Bycatch, The Unwanted Victims

Bycatch, The Unwanted Victims

Did you know every year at least 7.3 million tons of marine life are caught incidentally during fishing practices?  Most fisheries have target species for capture; and unfortunately, other animals that are not the target end up becoming hooked or trapped from unavoidable entanglement or capture in the fishing gear being used.  The term for this incidental capture and often mortality of non-target species is bycatch.

Bycatch is a threat to marine biodiversity worldwide and includes more species of animals than you may think.  Bycatch can be fish, sea turtles, seabirds, marine mammals, and even immobile animals such as corals and sponges.

With any issue, there will always be multiple viewpoints and sides taken.  Some sides think that bycatch is an acceptable consequence of supplying the world with wild-caught seafood.  However, quite often the scale of mortality in bycatch is so high that it threatens the survival of species and their environments which in turn can cause a fishery to eventually collapse. Fishermen do not like bycatch for many reasons as well.  Having to haul bycatch not only wastes their time but also can damage their gear.

Less selective fishing gear like gillnets, longlines, and bottom trawls are most commonly associated with bycatch.  Thousands of miles of net are set in the world’s oceans each day; and when longlines and gillnets are cast out, they can attract or entangle anything that happens to swim by the net.  The improvement in modern fishing gear has only made bycatch matters worse because the gear is often undetectable by sight and very durable.

Leaders in the fishing industry do realize there is a need to reduce bycatch and solutions for at least reducing these numbers do exist.  A well-known example is the turtle excluding device (TED) that was developed to allow captured sea turtles in bottom trawling nets to escape. Another example is from a recent study by researchers at the University of Exeter where they found that illuminating fishing nets with attached green battery powered LEDs reduced seabird death tolls by 85%, specifically looking at guanay cormorants in Peru.

Although these affordable and simple solutions for reducing bycatch have been implemented, bycatch continues to be a major problem.  Reducing the numbers is at least a step in the right direction, but long-term solutions such as a global shift to environmentally sustainable re-circulating aquaculture systems is a way to avoid bycatch altogether.

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