For many years we have been hearing about the plight of the fishing industry. The data on current fish populations remains dismal. In fact predictions of a complete collapse of fishing stocks by mid-century have been made by several observers. It is clear that for many species their populations have been totally exploited.
There are a number of reasons for this. For one thing there is an increasing human population which is consuming more fish. In some cases this is for health reasons while in others it may be a matter of convenience and cost. At any rate some groundfish species like cod and haddock have become scarce. Some fishing techniques such as the use of bottom trawling have greatly reduced their numbers, not to mention the damage inflicted on the benthic environment.
With a major loss of some species comes a shift in the food web of an ecosystem. Other organisms that are directly or indirectly dependent on the declining species are also affected. Some other populations may increase only to be exploited and harmed as bycatch or those that are inadvertently caught, but not taken, and are thrown back into the sea. Most of the bycatch does not survive. Controls on bycatch vary depending on the fishing technique employed.
Ecologists refer to these situations as exceeding the carrying capacity of the environment or the taking more than the maximum sustainable yield of a species. Unless catch limits are imposed, a fish population can easily be eliminated from one of the fishing areas. Our history with exploited species on land is replete with examples of sharply reducing an animal’s population or actually sending it into extinction. We are now seeing a similar scenario in the ocean.
However, it is not a hopeless situation. We know that periodic closures of some areas to fishing allow many of the populations to reproduce and recover in a relatively short period of time. Consumers can also have a big impact by choosing to eat the fish that are more abundant. Increased support and research in aquaculture may help sustain some widely exploited species. Aquaculture is increasing in the United States but has a long way to go before it reaches the levels seen elsewhere such as China.
We are basically witnessing another example in our troubled history of too much demand on a limited resource. Even those who depend on fish populations to make a living recognize that something must be done to sustain a viable and economically important industry. I think we will be struggling with these issues for many years until there is a collapse in the resource or a widespread solution to the problem.
Copyright Gil Newton 2009 Thanks to Chris Dumas for logo image.