comar interregional scientific conference; coastal systems...
TRANSCRIPT
Restricted distribution MARINF/85 Paris, April 1771
English only
UNITED NATIONS EDUCATIONAL, SCIENTIFIC AND CULTURAL ORGANIZATION
COASTAL SYSTEMS STUDIES AND SUSTAINABLE DEVELOPMENT
A COMAR Interregional Scientific Conference
Unesco, Paris, 21-25 May 1991
ABSTRACTS
UNITED NATIONS EDUCATIONAL, SCIENTIFIC AND CULTURAL ORGANIZATION
COASTAL SYSTEMS STUDIES AND SUSTAINABLE DEVELOPMENT
A COMAR Interregional Scientific Conference
Unesco, Paris, 21-25 May 1991
ABSTRACTS
TABLE OF CONTENTS
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Interdisciplinary Environmental Assessment of the Archipelago Sabana-Camaguey (Cuba), prior to Extensive Tourism Development Projects - P.M. Al&ado, L. Menendez and Antonio Magai
The Challenges of the Coastal Zone - J.T. Baker
Beach Stability and Coastal Zone Management in the Eastern Caribbean Islands - G. Cambers
The COMARAF Project - E.S. Diop
Wave Dynamics and Foreshore Protection in Relation to Coastal Systems and Sustainable Development in the South Pacific Counties - D. Esrom
Mangroves, Information Management and Science - CD. Field
Marine Information Service and Modeling Programmes for Coastal Development - V.K. Gaur
New Zealand Coastal Policy - J. Holdaway
Causes of Appearance of Anaerobic Conditions in Prebottom Waters of the North-Western Shelf of the Black Sea - M.V. Ivanov and A. Yu,Lein
Caribbean Coastal Marine Productivity (CARICOMP) - E. Jordan Dahlgren
Impacts of Sea Level Rise on the Argentine Coast - N.W. Lanfredi and J.L. Pousa
Fisheries and the Ecosystem: A Need for Protected Areas - II.]. Lindeboom
Late Quaternary Processes along the Rio Grande Continental Shelf L.R. Martins, C.M. Urien, I.C.S. Correa and I.R. Martins
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Management of the Coastal Zone: Impact of Onshore Activities on the Coastal Environment - I.D. Milliman
Coastal Zone Research, Biological Communities and Productivity - T.R. Parsons
Sandy Beaches Evolution and Management in North Africa - R. Paskoff
Warming Effects on Tropical Coastal Systems: A case from the Southern Caribbean (Venezuela) - P.E. Penchaszadeh, G. de Mahieu and S. Pauls
Development of the Natural Reservations of Mangroves along China Coast - Lin Peng
The Changing Coastal Systems - H. Postma
The Coastal Systems of East Africa: A Mangrove Ecosystem Case Study - AK Semesi
The 1989 Alaska Oil Spill: Ecological and Social Consequences - D.G. Shaw
Temperate Coastal Systems in Latin America - J. Stuardo
Coastal Zone and Mangrove Studies - M. Vannucci
Organization of the Benthic Macrofauna populations of the Ebrie Lagoon (Cbte d’Ivoire) - S.G. Zabi
Asia and the Pacific: Towards Rehabilitating the Coastal Systems. The Coastal Environment of the Pacific - Monika T. Rau
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Interdisciplinary Environmental Assessment of the Archipelago Sabana-Camaguey (Cuba), prior to
Extensive Tourism Development Projects
P.M. ALCOLADO Institute de Oceanologia
Academia de Ciencias de Cuba
L. MENENDEZ Institute de Ecologi’a y Sistemdtica
Academia de Ciencias de Cuba
Antonio MAGAZ Institute de Geografia
Academia de Ciencias de Cuba
The Archipelago Sabana-Camaguey stretches about 400 km along the Central North part of the mainland of Cuba. It is plenty of keys of varying sizes, and extense mangrove systems. The bordering keys have several beautiful well developed sand beaches facing to the ocean, and nice tropical untouched natural landscapes. Many luxuriant reef crests and reef patches fringe the shelf border. The inner water-bodies consist in varying sized interconnected macrolagoons, where muddy bottoms and grass beds are the dominant habitats.
This archipelago is being the object of extensive tourism development projects, and in the most western part, to oil exploitation. In order to provide adequate knowledge for a rational management of the keys and the sea, an interdisciplinary investigation is being performed since 1989. This research involves three institutes of the Academy of Sciences of Cuba (Institute of Oceanology, Institute of Ecology and Systematics, and Institute of Geography) among others of the Country (e.g. Cuban Institute of Hydrography, Cuban Institute of Geodesics and Cartography, National Institute of Hydraulic Re- sources, Center of Fisheries Investigations, etc.).
That investigation has different kinds of outputs that are being seriously taken into account by all enterprises and governmental organizations involved in the rational exploitation and sustainable development of the Archipelago. Among these outputs it can be mentioned:
l Recommendations for avoiding or minimizing man induced ecological impact by the construction of roads through the sea from the mainland coast to the keys, between keys, and through mangrove systems (bridges, sewers, relocation of projected ways, etc.).
l Zonation of sea and land use areas. l Zonation of the different categories of protected areas.
Zonation, species composition and community structure of the flora and the fauna of the sea and the keys.
l Zonation and description of the geomorphological features of the archipelago.
l Zonation of the landscapes of the sea and the keys. l Zonation of man induced modifications of the environment. l Zonation of the hydrological and sedimentological features of the sea. l Rules for the protection and improvement of the beaches. l Establishment of an immediate future monitoring programme.
Other national research institutions are involved in the investigation of many other items, such as meteorological regime, evaluation and control of disease vectors, hydraulic resources, local fisheries, etc.
The development of all the tourism infrastructure and road projects is closely supervised by the research institutions involved.
The Challenges of the Coastal Zone
J.T. BAKER Australian Institute of Marine Science
PMB W3 Townsville M.O. Queensland 4810 -Australia
The challenges of the Coastal Zone are best addressed in inter-disciplinary studies assessing the different processes that are involved. The paper outlines the Projected R & D Activities of the Australian Institute of Marine Science (AIMS) in the period 1991-96 and offers the opportunity for international collaboration.
In the planned research activities, studies will concentrate on tropical regions, in the coastal area out to the edge of the Continental Shelf. The research will be processed through four interactive programmes:
l Coastal Processes and Resources. l Reef Ecosystems. l Environmental Studies and Biotechnology. l Tropical Oceanography.
Additionally the paper outlines reef survey methodologies being used by the ASEAN nations to assess resource status.
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Beach Stability and Coastal Zone Management in the Eastern Caribbean Islands
G. CAMBERS P.O. Box 860, Roadtown
Tortola -British Virgin Islands, W.I.
The smaller Eastern Caribbean Islands, which form a chain from Grenada in the south to the Virgin Islands in the north, are heavily dependent upon coastal tourism as one of their major industries, in some countries it is the major industry. In addition the coastal zone is often the only area where there is flat land. As a result the coastal zones are intensely used for tourism, manufacturing, ports, fishing, residential and commercial development and communications. Despite this heavy dependence on the coastal zone, natural and man induced changes in the coastal zone have been largely ignored. However, as the degree of development increases, and as tourism grows in importance to the local economies, it is no longer possible to ignore these changes.
During the latter part of the seventies and the early eighties increasing media attention has been given to changes within the coastal zone. The major hurricanes of 1979,1980,1988 and 1989 have helped to heighten this awareness, as have the increasing problems caused by the removal of sand from the coastal zone for construction purposes, the problems caused by building too close to the high water mark, the destruction of coral reefs. As yet the potential effects of sea level rise have not been assessed in a quantitative manner in the region.
Against this background there was no in house expertise within these islands to advise Governments as to how to deal with these problems, and indeed the population base was in some cases so small, that it was unlikely that the local expertise would ever be available. (Population of these countries ranges from 10,000 to 130,000).
Within this framework, and as a direct response to a request for assistance in combating beach erosion in the region, a pilot project, COSALC 1 (Coastal Marine Systems of Latin America and the Caribbean) was set up within the framework of COMAR by Unesco. The title of the pilot project was Beach Stability and Coastal Zone Management in the Lesser Antilles and was started in 1985. In the initial planning there were two phases to the pilot project: (1) Visits to each island by a consultant to assess the problems and to provide an evaluation report; (2) In country workshops to be held in each island to promote awareness, discuss country problems and to determine a future direction for the project. Following phases 1,2, it became apparent that there were two major needs, one was to supply relevant audio visual material to assist with local education into the subject of coastal changes, the second was to assist the islands with the setting up of coastal monitoring programmes.
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During 1986 work proceeded on phase 3, individual sets of slides and pre- recorded cassettes were prepared for each island detailing their coastal changes, the causes and the consequences. These were distributed together with a film: “The Beach, A River of Sand” in 1987.
In 1987 work started on the establishment of coastal monitoring pro- grammes, and a programme was set up in Dominica whereby a consultant set up the beach and wave measurement programme and trained a local counter- part in the field techniques and data analysis. The counterpart then continued the monitoring throughout the year on a regular basis. The consultant main- tained contact with the local counterpart throughout the year to help solve potential and actual problems. After the first twelve months the consultant returned to Dominica to assist the counterpart in the analysis of the first year’s data.
Basically a similar programme has been followed for St. Kitts and Nevis in 1988 and for St. Lucia in 1990. An effort has been made to set up a monitoring programme in a new island each year. In addition annual visits are made to islands with ongoing programmes to assist in their data review, application of the monitoring data to solve coastal problems, and the design of modifications to the programmes.
A review of the programme in 1990 showed considerable successes in Dominica and Nevis with local counterparts running the entire programme with very little outside assistance. Problems had been experienced in St. Kitts due to the local counterpart having insufficient time to do the work, and in St. Lucia it was too early to evaluate the programme. Overall it was felt that the programme had been very successful in strengthening the capability of the islands to monitor and manage their coastal systems. Whereas previously these islands had had no expertise or data relating to coastal and beach changes, there is now a knowledgeable local person and the beginning of a useful data base.
It is planned that in the future, coastal monitoring programmes can be set up in all the islands of the region and that the scope of these programmes can be expanded to include other areas such as sea level changes. In addition there is an urgent need to establish a regional organisation or unit which can fulfil1 the functions of data bank, technical advice, administration, programme expansion and networking.
In review this pilot project has been successful in fulfilling its goal: to strengthen local capability to monitor and manage the coastal systems of the Eastern Caribbean Islands, although it is recognized that there is still a long way to go. Much of this has been achieved through Unesco’s recognition of the need for a regional project with a strong country bias. Thus the emphasis throughout has been on regional topics dealt with at the country level through in-country workshops, in-country training etc. It is felt that this has contributed signifi- cantly to the success of this programme.
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The COMARAF Project
ES. DIOP Regional Project Coordinator
C/o BREDA - B.P. 3311 Avenue Roume Dakar - S&n&al
After a short summary of the COMARAF project and its main objectives and implementation strategy, a synthetic review of the principal activities and results obtained during the two and half years functioning of the project is made, with special emphasis on the main African coastal systems: estuaries, mangroves, coastal lagoons, coral reefs, sandy beaches linked with coastal erosion phenomena.
This presentation will be followed by a case-study concerning particularly the functioning, evolution and recent environmental modifications of the West African estuaries and mangroves. In this last example, we will indicate the recent changes occurred, either from natural phenomena (importance and incidence of the desertification) or from anthropogenic factors, due in particular to the multiple uses of the mangrove areas in West Africa.
It will be certainly important to underline that most of the activities included in the initial project document, as the same as the recommandations made during the various COMARAF regional coordinating committee meetings, have been correctly executed.
Wave Dynamics and Foreshore Protection in Relation to Coastal Systems and Sustainable Development in the
South Pacific Countries
D. ESROM Environment and Conservation
Ministry of Home Affairs Private Mail Bag Port Vila
Republic Vanuatu
Coastal problems are often caused by engineers and planners mis- understanding which may consequently affect natural factors such as wave patterns and current movements along the coast.
It is for this reason that this paper intends to address a number of issues as they apply to the Pacific Island Countries.
Since most damage to the foreshore is due to wave attack there will be a brief outline of the way in which waves are generated and of the way in which they are transformed from their generation up until the time they reach the shore.
Before any foreshore protection is initiated it is important that the reasons for initial erosion or damage be known. There are many examples around the world where positive measures have either been a waste of money or have even made the situation worse because they did not address the underlying problems. This paper will outline some of the causes of erosion and will discuss the value of various levels of protection.
The last part of the paper outlines the types of protection that are available and practical. It will also discuss some of the advantages and disadvantages of each type of protection.
Mangroves, Information Management and Science
C.D. FIELD City Polytechnic of Hong Kong
Tat Chee Av. Kowloon Hong Kong
There are expectations that a scientific understanding of mangrove eco- systems will automatically lead to a capacity for their management and that there will be comprehensive exchange of reliable information. Both these expectations are false. It will be argued that basic studies of pristine systems are unlikely to satisfy the needs of management and that there is a poor exchange of information, much of which is unreliable. It is concluded that an easily accessed and credible information management system is urgently required and that many kinds of silvicultural, technological and economic expertise will have to be marshalled if tropical intertidal environments are to be used wisely for sustainable development.
Marine Information Service and Modeling Programmes for Coastal Development
V. K. GAUR Department of Ocean Development
New Delhi - India
A satellite based marine information service would be shortly made operational by the Government of India, Department of Ocean Development. The basic information will be provided by National Remote Sensing Agency (NRSA) Hyderabad and Space Application Centre (SAC) of the Indian Space Research Organisation, supported by National Institute of Oceanography, Goa, for direct sea truth collection and Centre for Mathematical Modeling, Bangalore, for development of algorithms, process models and higher data products.
Maps of sea surface temperature, potential fishing zones at 25 km spacing and coastal wetlands (I : 50,000) as well as surface winds, wave parameters and coastal bathymetry data will be regularly disseminated at appropriate intervals.
Four marine data centres at NIO, Goa; CMFRI, Cochin; ORSAC, Bhuvaneswar; and Anna University, Madras - all linked to NRSA and SAC - will develop special programmes to promote downstream uses of information amongst entrepreneurs, the general public and Government in designing development works and devising strategies and plans for protection and informed utilization of coastal areas and habitats.
The paper outlines a strategy for sustainable development of the coastal zone designed in view of the new information that will be routinely available coupled with data assimilative predictive models.
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New Zealand Coastal Policy
J. HOLDAWAY Auckland Conservation Board Department of Conservation
35 Ocean View Road Northcote -Auckland 9
New Zealand
New Zealand comprises an archipelago extending from the Kermadec Islands at about 30 degrees South latitude to Campbell Island in 54 degrees South, and with the main islands lying between 34 and 47 degrees. Its South Pacific location, largely temperate climate, geology and topography have produced a coastal environment which is unique. Because of the long geographic isolation it has been described as an ecological “continent”.
New Zealand coasts are diverse and distinctive. They include fjords, sounds, rocky coasts with varied formations, sand and gravel beaches, sand dunes, mudflats, estuaries, mangrove forests and harbours. They also include islands, many of which provide habitat for rare species of plants and animals.
Coastal management has been characterized by multiple agencies and legislation with conflicting purposes and inappropriate boundaries.
Unsatisfactory coastal management has left parts of the New Zealand coastline scarred by unnecessary reclamations, sprawling subdivisions and polluting landfills. A single policy to guide coastal management has been recommended on many occasions.
A comprehensive Resource Management Bill which would replace numerous existing statutes is at present before the New Zealand Parliament. Among other things it would provide roles in coastal management for all levels of government, and would require the Minister of Conservation to prepare a Coastal Policy Statement for the purpose of achieving the maintenance of the natural character of that environment, without precluding appropriate use and development. Protection of the interests of the indigenous Maori people is also required. The Policy would be binding on all Government agencies.
The format and content of such a Policy Statement have been the subject of intensive study and wide public discussion, and a draft Policy Statement has been produced. The Policy is discussed under a number of subject headings.
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Causes of Appearence of Anaerobic Conditions in Prebottom Waters of the North-Western Shelf of the Black Sea
M.V. IVANOV Institute of Microbiology
USSR Academy of Sciences
A.Yu. LEIN Vernadsky Institute of Geochemisty
USSR Academy of Sciences
The presence of dissolved hydrogen sulfide of microbial origin in deep- water part of the Black Sea has been known since the end of the last century. However, the recent two decades this toxic compound has been often found in summer months in prebottom waters in the shallow part of the sea. This has resulted in the death of benthic animals at the considerable area of the North- Western shelf of the Black Sea.
In order to find out the cause of appearence of hydrogen sulfide in this region we studied sulfate reducing bacteria distribution and s&ate reduction intensity in the sediments of western part of the shelf of the Black Sea.
The highest rates of hydrogen sulfide production were found in the coas ta1 silts near the Dnieper-Bug firth and the Danube estuary.
The distribution of hydrogen sulfide and other reduced sulfur compounds along the sediments and their isotope composition indicate that the process of sulfate reduction has been intensified the recent years. This depends on the increasing pollution of the North-Western part of the Black Sea with domestic sewage and also with dissolved nitrogen and phosphorus compounds discharged by river.
The intensification of sulfate reduction in shallow sediments well heated in summer results in the hydrogen sulfide emission into the water that initially adversely affects the oxygen regime of prebottom water and then leads to its hydrogen sulfide contamination.
The deficiency of dissolved oxygen in prebottom waters of the North- Western shelf of the Black Sea may results from microbiological methane oxidation. This gas as well as hydrogen sulfide is produced in anaerobic bottom sediments. Besides, numerous vents of methane were found in 1990 at the bottom of the shallow zone of the Black Sea. A considerable part of this methane is oxidized in water column by methanotrophic bacteria.
Caribbean Coastal Marine Productivity (CARICOMP)
E. JORDAN DAHLGREN Universidad National Autbnoma de Mexico Estacia -Puerto Morelos, Apto. 115277500
Cancun Q. ROO, Mexico
The coastal ecosystems of the Caribbean region are being gradually transformed and degraded as a result of increased human activities in the coastal zone. The need to implement rational utilization and management practices on the coastal zone of the region is thus urgent. However, this is not an easy task, because there is a limited scientific understanding of the structure and dynamics of the dominant ecosystems (mangroves, seagrasses and coral reefs). And also because, the technical and scientific expertise necessary to deal with these topics, tend to be insufficient in most countries of the region. On the other hand, the Caribbean is an interconnected system, with similar ecological and development problems, where regional solutions may be possible: an idea that gave rise to the CARICOMP project.
The CARICOMP project, presently in the implementation phase, seeks to contribute toward a proper management of the coastal ecosystems by increasing the level of scientific knowledge, as well as the technical and scientific level of scientists from the region. In this sense CARICOMP is a typical Unesco project, although there are several other interesting features of this programme, such as the establishment of a cooperative network of marine laboratories, that are discussed.
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Impacts of Sea Level Rise on the Argentine Coast
N. W. LANFREDI and
J. L. POUSA Laboratorio de Oceanografia Costera
Facultad de Ciencias Naturales Universidad National de La Plata
Casilla de Coweo 45 1900 La Plata -Argentina
The Argentine coast exhibits a variety of environmental settings, including estuarine and deltaic areas, marshes, sandy and pebbly shores, and cliff exposures. Different wave and tide regimes operate along the coast.
Although erosion typifies much of the nation 5,000 kilometers coastline, these problems are particularly severe in the Province of Buenos Aires with 40% of the country total population and one third of its coastline. The main urban developments, harbors, industrial complexes, and tourist resorts are located in this province. Floods are very dramatic on the Rio de LaPlata shores, which have the highest population density. Here the water level rose 4.75 m in 1940 and 3.85 m in 1958. In the latter case, more than a half million inhabitants were affected in different ways.
South of the Rio de La Plata, the oceanic shorelines show dissipative characteristics with a significant littoral drift (estimated in 400 x lo3 and 800 x 103 m3/year). There is high erosion in many areas; for example, the Mar Chiquita beach has been retreating about 5 m/year in the last decade. Beach sand mining for construction also contributes to erosion. Unplanned urban development can also account for property loss and damage. At Mar de1 Plats, the main tourist resort in Argentina, groins, jetties and seawalls have been constructed since the beginning of the century without the utilization of basic information, thereby partially solving local problems but increasing erosion along downdrift areas.
Fifteen tide gauge stations, a few of them with extensive records, are distributed along the Argentine coast. The 64-year record of Puerto Quequen located 120 km southwest of Mar de1 Plata, shows a rise in sea level of 16.09 cm/l00 year. This locality seems to be the most reliable, in terms of both historic data and tectonic stability.
Coastal plain flooding is also critical in areas such as the Rio Salado Basin, where topographic gradients are extremely low and the phreatic surface is very shallow. In addition, salt intrusion of coastal aquifers can be predicted as a combined result of sea level rise and coastal retreat. Overpumping has already
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created this type of problem in the city of Mar de1 Plata.
Urban development on the sandy coastline of the northern Buenos Aires Province has caused the elimination of extensive sand dunes, which are the only available storage bodies for groundwater. Beach erosion in this area is partly due to the restriction in sediment supply from the sand dunes.
The accelerated rate in sea level rise predicted for the next century will exacerbate the described processes. Although several impacts can be predicted for the Patagonian coast, they are far less dramatic than those in the northern coast because of the much lower population density and urban/industrial development.
In the absence of a general legal/organizational framework, institutional responses to coastal problems are limited to specifically oriented government offices, mostly at the provincial level. Some municipal counties backed by community organizations are involved in dealing with the development and management of coastal resources, although they usually lack expertise. It is expected that future efforts, based upon scientific evidence, will result in the adoption of legal administrative procedures for proper use and protection of the coas ta1 zone.
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Fisheries and the Ecosystem: a Need for Protected Areas
H. J. LINDEBOOM Netherlands Institute for Sea Research (NIOZ)
p.0. Box 59 - 1790 AB Den Burg Texel - The Netherlands
There are many signals that fisheries seriously affect the marine ecosystem. In the North Sea the catching of herring was totally banned because hardly any herrign could be found. Soon afterwards, it was the mackerel’s turn, and now the cod is rapidly declining. The fact that we need quota for sole and plaice is not due to the abundance of fish. The blue tuna and the greater weever have totally disappeared from the North Sea, and the mean lenght of some non- commerical fish species have decreased during the last twenty years. This and the disappearance of dolphin and porpoise along the dutch coast are clear signals that there is something changing. Recent research has shown that beamtrawling seriously affects the benthic ecosystem.
In general it appears that the intensive fisheries have forced a selection to take place from a diverse system to one where only fast growing, good reproducing, smaller organisms can survive. The large, slow growing bivalves are disappearing while worms take their place. The slower reproducing fish such as sharks and rays have more or less disappeared from large parts of the North Sea, the big cods have gone, while a number of smaller, faster growing species have increased.
Because of these signals the dutch government initiated a study called “Protected areas in the North Sea: needs and possibilities” with the following objectives:
l To preserve, rehabilitate and develop natural values in the Dutch sector of the North Sea by limiting the effects of those human activities that cause detectable changes in the North Sea ecosystem.
l To protect groups of animals which are an integral part of the natural values of the Dutch sector of the North Sea and whose existence or “normal” functioning is currently threatened.
The study showed that fisheries is a frequent large-scale activity which throughout the Dutch sector of the North Sea has resulted in considerable changes within the ecosystem. At least 10 benthic species have disappeared or their numbers have decreased substantially.
In the final report, which will be published on May 15, the objectives and related criteria which were used for the designation and the selection of areas
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which qualify for a protected status are given. This lead to the conclusion that the only way to protect the ecosystem in the Dutch sector of the North Sea, is the establishment of two protected areas which are closed for all types of fisheries throughout the year.
The outline of the final report, as well as the major conclusions including the effects of and measures against some other human activities will be discussed. The need for a world-wide fisheries policy, which takes into account the effects of fisheries on the non-commercial aspects of the ecosystem, will be stressed.
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Late Quaternary Processes along the Rio Grande Continental Shelf
L.R. MARTINS; CM. URlEN; I.C.S. CORREA; I.R. MARTINS CECO Instituto de GeocienciaslUFRGS
Campus do Valle, Predia H2 Avenida Bento Goncalves 9500 91500 Port0 Alegre, RF Brazil
The Rio Grande continental shelf presents on its Late Quaternary geological record, numerous evidences that show the influence of the sea level fluctuations as a control parameter of the sedimentary processes.
At the end of the Pleistocene, the sea level reached its lowest position -140/-150 meters), near the actual shelf break. Because of the glacio-eustatic lowstand, the continental shelf was converted into an extensive coastal plain, on which fluvial systems were overimposed. They have to arrive at the shelf border building in some places a series of deltaic complexes, most of them connected with sub marine canyons and fans (like the Rio Grande Cone), filling shifting depocenters as a sedimentary prism on the continental rise. This sedimentation pattern generates a sedimentary progradation model of fluvial origin.
After the Ice Age, the sea level raised in a transgressive motion started to flood the Pleistocene coastal plain and its associated environments (deltas, estuaries, lagoons and wetlands), with a consequent lateral migration of the coastline in direction to the continent, through an intermittent movement. Aligned scarps, abandoned shorelines, as well as shoals relict of ancient barriers and filled valleys were observed, which were builded during sea level still- stands. Ancient shorelines were identified at-130/-120,-60/-70,-332/-45 and -2O/-25 meters. Coarse materials as bioclastic sands, coquina and beachrock fragments indicate also these temporary stillstands, leaving shoreline relicts mantled by palimpsest sediments.
Break off the maximum Holocene ingression, started the regression to approximately the actual sea level position. A new barrier island isolated the Mangueira Lagoon at south and the necklace of smaller lagoons in the northern part of the coastal plain was developed.
This new sea level stabilization creates a regressive microphase with the development of beach ridges and dune fields. Suspended load of the Rio Grande do Sul fluvial systems is almost entirely trapped along the Patos and Mirim Lagoons and just few amount reaches the inner continental shelf through the Patos inlet. Bioclastic carbonate sands, heavy minerals placers and quartzose sands are the most important occurrences of economic value materials.
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Management of the Coastal Zone: Impact of Onshore Activities on the Coastal Environment
J.D. MILLIMAN Woods Hole Oceanographic Institution
Woods Hole, Massachusetts 02543, U.SA.
The coastal zone has far greater impact on human activities than any other marine environment, but the reverse is also true. The management of the coastal zone therefore must take into account both the effect of human activities as well as impacts resulting from corresponding changes in the coastal zone. Low-lying deltas, particularly those in southern Asia, maybe particularly vulnerable in the near future, as their rapid buildup over the past several millenia appears to have due in part to anthropogenically enhanced terrestrial erosion and river discharge, which soon will be negated by construction of dams and other river diversions.
Because corrective measures can be difficult and expensive, both potential benefits and impacts should be evaluated before future onshore projects are initiated. Among the important parameters to be delineated are rate of subsidence, sediment budget (both sources and sinks), oceanographic regime, biological and chemical regimes.
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Coastal Zone Research Biological Communities and Productivity
T.R. PARSONS Department of Oceanography
University of British Columbia Vancouver, BC, V6T 1~5 - Canada
On the basis of their primary productivities, coastal zones may be divided into at least four communities. Starting from the land and moving seaward these are the 1) salt marsh or mangrove, 2) sea grass, 3) mudflat or sandbar, and 4) pelagic communities. The most productive of these communities is the salt marsh, or in lower latitudes the mangrove community, both of which have productivites which may exceed 1000 g/C/m* per year. By contrast the plank- ton community in the pelagic zone may be limited by light and turbulence to less than 200g/C/m* per year. However, due to the high protein content of phy- toplankton as compared with the high carbohydrate content of marsh grasses and mangroves, the efficiency of the food chains from primary to secondary producers is much greater in the case of the pelagic community.
The impact of man on these four communities differs according to the location of each. The most severely impacted is generally the marsh grass or mangrove community. This habitat is easily over-run by housing and agricultural development. Consequently as much as 90% of some of these nearshore communities have been eliminated. Harbour development generally affects the mudflat and sea grass communities, while the pelagic zone is most often impacted by waste disposal (e.g. sewage). The problems of protecting these natural coastal habitats will be discussed with particular reference to local conditions in the coastal zone of British Columbia.
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Sandy Beaches Evolution and Management in North Africa
R. PASKOFF LumiLre University, Lyon, France
Chairman, Commission on the Coastal Environment International Geographical Union
Sandy shorelines are extensive in North Africa and, especially in Tunisia and Morocco, they have been largely used to develop tourism which has become an important economic activity in these countries.
Beach formation appears to be mainly the outcome of shoreward sand movement, initiated during the Holocene marine transgression which brought the sea to approximately its present level some 6,000 years ago. The sea floor sand supply ceased when the modern stillstand was established. Consequently, beaches mainly represent an inheritance dating back to a period characterized by abundant sediment supply. This is an important point too often forgotten by planners and decision makers.
Erosion started on many North African beaches well before the boom of the tourist industry at the beginning of the sixties. This fact must be related to a steady sea level rise evidenced by tide gauge data recorded in Tunisia as well as in Algeria and Morocco. It has taken place during the last hundred years at an average rate of 2 mm/yr, this figure increasing to 5,5 mm/yr in the gulf of Gabes, Tunisia, where an active subsidence is going on.
After World War II, building of dams onNorth African rivers for irrigation purposes increased in number. As a result, fluvial sediment supply to the sea drastically diminished, leading to the onset or the acceleration of erosion on beaches. The sandy beaches of the gulf of Tunis were adversely affected by the induced effects of sediment trapping in several reservoirs impounding the Medjerda river.
Jetties and breakwaters built to enclose harbours, particularly in the case of large harbours, such as Bizerte in Tunisia or Agadir in Morocco, dramatically disturbed coastal dynamics, starting deposition on the updrift side of the longshore current and recession downdrift.
On the Mediterranean shores of North Africa, extensive vegetation of Posidonia oceanica plays an important role in beach sedimentary equilibrium by slowing down approaching waves and trapping nearshore sediments. Erosion is enhanced when submarine sea grass meadows deteriorate in coastal waters polluted by urban sewage or industrial effluents.
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There is no doubt that the development of sea shore tourism has increased erosion on North African beaches, essentially through sand mining and foredune destruction which both have aggravated the sediment deficit. Consequently, the shoreline retreat has been enhanced.
Traditional hard anti-erosion structures, such as boulders heaps, sea walls, groynes, and breakwaters have been largely used to slow down beach erosion. Unfortunately, they may induce harmful effects on the environment. A better approach to mitigate beach erosion hazards is dune restauration and artificial beach nourishment, soft methods, more in accordance with nature, which have not been often used so far. Enforced regulations prohibiting constructions to close to the beaches and defining setback lines periodically revised according to shoreline retreat also represent good protecting measures.
An understanding of beach changes - when, how, and why they are taking place - constitutes a previous and indispensable step before planning and developing tourism along the fragile North african beaches.
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Warming Effects on Tropical Coastal Systems: A case from the Southern Caribbean (Venezuela)
P.E. PENCHASZADEH, G. de MAHIEU, S. PAULS Instituto de Temologia y Ciencias Marinas
Universidad Simon Bolivar Caracas - Venezuela
As a result of eight years study on the effects of a thermoelectric facility (Planta Centro, Venezuela) some changes in the surrounding communities were recorded. Among the aspects included are the area1 influence of the thermal effluent, physico-chemical parameters and variation of the amount of suspended materials, sediment dynamics and possible effects on plankton, fish and soft-bottom communities. Those results were complemented with lethal and sub-lethal effects of warming in laboratory conditions for a number of representative dominant soft-bottom invertebrates. From the ecological study we found that a Thalassiu testudinum bed, suffered a reduction on productivity rates and total leaf lenght, while its annual turnover rate has stabilized in 13.3 times its standing crop biomass. On sandy bottoms O-10 m depth a high species-replacement rate was recorded; only 40% of the total macrofauna original species were still present at the end of the study.
The experiments on temperature raising effects on some soft-bottom organisms (Tivela mactroides, VOYUX denticulatus, Weterodonux bimuculutus, MuzutIuniu ucicuZufu and Cmitium muscurum) had shown very interesting burrowing patterns changes. Lethal temperatures (LT50 values) varied between 32.2OC and 37.5”C among the considered species.
A general discussion on the soft-bottom food web structure is given in relation to species composition changes.
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Development of the Natural Reservations of Mangroves along China Coast
LllV PENG Department of Biology
Xiamen University Xiamen, 361005
Xiamen, Fujian, P.R. China
This paper deals with the distribution of mangrove species and the development of the natural reservations of mangroves along China coast.
29 species of mangrove belonging to 20 genus in 16 families in China were reported by author in 1984. In this paper, recent discoveries were added 2 new species and 6 new records. So there were 37 mangrove species belonging to 25 genus in 20 families in China.
From 1980 to 1990,5 mangrove reservations were set up one after the other. They are Dongzhai (19”54’N, Hainan Province), Towwan (19”34’N, Hainan), Futian (22”30’N, Guangdong), Jiulongjiang (24”29’N, Fujian) and Shankou (21°28’N, Guangxi), that their established time were 1980,1981,1982,1988 and 1990 respectively. In this paper, some important aspects were discussed for further protection and management of the mangrove reservations.
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The Changing Coastal Systems
H. POSTMA Netherlands Institute for Oceanic Sciences
Texel - The Netherlands
Rocky coasts, beaches, river mouths, fjords, estuaries and lagoons, barrier islands, intertidal flats and wetlands: our coasts are characterized by a large variety of forms shaped in the course of geological history. To these can be added those originating chiefly from biologic activity such as coral reefs, sea grass and kelp beds, and mangroves.
Together, these coastal systems represent an almost infinite variety of niches in which creatures have abundantly developed, both in species and numbers. Speculations about theorigin of lifeoften point to coastal waters as the first habitats. Young marine animals seek refuge in them to grow up in places where sufficient food and shelter against predators are available. Birds use them to gain energy for their long distance migrations.
For human beings coastal waters have as far as one can go back into the past been an important food source and often the only available source for protein. This is still the case in tropical waters, but was no more than a few centuries ago also the case in, for example, western Europe. The early development of very ingenious fishing techniques proves the existence of stable societies who made the utmost of available resources in a symbiosis between man and nature.
The development of modern techniques, not only for fishing but also for other forms of exploitation, has largely destroyed these original patterns. The rapid increase of world population, of which more than half lives in or near the coastal zone, has on one hand caused overexploitation and on the other hand made these regions less essential for staple food as other sources became available. Mass cultivation of some species, such as shrimps and shell fish for which there is much demand, became a new economic factor. Only in relatively remote tropical areas the old patterns of existence are still retained.
In addition to these changes, which because of their cultural aspects attracted the attention of Unesco from the beginning of its existence, other changes occurred which became direct threats to the survival of coastal systems. These are not only caused by demographic pressure but also and often mainly by unthoughtful and often harmful use of the coastal zone. A long list of them can be given. Foremost is perhaps water pollution, threatening extinction of rare species and of complete ecosystems. In the second place comes direct destruc- tion of specific habitats such as mangroves and coral reefs. Threats are also topographic changes and losses of wetlands by land reclamation, urban development, harbour construction, sand exploitation and acceleration of sea
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level rise. Recreation may sometimes be considered as a nuisance but has also done a lot to make a wide public aware of the great beauty of the coastal zone and the necessity to protect this splendid environment.
It has taken many years before it was recognized that such threats can only be averted by careful management. This is now generally accepted but this awareness has often not yet been followed by adequate action. A balanced management is mostly not simply programmed because of conflicting interests. These interests vary from complete protection of nature on one hand and full exploitation on the other.
Two intergovernmental organisations have in an early stage taken the lead to assist countries in developing management programmes. These are FA0 and Unesco. After a few decades they were joined by UNEP. The first organization has especially assisted in developing regional programmes for fisheries, the second developed more than one programme. The Man and Biosphere (MAB) programme has coastal system components, stressing the needs from conservation. The Intergovernmental Oceanographic Commission (IOC), has gone into problems of exchange between coastal and shelf waters and the blue ocean and specifically looked at marine pollution. The Division of Marine Sciences has developed the COMAR programme.
COMARstands from “coast marine project” and is an effort to increase our scientific understanding of coastal waters and to transfer this knowledge to participating countries for the benefit of better management. Because it leans heavily on scientific information, it has from its start sought close cooperation with the scientific oceanographic community as organized by the Scientific Committee for Oceanic Research (SCOR) of ICSU.
Its inception took place in 1981 but long before that year the division had already started activities which in retrospect are precursors of COMAR. They resulted in a number of books and reports (see list of articles) which now can be considered as a basis of COMAR Experts from both developed and developing countries participated in these publications. Cooperation between these experts formed a group or people devoted to global development of coastal science and to assistence of Unesco.
The demand from COMAR has come mainly from developing nations in tropical regions. The principal marine ecosystems in these regions are-next to lagoons, estuaries and bays -mangroves, coral reefs and seagrass beds and the programme was organized accordingly. It was soon evident that a regional approach was necessary to handle the programme, the principal regions being Asia and the Pacific, Africa, Latin America and the Caribbean, and Mediterranean and Red Sea. The programmes are carried out with a relatively small budget but additional funds could often be obtained from other intema- tional organizations such as UNDP and UNEP. A small consultative panel assists the Division in selection and general guidance of the programmes.
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In articles following this opening paper various sections of COMAR will be discussed and the reader is referred to these articles. Looking into the future it seems evident that COMAI activities will be influenced by a number of ongoing developments. One of these is the start of the International Geological and Biological Programme (IGBP) of ICSU which will soon have a coastal marine component. COW can on one hand profit from this programme by using it as a framework for choosing priorities. On the other hand it can serve as a window for IGBP to many tropical countries. It will have to retain its own identity, however, by continuing to stress aspects which are not included in IGBP, such as management, worldwide training and education, and socio- economic factors.
Aspects that will need specific attention are the effects of climate change. These are not only related to sea level rise but also to changes in continental input such as river and sediment discharge and to possible changes in nearshore water circulation. Changes in salinity and temperature, the former now already apparent for example in the Sahel region, have a profound influence on ecosystem structures.
Another factor that will influenceCOMARactivities is the recent emphasis on “sustainable development”. To give a meaning to this term predictive capabilities are essential for which scenarios based on ecosystem models are necessary. This requires the collection of extensive data sets which are mostly not available. Predictive capability does not only allow us to look into the future but can also be an important instrument for the rehabilitation of deteriorated coastal systems. A programme of rehabilitation does not simply mean restoration of an old ecosystem, but the creation of good conditions for a new ecosystem that may or may not be similar to the old one but in any case is characterized by the old biodiversity.
Based on its experience and network of connections COMAR will also in the future play an important role in promoting coastal marine research and management.
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The Coastal Systems of East Africa: a Mangrove Ecosystem Case Study
A. K. SEMESI Department of Botany
University of Dar es Salaam P.O. Box 35060
Dar es Salaam, Tanzania
An overview of the coastal systems: the coral reefs, seagrass beds, and the mangroves in the East Africa Region is presented. The mangrove ecosystem is treated in detail. To illustrate the problems and issues on mangroves the findings of a survey carried out in selected areas in Tanzania is used. Recommendations on appropriate management of the mangrove ecosystem are also presented.
The issues addressed in the paper are: conservation values of the man grove ecosystem for protection of coral reefs, reduction of coastal erosion; and mangroves as a source of plant and animal genetic stock. Interdependence of the mangrove ecosystem on both inland and marine environments; and the need of raising public awareness. The close relationship between the mangroves and human communities is recognized as the need to control commercial exploitation for poles and salt production. The value of clearly defined mangrove management zones with different uses and management strategies is empha-sized.
A major problem of coastal ecosystem management in the East Africa Region is lack of data or written reports. There is also a lack of indigenous expertise.
Aerial photographs were used to assess mangrove status in Tanzania. Discussion with many individuals and institutions gave rise to the recommendations presented here.
In order to overcome some of the problems, efforts are being made to raise the state of knowledge on coastal systems by instituting regional programmes which would work on such issues as planning feasibility studies, running seminars and workshops, project coordination, training, collaboration, inter- calibration exercises etc.
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The 1989 Alaska Oil Spill : Ecological and Social Consequences
D.G. SHAW Institute of Marine Science
University of Alaska Fairbanks, Alaska 99775-1080, U.SA.
Major oil spills, such as the release of 40,000 tons of crude oil into prince William Sound, Alaska by the tankship Exxon Valdez in March 1989, account for a small faction of the total anthropogenic input of petroleum to the marine environment. Yet major spills can result in significant acute impacts, can trigger ecological changes requiring decades for recovery and can command considerable public attention. Thus catastrophic oil spills in general and the 1989 Alaska spill in particular differ from other chronic human alterations of coastal marine systems. These differences include both ecological consequences and popular human perceptions of the significance of the impact. This paper will describe some of the ecological consequences of the 1989 Alaska oil spill in the context of the physicial and biological setting in which this spill occurred and consider how the setting influenced those consequences. The paper will also examine immediate and longer term popular responses to this spill.
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Temperate Coastal Systems in Latin America
J. STUARDO University of Concepcidn
Concepcidn - Chile
Temperate coastal systems in Latin America have traditionally been studied following the main tendencies of the international research. Thus, descriptive faunistic/botanical approaches and reports characterized the first European expeditions of discovery and knowledge from the XVI century to the middle of the present century influencing the local development of marine biology, followed by ecological surveys of the intertidal during the fifties through the seventies, the discipline oriented and autoecological studies prevailing up today (e.g. bottom communities and resource oriented studies) and lately, the ecosystem approach and environmentally oriented studies of the last decades. Instances of these studies have been analyzed in relation to marine biogeography and are briefly reconsidered in the light of JGOFS new concept of biogeochemical provinces.
Projecting the role of the international organizations and satisfied the initial efforts to enhance development through individual training and education, a new order of international assistance was established, searching to indentify:
a) common characteristics and goals for research and training at the sub- continental and regional level
b) common aims for development of the various countries; c) national administrative facilities for the scientific and technological
organization and international cooperation. COMAR-COSALC ap- peared as a result of these aims while two other necessities echoed in Latin America the overall world needs of understanding, cooper- ation and interaction;
d) favoring directionality of actions towards environmental and de- velopmental problems; and
e) organization of research serving a holistic-systemic approach to the terrestrial, aquatic and atmospheric problems determining develop- ment and conservation.
Following the first meeting of COMAR-COSALC at Caracas (1982), and an ensuing one at Montevideo (1986), it was recognized that aside form the need of studying processes and problems priorized for the major coastal systems, the following ones were identified for the temperate and cold parts of South America:
A. Transient or seasonal (periodic) ecosystems. 1. Climatic or blooming (e.g. of short-term effects: red tides; of long-term effects: El Niito)
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B. Permanent ecosystems. 2. Rocky shores. 3. Sandy shores. 4. Upwelling. 5. Estuaries and coastal lagoons 6. Saltmarshes and wetlands. 7. Fjords and archipel zone of estuarine type.
The study of long term climatic effects upon the coastal environments such as El Nifio, have marked many of the national and international research activities of the last two decades in the South Eastern Pacific and they are well represented in studies carried out both in Peru and Chile, although in the latter these phenomena do not seem to affect the waters south of Coquimbo. Red tides, on the other hand, have been periodically recorded in central Chile and in Argentina, but particularly in the archipelagos of southern Chile and around the Magellan Strait. The input of freshwater into the coastal system and the increase of pollution (and eutrophication) seem to be directly related to these events. No research project is carried out or has been proposed under the sponsorship of COMAR-COSALC.
Intertidal ecology of rocky shores being largely developed in temperate areas has interested research groups mainly in Chile and Argentina since the early sixties and, recently, some proposals have been made to COMAR- COSALC to carry out cooperative work among neighbouring countries. In Chile, however, and to some extent in Argentina, these studies have a strong interest in relation to the exploitation of invertebrates and algae of economic importance and the impact of man on the ecological balance. Sandy beaches predominate in subtropical areas and have also been studied regarding the autoecology of some bivalves of economic importance, particularly in Chile, north of Argentina, Uruguay and southern Brasil.
Equally important for the understanding of fisheries, recruitment, general productivity and the oceanographic dynamic processes along the coasts of Chile and Peru are the phenomena of upwelling. Consequently, various govem- mental and private institutions and universities carry out research both of national and international interest and have requested the support of COMAR- COSALC. Estuaries and coastal lagoons (or “lakes”) in the west coast of southern South America and coasts of Patagonia are of minor importance compared to the estuary of Rio de la Plata and coastal lagoons of southern Bras& but of far greater importance is the relationship between increase of latitudinal rainfall and the input of rivers into coastal waters, from central Chile to the south, resulting in outwelling of nutrients, organic matter (also pollutants) and sediments into coastal areas and the formation of fronts with recognized increases of primary and secondary productivity. A strong interest in the combined dynamic and ecological processes involved in this relationship has resulted in present studies by local groups in Chile, Argentina and Brasil, deserving national and inter- national cooperative research.
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The ecology of saltmarshes and wetlands has awakened less interest and scarse research is carried out within the area, often included in the ecology of estuarine and coastal waters.
Finally, the existence of large coastal areas in austral South America physically defined as of “estuarine type”, represent a system of high productivity and planetary projection due to its large potential for the exploitation of fisheries and aquaculture, and as a biosphere reserve still very little polluted and underpopulated. All of this makes it a point of strong interest for present day research in Chile and Argentina.
To favor all these undertakings COMAR-COSALC has appeared as a mean to enhance the subregional capacity for research, promote the coordination of groups facing similar problems, intensify training and skill of young scientists within the subregion, and develop a subregional system of coordination and promotion centered on national committees and an ad-hoc Coordinting Scientific Committee formed by the national coordinators of the five participating countries. An analysis of the subregional capabilities regarding training and research undertook by regional consultants has proposed the development of a few integrated parallel projects, the strengthening of some graduate courses offered by different countries and coordinating workshops for the exchange of experiences, sampling design, inter-calibration techniques, and the like. These proposals are being complemented by a most stimulating outgrowth of institutional activities within each country both as advanced research and advanced training and graduate programmes.
Of particular interest regarding the endowment of national capabilities in environmental sciences is the international university project EULA (for Europe- Latin America). Initially sponsored by the Council of Europe and presently supportedbytheItaliangovernment,itiscenteredonthemanagementof hydric resources (considering the interrelationship of terrestrial, freshwater, estuarine and marine components) as a basis for sustained development. Now started as a pilot project in Chile combining mission oriented research and graduate and technical education it is being proposed to expand to several other Latin American countries.
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Coastal Zone and Mangrove Studies
M. VANNUCCI SZo Paul0 -Brazil
Two aspects will be considered:
1. The reasons why the coastal zone throughout the world is in need of special attention;
2. The level of preparedeness to tackle the problems of the coastal zone.
1. Speaking in terms of zoogeography, oceans unite and lands divide. Coastal zones are more closely related to each other than the land masses that they border. Human population density, with all its consequences, is highest in the coastal zone and along river estuaries and deltas. Coastal zones are often more readily accessible to dwellers of other coastal zones than to inland dwellers. The coastal zone is subject to intensive changes (often degradation) caused by physical (climatic, geophysical, oceanographic) progressive or sudden interference (cyclones etc.) or by the action of the human population Wilding of harbours, industrial estates, airports, cities etc.). All these changes have a profound effect on the productivity of the coastal zone. These effects may be positive, i.e. enhance productivity (ex: coastal silvi-agri-aquaculture) or negative (destruction of the biosphere, pollution etc.). If left undisturbed, the intertidal and infratidal area of the coastal zone are among the most productive of the world (mangroves, sea-grass beds, coral reefs, coastal fisheries, sea-level production of salinity tolerant crops etc.). There are also other reasons why the coastal zone is in need of special attention, important among them is the predicted mean sea level rise. For all these, and other reasons, Unesco has reacted by organizing the COMAR programme that has proved its worth.
2. The state of preparedeness to tackle the problems of the coastal zone varies geographically, geophysically and ecologically. It varies geographically according to the state of affluence or poverty of the bordering countries, of localized acuteness of physical environmental problems; of human population density and similar. It varies geophysically according to topographical, geological, climatological, oceanographical and hydrological conditions. Ecologically, the state of preparedeness to tackle the problems of the coastal zone vary because of the degree which the human impact - for good or bad - has had on the living and non living elements of the coastal zone.
Coordinated efforts to increase awareness, intensify relevant research,
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improve training at all levels and provide continuous monitoring of changes in the environment are under way in different parts of the world to face the problems posed by over-exploitation of natural resources and of pollution and to foster preparedeness to face the threat of mean sea-level rise. At some places where sediment load it great, the mangrove ecosystem may be growing out at sea at a rate sufficient to counterbalance sea level rise.
Focus will be placed on Mangrove ecosystems as an example of fruitful and functional networking. The RMCC network was created by COMAE; it provides exchange of expertise and information among the National Mangrove Committees of the different member countries. Examples are drawn from extreme conditions, as for instance the mangroves of Iriomotejima in Japan or those of the deltas of major rivers, like the Ganga-Brahmaputra system.
Finally conclusions will be drawn on what can be done - or expected - to face the problems posed by sea level rise. Conclusions will also focus on how to evaluate and assess what could or will be lost in different types of coastal areas by the predicted sea level rise, and how to adjust to it.
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Organization of the Benthic Macrofauna populations of the Ebri6 Lagoon (CBte d’Ivoi.re)
S.G. ZABI Laboratoire d’kcologie benthique
Centre de recherches ockanographiques B.P. V18, Abdijan - C6te d ‘Ivoire
Study of the organization of the benthic macrofauna populations of the Ebrie lagoon was performed by using diversity index H and equitability coefficient E both based on the importance value N of the species.
This study shows that the main populations units related to Puchymeluniu uuritu and CorMa trigonu display mean values of diversity index respectively equal for Ho to 2.847 and 2.898 and for H, to 2.598 and 2.772.
Corresponding mean values of coefficient E are respectively for Eo 0.79 and 0.78. It is likely for coefficient E, showing mean values of 0.71 for the P. uuritu population unit and of 0.75 for the C. trigunu population unit.
Relationship of coefficients H, E, and N allowed to define a new equitability coefficient K and to propose another new coefficient C named Organization Capacity. Results obtained permitted to notice that more than 80% of the 40 populations identified in the Ebrie lagoon have C values greater than mean value of C (Co and C& One can therefore state for their good organization capacity.
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Asia and the Pacific: Towards Rehabilitating the Coastal Systems.
The Coastal Environment of the Pacific
Monika T. RAU Zoology Department
South Parks Road Oxford OX1 3PS, UK.
The Pacific Ocean is vast, bordered on the East by Canada, the United States of America and South America, on the South by Antarctica, on the west by Australia and Asia, and on the north by USSR and Japan. It is the biggest ocean on earth. Countries in the Pacific region include: Australia, Cook Islands, Federated States of Micronesia (FSM), Fiji, France, Japan, Kiribati, Nauru, New Zealand, Palau, Papua New Guinea (PNG), Western Samoa, Solomon Islands, Tonga, Tuvalu, USA., and Vanuatu. Of these, Australia, France, Japan, New Zealand and USA, are donor countries, while the rest are developing countries. Excluding the donor countries, the population of the developing countries make up less than 7 million people and 50% of these are in PNG which is also the biggest country in this group. Help in management and conservation of the coastal environment is needed most in these small developing countries.
There are four major types of coastal systems: (1) Coral reefs (2) Seagrass meadows (3) Estuaries (4) Mangroves
Coral reefs and seagrass meadows are found throughout the tropical and subtropical areas of the region. Coral reefs include atolls, barrier reefs, fringe reefs and patch reefs. The form and extent of these reef types depend on their location and geological history. Coral species richness and reef structural diversity is highest in the western Pacific region. The occurrence of seagrass meadows is related to the presence of coral reefs. Seagrass often grows in sheltered lagoons behind reef crests in sandy or coral rubble areas. Both require clear water where sunlight is maximum for optimum growth. Sometimes in sheltered clear water bays, corals and seagrass meadows may be found growing adjacent to mangrove plant communities. Estuaries are found in larger islands such as Australia, Fiji, PNG, Solomon Islands and Vanuatu. Their formations are the result of coastal erosion, mixture of large quantities of freshwater from big rivers, runoff and seawater. Estuarine waters are characterised by high turbidities of the water column
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and lower salinities, in contrast to the open ocean. Mangrove forests occur throughout the region and similar to the coral reefs, species and structural diversity increases from east to west. They are absent on some of the islands in the East (eg. Cook Islands). The largest and most diverse systems occur in the much larger countries like Australia, Fiji, New Caledonia, PNG, Solomon Islands and Vanuatu. They grow best under estuarine conditions and thus are usually found adjacent to estuaries.
The people of the Pacific depend on the coastal resources for their survival. Natural resources from the coastal marine habitat provide their major source of protein and in many cases the only source of income. The shells are used as traditional currencies, and ornaments in many cultures. With the increasing pressure of the exploitation of the resources both on land and sea, the whole coastal region in the area is undergoing changes which will greatly affect people’s lives. Large scale agricultural activity, massive logging operations, relocation of large numbers of people, run off and mineral mining cause an increase in sedimentation rate, erosion, nutrient enrichment, sewage and chemical pollution of the waters. Increased sedimentation and chemical pollution kill coral reefs, seagrass and fishes. Tourism industries along coastal areas are increasingly destroying mangrove areas for construction of roads, houses and hotels. Increased large scale fishing offshore by foreign companies is also having a negative impact on inshore subsistence fisheries.
Natural catastrophies are common and they devastate many areas of the Pacific. For example, the western Pacific experiences the highest number of tropical storms per year (about 68%) than anywhere else in the world. There is an “el nine” cycle which brings severe drought to the area every seven years or so. Ciguatera and red tide outbreaks have increased in the last 20 years. Sea-level change due to the much talked about “green- house effect” will have a serious effect on the small island nations, particularly the atolls and other low islands. A rise in sea level will have a catastrophic effect on water table, vegetation and human settlements on these low islands.
There is thus an increasing need to assess the situation in the region so some control can be instigated. Short and long term research projects should be set up with the cooperation of governments of the region to monitor these changes.
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