Over Fishing

photo M. Noonan

As the human population continues to explode, the demand for food grows with it. Over-fishing by humans is a consequent huge threat to all species in the ocean and has led to widespread migrations by marine mammals in search of remaining fish. It is not that we are saying that all use of fish is wrong. But when humans take too much, the entire ecosystem in each area of the ocean can be seriously disrupted and too little is left for predators like killer whales which also depend on the fish.

Salmon is one extremely popular fish species among commercial and sport fishermen. Every year, the salmon of the Pacific Ocean make "runs" to their freshwater spawning grounds in the Pacific Northwest of North America. Fishermen know the peak times during the year to catch these fish and they have the ability to net huge areas. When this happens, orcas, seals, and sea lions that come to the same areas for the same fish have too little to feed upon.

What Is Being Done

photo M. Noonan

Many fishery enhancement programs have been developed by governments around the world. We ourselves, studied the Canadian program at the Big Qualicum fish hatchery on Vancouver Island. There, and at many other locations, professional aquarists catch adult salmon as they make their way upstream to spawn. They artificially harvest their eggs and sperm and provide artificial habitat fertilization of millions of new fish. The resultant salmon fry are fed and closely monitored for health concerns. Hundreds of millions of baby fish are cared for in this way for years until they are ready to be released back into the streams where they will swim out into the ocean to become adults. They serve to support commercial and sport fisheries. But they also support the salmon-dependant wildlife like killer whales. And some of the fish artificially bred in this way survive the fishing nets and natural predators so that they can return to fresh water streams on their own to spawn a new generation of salmon for the future.

photo M. Noonan

A fairly new alternative is the salmon farm. In this case, salmon are raised to adulthood in enclosures in inland salt-water areas. We inspected salmon farms of this type in a number of locations in British Columbia. 

photo M. Noonan

These farms are growing in popularity, but a number of questions remain about their impact on the environment. For one thing, most farms utilize Atlantic Salmon even though they are located in the Pacific Ocean. When these fish escape (as some inevitably do), the impact they have on the local populations of wild fish is unknown.

For another, there is evidence that certain fish diseases tend to break out in fish farms due to the unusual crowding that necessarily occurs. There is concern that such diseases could spread to wild populations and there is also concern about residual antibiotics (used by farmers to treat their fish) working their way into the human food products. Lastly, the sea bottoms in the areas around these farms often become densely packed with a thick, muddy waste that stems from the concentrated number of Atlantic Salmon enclosed in the farm nets. The concentrated waste often kills bottom-dwelling fish, clams, crabs, and kelp.

What You Can Do

We donít argue that everyone has to stop eating fish in order to avoid over-fishing problems. However, by recognizing where our food comes from, and the potential environmental effects that different food production practices can have, we can do our best to favor food products that have the least detrimental effects on the environment.

We can also work to support legislation that regulates the amount of fish being taken from our oceans. We need to leave enough fish in our oceans for the animals that live there and depend upon them.

Content provided by Canisius College students under the direction of Michael Noonan, PhD.