It is admitted that biodiversity baselines have shifted to lower values. It is very clear for species used as food such as fish.
Fishery scientists like Daniel Pauly of the University of British Columbia stated that fisheries have declined worldwide, and now strongly suggests protection of fishery stocks.
Not only fisheries species, but also marine species in food chains leading to the production of fishery species have declined.
The phenomenon has been labeled “shifting baselines” and is also applicable to terrestrial biodiversity.
Baselines are important because they serve as starting points in assessing success of conservation projects.
The question is, by how much has Philippine marine biodiversity declined during the past 100 years? To answer this question, we have to go back to past records of surveys on Philippine marine resources 100 years ago.
But there are no such records. The quantitative survey methods that are used to determine standing stocks of tropical marine organisms were developed only in the mid-1980s.
The earliest recorded quantitative estimates of coral reef fish biomass were made in the 1950s to 1970s, all in places outside the Philippines. They are not so useful for our purpose, although they serve as indications of the variations of reef fish biomass worldwide as they are based on the sites on reefs and the geographical location of these sites.
The variations are so large (10-200 tons per square kilometer), they probably do not reflect the actual past situations in the Philippines.
To have an idea of how much fish existed in the majority (67 percent) of Philippine coral reefs 100 years ago, let us take the example of Tubbataha reefs. Records of target (food) fish biomass in the late 1990s indicated about 80 tons per square kilometer.
Some records of 200 tons per square kilometer have been reported later. Coral reefs protected from fishing for more than 20 years in southern Philippines under our research program show fish biomasses of 120-150 tons per square kilometer.
Thus, we postulate that most reefs 100 years ago had fish biomasses exceeding 100 tons per square kilometer.
Compare this figure with what we have found in many coastal areas of southern Philippines — five to 15 tons per square kilometer, about 5 to 10 percent of what it used to be 100 years ago!
This is the reason why more of our coral reefs should be converted into no-take marine reserves as recommended urgently by many marine biologists.
For coral reefs, the initiative pioneered by Dr. Ed Gomez in the 1970s established the fact that the baseline for that period is only about 5 to 10 percent of coral reefs in the country had a live coral cover of at least 60 percent.
The question is what was the live coral cover 100 years ago? To answer this question, let us consider areas less frequented by people — the Spratlys in the West Philippine Sea.
In 2005-2007, the Department of Foreign Affairs, through the initiative of Ambassador Alberto Encomienda, sspearheaded the survey of the coral reefs in the Spratlys.
Some reefs had low live coral cover of 20 percent but the majority had high coral cover of 90 to 100 percent.
It might be inferred that if two-thirds (67 percent) of the coral reefs in a particular area have high coral cover, this could be the status of Philippine coral reefs 100 years ago.
Compare this percentage with that existing today (five to 10 percent), and one will conclude that indeed, the baseline has retreated substantially.
It is clear that the baselines for our coral reefs have shifted downwards, threatening the sustainability of these resources. We must act now to conserve these resources.