Basic Concepts in Environment, Agriculture and Natural Resources Management: An Information Kit (IIRR, 1993, 151 p.): Freshwater and marine ecosystems: Philippine marine fisheries

Basic Concepts in Environment, Agriculture and Natural Resources Management: An Information Kit (IIRR, 1993, 151 p.)

Introduction

Use of workshop

Workshop participants

Support staff

Glossary of commonly used environmental terms

List of references

Ecological basics

Ecosystem degradation

Habitat and niche

The food chain

Biological magnification

Nitrogen cycle

Society and the carbon-oxygen cycle

Health consequences of environmental degradation

Population and the environment

Freshwater and marine ecosystems

Freshwater ecosystems

Estuarine-mudflat ecosystems

Seagrass ecosystems

Mangrove ecosystems

Coral reef ecosystems

Human intrusions into the water cycle

Diversity of coastal and marine resources

Philippine marine fisheries

Marine turtles

Marine food web

Ocean pastures

The menace of algal bloom

Red tide (Dynamics and public health aspects)

Forest ecosystems

Tropical forest -ecosystems

Protected areas: a tool for biological diversity conservation

Environmental effects of overexploitation for fuelwood in nearshore coastal resources

Biological diversity: and wildlife conservation

Wildlife trade

Global warming and acid rain

Climate change and the greenhouse effect

How deforestation contributes to the greenhouse effect

Acid rain

Pollution

Toxic and hazardous wastes

Pollution and long-term effects on the human body

Urban pollution: The metro Manila environment

Mining operations: environmental effects on soil, water, communities and atmosphere

Pesticides: environmental and health effects

Others

Philippine commercial energy sources, 1990

Common property resources in crisis

Degradation of the uplands

Lowland degradation

Environmental issues in animal production

Plant genetic resources

Natural hazards

Philippine marine fisheries

Major source of livelihood and food

Broadly, marine fishery pertains to the harvesting of the wild populations of marine animals. Philippine waters abound with a variety of marine organisms that are utilized for food and other industries (e.g., marine natural products, shellcraft). Because the country is an archipelago, marine fisheries are the primary source of livelihood in coastal areas. Moreover, fish and shellfish are major sources of protein in the diet of Filipinos. The most commercially important marine animals are: fish, molluscs (e.g., marine snails, mussels, squids); crustaceans (e.g., crabs, lobsters, shrimps) and echinoderms (e.g., sea urchins, sea cucumbers).

Nearshore waters

As in other parts of the world, the major fisheries in the Philippines are concentrated in waters overlying the continental shelf (shallow underwater extension of a continent; usually limited in depth to 200 m). This is because inshore waters have a much higher primary productivity than deep open-ocean waters and, therefore, support larger populations of marine organisms at all trophic levels. Of the total landed fish in the country (approximately 2m tons in 1987), 25 percept come from coral reefs (27,000 km² - total area nationwide) alone. It is estimated that a coral reef in a good condition can annually yield as much as 30 m tons of fish per km². Aside from fish, a majority of benthic (bottom-dwelling) marine invertebrates are harvested from coral reef and adjacent seagrass areas. A wide range of fishing gears are used to harvest the diverse marine resources in these productive and diverse ecosystems.

Declining marine populations and degraded habitats

There has to be a limit to the harvesting of natural populations. A significant fraction of the populations must be left as breeding stocks to replenish the population. Subsequently, juveniles must be allowed to grow to reproductive maturity. Otherwise, natural populations will progressively diminish and may become extinct.

There are clear signs that many of the Philippines' fishery resources are already overexploited. The average size of fish and invertebrates caught by fishermen has declined. Likewise, there is an increase in the fishing effort needed to catch the same amount of fish. The pressure of increased demand for food and poverty due to the rapidly increasing human population promotes the over exploitation of marine resources. Moreover, the degradation of marine habitats due to destructive fishing methods (e.g., blast and cyanide fishing) and sedimentation, particularly in near shore waters, has accelerated the decline of marine fisheries. Appropriate management measures that will allow our overexploited marine populations and degraded habitats to recover need to be urgently implemented.