This thing called life

This thing called life

The cruel calculus of conservation: the numbers game facing the Western and Central Pacific Fisheries Commission

Tuna aren’t the only animals caught up in the tuna fishery. angrysunbird/Flickr

The WCPFC (Western and Central Pacific Fisheries Commission) is meeting this week in Korea in an attempt to regulate the world’s largest tuna fishery. An earlier attempt in March this year failed to get hundreds of delegates from dozens of countries to agree on how to prevent overfishing and ensure the sustainability of an industry worth $US 5.5 billion last year.

Several island nation members rely entirely on this fishery for their financial viability, and all of them rely on the management of fish stocks to ensure a future for the industry. Nevertheless, the complexity of the task is proving overwhelming. Conservation scientists have not prevailed despite widespread agreement on the need for action.

How complex can it be? The Commission was established in 2004, after six years of negotiations. It comprises members from 25 countries and 8 territories, as well as 11 cooperating non-members, for a total of 44 different political viewpoints.

The commission is responsible for management of a part of the Pacific Ocean that is over 10,000 kilometres across, or almost 20% of the earth’s surface. They manage the fisheries of five species of tuna (albacore, bigeye, bluefin, skipjack and yellowfin), three species of marlin (black, blue and striped) and the swordfish. Each of these species has unique behavioural patterns, feeding grounds, and conservation issues.

In 2011, the tuna catch was 2,244,776 tons, which comprises 79% of the total fish caught in the Pacific Ocean, and 55% of the global tuna catch. Globally, at 4,077,814 tons, the tuna catch was the lowest in 10 years.*

These fish are caught using 10 different kinds of gear or approaches (trap, gillnet, harpoon, longline, pole and line, troll, hook and line, purse seine, recreational and trawl). Of these the purse seine fishery is currently the dominant one, with the number of vessels and effort (traps set) at an all time high. Despite this, last year the purse seine catch was the lowest for 3 years.

The fish targeted by this industry are not the only victims of the fishing industry. By-catch is unavoidable most of the time, and the species that die as a side effect of all this fishing include whales, sharks, dolphins, rays, octopus and squid, turtles, seabirds and other fish.

Five species of sea turtles are affected, three endangered and two critically endangered. Leatherbacks are more likely to be caught by longlines, while the Olive Ridley turtle is taken most often by purse seiners.

Nine species of dolphins and nine species of whales are affected. The three most commonly caught species are spotted dolphins, spinner dolphins, and common dolphins. In 2011, a total of 986 dolphins of those three species were killed by the fishery. On the other hand, some species of dolphins, such as the short-finned pilot whales, have increased in abundance in recent years, possibly because of the decline of their competitor, the spotted dolphin.

Sharks and rays are common by-catch in the tuna fishery. Silky sharks and white-tip sharks are the most affected, but hammerheads, thresher sharks, makos and the enormous whale shark are also impacted. In addition to the six shark species, several species of manta rays and stingrays are commonly caught and killed.

Over 100 species of seabirds fly over the Pacific, many of which rely on prey driven to the surface by schools of tuna or dolphins. Albatrosses and petrels are susceptible to being caught by baited hooks on longlines, because they are adapted to scooping fish up from the ocean’s surface. One study estimates 40 seabird mortalities per million hooks on longline vessels. Many albatross species are endangered, and all of them are affected by the tuna fishery.

I could not figure out how many species of squid or octopus were implicated, although they are commonly found in the fisher’s nets, much less the countless smaller creatures that lie at the bottom of the oceanic foodweb: jellyfish, phytoplankton and zooplankton.

The total number of species affected by the decisions made by the WCPFC is large: hundreds of vertebrates, thousands of invertebrates, and who knows how many plants and algae.

But one of those species is us. The delegates at this week’s meeting have [over 100 papers to read](http://www.wcpfc.int/node/4587, 39 reports from member countries, and dozens of important decisions to make. These decisions affect the economies of nations, the fate of individuals and businesses, and the future of the Pacific Ocean ecosystem.

When we are harvesting limited natural resources such as the ocean’s fish, careful management is the difference between a future for the industry and a complete devastation of our planetary plenty.

We wish the commission the very best of luck, because this is not just a numbers game. It is a cruel calculus, affecting us all.

*The measurements in this paragraph previously read “megatons”, but have been corrected.