Two changes in the oceans that are driven by climate change are surface sea water temperatures and acidity.
Several studies have documented the effects of these two changes on global fisheries. Some of these studies have been summarized by the famous fishery scientist Daniel Pauly in a comprehensive lecture held December 2013 in Los Baños, Laguna.
Dr. Pauly in his lecture presented several graphs based on published papers authored by him and several other colleagues. Aside from climate change, these graphs reflect the global effects of human overexploitation of the fisheries resources.
So we have to focus on unwise use and climate change at the same time.
He gave the following summary of his lecture: “1. Present trends, if extrapolated, suggest that global fisheries catches will decline further, particularly in the tropics; 2. Some of these trends could be reversed if more countries agreed that stock rebuilding (through restrictive quotas and large marine reserves) is crucial; 3. New arrangements will have to emerge faster than previously, because things are deteriorating fast.”
Fisheries scientists have coined a new term, MTC (Mean Temperature of Catch) to describe the warming-induced changes in catch composition of Large Marine Ecosystems (LMEs).
This means that there is a trend of preponderance of warm-adapted species of fish in temperate waters, and near absence of cool-adapted species in tropical waters.
Earlier reports prior to Dr. Pauly’s lecture have documented the decreasing trend of cool-adapted species in tropical countries, and this could include the Philippines, especially the tuna species.
But research, thus far, have not been conducted to document this trend in Philippine waters.
The trend toward acidity of tropical waters has been reported in the Pacific area, but the results have been interpreted as indicating resilience of coral reefs. It is hoped that more research on this topic will soon be done in our coastal areas with reference to fisheries.
The three recommendations of Dr. Pauly should be heeded by our fishery scientists and administrators soon before things become worse.
The second recommendation is particularly urgent. Our country should join other countries to implement certain actions to prevent the deterioration of our fishery stocks. We have done quite a lot on the rebuilding of our fishery stocks in shallow areas, but we need to expand to the deeper parts of our oceans, where many of our food species are found.
It is important that the coverage of our no-take marine protected areas be expanded, to include the deeper areas, of which we have none at the present time. The shallower seas of the country may become devastated by the rising warm temperatures.
It is, therefore, necessary to identify deeper areas for protection. These protected deeper areas could serve as sources of recruits for the shallower seas.
______________________________
Author’s email: [email protected]
