Breams" (~canthotiaerus berda), several dozen crabs ( ~ c y l l a serrata , Portunus pelagicus, "mangrove crabs", " f igh te r crabs", "ca1,edonian crabs") and Stomatopodes ( ~ q u i l l a ) .

The water contained i n the pond rapidly took on a brownish colqur, indicat ing a high density of diatoms. There were almost no . green algae, whereas colonization of the banks had previously been a problem.

A s ignif icant growth of Copepods was noted around 10 July. It did not however endanger the overal l equilibrium.

I n order t o susta in the growth of the stock of Penaeides supplementary food was used, upon which the shrimps fed actively. It consisted exclusively offresh f i s h minced by hand with a household mincer. The minced f i s h was placed par t ly i n control f eed ing t r ays but once the shrimps had shown sustained appeti te f o r it, the food was broadcast from the banks and the dike, it was d i s t r ibu ted over the surface vhich proved most a t t r ac t ive t o the shrimps.

The f i s h used was mostly clupecoid-like f i s h cal led "Japa- nese sardines" (known a s "Konoshiro" i n loca l language). A few "Pomadasys hasta" ( "~ roc ros" ) were sometimes added and most of the small f i s h consisted of f i s h loca l ly called anchovy, sardines and "pretres". The volume and frequency of feeding varied according t o the appet i te of the shrimps. It should be pointed out t ha t i n June and the beginning of July, a s ign i f ican t portion of the food was not used. Therefore, t o lessen the r i s k of pollution, the heads, t a i l s and sca les of the biggest f i s h were discarded before mincing. m

14

The d is t r ibu t ion was a s follows:

Period

5 - l 7 June

1% - 30 June

1 - 10 July

11 - 20 July

21 - 31 July

1 -...l0 August

1 1 - 20- August . . . .

21 - 31 ~ u g u s t

1 - 10 Sept.

11 - 20 Sept.

21 - 30 Sept.

1 - 10 Oct.

i

Total food dis t r ibuted

g.

8 000

22 000

22 000

18 000 .

17 000

30 000

32 000

30 000

25 000

20 000

42 000

28 000

Estimated l ive- Daily feed/ ' weight r a t i o :

IX. Further stocking of pond , . . . . .

After the sample batch of 447 shrimps was collected on 10 ' '

August,:fishing was continued, using a simple capetchade net t o obtain f r e sh 'food. . Live Penaeides and Metapenaeides shrimp caught. with t h i s . . netwere.;intro&ced into . the pond, serving a s .the bas i s f o r a . . new , : stock.: By 10 October, 6.216 l i v e shrimp had been introduced i n t o the pond (.not . . including the ,477 specimens introduced ~. on 10 gust).

. . . ~ .: ,

The breakdown was as follows: '% Humbe;..;f ' .

. ' shrimps' ,,

Shrimp caught ' f o r i n i t i a l stocking (25 Kay t o 9 July). 5.363 - .. .................... - &imp caught end of July i n Tontouta 55 - Fishing i n f ront of pond, 5 t o 7 August ................ 402 --

Total on 9 August: 5.820

.................................... - Sample on 10 August -& Shrimp remaining on 11 August: 5.373

........................ - Shrimp caught 11 t o 24 August 276 - Shrimp caught 30 August to 20 September ............... 192 .............. - Shr im~ caught 24 September t o I 0 October 3 t o t a l number of l i v e shrimp introduced: 6.216 -

X. Operations involved i n i n i t i a l harvestine . .

I n order t o observe the growth of shrimp and to make stock estimates, night-fishing was carried out f ive times between 10 and 14 October, using the gangy-type fixed net.

The following i s a breakdom of the catches made:

i Penaeus asrguiensis 1 Metaue 1 period Males Females ' Mal

l i N o . / - , q . 1 6 ; , E. >i7 10 October 615 , 5.991 10.363

11 October 424 1 3.925 848 14.50

12 October 380 3.561 188 3.241 20

13 October 178 1.732 60 1.048 6

14 October 197 1.895 136 2.469 4

Total 1.814 17.104 1.839 31.623 41

e s Females

86

338 46 6 24

The homogeneity and well-balanced nature of the stock fished are t o be noted. The average weight of the specimens, weighed when drained of water, was i n the case of P. merguiensis, 9.4 g. t o r males and 17.2 g. f o r females, and i n t h a t of M. mnoceros only 8.2 g. f o r males and 13.5 g. f o r females.

The very small number of Metanenaeus monoceros caught may be taken t o indicate tha t the gangy-type ne t is l e s s eff icacious f o r f i s h i n g this species, which buries i t s e l f i n the sand. on the other hand, s tays on the bottom without burying i t s e l f , and seems t o be very easy t o catch by v i r tue of the f a c t t ha t it moves around more. It was possible t o make more detai led observations while measurements were - taken of a l l specimens of M. monoceros and 400 specimens of P. mermiensis.

Reference should a l so be made t o two mature Penaeus semisul- -females caught, one of which weighed 25 g. and t h e other 40 g. Among the smaller and l i g h t e r specimens introduced since the end of August, catches wore considerably reduced and involved Penaeus mersuiensis, 10 males weighing 40 g. i n all (4 g. each) and 8 females 51 g. (6.5 g. each).

Thus between 10 and 14 October, 3.742 adult specimens were caught, tha t may be assumed t o belong t o the population of 5.373 shrimps placed a l ive i n the tank before 11 August. The catch percentage is very high (69.9%), indicat ing an extremely high survival ra te . This can be ver i f ied more precisely during the next f i sh ing operation, which should take place around mid-December 1973.

g

oyster farmer i n , Ouenghi a n d the owner of a high-quali'ty sea-food s tore i n Noumea, was a great success. 37 k i lo swere sold f o r a t o t a l of

average price .per. .kilo was. 1,200. .fr. CFP.., .. ~.

. . . , .

,200 fr CFP' par k i lo (.$A 1 0 o r SUS 1.5.)-.m$y ,..and i s iri f ac t , . r a t h e r . high. .. ~~owever,..to, bave.a. b e t t e r .. g of the l eve l at tained, it should b e b o r n e . i n mind t h a t d o n i d domestic market is iccustomed t o importing food . 'products .

; a t &tremely high pr ices , i t s considerable purchasing power being- , ". e

conditioned by a standard of l i v ing boosted by. mineral wealth. and ,. . ,. , . . 1 heavy . , industry. . .

. . . . . . . , .. . . , - ,

. ... Further, the farmed.shrimps.were very,favourably received,,

' . ~ by . . . . consumers ~ . . a s the produce was remarkably f resh and very homoge&o~s."' ,. . .~

There is no doubt t h a t t h e .consumer is b i a s e d i n f from the rear ing pond, a s they have a f i r b e t t e r -

. . . . . . .~~

ober i s not a favourable time f o r s e l l i n g nd eaceecled t h e Supply s o t h a t individual s a l e s

, . . . . , , . . .

. .. , . , . ~

. . . . ,.. . rs have o f f e r e d t o buy produce expec

the next harvest which, scheduled a s i t is f o r the Christm&s.season,.'is e r price t h a t can a s o f now be assessed at being fr OFF. par k i l o ($A 15,. $US 22). , '

. , , . ., ~ ~

. . , ~ . ,,. , .

ectat ions are t o be baded o n such s a l e . p r i c e s ; i t : envisage the establishment of some p i l o t farms whic

s¥fcicated~techniques, making f o r much higher" drger shrimp stocks:. ,.;. ~ . . .~

. . , . . . ;.. .. . . .. . , - .

. , ~ . . . . . .,.

, , . . .. . r ~. . . . .. , ~, ' . 1 n i t i a l experiments involving the. c o n t ~ o l l 6 d ' farming, o:f ~.,,

ides shrimp i n St.. vincent 'S' Bay indicate that^:" . . . .. ;... ., .;.it .Is possible to hope f o r economically.' f eas ib le ' results' provided one ,.

7 , . . . can readily obtain several hundred thousand post-larvae t o s u p p l y the' stock of juyeni les . tha t can get the maximum benefi t from the favourable

., hydrologic& +d. .. c l ima t i c .. . conditions i n rearing 'pond

..:up,at ~ ~ moderate. cost in. many locat ions o n South , . ~ a c i f , . , L . .

.~ , . . ,,:.. . ., , . ' . . . . . .

. . .

The remarkable r e s u l t s obtained by CMEXO in the Vairao laboratory i n Tahi t i , allow one t o hope tha t by the end of 1973 or the beginning of 1974 a t the l a t e s t , f u r the r experiments on these l i n e s w i l l be carried out i n the St. Vincent's Bay Hariculture Demonstration Centre, taking i n t o account i n i t i a l data collected since work began i n August 1972.

More par t icular ly , i t may be hoped tha t thanks t o the judi- cious ro ta t ion of generations - with small tubs being used f o r pre- growing the shrimp - there would be three main harvests per year.

A s behaviour var ies between d i f fe ren t species, g rea te r numbers of shrimps can be farmed, associating species tha t ordinar i ly l i v e buried i n the sand (~enaeus semieulcatus, P. monodon, Itetauenaeus monoceros) with a species tha t always remains above the sand f loo r l i k e Pena~us

o merauiensis.

Recent progress achieved both i n Japan and the United States , i n Europe a s well a s i n Tahit i , i n developing a cheap and standardized feed i n the form of manufactured pe l le t s , w i l l help i n the t r ans i t i on from the present stage, involving research i n a small number of special i - zed ins t i tu t ions , t o the prac t ica l application of the r e s u l t s i n shell- f i s h farms tha t could bring i n a considerable amount of income both t o the private investors and the t e r r i t o r i e s concerned.

BIOMETRY

Although produced from natural stock tha t is necessarily heterogeneous, f ished a t random with capetchadee,the stock i n the pond was found t o be surprisingly homogeneous. This confirmed the i n i t i a l indications of the f i r s t t e s t s carr ied out at the end of 1972< -As i n December 1972, the number of samples being f a r l a rger , the Penaeus merauiensis males are shown t o be grouped together i n a narrow bracket (over 80̂ of the specimens weighed being within the 9.00 to 9.99 g. range). The females, a s was t o be expected since t h e i r individual weights vary great ly according to the sexual stage, were more widely dis t r ibuted. Nevertheless, over €307 are within the 16.00 t o 18.5 g. range.

Penaeus merguiensis : Distribution of mean weight in grams

. , . . ., . . . . , . . %

, , .~ ! Males ema ales  ¥ : '  ¥ : . ,

. . i , '~

W e i g h t i n g , 1 No. 1 % 11

A more detailed morphometric study involving 50 specim6ns of each .sex made it possible t o determine .the length/weight r a t i o i n the two.iexes and the stage . . of sexual maturity among the females. . , ~ .. . .

i

Weight i n g* ' No. . . I- I %

Mortihometrv. : Guide marks involved i n the two measurements made

14.00.-14.49

14.50 - 14.99 15~00. - 15.49 .1 5.50. -:.l 5:..99

16.00 - 16.49 16.50 - 16.99 17.00 - 17.49

l

l T.L. = l

Total length i s length from the o rb i t a l recess t o the I t i p of the middle segment of the te lson

17.50'- 17.99 170" . . .

13.9

18.00 - '18 .'49 F. 180 . 14.7

18.50 - 18.99 '90 7.3 . . . .

19.00 - 19.49 40 3.2

. .

10" .

, 20.. . ,.

70

140 ,

240

251

. , . 0.8':

- 1..6: :.

. . 5.7 . ,

,. 11.4 . . . . . . . . 19.6

21,.0.

Morphometry of a random sample of 50 males and 50 females

Penaeus mereuiensis

- 0

.....

, a

Sexual stage

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Weight in

9.0 7.0 8.5 8.0 9.0 8.0 8.2

. 8.0 8.0 8,O 8.0 8.0 8.0 9.0 8 -5

T.L.

9.2 9.3 9.3 9.5 9.5 9.5 9.5 9.5. 9.5. 9.6.

. . . 9.6. . . . . . . . . m 9.7 - 9.7 - 9.7

9.8

C.L.

2.0 2.1 2.1 2.2 2.3 2.2 2.3 2.2. '

2.2 2.2

2v.3 , ,

2.2 2.3 2.4 2.4

T.L.

12.3 12.0 12.8 12.5 12.3 11.4 11.8 12.2 12.3 13.0 11.2 12.0 10.9 12.3 12.3

.. 9 - O 10.0 8.5 8.0 8.0 9.0

' 9.0 9.0

' 9.0 ' 9.0

9.0 ' 9.0 9.0

10.0 9.0

' 9.0 10.0

9 . 0

9.8 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.1 10.1 10.2 10.2 10.2 10.2 10.3 10.3 10.3

2.5'. 2.2 2.4 2.2 2.2 2 2 2.3 2.4 2.3 2.5 2.3 2.3 2.3 2.5 2.4 2.1 2.4 2.3 !

11.8 12.7 11.9 11.8 12.4 11.9 11.5 12.4 13.0 12.2 12.5 12.0 11.6 12.8 12.4 12.5 12.3 12.4

C.L.

3.2 2.9 3.4 3.3 3.3 2.9 3.0 3.7 3.1 3.3 2.8 2.9 2.4 3 -0 3.1

10.3 1 2.3 10.3 I 2.4

0 1 1 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3.

11.5 11.6

Weight i n K.

17.0 17.0 20.0 18.0 18.0 15.0 15.0 18.0 16.0 19.0 13.0 . . . 17.0 11.0

15.0 18.0

3.2 3.3 3.2 2.7 '

3.2 3.1 3.0 3.3. ,

3.4 2.8 '

3.2 '

2.7 3.1 3-2 3.2 3.1 3.0 3.3 ~

'9.0 I 9 . 0 I

l

15.0 , 20.0

16.0 17.0 18.0 18.0 15.0 18.0 20.0 17.0

' 18.0 16.0 16.0 20.0 19.0 18.0 17.0 18.0

3.0 3=0

3 3

14.0 15.0

3.3 2.9 3.4 3 .3- 3 . 3

10.3 10.3 10.3 10.4

16.0 ' ' 15.0

19.0 - 18.0. 1 19.0

9.0 ' 9.0 " 9.0

9.0 I 10.0 1 10,O i 9 . 0 ' i

'10.0 1

2.3 2-3 2.3 2.5 -

10.5 1 2.5

:: 10.5 10.5 2.6 10.5 1 2.5 10.6 1 2.3 10.7 i 2.4 10.7 1 2.4 10.9 ' 2.6 i

, l I

3 1 12.4 3. 11.6

i

.v.

3 3 3 3 . 3.4

2.5 3.5" .

3.2 10.5

12.5 12.6 13.0 12.9 . 19.0

'12.0 .' 20.0 ' 16.0

9.0 1 ' 11.0 1 10.0

3 1 1 1 . 0 3 12.8

12.0

3 3 3

3.4 1 18.0 3.5 20.0 13.0

12.9 12.6

3.6 3.6

18.0 18.0

I i

Key t o Table. pace : , . . ~, , , . . .

T.L. : Total length i n cm from the o r b i t a l recess t o the t i p of the middle segment of the telson.

. . . ~ . . . ... C.L. : Length of carapace is length from the o r b i t a l

recess t o end of carapace ( in cm). . . , . . . . . . ..... .

Weight i n grams.

Sexual stage: 0 = immature . S

1 = s t a r t

2 = mature

3 = about t o spawn

1t i s worthwhile pointing out the charac te r i s t ics of females , . . found t o b e s t i l l carrying spermatophores a f t e r moulting. , ~

. ,

Penaeus mer&.uiensis females t ha t have moulted, and still carry stiermatophores:

~, .

. .

Though the number of petapenaeus mono&erag present was ;&all, i t was considered tha t - i n view of t h e i r v 5 y par t icu la r behaviour, t o n o t e the biometric charac te r i s t ics of samples from t h i s species.

. .

Total length . . .

10.7 11 .O

. 11.2 . ,

. 11.2 11.3 11.3 . *

11 -5 . 11.5

11.5 . . . 11.5

11.8

. . 12.0 12.0

' " '12.0 12.0 12.0 12.2

. ' . 12.3 , 12.5

v .. 12.5 . . . 12.7

, . . . . ,

Carapace length

2.6 2.6 2.2 2-2 2.5 3.0 . . 3.0 - . . 2.6 2.5 2.7 3.1 2.6 2.5 2.6 3.0 2.5 2.7 3.3 3.2 3.3 3.3

l

. . Weight in g.

12.0 15.0 15.0 . . 15.0 14.0 16.0 16.0 16.0 15.0 15.0 17.0 16.0 17.0 16.0 18.0 18.0 18.0 19.0 . . 18.0 18.0 19.0

7,

,

. .

. . ,. .

~orphometry of Hetawnaeus monoceros males:

. . . .

Total length

Carapace length

Weight i n g.

Deeu-water f i sh ing i n some is lands of the South-West Pac i f ic *) ,... ~. . . . . . < . , . . . ... ~ . . .

. .

Deep-water f i sh ing can, f o r -practical purposes,. :be l imited t o t ha t practised a t a depth of between -120 and 400 metres.' I n f a c t , f i shes-of commercial importance, with the exception of oil-f ish, grow scarce beyond the 250 m mark. Such f ishing i n deep-water undertaken i n theHew Hebrides and i n Bare (Loyalty- ~ s l a n d s ) , where, a s there i s no reef , it is possible t o go f i sh ing at night. I n New Caledonia, a s the waters of the lagoon are so f u l l of fish,.deep-water f i s h i n g i s only carr ied out on an experimental basis. T h e same applies to:: the a t o l l s of French Polynesia. . I n Tahi t i , about ten' fishermen a re s t i l l ' engaged i n night-fishing f o r oi l - f ish ( ~ r a v e n a ) , touching depths of 450 metres, other deep-sea f i s h having prac t ica l ly disappeared. This kind of.' f i sh ing is mainly 'centred on the capture of snappers which can be very 'p len t i fu l

. ~

indeed!and are much valued. ,. . , ~. .

I. Fishing metho'ds and gear ,~ . .

When the weather is f ine a n d i n places where the slopes are not too steep, it i s b e t t e r t o l e t down-the l i n e with a temporary sinker (expendable sinker. such as rock, iron, etc.) about 2 kg i n weight - which can be released n e a r t h e bottom with a jerk - ra ther than a f i x e d sinker, which makes f o r the l e s s sensi t ive fishing. When the d r i f t i s f a s t over a changing ocean-floor, use must be made of a permanent weight of 0.8 t o 2 kg, generally of - lead, t o ensure that: the f i sh ing l i n e s tays close t o the bottom. I n such cases, it i s advisable t o f i x the lead-weight i n the centre of a metal rod (of brass o r galvanized i ron) 90 cm long with a diameter of about' 5 mm. This would prewnt the s inker ' s ge t t ing l o s t ' i n a rock 'crevice, such losses being actual ly almost a s common-between depths of 120m and 250 m as on markedly uneven'coral beds between-30 and. 60'm below the su r f ace . , A s regards leaders, we would recommendthe use of ; 4 o r 5 , about 65 cm apar t , f i t t e d with double-circle hooks 'Hoa 5 t o 7..

.. . ,

Instead of a v e r t i c a l l i ne , , held i n the hand o r - ' m off a ree l , a bottom l i n e (or longline) may be used;. provided with a dozen hooks f i t t e d on leaders 1 m long, about 3 m apart. This bottom l ine , about 40 m

0 long, i s weighed down a t thefree end by .a .4 kg chain, its buoy-cable end being attached t o a c h a i n weighing 6 kg.-. Before being released, the longline is l a i d out. ' in the shape of a UÃ both its endsbeing kept i n the boat. Then the f r e e e n d with its s i n k e r i s e a s t i n to the water, the other end being held t i l l ' t h e longline is played out a s the motor-s tar ts and. the boat goes slowly forward. Now the second sinker still holding the longline i s cast. i n to the water so t ha t the l i neex tend ing almost horizontally on the surface, s i n k s , t o the bottom dragging:dowl the single bttoy-cable. The bottom l i n e i s generally ra ised a f t e r 20.minutes. . .

. . , . . .

. : . .

This information r e l a t e s t o f i sh ing car r ied out close t o - t he ocean^ f loor , and not ' t o subsurface f i sh ing&uch as is practised i n the case of tuna, '&p#~s (~ampr i s ) , and b5e- (Taractes).

'

. . . ~ ..... . . . . . .. . . . . . . . . . . . . .. .. .. -

11. Deev-water f i s h

.a) Prlst i~omoides: Flavescens, Filamentosus, m, Sieboldi . . ~. . . .

b) Etel is : Carbunculus, Oculatus

2. GROUPERS

Epinevhelus; C h l o m s t i w , Comvressus, -q .

Seriola purciurascens

a ) There is a difference of 10 un i t s on the number of sca les present along the l a t e r a l l i n e i n snappers belonging t o the genus Pristipomoides:

2.C2E 50 scales Flavescens, Filamentosuq 60 - 62 scales Sieboldi 72 - 74 scales

, . . They are characterized by a pearly pink coloration, a shape s imilar t o tha t of sea-breams o r beckers, and a continuous dorsal f i n . The meat of these f i s h is excellent. .. . .

PRISTIPOMOIDES FLAVBSCENS ( ~ e l l o w snapper) . - . . . . .. . .

.. . . . The top of the head presents a mottled l i lac-pink t o olive-yellnw appearance. Both the l a t e r a l l i n e . and the pectoral f i n of t h i s f i s h are yellow, and the caudal f i n . pink :with a yellow fringe. There are a lso

. . .. large yellow spots on the dorsal membrane. ~ ~

The habi ta t of t h i s snapper i s between depths of 150 and 300 m. It is widespreadbeyondthe great Mew Caledonian reef and off the Guvea Atoll ( ~ o ~ a l t ~ ~ s l a n d s ) . It does not seem t o be very mobile. While all other species of snappers are found i n the Indian Ocean and the Pacific, the "Yellow" one i s a t present found only i n Mew Caledonia.

Haxinum weight: 3 kg.

PRISTIPOBOIDES FILAMENTOSUS (ROSY Job-fish, ~ ~ a k a p a k a ) *)

The difference between this species and the preceding one, though hard t o determine by merist ics, can e a s i l y be made out through the f a c t tha t flavescens has a predominantly yellow coloration, and that the caudal f i n of filamentosus has a red border.

*) See f igure

, . - . , .~ , . . . . . . . . ~ . ,. T h i s white snapper, which is very mobile, is ' fouhd"inschoo1s

c a p r i s i n g over a hundred f i s h , which it has been possible t o observe i n the Loyalty Islands a t depths of 40 m. The habi ta t of this f i s h Ay go from depths.of 50 30.289 m ? , It is. sometines caught i n channels by. Hew Caledonian fishermen; -.Tfig.i& the that i s 'best Imown among in Mare, who catch it along with Gymnocranius a t a depth of .between 80: . ,. and- . 100 . m.

. . . . . . - , - . . . . . . . . . . . . . . . . .

Msximuxa weight: 6 kg.

Synonyms: P. microlepis, P.violascens, .P.roseus,. Avsilus microdon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... ........

PEISTIPOMOIDES SIEBOLDI ( ~ a l i k a l i ) ... 0

Generally swill i n s i ze (T .L. 28cm);:iri Hew . ca ledonia , , i t is rarely caught with the b ig hooks used f o r deep-water fishing. c2

It is distinguished by the f a c t t ha t the sca les fo&d..ali ig the. numbering 73-74, are r a th ...c . . . . : . . " .. . . . . . . . . . . . . . . . , ..

,. ~ ~ . , . .~ . . . . . . .

PEISTIPOKOIDES TTPUS . . .....

. . . . . ~ ~~ ,

T h i s b ig f i s h i s p l en t&i l k o ~ t h ' 6 f t h e xsl+ .of Pines a t depths of between 190 and 210 m. A s t h i s area has a r&plarinsular shelf sloping only s l i gh t ly , ,.(sometiq.es the depth increases by o n l y 100 m . over a distance of 2 miles), trawl-ing may be resokted t o in . places. . .

. . ~ . , . . . . . . . . . . . . - ~ . , .~, .~.b.,

Maximum weight: 6 kg.

. . ~. ' . . ~. . . : , , . , - ~ . ~ ; . . . . . . . . . . Synonyms: P. b rev i ros t r i s , P. mtiltidens. ,. . . .~ . ~ . - , . , , <:

-. . a h e r s o f t h e g e n ~ i q E t 6 1 i ~ a r e found a t greater depths, are larger ,

$&&&er and s t i l l b e t t e r 'than those belonging t o t h e genus ,~ ,.

~ r i s $ i ~ o m o l & i . " Their <dorsal f i n s are ,. d i~con t inuous .~ and. ' there are . . . . . . ., .> 50 sca les on t h e i r l a t e r a l l ine . ~

.

, .. ,,:, - . . . ETELIS C A B B T O O U ~ ~ S i) . . *) .~. .

, . . 3 . : . . . . . . , . . , . . . , -. . . .., , '~

. '. - , . . . phis: is the: - la rges t of the snappers, .-and. it. c& weigh, as much as 30 kg. It is .deep red. i n . colour, ,.with a s l i g h t l y orange tinge,. , The l a t e r a l l i n e of t h i s f i s h is t in ted yellow.

. .

The caudal f i n is short and white a t the t i p of the lowerlobe. It l i v e s a t a depth of 230 t o 350 m, at the foot of under water c l i f f s rising from a rocky bottom'. i n Hew Caledania,suiall:or l a rge s.peciiens..are 'caught. Fish ~: ., , . weighing between 2 kg and 10 kg have not been met with.

. . . . ~' :, . . ~ .. ~ . .,, . . : . . . . ~ . . . . .

*) See f igure

ETELIS OCULA'rUS

This magnificent cherry-red f i s h d i f f e r s from the preceding one i n tha t its dent i t ion is l e s s adequate, i t s shape more slender and the upper lobe o t its caudal f i n frequently elongated. Red in colour, the l a t t e r reminds one of a tongue of f i r e .

This E t e l i s goes down t o a depth of 400 m i n Mew Caledonia and the Loyalty Islands. Its d i e t includes s m a l l deep-sea squids, l an te rn f i s h and barracudas ( ~ e s t i d i i n a e ) . Maximum weight: 20 kg.

" Synonyms: E t e l i s corruscans, E. evurus

> Both species occur i n almost equal numbers i n Hew Caledonia. In

Polynesia E. carbunculus i s more common than E. oculatus.

2. GROUEERS

EPINEF'HELUS COBPRESSUS

This b ig grouper is ident i f ied by the f a c t t ha t there a r e great gaps i n its dorsal membrane betweenthe spines, its ra ther compressed shape and its dark violet-brown colour.

Younger specimens bear e ight very d i s t i n c t black v e r t i c a l bands, whichare not a s c lear ly distinguishable i n f i s h weighing over 10 kg.

Epinephelus compressus is found i n Lifou, where we caught it around the Torche Bank, a t a depth of 290 m, where t h i s species of grouper i s plent i ful . It is also fami l ia r t o the Marquesas Islanders.

The record f o r the heaviest f i s h caught (60 kg) i s held by the Marquesas.

Epinephelus compressus was described f o r the first time i n 1964, i n the Reunion.

-, This f i s h has a maroon-green skin with 3 o r 4 brownish-black bands

tha t a l te rna te with a garland made up of dots. It a t t a i n s a length of 90 cm and a weight of 5 kg. Smaller specimens are encountered s t a r t i n g from a depth of 140 m, adul ts going down i n Haw Caledonia t o as much a s 260 m. This i s the commonest deep-water grouper found i n the Indian Ocean and the Northern Pacific. I n i t s place i s found i n Polynesia a very s imilar species, E.tuamotuensis.

The meat of t h i s f i s h is mediocre i n qual i ty and has led t o some minor cases of f i s h poisoning i n Mauritius.

EPINEEHELUS CHLOROSTIGMA

Covered wifh very small olive-g*een t o brown haemetite hexagonal s p o t s , closely spac&d;- I t a t t a i n s a length 'of 9 0 3 and. 9 kg. specimens caught at depths'Between150 -and 2 2 kg.' The meat i s 'very f ins.- . . ~

This f i s h i s caught near the bottom a t dep$hs.varying.betwe,en.140 and 300 m. The l a rge r specimens, which may weigh asmuch 4s 25 k g , are found at grea te r depths. . . . . . .,, :~ . . . . . " . , . The meat, which ... is mediocre i n . q u a l i . ~ S

Japanand Hawai .. ~ . . .

...

This inventory of deep-water f i s h found a t depths of 120 t o 350 m is somewhat theoret ical . In deep water are a l s o f o u n d . f i s h caught. in the

. . . shallows of the lagoon such as:

. . . . . J . . . . . . . .

. . ~. . %xesceni up' to 1'30 m. , .. , ..

., . . . . . . , . .~ ..

Lut.ianus bohar up t o 240 m.

. . . . . . . . . . Sharks t ha t go down t o depths of up t o 300 m are Carcharhinusmilberti,

(sand bar) and f present i n d u d

. . . . .

The Developnent of Tuna and Skip.iack Fishing i n French Polynesia

and Experience i n Live-bait Techniques

It is a well-known f a c t t ha t the waters of French Polynesia, par t icu la r ly around the Society Islands (windward and ~eeward) abound i n skip jack (~atsuwonus pelamis) and yellowfin tuna (iieothunnus albacora) , which during the season cone together i n surface-shoals off these islands.

Surface-tuna and skipjack f i sh ing using a pear l s h e l l l u r e has been t r ad i t i ona l ly practised by Tahitians f o r a long time. Nowadays they

v use small, f a s t boats maimed. by a creir of three, i n f l e e t s consist ing of

about 100 c ra f t .

I n 1972, there were i n the Society Islands ninety-seven skipjaok f i sh ing boats involved i n pear l she l l l u r e f ishing, with 84 i n the Vindward Is lands ( ~ a h i t i and ~ o o r e a ) and. 13 i n the Leeward Islands. T h i s f l e e t grew rapidly, doubling over the 5 years between 1967 and 1972. Overhauling i s carr ied out by loca l shipbuilders who, i n 1972, turned out 12 new boats.

It i s d i f f i c u l t t o have a c l ea r idea of catches made by Tahitian bonito boats, a s they do not go out f i sh ing regularly and a s half the boats a r e not actual ly i n full-time use, e i t he r f o r want of crew, through docking f o r maintenance purposes or owing to the f a c t t ha t f i sh ing time is so closely dependent on seasons, when the market i s glutted, and pr ices f a l l i n conse- quenc e .

The only place where s a l e s can r e a l l y be checked i s the Papeete IIunicipal Market, where s a l e s from the operations o f l oca l fishermen amounted t o 54 tons of tuna and 450 tons of skipjack i n 1971, and 34 tons of tuna and 536 tons of skipjack i n 1972. These quant i t i es have at l e a s t t o be doubled, i f not t rebled i f one i s t o have an idea of the production actual ly achieved, f o r many fishermen s e l l t h e i r catches d i r ec t ly t o l oca l dealers ( ~ h i n e s e grocers i n par t icu la r ) o r get a l l they can off t h e i r hands through t h e i r families, and f r iends l i v ing i n the d i s t r i c t s (roadside o r door-to-door sa les ) . So tha t only the surplus i s supplied t o the Papeete City Market. However, even a t a generous assessment, the production of the l oca l bonito-boat f l e e t could hardly exceed 2,000 tons per year - 1,700 tons i n t he Windward Islands (Tahi t i accounting f o r 1,500), 200 tons i n the Leeward Islands and 100 tons i n the other i s land groups. T h i s i s ra ther low and f a r below the possible " yield from the na tura l stock.

- The Fisher ies Department of the Terr i tory of French Polynesia therefore decided t o carry out research in to the p o s s i b i l i t i e s offered by l ive-bait f i sh ing techniques. I n 1972-1 973, following an agreement reached with an American f i r m , three l ive-bait f i sh ing vessels came t o carry out t e s t s which, though mainly involving the Windward Islands, were a l so extended t o the Leeward Islands and. even t o ce r t a in areas around the Tuamotu and Marquesas Islands.

I n the .Windward Is lands ( . ~ a h i t i , Moorea, lYaiao), the i n i t i a l l ive-bai t ' f ishing ' operations, c a r r i e d out between February and June 1972 with t he boat B yielded only f a i r to:middlkng r e ~ ~ l t s ~ with an average per t r i p of a mere 337.5 kg of f i sh , the t o t a l number of f i sh ing t r i p s being 28. A second operation was organized between December 1972 and February 1973 wit11 the boat m; and very encouragil~g r e s c l t s trere obtained i n the course of 19 f i sh ing t r i p s , w i th a recorded average of 5,355.5 kg of f i s h caught per t r ip . . . Further Redonda, a third, boat, put out t o sea f i v e times betweenthe end o f March. and the beginning o f April 1973, returning with almost 1,000 kg o f f i s h per t r i p .

It should be pointe&' out : t H a t a considerable percentage of the catches comprised la rge skipjack tuna of o v e r 8 kg. Weighing on an average 13.3 kgbetween February andJune 1972, ancl 1T.9 between December1972 and - February 1973, these f i s h bring up special problems both a s regards the . .

most sui table bait-size and, the f i sh ing gear t o be used. . ~

- .

. . Researchwasalso carr ied out i n the Leeward Is lands. I n 20 f i sh ing t r i p s between February a d September 19.72, the Moetu recorded an. average y ie ld of 577.7 kg of f i s h per t r i p , i .e. about =ore than was recorded i n the Windward Islands during the s m e period.. The W, .,: operating from the end of December 1972 t o the beginning of January 1973, '' confirmed Leewad. Islands prospects with a. y ie ld over 6 f i sh ing t r i p s of

. ~ , 3,018 kg per trip, which i s excellent.

. . . . .

Finally, t h e few t r i a l s made i n t h e Tuamotu Archipelago were disappointing, though i n the Marquesas Islands t h e slcipjack population seems t o be considerable and l i ke ly t o provide mammoth yields , a t l e a s t i n season.

The information accumulated, i n the course of the.experiments oarr ied out by the &&, the and the Redonda, is only a .begi&ng,

: and there a r e still many problems t o be solved before progress can be made i n s e t t i n g tip l ive-bait f i shery operat ing along i n d u s t r i a l l i n e s . -:., . ~. . . ,

. . .

. . . .. . .

. . . . . ..

. .. *

Live-bait Skip.iack f i shery Experiments m N

i n various French Polynesian Island Groups

l Fish caught

Skipjack 1 . Total lellowfil

tuna 1 Boat 1 P e r i o d 1 Trips E Leeward. Islands l l l l

20 - 25 Feb. 72 19 - 30 March 72 1 - 7 Ju ly 72

21 - 24 August 72 28 August - 8 Sept. 72

, ANELA 14 - 20 Dec. 72

14 - IS January 72

Tuamotu

BOETU 24 July - 3 August 72 4

ANELA 3 - 7 December 72 3 4 6 663

Marquesas

ABELA 19 Februaxy - 25 March 73 5 27 Hay - 7 April 73 1 391 1173

Boat

....: . .

MOEW < . .,,., , .:<..

,, , .

. . . . . .

. .

:. .' . , t . ~ "

. . . . . . . . . .&

. . . . . . .

MOETU

mLA , .

. . . . . . . .

. . . . , .:.. #,.

mLA

-BEBOBDA

Results af Experimental Live-bait Fisherv in the Windward Islands ( ~ a h i t i , Hoorea, b i a o )

15 - 18 Feb. 72 1 32 64 .... .ll.TErch"72~.:.. Ã ‘ ...... 34. ...... 68 -

...... 13 - 18 72 .:

. . . . . . . . . 30 napch-2. .Apr i l -7.2. -.---3 . . . 4 - 8 April .72 .". '2. ,50 150

10 - 13 April 72 3 108 216 17 - 2 2 April . ~. 72 . . 3 98 '25 - 29 April. 72 . . 2, ;,, , :

9 - 19 Bay . 72 . 5 . 229 23-28May 7 2 4 , . ~

29 Hay - 2 ~ & e 72 2 22 5 - 10 June ' 72 2 : ,

~ . ~ , 7 - 11 J&. 73 12 Jan. 73

' 48 'TOO

.....

360 1200

EXPLORATORY SHRIMP TRAPPING

IN THE H A W A I I A N I S L m

P . S t r u h s a k e r and D n Cc Aas ted Sou thwes t F i s h e r i e s C e n t a r

N a t i o n a l Mar ine F i s h e r i e s S e r v i c e , NOAA Hono lu lu , HI 96812

.. , . I n t r o d u c t i o n . . . .

Dur ing 1967 and 1960 t h a . N a t i o n a 1 M a r i n e F i s h e r i e s S e r v i c e (NMFS) d e v o t e d f o u r c r u i s e s of t h e R V Townsend Cromwell t o d e m e r s a l r e s o u r c e s u r v e y s i n t h e Hawaiian I s l a n d s . The p r i m a r y s a m p l i n g g e a r s u t i l i z e d were s h r i m p t r a w l s , a l t h o u g h limited s h r i m p t r a p p i n g e x p e r i m e n t s were c o n d u c t e d ( Y o s h i d a , 1 9 7 2 ) . T h e s e s u r v e y s d e m o n s t r a t e d t h a t t h e p e n a e i d s h r i m p ( P e n a e u s m a r q i n a t u s ) w a s a v a i l - a b l e i n modes t amounts and amenab le t o h a r v e s t by s h r i m p t r a w l s . Two s p e c i e s . o f c a r i d e a n s h r i m p s ( H e t e r o c a r ~ u s e n s i f e r and H. l a e v i - -1 were a l s o t a k e n . i n , s m a l l numbers w i t h t h e t r a w l s . However, t h e i n i t i a l - i n v e s t i g a t i o n s i n d i c a t e d t h a t . t r a p p i n g , r a t h e r t h a n t r a w l i n g , was a more e f f e c t i v e m e t h o d f o r h a r v e s t i n g t h e s e l a t t e r s p e c i e s .

C l a r k e (1972) c o n d u c t e d t r a p p i n g s u r v e y s d u r i n g 1969 and 1970 a t s e v e n l o c a l e s o f f Oahu, Hawaiian I s l a n d s . The s a m p l i n g g e a r c o n s i s t e d of s e v e r a l t r a p t y p e s , b u t a l l were uncove red t r a p s . These s u r v e y s p r o v i d e d d a t a on t h e d e p t h d i s t r i b u t i o n s o f E. l e n s i f e r and d. l a e v i q a ~ u ~ and ~ n d i c a t e d t h a t t h e s e s p e c i e s - w e r e p r e s e n t i n s u f f i c i e n t q u a n t i t i e s t o s u p p o r t a commerc i a l f i s h e r y .

F u r t h e r t r a p p i n g t r i a l s were c o n d u c t e d by t h e NMFS d u r i n g f a l l , 1972 a t v a r i o u s l o c a l i t i e s i n t h e m a i n 'g roup of t h e Hawai ian I s l a n d s . T h e s e t r i a l s were o f a p r e l i m i n a r y n a t u r e , and a v a r i e t y o f t r a p t y p e s , b a i t c o n t a i n e r s , and b a i t s was u t i l i z e d . I t - w a s d e m o n s t r a t e d a t t h i s t i m e t h a t t r a p s c o v e r e d w i t h b u r l a p were more e f f e c t i v e i n c a p t u r i n g Ha e n s i f e r t h a n were uncove red t r a p s . I t was a l s o d e t e r m i n e d t h a t p r o p e r c a t c h pr.ese.rv.ati.0.n ... of . . t h i s . . s p e c i a s was e s s e n t i a l t o i n s u r e a q u a l i t y p r o d u c t . . .

We a l s o have d a t a f rom 23 se ts o f o u r g e a r o f f Oahu by s t a f f members o f t h e Hawaii I n s t i t u t e of Mar ine B i o l o g y , U n i v e r s i t y o f Hawai i d u r i n g May 1973.

Methods

The t r a p s measu re 2 by 2 by 4 f t . The frame i s c o n s t r u c t e d o f 3/8-inch d i a m e t e r s t e e l b a r 2nd is c o v e r e d w i t h 1/2-inch s q u a r e mesh g a l v a n i z e d wire s c r e e n . Th s i d e s , t o p , and bot tom a r e t h e n c o v e r e d w i t h b u r l a p . The t u n n e l s ( o n e a t a a c h end ) a r e a l s o con- s t r u c t e d w i t h t h e s c r e e n ( b u t a r e uncove red ) and t a p e r t o 2- t o 3- i n c h o p e n i n g s a b o u t o n e - t h i r d t h e d i s t a n c e i n f rom e a c h end. B a i t c o n t a i n e r s are c o n s t r u c t e d w i t h 1/2-inch wire s c r e e n and are s u s p e n d e d i n t h e t r a p be tween t h e two t u n n e l e n t r a n c e s . One t o two pounds of chopped b a i t a r e s u f f i c i e n t f o r sets o f 12-14 h o u r s .

Each t r a p h a s a 7 - f t wire b r i d l e a t t a c h e d t o . o p . p o , s i t e ~ . c a s n e r s on t h e t o p o f t h e t r a p . The b r i d l e h a s a s n a p e t t h e c e n t e r f o r a t t a c h m e n t t o t h e g r o u n d l i n e . The ground l i n e s and buoy l i n e s c o n s i s , $ o f . . . . . . . . . 1 / 2 - i n c h p o l y p r o p . y l e n e . . r o p e . The t r a p s a r e s p a c e d a t ID-fathom . i r i t '&va l s , and t h e first and l a s t t r a p s ¥o a . . s t r i n g h a v e

.5-pound a n c h o r s a t t a c h e d , t o a t r a p c o r n e r . We u s u a l l y f i s h e d s i x o r e i g h t t r a p s t o a s t r i n g , b u t t h i s would v a r y a c c o r d i n g t o . t h e

. c a p a b i l i t i a s , o f t h e . . . . . . . . v s s s e l . We have o u r buoy l i n e s m a d e u p i n t o 10.0-fstho.m l e n g t h s , a n d "thee ere s t o r e d i n p l a s t i c g a r h a g e con- t a i n e r s of a p p r o x i m a t e l y 4 0 - g a l l o n c a p a c i t y . The ground l i n e i s . .~ .

, made up w i t h t h i s l i n e b y fo rming l o o p s f o r a a c h t r a p a t 10-fathom i n t e r v a ; l s i n t h p d i s t a l p o r t i o n of t h e first 100-fathom section'. T h e p r o p e r , n u m b e r o f . IOU-fathom s e c t i o n s a r e t h e n added a s t h e t r a p s are set i n o r d e r t o g i v e a n e x c e s s amount o f buoy l i n e on t h e - o r d e r of 50-150 f a thoms g r e a t e r t h a n t h e d e p t h o f w a t e r b e i n g f i s h e d .

: J u s t b e f o r e the . e n t i r e amount of l i n e i s pdyed o u t , a b u o y is a t t a c h e d a n d se t a s t h e f i n a l f e w f a thoms a r e r u n o u t . .:A w e i g h t

i s s n a p p e d o n t o t h e b u o y l i n e a b o u t 10 f a t h o m s be low t h e b u o y t o . . a s s u r e t h a t . t h e p o l y p r o p y l e n e l i n e d o e s n o t f l o a t a t t h e s e a s u r - face. ,Th,e s e t is r e t r i e v e d w i t h a ~ e r c o * c r a b - p o t h a u l e r ; . . . t h e . . . . . . . 100-

f a t h o m s e c t i o n s a r e s t o w e d d i r e c t l y i n t o t h e i r c o n t a i n e r s a s t h e l i n e comes a b o a r d .

.. , . . . .

. . Bec,euse t h e t r a p p i n g o p e r a t i o n s were i n t e r s p e r s e d . w i t h  ¥ o t h e v e s s e l programs, . t h e t r a p s were s e t a t dusk and r e t r i e v e d a t dawn.. We do n o t . h a v e d a t a on d a y t i m e . c a t c h r a t e s .

. -. . , .:: . ~

,. . . , . . . . - . , " ~ . ~ .

: . ,. c . . . ~. , ,.

* R e f e r e n c e t o t r a d e names d o e s n o t i m p l y e n d o r s e m e n t by t h e N a t i o n a l ~. Mar ine F i s h e r i e s S e r v i c e , NOAA.

. , , , -

D i f f e r e n t t y p e s of t r a p s , b a i t c o n t a i n e r s , and b a i t s were t e s t e d ' by v a r i o u s c o m b i n a t i o n s o f t h e s e f a c t o r s on se t s o f f o u r t o e i g h t t r a p s p e r s t r i n g . T r a p s m e a s u r i n g 1 by 2 by 4 f t were less a f f e c t i v e t h i n t h e l a r g e r t r a p s m e a s u r i n g 2 by 2 by 4 f t . ~ r a ~ s w i t h 1-inch mesh wire s c r e e n i n g c a u g h t fewer h. e n s i f e r ( t h r o u g h e s c a p e m e n t ) t h a n t h o s e w i t h 1/2-inch mesh s c r e e n i n g . Com- p a r i s o n be tween a l t e r n a t e d c o v e r e d and u n c o v e r e d t r a p s d u r i n g e i g h t sets o f f o u r to s i x t r a p s r e s u l t e d i n t h e c o v e r e d t r a p s o u t f i s h i n g t h e uncove red t r a p s by 2.5-10 times. P o s s i b l y t h e c o v e r i n g on t h e s i d e s o f t h e t r a p c o n c e n t r a t e s t h e b a i t s c e n t n e a r t h e e n t r a n c e s a t t h e e n d e o f - t h e t r a p s , r e s u l t i n g i n g r e a t e r c a t c h r a t e s . Q u i t e

' p r o b a b l y t r a p s c o n s t r u c t e d of any m a t e r i a l t h a t conforms t o t h e b a s i c d e s i g n p r i n c i p l e of t h e c o v e r e d t r a p would b e e q u a l l y e f f e c t i v e .

S e v e r a l b a i t c o n t a i n e r t y p e s were t e s t e d . C o n t a i n e r s , c o n s t r u c t e d o f 1/2-inch mesh s c r e e n i n g ( m e a s u r i n g 6 by 6 by 6 i n c h e s )

were g e n e r a l l y s u p e r i o r t o p l a s t i c c o n t a i n e r s o f t h e same s i z e p e r - f o r a t e d w i t h 1/4-inch h o l e s o r b a i t wrapped i n c h e e s e c l o t h .

F i v e t y p e s of b a i t were t e s t e d : f i n e l y ground f i s h , s q u i d , s h r i m p (1. e n s i f e r ) and c o a r s e l y chopped f i s h a n d . s h r i m p . Chopped f i s h ' s p e c i & t h a t are o i l y o r b l o o d y were found t o b e t h e b e s t b a i t s . P o s s i b l y t h e . f i ne -g round . b a i t s d i s p e r s e d t o o r a p i d l y . F i s h a n d sh r imp were s u p e r i o r t o s q u i d .

Ca tch r a t e s o f g. e n s i f e r o b t a i n e d d u r i n g 1972 were h i g h l y v a r i a b l e d u e t o t h e v a r i e t y o f t r a p s , b a i t c o n t a i n e r s , b a i t s u t i l i z e d and d e p t h s s ampled . A t t h i s time t h e b e s t c a t c h e s r a n g e d be tween 15 end 6 3 pounds p e r t r a p f o r a n o v e r n i g h t s e t .

More r e l i a b l e d a t a on c a t c h v a r i a b i l i t y w a s p r o v i d e d by 21 sets o f c o v e r e d t r a p s ( f o u r p e r s e t ) o f f t h e s o u t h c o a s t of Oahu

i n d e p t h s of 200-220 f a t h o m s d u r i n g s p r i n g , 1973. Only o n e b a i t : t y p e ( f i s h ) was u t i l i z e d . Dur ing t h i s . ser ies o f s e t s c a t c h e s of

H. e n s i f e r r a n g e d f rom 2 t o 34 pounds p e r t r a p . a n d a v e r a g e d 15.2 - pounds p e r o v e r n i g h t set. c o n s i d e r a b l e v a r i a t i o n i n c a t c h ra tes be tween l o c a l i t i e s was n o t e d .

, .. . . . . . . . T h e s e c a t c h e s o f d. e n s i f e r . w i t h c o v e r e d t r a p s g e n e r a l l y

exceeded t h o s e e x p e r i e n c e d by C l a r k e (1972) o f f t h e n ~ r t h e a s t , ~ c o a s t of Oahu w i t h uncove red t r a p s . C a t c h e s t h e r e f o r n i n e s e t s i n ~ ~ t h e

m 150-250 f a t h o m d e p t h r a n g e v a r i e d f rom 0 .6 t o I f .9 pounds p e r t r a p and a v e r a g e d 4.5 pounds. . -

. . . ..

3 4 - 1

The l a r g e r H. l a e v i q a t u s i s a p p a r e n t l y much less a b u n d a n t t h e n H. e n s i f e r . Our u s u a l c a t c h e s o f ^_. l a e v i q a t u s were 1-3 pounds , b u t o c c a s i o n e l l y r a n g e d up t o 9 pounds p e r t r a p . C l a r k e ( 1 9 7 2 k ; e x p e r i e n c e d similar c a t c h r a t e s .

. . -. '

T h a ^ ' m ~ d e s s i z e g$oup' kf Jj.! e n s i f er r e t a i n e d by t h e 1/2- i n c h -m&h trap+ r a n g e f rom 35 t o 4 5 i n d i v i d u i l s p e r p o u n d ( h e a d s o n ) . The l a r g e s t i n d i v i d u a l s of 1. l a e v i o ~ t u s r a n g e f r o m 8 t o 12 p e r pound. F o r b o t h species t h e t a i l ( w i t h s h e l l ) c o m p r i s e s e b o u t

. , . . . ' t h e t o t a l body w e i g h t . . ,: . . . . . .: . . . . . . . . . . . ;- . .

~ . . ~ ~

. . . . . . . . . Claxke (1972). f o u n d t h a t .H.. e n s i f e r o c c u r s . i n . d e p t h s . o f -00-400 ... f a thoms i n t h e .Hawaiian I s l a n d s , , . . h u t is most abundan t -be tween

. 1 5 0 , a n d , 2 5 0 f a t h o m s . Shrxmps . t a k e n - : i n t h i s ' l a t t e r d e p t h r a n g e - were f o u n d - t o b e s i g n i f i c a n t l y l a r g e r t h a n - t h o s e t a k e n a t t h e u p p e r and

à £ - l o y e r . l i m i t of t h e t o t a l d e p t h r a n g e . , & , l a e v i q e t u s o c c u r r e d i n dep ths .o f . 2DD-400 f a t h o m s ; t h e r e was no o b v i o u s t r e n d i n i a b u n d a n c e

. b e t w e e q , 2 5 0 and 400 f a t h o m s . Our f i n d i n g s ' d u r i n g a l l s u r v e y s -e re i n a c c o r d w i t h t h e s e r e s u l t s . The o p t i m a l d e p t h r a n g e f o r H.

0 0 e n s i f e r c o r r e s p o n d s t o bo t tom t e m p e r a t u r e s - o f 7 -13 C.. -~

: ., . . . . The trkfcis h i v e been f i s h e d on a v a r i e t y o f bo t tom t y p e s . T h k ' b n l y c b n & t r a i n t i a r e t t i a t t h e s l o p e m u s t ' b e g e n t l e enough t o p e r m i t t h e t r a p s t o f i s h w i t h o u t d r i f t i n g o f f a n d t h e bo t tom must

. . b e smooth enough t o o b v i a t e t r a p loss . . . ,.. , , . . .. ;, , ... , . ,

. . Attempts t o m a r k e t t h e two spec is i o f H e t e r o = a r p & i n ~ H a w a i i h a v e been g e n e r a l l y u n s u c c e s s f u l i n t h e p a s t . T h i s i s d u e t o en=yr i a t i t * ;b re ikdown of t h e c h i l l e d t a i l meat w i t h i n 12 -24"hour s which r e s u l t s i n a s o f t and u n a c c e p t a b l e p r o d u c t when c o o k e d . We

. ~

found t h a t c o o k i n g t h e s h r i m p i m m e d i a t e l y e f t e r c a t c h i n g r e s u l t e d i n a c h i l l e d s h e i f l i f e o f 3-4 days. O n e t e a t of immed ia t e f r e e z i n g . . , 0 o f r aw s h r i m p ' i n a b r i n e s o l u t i o n a t a b o u t -20 C r e s u l t e d i n .. , s u p e r i o r p r o d u c t . After b r i n e f r e e z i n g , t h e s h r i m p were , i n a c o n v e n t i o n a l freezer and t e s t e d a t i n t e r v a l s ove r "a 2-week and found t o b e v e r y a c c e p t a b l e . Very l i t t l e s a l t was t a k e n up by t h e s h r i m p s d u r i n g . . : . b r i n e , f r e e z i n g .

. . - ,..:: .. ,. . . . . . . . , ~ . . . . .

Cdre must b e t a k e n n o t t o ove rcook t h e s e species , , B o i l i n g t i m e k o f ~ 2 - 4 " h i n u t e s " a r e a d e q u a t e f o r t h e f r o z e n sh r imp . ~. The t a i l meat c S k 6 e s h e l l e d e a s i l y f o r o t h e r meth'ods o f p r e p a r a t i o n by

. . b r i e f l y t h a w i n g w i t h r u n n i n g water. .

., ?.

H. e n s i f e r is known t o o c c u r i n t r o p i c a l waters f rom t h e - w e s t e r n A t l a n t i c - t o ' : H a w a i i . Th i s : s p e c i e s , and /o r a congene r undoub- ¥Eedi occurs i n a r e a s ' o f t h e S o u t h P a c i f i c * The s t a n d i n g b i o m ; s s o f

:H. - e n s i f e r h a s been g r e a t l y u n d e r e s t i m a t e d i n t h e p a s t b e c a u s e s h r i m p t r a w l s a p p e a r t o b e i n a d e q u a t e s a m p l i n g d e v i c e s f o r t h i s pu rpose .

If members o f t h i s genus are a s abundant'inother'regions{of t h e t r o p i c s a s i n Hawai i , t o g e t h e r t h e y p r o b a b l y r e p r e s e n t a b i o m a s s e x c e e d i n g t h a t of any c o m m e r c i a l l y e x p l o i t a b l e t r o p i c a l c r u s t a c e a n .

Developing the Exploitation of Trochus niloticus Stock on the Tahiti Reefs -

Readers of our Newsletter have already been informed that the stock of trochus (troc11u.s niloticus) which has developed on the reefs of Tahiti, from a few dozen specimens introduced in 1957 from New Caledonia has started' to be methodically harvested (see SPIFDA Newsletter 'So. 3-4, March 1972, p. 32).

Begun in the southern part of the island (~ahiti Iti peninsula, districts of Tautira and ~ueu), the harvesting, strictly supervised, was gradually extended to the whole ofthe island and over four diving periods .. from November 1971 to June 1973, more than 350 metric tons of shells were marketed (from over 450 tons of live specimens, for a value of about 5 million Frs CFP (equivalent to about US$ 70,000).

Results of the t-.dLvinz operations

District

VAIRAO MAATAIA TBAHDPOO PAPEARI

I 3rd Period FAAA -

POTAAUA PAEA PAPARA PAPAEA (mortal.) PAPEARI PAPEAEI (mortal.) M&TAIEA

PIRAE ARm FAAOHE JWAAHITI PUEU MANINA TIAEBI HITIAA

Diving period. from t o

. .

feaber o diving days

Gross weigh- in kilos

Set weigh of shell, markete~ kilos

Sale value in

Francs CFP

thes.eexc.ellent results are due to a carefully planned and . . . . . . . . . . . . . .

controlled organization. Illis 'could, be set up since trochus shell is a completely new resource which has at no time been a part of the tradi- tional socio-economic system, so that it was excluded from all custom-based constraints,.md competition between rival family or professional groups. Harvesting is authorized throughaspecial ordinance of the Governor of French .Polynesia, which determines the opening and closing .of the diving Season,,andthe.appropriate quotas per village and per district... The, size of trochus shells should be over 8 centimetres and under 12 centimetres. The fleshly portion is to be removed either by immersion inwater or by means o'f a metalhook. Any trochas shell that has been immersed in boiling water-for more than-30 minutes is considered, as being unfit for sale, and ,:isto be destroyed by the Fisheries Department staff. ,~,. ~~ , . .

. . . :, . . . . . . All trochus.shells harvested are to be submitted to a Control

Committee which certifies their placeof origin andsupervises sales . . . -The Committee in each village comprises representatives of the Local Council and those of local fishermen, along with a member of the Chamber of -

,

Agriculture and two officers from the Fisheries ~e~artment. ~ G e r s must

. . have . . . . a permit . . . . issued by the Fisheries . . Department. . . . .

. . This system ensures the oonse'rvation of trochus stock now well established on the Tahiti reefs. - Further, it makes for sales that 'are fully

.. , satisfactory lotto for fishermen and buyers. . . . . . . . . . . . . . . . . . . . . . . . . . . . * . . -. .

Apart from being in charge of the technical organization involved C in the pro&ess of harvesting andmarketing,, the Fisheries Department of

French' Polynesia has undertaken highly advanced scientific research on the . . . . . . . . . . . . . . . . characteristi&s of the newstock., This study of dynamic ecology . . . . . . . . . is the

. . , subject of a Ph.D thesis in Biological Sciences which is to be submitted . . in paris (~orbonne and i~lps'eum National dlEi.stoire ~aturelle) at the end;..of . ~ 1973 by Philippe SIU, a native of the Territory and a biologist in the

Territorial Fisheries Department. .~ . . . . ~

. . . .

. . . . . . . . . . Trochus flesh is beginning to be used in the manufactureof dried food in pellet form for the rearing of shell-fish (~acrobrakhim and

, ~enaeidsiyim~s). The CasS.0 Laboratory in Tahiti has developed a dry food made from trochus shell and skipjack, which is very for shell-fish and has a very high conversion ratio.

. .

Development of the "Turtle Pro.iectt' in French Polynesia

The Department of Fisheries of French Polynesia has continued its efforts towards better knowledge of the problems involved in the con- serration of green turtle (~helonia mydas) stock in the Tropical and Equatorial Pacific.

Tdcing into account the advice and recommendations of SPIFDA consultants Professors Hirth m d Hendrikson, a tagging programme Iras initiated at the beginning of 1972 (see SPIFDA Newsletter No. 5, Hay 1972, p. 23-24) with support from the SPC and SPIFDA. An initially encouraging result came when faro tagged turtles were recovered in July and August 1972, in Fiji and Tonga respectively (see SPIFDA Iiewsletter No. 6, September 1972,

- p. 14). Despite difficulties and the cost of operations to be carried out in the Scilly atoll (~enua ~ra) the French Polynesia Fisheries Department went ahead with its tagging programme in December 1972 and February 1973, which made for the recovery of two turtles in Fiji and Wallis, tagged in February 1973. As the SPIEDA Project is about to terminate, it is timely to review the progress achieved through this joint effort.

Catching and tagging turtles

Under the supervision of 1.k Jean TAPU, French Polynesia's Chief Fisheries Officer, a team visits periodically the Scilly atoll, vest of the Society islands group, where it is common knowledge that turtles come regu- larly and in great numbers to lay eggs. The turtles are caught either on the beach or by diving, and kept in pens constructed within the closed lagoon, formerly used to hold turtles awaiting despatch to the Papeete market. When enough turtles have been collected, measurements are taken and the turtles are tagged before being released into the lagoon, from which they can get back to the open sea, crossing the reef barrier at high tide. As the island of Scilly is so far away from Tahiti (500 km), such operations can only be carried out two or three times a year. Details of the work done are given below:

1st operation

During April 1972, 67 female green turtles uere tagged, being released on 30th April. All the turtles had been caught on the beaches of the atoll from January 1972, and had to be kept in pens and fed on green leaves during their captivity. Tag numbers were 13 to 98. Measurements made: total length and width of shell, plastral length, iridth of head.

2nd operation

During December 1972, 166 female green turtles and 15 nale ones were tagged and released. 32 turtles had been caught in October and November and held in the pen. 147 turtles, 13 of which were males, were caught in the course of the operations which were all effected outside the reef on the outer sea-slope. The same measurements were made on all the turtles as in the case of the 1st operation. Besides this, it was possible to weigh 148 females and 7 males. Tag numbers from 68 to 75, 101 to 21 2 (186 missing) and 1301 to 1361 .

3rd operation

Ie of ~ecedber 1 972 to mid-irel5ru~i-y 1973, 107 females turtles were caught on the beaches of the atoll and placed in pens. After theywere tagged, measured arid Weighed, they were released, on February 1.9th,

$973. , Tagnumbers 1362 to 1468. .. . , . . ,

thus, during operations carried out in three series, 353 green turtles (~helonia avdas) were tagged and 'measured, of which it was possible to7vfeigh~ 262. . The total weight of the 353 turtles released may be taken to be 43,00Okilos, representing a potential market value. of about 5 million fxanca^ CFP ($US 65,000) in the Papeete market. . ' .

~, . .. , . . . .

, . SoLe numerical data are given in the following tables; . . , . . ,

Size in centimetres* i-urtles tamed in Scilly atoll by the Fisheries De'oartmnnt of Trench Pol.ynesia - .

30 April 1972 females

Decembe females -

1 1,

1 1 2 1 3 1 2 3 9 5

14 14 8 7 9

12 1,7 4

14 7

10 6 3 3 3 1 3 1

166

1972 males

1 1 1 1

3 1

1

2 1

1

13

February 1973 females Total

39

. . . . . . . . . . . . . . . . . . . . . . Wei~ht of turtles tamed in Scilly atill.> taken before they ire& released in the sea

Weight in kilos

70 - 79 80 - 89 9 0 - 99

100 - 109 110 - 119 120 - 129 130 - 139 140 - 149 150 - 1.59 160 - 169 170 - 179 180 - 189 190 - 199 200 et plus

Total

Bimation of turtles tagged. in Scillv

4 turtles tagged in Scilly were caught 3 10 4 months after their release in an area about 1,500 to 2,000 nautical miles to the west.

Date of release

30.4.72

30.4.72

19.2.73 19.2.73

9.8.72 Vavau island, Tonga archipelago

26.7.72 Rabi island-Vanua Levu, Fiji arch.

26.6.73 Wallis island mai 73 Lami Point (Suva)

Viti Levu island, Fiji archipelago.

This brings out clearly the fact that all South Pacific island groups are involved in migrations by green turtles (~helonia mydas). The phenomenon calls for a regional approach if one is to obtain concrete results in conserving and developing stocks of tills species, considered everywhere as symbolizing the constancy of the island :ray of life.

Ensuring that green turtles are protected by very strict rules in French Polynesia (see the neu test promulgated in December 1971, SIPFDA Newsletter Ho. 5, Hay 1972, pp. 25-26) would hardly seem to serve any purpose if elsewhere the indiscrimirite massacres of these animals were to be continued.

Catch Da ta , American Samoa Tuna Lonql ine F i s h e r y . 1972

.. L 9<

T o t a l hook: Hanth .. . ( thousands ..;,

J ~ ~ U ~ Z Y 2,735 .!

February S.

2,822

l & c h 2,951

A& 3,057

M ii 3,667

~ & t e + -. 3,353 2

J u l y .?,, 3,891

A ~ ~ U S ~ ,.. 3,252

September ... 2,415

0 c t o b e r 2,164

~ o v a m b e r 2,439

~!&ernber -, 2,741

T o t a l 35,487 t SS^~SSSSSSSS=SSSS=~=^======

Albac Thousands

o f f i s h

e - c/101 hooks

Biqeve Tuna

The above d a t e a r e summarized by months f o r t h e y e a r 1972.

Because of t h e l e n g t h o f t h e f i s h i n g t r i p s , t h e d a t a f o r t h e l a s t q u a r t a r a r e p robab ly incomple te .

' ,

Yellowfin Thousands

of f i s h

2 8

4 6

5 3

37

2 8

22

2 6

23

25

13

13

14

328 ===================,

The t u n a f i s h e r y i s mads u p p r i m a r i l y o f Korean and Taiwanese v e s s e l s . J a p a n e s e v e s s e l s had e s s e n t i a l l y p u l l e d o u t o f t h e f i s h e r y i n 1972. The d a t a p r e s e n t e d were d e r i v e d f rom logbook r e c o r d s c o l l e c t e d by t h e Honolulu Labora to ry , N a t i o n a l Marine F i s h e r i e s S e r v i c e . Logbook r e c o r d s were c o l l e c t e d from an a v e r a g e o f 70% o f t h e t r i p a c t u a l l y made. Hence, t h e c a t c h p e r 100 hooks s t a t i s t i c s were c a l c u l a t e d d i r e c t l y from t h e d a t a , w h i l e t h e t o t a l c a t c h and hooks d a t a were e s t i m a t e d u s i n g t h e logbook i n f o r m a t i o n and t h e p e r c e n t of t r i p s made by t h e f l e e t t h a t were a c t u a l l y sampled.

Tuna C / l O O hooks

1 .O

1.6

1.8

1.2

0.8

0.6

0.7

0.7

1 .O

0.6

0.5

0.5 >

0.9