seasonal distribution of seasonal distribution of...

SEASONAL DISTRIBUTION OF SEASONAL DISTRIBUTION OF SEASONAL DISTRIBUTION OF SEASONAL DISTRIBUTION OF

NEMATODESNEMATODESNEMATODESNEMATODES

INTRODUCTION

The seasonal distribution of parasites is an important factor to understand the

intensity of infection in the edible fishes of a given region. The distribution of

nematode parasites mainly carried by the infected host which may be harmful, such

hosts and parasite relationship is parasitosis. In some infections to the hosts where

there is no damage of tissue, such relationship between them is referred to as

parasitiasis. Thus the distribution of nematode parasites in any given area much

depends on either parasitosis or parasitiasis or both (Plate no 56, Fig no 1-6). In

some nematode parasites like anisakids, release their eggs into the water where

they become larvae and lead a zooplanktonic life and carried to different places till

they find entry into the fish host. Nematode larvae are more harmful than adults

and can penetrate into the tissue of various organs. Livers are more frequently

invaded by the larvae, quiet often hundreds of them are present in this organ,

causing severe tissue damage and destruction of cells (Plate no 57, Fig. no 1-5).

Due to their smaller size they can circulate within blood stream and can reach to

any of the organ of the fish including brain, eye, skin, muscles and gills etc.

PLATE-56

Fig 1 : Liver infected with Nibea maculata.

Fig 2 : Same. (Enlarged view)

Fig 3 : Nematode cysts in the stomach of Saurida

undosquamis.

Fig 4 : Liver infected with Johnius sp.

Fig 5 : Liver infected with Otolithus argenteus.

Fig 6 : Stomach infected with Otolithus argenteus.

PLATE-57

Fig 1 : Liver showing larval nematodes. Heavy infection

showing complete destruction of the tissue in host

Mulloidichthys auriflamma.

Fig 2 : Viscera showing larval nematodes in

Mulloidichthys auriflamma.

Fig 3 : Eustrongylides sp larva infecting body cavity of C.

punctatus.

Fig 4 : Eustrongylides sp larva infecting intestine of

C. punctatus.

Fig 5 : Eustrongylides sp larva infecting intestine of

C. punctatus.

Distribution of nematode parasites in different marine fishes were

examined from January 2007 to December 2009. Prevalence of infection, mean

intensity and relative density were studied.

In 2007, the highest prevalence of infection (38.5%) was recorded in May

and the lowest (3%) in February. The highest mean intensity (3.3%) was

observed in March and lowest in June (1.3%) and highest relative density (0.6%)

was observed in May and lowest (0.1%) was recorded for three months i.e

March, August and September (Table -1, Graph-1, 2, 3).

In the year 2008, the highest prevalence (14.2%) was recorded in May and

the lowest (1.4%) in November. The highest mean intensity (1.7%) was

observed in July and lowest (1.0%) in September and November and highest

relative density (0.2%) was observed in May and lowest in April, June and July

and was nil in eight months i.e January, February, March, August, September,

October, November and December (Table-2, Graph-1, 2, 3).

In the year 2009, the highest prevalence (20%) was recorded in May and

the lowest (1.5%) in November. The highest mean intensity (1.5%) was

observed in August and lowest (1.0%) in November and highest relative density

(0.2%) was observed in May and was nil in six months i.e January, February,

July, August, November and December (Table-3, Graph-1, 2, 3).

The present study deals with the effect of seasons on total nematode

population from the hosts collected during three annual cycles, 2007-2009.

Each annual cycle comprises

(1) Rainy Season (July to October)

(2) Winter Season (November to February)

(3) Summer Season (March to June)

From the table-4, it indicates that in three years, the incidence of infection was

moderate in winter and has risen considerably in rainy season and reached its

peak in summer season (Graph-4).

To understand, which species of marine fish is more prone to nematode

infection, an in-depth study was conducted. In these three years the highest

prevalence of infection was recorded in the fish Upeneus vittatus (62.5%) and

lowest (8%) in Muraenesox talabanoides (Table-5). The prevalence in other

fishes observed has been as follows- Thryssocles mystax (50%), Upeneus

sulphureus (50%), Saurida undosquamis (46.6%), Decapterus russelli (44%),

Trachinocephalus myops (41.6%), Apogon glaga (41.6%), Lutianus bohar

(41.6%), Alectis indica (40%), Pentaprion longimanus (40%), Pterois russelli

(37.5%), Thryssocles dussumieri (36.6%), Johnius sina (33.3%), Aesopia

cornuta (33.3%), Saurida tumbil (30%), Sphyraena langsar (30%), Johnius

dussumieri (30%), Linophora vagabunda (30%), Cynoglossus bilineatus (30%),

Mulloidicthys auriflamma (27.5%), Trichiurus savala (22.5%), Holocentrus

lacteo-guttatus (20%), Johnius axillaris (20%), Johnius aneus (20%), Drepane

punctata (13.6%), Muraenesox cinereus (13.3%) and Nibea maculata (12%)

(Graph 5-10).

It is evident from this study, that nematode parasites exhibit a marked

seasonal occurrence, as the peak infection was recorded among the fish Upeneus

vittatus, Thryssocles mystax, Upeneus sulphureus, and Saurida undosquamis

with the occurrence of Contracaecum in the summer season i.e. from March to

June (Table-6, Graph-11, 12).

TABLE-1 PREVALENCE, MEAN INTENSITY AND RELATIVE DENSITY OF

NEMATODE INFECTION RECORDED FROM MARINE FISHES OF

VISAKHAPATNAM COAST, FROM JANUARY TO DECEMBER - 2007.

NO. EXAM = NUMBER OF EXAMINED FISHES, NO. INF =NUMBER OF INFECTED FISHES,

TOTAL P. = TOTAL PARASITES, M.I = MEAN INTENSITY, R.D = RELATIVE DENSITY

MONTH

NO.

EXAM

NO.

INF

TOTAL

P. PREVALENCE M.I

R.D

JANUARY 55 0 0 0 0 0

FEBRUARY 66 2 5 3 2.5 0

MARCH 74 3 10 4 3.3 0.1

APRIL 67 13 19 19.4 1.4 0.2

MAY 70 27 44 38.5 1.6 0.6

JUNE 80 19 25 23.7 1.3 0.3

JULY 75 0 0 0 0 0

AUGUST 72 5 12 6.9 2.4 0.1

SEPTEMBER 78 6 13 7.6 2.1 0.1

OCTOBER 65 8 16 12.3 2 0.2

NOVEMBER 58 0 0 0 0 0

DECEMBER 60 0 0 0 0 0

TOTAL 820 83 144 Standard

Deviation = 1.15



VISAKHAPATNAM COAST, FROM JANUARY TO DECEMBER – 2008.



MONTH NO.

EXAM NO. INF

TOTAL

P. PREVALENCE M.I

R.D

JANUARY 66 0 0 0 0 0

FEBRUARY 70 0 0 0 0 0

MARCH 66 5 6 7.5 1.2 0

APRIL 64 8 9 12.5 1.1 0.1

MAY 70 10 16 14.2 1.6 0.2

JUNE 72 8 11 11.1 1.3 0.1

JULY 65 4 7 6.1 1.7 0.1

AUGUST 72 2 4 2.7 2 0

SEPTEMBER 70 4 4 5.7 1 0

OCTOBER 66 4 6 6 1.5 0

NOVEMBER 70 1 1 1.4 1 0

DECEMBER 64 0 0 0 0 0

815 46 64 Standard

Deviation =

0.68



VISAKHAPATNAM COAST, FROM JANUARY TO DECEMBER – 2009



MONTH

NO.

EXAM

NO.

INF

TOTAL

P.

% OF

PREVALENCE

M.I R.D

JANUARY 60 0 0 0 0 0

FEBRUARY 75 4 5 5.3 1.2 0

MARCH 65 7 8 10.7 1.1 0.1

APRIL 68 9 11 13.24 1.2 0.1

MAY 70 14 17 20 1.2 0.2

JUNE 72 11 13 15.2 1.1 0.1

JULY 70 5 6 7.1 1.2 0

AUGUST 65 4 6 6.1 1.5 0

SEPTEMBER 68 6 8 8.8 1.3 0.1

OCTOBER 70 8 10 11.4 1.2 0.1

NOVEMBER 66 1 1 1.5 1 0

DECEMBER 71 0 0 0 0 0

820 69 85

Standard Deviation =

0.48

TABLE-4 PREVALENCE AND MEAN INTENSITY OF NEMATODE INFECTION RECORDED SEASONWISE IN MARINE FISHES OF

VISAKHAPATNAM COAST (2007-2009)

YEAR SEASON NO OF

EXAMINED

FISHES

NO OF

INFECTED

FISHES

TOTAL

PARASITES

PREVALENCE

(%)

MEAN

INTENSITY

+ S.D

2007 RAINY

WINTER

SUMMER

290

239

291

19

2

62

41

5

98

6.5

0.8

21.3

2.2 + 1.09

2.5 + 1.25

1.5 + 0.94

2008 RAINY

WINTER

SUMMER

273

270

272

14

1

31

21

1

42

5.1

0.3

11.3

1.5 + 0.42

1 + 0.5

1.3 + 0.21

2009 RAINY

WINTER

SUMMER

273

272

275

23

5

41

30

6

49

8.4

1.8

14.9

1.3 + 0.14

1.2 + 0.64

1.1 + 0.05

TABLE-5 PREVALENCE OF INFECTED MARINE FISHES AND PERCENTAGE OF NEMATODE INFECTION FROM JANUARY 2007 TO DECEMBER

2009.

S.NO NAME OF FISH

NO.OF

EXAMINED

FISHES

NO.OF

INFECTED

FISHES

PREVALENCE

NEMATODES

RECOVERED

(No)

MEAN

INTENSITY

ORDER:CLUPEIFOR

MES

FAMILY:ENGRAULI

DAE

A N C H O V I E S

THRISSOCLES MYSTAX

THRISSOCLES

DUSSUMIERI

40

22

20

8

50

36.3

32

15

1.6

1.8

ORDER:

SCOPELIFORMES

FAMILY:SYNODON

TIDAE

L IZARD FISHES

SAURIDA UNDOSQUAMIS

SAURIDA TUMBIL

TRACHINOCEPHALUS

MYOPS

30

20

12

14

6

5

46.6

30

41.6

19

9

6

1.3

1.5

1.2

ORDER:

ANGUILLIFORMES

FAMILY:

MURAENESOCIDAE

FALSE CONGER

EELS

MURAENESOX CINEREUS

MURAENESOX

TALABANOIDES

15

25

2

2

13.3

8

3

3

1.5

1.5

ORDER:

BERYCIFORMES

FAMILY:

HOLOCENTRIDAE

SOLDIER FISH

HOLOCENTRUS LACTEO-

GUTTATUS

10 2 20 4 2

ORDER:

MUGILIFORMES

FAMILY:

SPHYRAENIDAE

SEAPIKE

SPHYRAENA LANGSAR

10

3

30

5

1.6

ORDER:

PERCIFORMES

FAMILY:

APOGONIDAE

CARDINAL FISH

APOGON GLAGA 12 5 41.6 5 1

FAMILY:

CARANGIDAE

TREVALLY

DECAPTERUS RUSSELLI

ALECTIS CILIARIS

25

10

11

4

44

40

12

7

1.1

1.7

FAMILY:LUTIANID

AE

SNAPPER

LUTIANUS BOHAR

12

5

41.6

7

1.4

FAMILY:

GERRIDAE

SILVER-BIDDIES

PENTAPRION

LONGIMANUS

30 12 40 15 1.3

FAMILY:

SCIAENIDAE

JEWFISH

NIBEA MACULATA

JOHNIUS DUSSUMIERI

JOHNIUS SINA

JOHNIUS AXILLARIS

JOHNIUS ANEUS

25

10

30

10

10

3

3

10

2

2

12

30

33.3

20

20

5

4

12

4

4

1.7

1.3

1.2

2

2

FAMILY:

MULLIDAE

GOAT FISH

UPENEUS SULPHUREUS

UPENEUS VITTATUS

MULLOIDICTHYS

AURIFLAMMA

30

40

40

15

25

11

50

62.5

27.5

20

30

30

1.3

1.2

2.7

FAMILY:

DREPANIDAE

SPOTTED BAT

FISH

DREPANE PUNCTATA 22 3 13.6 5 1.7

FAMILY :

CHAETODONTIDAE

CORAL FISH

LINOPHORA VAGABUNDA 10 3 30 5 1.7

FAMILY:

TRICHIURIDAE

RIBBON-FISH

TRICHIURUS SAVALA 40 9 22.5 14 1.6

FAMILY:

SCORPAENIDAE

STING-FISH

PTEROIS RUSSELLI

8

3

37.5

6

2

ORDER:PLEURONE

CTIFORMES

FAMILY :

SOLEIDAE

HORNED SOLE

AESOPIA CORNUTA 3 1 33.3 1 1

FAMILY:

CYNOGLOSSIDAE

TONGUE-SOLES

CYNOGLOSSUS

BILINEATUS

30 9 30 11 1.2

TABLE-6

LIST OF FISHES WITH NEMATODE INFECTION

SNO NAME OF THE FISH NAME OF THE

PARASITE

RECOVERED

NUMBER OF

PARASITES

RECOVERED

LOCATION OF THE PARASITE

1

2

THRISSOCLES MYSTAX

THRISSOCLES DUSSUMIERI

CONTRACAECUM

VITTATI

PARANISAKIS SP I

PORROCAECUM SP

32

10

5

BODYCAVITY,STOMACH,LIVER,INTESTINE, MUSCLES

LIVER,

STOMACH

3

4

5

SAURIDA UNDOSQUAMIS

SAURIDA TUMBIL

TRACHINOCEPHALUS MYOPS

CONTRACAECUM SP

INDOCUCULLANUS

ARABIANSAE

CONTRACAECUM SP

19

9

6

BODY CAVITY, STOMACH, INTESTINE

INTESTINE

AIRBLADDER

6

7

MURAENESOX CINEREUS

MURAENESOX TALABANOIDES

RAPHIDASCARIS SP

RAPHIDASCARIS SP

NEOGOEZIA

ASPINOSA

3

2

1

INTESTINE

INTESTINE

STOMACH

8 HOLOCENTRUS

LACTEOGUTTATUS

RAPHIDASCAROIDES

SP II

4 STOMACH

9 SPHYRAENA LANGSAR

PARANISAKIS SP I

5 INTESTINE

10 APOGON GLAGA

CONTRACAECUM SP 5 BODY CAVITY

11

12

DECAPTERUS RUSSELLI

ALECTIS CILIARIS

CONTRACAECUM SP

RAPHIDASCARIS

DIADONIS

12

7

STOMACH, INTESTINE

INTESTINE

13 LUTIANUS BOHAR

PARACAMALLANUS SP

7

STOMACH

14 PENTAPRION LONGIMANUS

CONTRACAECUM

VITTATI

15 LIVER, INTESTINE

15

16

17

18

19

NIBEA MACULATA

JOHNIUS DUSSUMIERI

JOHNIUS SINA

JOHINUS AXILLARIS

JOHNIUS ANEUS

RAPHIDASCARIS SP

RAPHIDASCAROIDES

SP I

PORROCAECUM SP

CONTRACAECUM

VITTATI

PARANISAKIS SP I

PORROCAECUM SP

3

2

4

12

4

4

INTESTINE

INTESTINE

OVARIES

BODY CAVITY

BODYCAVITY

AIRBLADDER

20

21

22

UPENEUS SULPHUREUS

UPENEUS VITTATUS

MULLOIDICTHYS

AURIFLAMMA

CONTRACAECUM

VITTATI

CONTRACAECUM

VITTATI

GENDRIA SP

RHABDOCHONA SP II

20

30

10

20

STOMACH , LIVER , INTESTINE

BODY CAVITY,STOMACH

LIVER

STOMACH

23 DREPANE PUNCTATA

PARANISAKIS SP I

5

LIVER

24 LINOPHORA VAGABUNDA

RHABDOCHONA SP I 5 INTESTINE

25 TRICHIURUS SAVALA

ALIASCARIS SP

CAMALLANUS SAVALA

N.SP

6 8

LIVER, INTESTINE INTESTINE

26 PTEROIS RUSSELLI

CONTRACAECUM

VITTATI

PARANISAKIS SP II

PROLEPTUS SP

3

2

1

BODY CAVITY

OVARY

STOMACH

27 AESOPIA CORNUTA

CONTRACAECUM

VITTATI 1 BODY CAVITY

28

CYNOGLOSSUS BILINEATUS

CONTRACAECUM SP

11

BODY CAVITY,STOMACH,INTESTINE

EFFECT OF TEMPERATURE ON THE INTENSITY OF INFECTION

IN MARINE FISHES

Environmental factors are of crucial importance influencing the parasitic

infection in fish and the subsequent expression of pathogenic potential. It has

been observed that the nematode infection relates to the environmental factors

like temperature and salinity. These two important parameters distinctly

influence the intensity of nematode infection in the marine fish community. It

has been observed in the laboratory, 2ml of 60+1

0 C of habitat water when

added to an active nematode, which influences to restrict the movement. In a

similar way 400C +1

0 increases the activity of the nematode parasites. This

shows clearly the effect of temperature is directly proportional to the intensity

of activity of a nematode which influences the intensity of infection. This

factor clearly has been observed in the marine environment where the intensity

of nematode infection to the fish is higher during the periods of high

temperature and less infection during the periods of low temperatures.

On the basis of the available information provided by the National

Institute of Oceanography (N I O) that the marine environment especially of

the coastal regions there are two peaks of high temperatures in each year

recorded from 2007 to 2009. In these peak periods the intensity of nematode

infections was also recorded high. This is an indication that the high

temperature of the coastal marine environment plays an important role for the

intensity of nematode infection to the marine fish.

In the year 2007, two peaks of high temperatures were recorded. The

first peak of high temperatures 30.040C and 29.56

0C were recorded during the

month of May and June respectively. In these two months the high intensity of

nematode infection among the fish is recorded as 62.8% and 31.2%

respectively. Among the infected fish Thryssocles mystax and Upeneus

sulphureus were infected by the nematode parasite Contracaecum vittati. The

second peak of high temperatures i.e 29.060C and 29.44

0C were recorded

during the month of September and October respectively. In these two months

the intensity of nematode infection in the fish is also high as 16.6% and 24.6%

respectively. Mulloidicthys auriflamma and Alectis indica were infected by the

nematode parasite Rhabdochona sp and Raphidascaris diadonis (Graph 13).

In the year 2008 the first peak of high temperatures 30.0C and 30.12

0C

were recorded during the month of May and June respectively. In these two

months the high intensity of nematode infection among the fish is recorded as

22.8% and 15.2% respectively. Among the infected fish Saurida undosquamis

and Johnius sina were infected high by the nematode parasite Contracaecum

sp and Contracaecum vittati. The second peak of high temperatures 28.990C

and 28.090C were recorded during the month of September and October

respectively. In these months the intensity of nematode infection in the fish is

also high as 5.7% and 9% respectively. Pentaprion longimanus and

Trachinocephalus myops were infected by the nematode parasite

Contracaecum vittati and Contracaecum sp (Graph 13).

In the year 2009 the first peak of high temperatures 30.160C and 29.24

0C

were recorded during the month of May and June respectively. In these two

months the high intensity of nematode infection among the fish is recorded as

24.2% and 18% respectively. Among the infected fish Upeneus vittatus,

Saurida tumbil and Trichiurus savala were infected high by the nematode

parasite Contracaecum vittati, Indocucullanus arabiansae and Camallanus

savala n.sp. The second peak of high temperatures 29.550C and 29.57

0C were

recorded during the month of September and October respectively. In these

months the intensity of nematode infection in the fish is also high as 11.7% and

14.2% respectively. Among the infected fish Sphyraena langsar, Thyrissocles

dussumieri and Cynoglossus bilineatus were infected high by the nematode

parasite Paranisakis and Contracaecum sp (Graph 13).

The low temperatures were recorded as 25.842720C, 27.85814

0C and

26.720410C during the months of January, November and December

respectively in the year 2007. In these three months the percentage of infection

is nil. In other months less intensity of infection was observed (Graph 13).

The low temperatures were recorded as 26.111390C, 26.695

0C and

26.409770C during the months of January, February and December

respectively in the year 2008. In these three months the percentage of infection

is nil. In other months less intensity of infection was observed (Graph 13).

The low temperatures were recorded as 25.636130C and 26.62484

0C

during the months of January and December respectively in the year 2009. In

these two months the percentage of infection is nil. In other months less

intensity of infection was observed (Graph 13).

EFFECT OF SALINITY ON THE INTENSITY OF INFECTION IN

MARINE FISHES

Salinity is another important parameter for the survival of animals in the

marine environment and regulates their distribution. During this study data has

been collected to examine the influence of salinity on infection and distribution

of nematode parasites in the coastal marine waters of Visakhapatnam.

According to the information of the operators of the trawlers and fishing boats,

they operate between 5 to 90 meters depth. Information on salinity in the

coastal waters of Visakhapatnam coast has been obtained from National

Institute of Oceanography (N I O) for a period of three years i.e from January

2007 to December 2009. During this period there was not much variation in

salinity in the horizontal depth stratification. Salinity ranged between

33.407o/oo to 34.702

o/oo (Graph 13).

seasonal distribution of seasonal distribution of...

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