The search for sustainable development strategies as applied to biological resources has been going on for some time without convincing many people that such strategies are effective. In fact, many people seem to have concluded there is no such thing as sustainable development of biological resources.
Some argue that such resources are bound to degrade over time as a result of human use due to the operation of natural laws such as those of thermodynamics and nutrient cycling.
To be sure, there is some truth in this view. But I think it is overly pessimistic, and it underestimates the ability of people to innovate practices that approximate the workings of the natural world, as described in scientific studies.
Natural science tells us that energy (ultimately coming from the sun) is consumed, and that the laws of thermodynamics, which states that the greater part of energy is lost every time it is transferred from one trophic level to another, limit natural productivity.
We cannot do anything about this fact. But natural science also tells us that nutrient materials are recycled, and we can direct the cycling of nutrients in ecosystems to attain the desired production efficiency.
The latter principle is the basis for sustainable use of resources implied in the Wetlands Convention statement of “wise use of wetland resources.”
Wise or sustainable use implies production of goods for human use in an ecosystem that is maintained in a stable condition and does not degrade or lose its ecological functions.
The question is: Are there examples to show that human communities benefit from the production of goods by ecosystems that have remained stable and functional over decades of time as a result of protective management?
To answer this question, I describe here a couple of natural experiments we have performed on two small islands of the country. The first example is a small island of Sumilon off the southern tip of Cebu, where we had a 10-year natural experiment in 1974 to 1984.
The reef was zoned into two parts: about 25 percent of the coral reef of this island was made a no-take marine reserve, where no fishing was allowed, and 75 percent was reserved for fishers as their fishing ground with strict protection from destructive fishing methods.
Beginning in 1976, the fish yield from traps set in the fished 75 percent of the reef area was monitored. This showed a steady increasing annual trend in fish catch from about 9.7 tons in 1976 to 16.8 tons in 1983-84.
In 1985, a politician violated the no-take reserve by illegally fishing the reserve. The fish yield in the fished zone declined to 11.2 tons in 1985-86, showing that the increasing trend in fish catch in 1976-1984 was most likely due to spillover from the no-take reserve to the fished area.
The second example is Apo Island off southern Negros Oriental. On that island, the coral environment was (and is until now) strictly protected. But close to 15 percent of reef area is a no-take marine reserve, and 85 percent is fished area for local residents.
Since 1981, four studies on the fish catch from the fished area showed a steady, sustained catch of 15 tons every year. The fish biomass in the no-take reserve increased from ca 20 tons to 150 tons per km2 during the 20 year period from 1982 to 2002.
Studies on corals indicated a healthy marine environment except in 1998 when the El Niño reduced the live coral cover. But the reef recovered after the bleaching event to more than 60 percent live coral cover.
Of the sustained fish catch of at least 15 tons every year, about 10 percent or 1.5 tons spilled over from the no-take marine reserve, based on research findings.
Thus, sustained and stable fish catch and environmental stability resulted from the zoning of the reef into the protected no-take zone, and the fished zone and from the good management by the local community of Apo Island.
The two examples, which are replicable in other coastal ecosystems, show that sustainable use of biological resources is possible.