Longlining, Overfishing & Atlantic Swordfish

Case Study

Fishermen today have not experienced the catch sizes of their predecessors.

According to many fishermen and merchants, North Atlantic swordfish populations are healthy and existing regulations are sufficient to protect them. But many marine scientists disagree, citing a wealth of scientific data indicating a severe decline in North Atlantic swordfish populations. Other scientists suggest that the total volume of fish in the ocean today is merely a fraction of the biomass that existed a century ago.

Longliners deploy up to 60 miles of baited hooks to catch highly migratory species such as tuna and swordfish. A primary concern of scientists is that the ever-growing fishing effort may now be altering the balance of ancient marine ecosystems that nearly all fisheries and marine life depend upon. With fewer and fewer fish left in the water to reproduce, the future harvest potential is diminished. Diminishing numbers of fish without a corresponding decrease in the fishing effort eventually leads to a population collapse, rendering the fish stock commercially extinct. International regulations discourage fishermen from landing juvenile swordfish.

International regulations discourage fishermen from landing juvenile swordfish.

Today, an international fleet of thousands of longliners fish the world's oceans, landing millions of tons of tuna and swordfish every year. As with bottom trawling, longlining has become so efficient, and the global fleet so large, that it can remove more fish than what the stocks can bear. The U.S. government has closed some territorial waters to longlining, but because billfish and tuna migrate across the open ocean, they are hunted by an international fleet.