Marine Resources And The Environment


Back To : The Environment

Coast

Marine Resources

Introduction / Living resources : Fisheries / Mangroves / Corals

Non living resources: Coral sand / Fossil corals / Common salt.

Sources Of Marine Pollution

Protection of the Marine Environment

Proclamation of the Balaclava Marine Park

Proclamation of the Blue Bay Marine Park

Conclusion

Bibliography


Introduction

The marine resources of Mauritius, made up of living and non living resources, are found within its coastal waters and Exclusive Economic Zone (E.E.Z).
The Marine environment consists of the coastal waters, estuaries and the ocean waters including the sea bed and the fauna and flora within those waters.

Living Resources

Fisheries

The fisheries resources exploited by Mauritius are found in the following:-

(1:a) the lagoon and off lagoon areas of Mauritius

(1:b) the lagoon and off lagoon areas of Rodrigues

(1:c) the lagoon area around Agalega

(1:d) the banks areas along the Mauritius-Seychelles ridge, stretching from St Brandon to Saya de Malha and around the Chagos Archipelago.

Fishable areas in square Kilometres are:

Mauritius..............1208

Banks:

St Brandon...........2950

Nazareth..............7625

Saya de Malha....28350

Islands:

Chagos................6830

Rodrigues............1688

Agalega................150

Tromelin................nil

______

Total 48801

Fisheries can be divided into the following categories:

Coastal ( Artisanal ) Fishery

Banks Fishery

Tuna Fishery

Aquaculture

Coastal (Artisanal) Fisheries

Artisanal fishery is carried out inside the lagoon as well as off lagoon, near the outer reefs. Fishermen use pirogues of 6 to 10 metres long built out of wood. They use traditional implements such as hooks and lines, basket traps, large nets, gill nets, canard nets, cast nets and harpoons.

In 1995, there were around 2700 fishermen with 1073 pirogues in operation in Mauritius. 75% of the pirogues are equipped with out board motors, 25% equipped with oars and sails and a mere fraction of the total fitted with inboard motors.

The catch in tonnes from the lagoon and off lagoon in Mauritius has stabilised around 1600 tonnes per year.

Annual Catch in tonnes, Mauritius Island

Year

Catch

1991

1568

1992

1775

1993

1583

1994

1663

1995

1443

1996

1616

In 1996, 997 tonnes came from the lagoon and 619 tonnes were off lagoon catches.

A further 30 tonnes come from Agalega.

Note that in 1977 the total catch was 2120 tonnes and that fell to 1300 tonnes in 1985.

The state of the Environment report 1991 states that the maximum sustainable yield for the island of Mauritius is around 1700 tonnes annually. It is clear that with an actual catch of 1600 tonnes annually, there is little room for errors. Very quickly and unwittingly over-fishing could become a reality, if it isn't already.

Journée mondiale de la pêche Les pêcheurs mauriciens face aux nouveaux défis

Coastal Zones of Rodrigues and Its Lagoon

Efforts are being made to encourage off lagoon fishery in Mauritius by the development of Fish Aggregating Devices (FADs). FADs consist of floating devices anchored at sea that attract migratory pelagic fishes such as tuna ( Thunnus sp.), dolphin fish ( Coryphaena hippurus), wahoo (Acanthocybium solandri) and marlin ( Makaira sp.). In 1995, there were 26 Fads in operation around Mauritius with close to 300 fishermen fishing around the Fads, half of them being actively engaged in this type of fishing.

It is estimated by the Albion Fishing Centre ( Annual Report 1995 ) that an annual catch of 700 tonnes is realistic in the short term.

Banks Fishery

The banks are fishing areas located along the Mauritius-Seychelles ridge. These are the Saya de Malha and Nazareth Banks, the St Brandon group of islands and the Chagos Archipelago. There are 15 boats in operation on the banks and the catch is about 5200 tonnes annually.

90% of the catch from the banks consists of fishes from the Lethrinus species known locally as "Dame Berri" and "Caya". The remaining 10% consists of "Carangues", "Vacoas", "Croissant" and "Vieilles".

The following table illustrates the annual production (in tonnes) by banks for the 1991-1995 period.

Year

Saya de Malha

Nazareth

St Brandon

Chagos

Albatross

Total

1991

1782

793

369

358

161

3463

1992

2835

980

446

317

194

4762

1993

3173

1358

550

195

261

5577

1994

3167

1591

224

307

232

5521

1995

2682

1609

470

218

312

5291

The State of the Environment report 1991 states that the total annual allowable catch on the Saya de Malha bank had been established to be about 1900 tonnes. In view of the above figures it is clear that either some degree of over fishing is going on or that the estimate of the total annual allowable catch should be reviewed.

In fact for the fishing season of September 1995 to August 1996, the total allowable catch ( TAC ) had been set at 4752 tonnes by government and this TAC is set to be reduced by 5% each year till the year 2000 to permit the resources to recuperate ( 1995 Annual report of Albion fisheries research centre).

This alone indicates that over fishing on the banks has occurred and measures must be taken to prevent collapse of the fishing stock in the future.

Tuna Fishery

Tuna is fished in the Indian Ocean by either purse seine or longlines ships. In 1995 the catch unloaded by purse seiners was 7367 tonnes and 14,772 tonnes were transhipped in Mauritius by longliners.

The main fishing ground for purse seiners is the western part of the Indian Ocean form 49 E to 71 E and 9 N to 7 S.

The species composition indicates that around two-thirds of the catch is made up of Skipjacks, 20% by Yellowfins, 10% by Bigeyes and the remainder by other species. Whereas 76% of the catch by longliners transhipped in Mauritius is made up of Albacore ( Thunnus alalunga ).

Longliners come from Taiwan mainly with some from Japan and South Korea. In 1995 there was only one longliner from Mauritius.

Aquaculture

The raising of fish and other marine organisms in coastal waters is carried out in barachois which are coastal areas enclosed by stone walls. In 1995, 24 barachois were operative which produced 44 tonnes of fish.

Marine shrimp culture is also carried out and yielded close to 3 tonnes in 1995.

Mangroves

Mangroves are flowering plants that grow in the inter tidal areas of shores and estuaries. They are found in both Mauritius and Rodrigues and are important to the coastal ecosystems for the following reasons:

(1) Coastal soil erosion is prevented and the effects of waves on the coastline is dampened.

(2) Terrigenous sediments are retained, protecting the lagoon from sedimentation.

(3) Crabs, shrimps and juvenile fishes find habitats and nursery grounds.

(4) Leaves and detritus trapped by roots of the mangrove become food for a number of marine organisms.

The two species of Mangroves found in Mauritius and Rodrigues are Rhizophora mucronata and Bruguera gymnorhiza.

(Mangrove afforestation in Black River district)

Mangrove cover has substantially decreased over the years and the government which has recognised the importance of these plants has initiated a programme of afforestation. From 1992 to 1995, over 33,000 square metres have been replanted with about 9000 mangrove seedlings.

State Of the Marine Environment

Introduction: It is believed that the open seas around Mauritius are relatively clean. The major marine environmental problems arise on the coastal zones due to human activities and natural processes on land and at sea.

The human activities that have impacts on the marine environment are agriculture, industry, infrastructure and hotel development, fishing, coral and sand extraction, dredging, siltation due to deforestation.

Natural processes that have impacts on the marine environment are cyclones and wave action.

The negative impacts of human activities on the marine environment are manifold and can consist of the following: disruption of local ecosystems, deterioration of the water quality, erosion of shores, destruction of coral communities, decreases in fish productivity, pollution of the seas by industrial effluents, sewage and agricultural run off, sedimentation.

These negative impacts are visible in Mauritius today to varying degrees of magnitude. In this section we shall attempt to describe those impacts. The reader should bear in mind that in most cases the information at hand is sketchy or in some cases extremely controversial.

Sources of Marine Pollution in the Lagoon

Measures Taken for the protection of the Marine environment

Over the years a number of measures have been taken to protect marine ecosystems.

These include:

  1. The interdiction of the removal and sale of corals and shells.
  2. The interdiction of underwater spear fishing.
  3. A closed season for net fishing.
  4. A minimum size mesh for nets.
  5. The interdiction of the use of dynamite for fishing.
  6. A national coast guard and fisheries protection service for the surveillance and protection of coastal zones.
  1. The Legal Framework for the Protection of Maritime Zones

Conclusion

Coastal marine resources are very important for the local economy. By all accounts the maximum sustainable yield for artisanal fishery, bank fishery have been reached or even surpassed. There is an urgent need for proper and rational management of these resources in order to achieve sustainable development.

It is very important to realise that ultimately the lagoon is the sink for a number of land based activities. Pollutants and waste arising far inland can have dramatic effects on the health of the lagoon.

Hence the management of marine resources cannot be done in isolation from inland activities. Especially for such a small country like Mauritius.

In short, the environment must be managed with a country wide perspective in mind.


Bibliography

  1. Government of Mauritius, State of the Environment Report 1991
  2. Albion Fisheries Research Centre, Annual Report 1995



  1. Date on the Web: 10th of February 1998

Last Update: 2nd of November 1998