Numerous studies have been conducted in order to find out the effects of overfishing in the aquatic ecosystem. The Philippines, known as “the center of the center of marine shore fish biodiversity” is not spared from the adverse effects of overfishing.

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Aside from affecting populations of target species, overfishing alters the dynamics and processes of the aquatic ecosystem. The decline of shallow coastal water resources leads to the exploration of deeper waters. Fishing deeper means fishing for increasingly longer-lived and thus, more vulnerable species since they have little resilience to overexploitation. Such practice began in the late 1960s and can be observed until now.

Pauly, et al. (1998)¹ documented the estimates of trophic levels for 220 different species or groups of fish and invertebrates covering all statistical categories included in the official Food and Agricultural Organization (FAO) landings statistics. Trophic level refers to the feeding position of a species in the food web (i.e., producers and consumers). Changes in the trophic level can potentially affect energy flow and nutrient cycle in an ecosystem.

The study shows that exploitation of the ocean has gradually led to a shift in the fisheries sector. In the past, high trophic level and piscivorous (fish-eating) fish were caught in high numbers. However, at present, the more dominant species are low trophic level invertebrates and planktivorous pelagic fish.

This is a challenge for conservationists because deeper waters also serve as the last refuge of coastal stocks. If overfishing continues, the bottom part of the ocean will also be exploited. Conclusively, the authors believe that fisheries management should focus on rebuilding fish populations especially in marine protected areas.

In the Philippines, Alava and Cantos (2004)² said that species conservation goes hand in hand with habitat protection. They also noted that the implementation of conservation programs in the country is usually hampered by budget constraints and constant shift in priorities brought about by changing political leadership. Thus, an integrated approach in conservation must involve not only government agencies but also other stakeholders including NGOs, academe, people’s organizations and the local community.

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¹ Pauly, D. et al. 1998. Fishing down marine food webs. pp. 860-863. In Science 279.

² Alava, M.N.R. and J.A.B. Cantos. 2004. Marine protected species in the Philippines, p. 109-117. In DA-BFAR (Department of Agriculture-Bureau of Fisheries and Aquatic Resources). In turbulent seas: The status of Philippine marine fisheries. Coastal Resource Management Project, Cebu City, Philippines. 378 p.