There’s More Than One Way To Catch A Fish: Why That Matters

Many consumers want to know where their food comes from and how it might align with their own ideals in terms of sustainability and environmental protection. When it comes to the harvest of food from the oceans there are international and national regulatory systems in place to prevent over-fishing and those are becoming even more sophisticated with tools such as sonar for population assessments, and DNA-based tracking of specific sub-species populations called stocks.

For fish that are “wild-caught” as opposed to farmed there are issues to consider when it comes to exactly how the fish are harvested. A particularly important question is whether the fishing method results in the unintended capture of other sea life – the term for this in the industry is “bycatch.” That might include an abundant fish species that isn’t desirable to humans and those are typically just dumped back into the ocean. In some cases it could include some rarer, highly desirable kind of fish that would be saved to command a premium price. Unfortunately, the bycatch might include sharks, turtles, or other beneficial species.

There are two common fishing methods that tend to result in a considerable amount of bycatch. One method (pictured above) is called “purse seine” in which something called a Fish Aggregation Device or FAD
FAD
is placed in the water to attract a school of the target fish species, but also others. Once such an aggregation occurs, a boat circles around it laying out the net (1); the net is then drawn in to crowd the fish near the boat (2) and then the fish are scooped out of the water and brought on board. In this process the bycatch includes some of the target species that are too small and large predators that are also attracted to the school.

There is another fishing method called “long-line” (pictured above). In that case a primary line with floats that can be as long as 20-30 miles with is laid out in the open ocean with baited side-lines. This method isn’t fully selective and typically results in between 8 and 20 percent bycatch of non-target species.

Some fishing vessels have mandatory observers that document the harvest and record bycatch data, but more commonly for purse seine vessels the bycatch is dumped before the intended catch is transferred to another boat which then takes it to a cannery.

There is a company called Wild Planet that has built its tuna brand around sourcing fish in a way that leads to very little by-catch. It’s founder, Bill Carvalho, was already in the seafood industry when he visited the Monterey Bay Aquarium in 2001 and saw an exhibit that characterized the oceans as being at a breaking point. This made such an impression on him that he decided that he wanted to take his company in a new direction which would minimize disruption of the marine environment, and which would protect ocean resources for generations to come. To do this they sought out “artisanal” fishermen who use the “pole and line” method of fishing.

For this method of fishing the boat goes to a location where the tuna are running and throws overboard a load of live anchovies. The tuna perceive that activity as a swarm of one of their favorite foods and come there to feed. A crew of fishermen on the boat using poles with lures on a short line land the individual tuna one at a time. This is a very selective method and out of a years’ worth of catch (13-15,000 fish) may only hook 4 to 5 individuals of non-target species.

Wild Planet specializes in Albacore and Skipjack tuna which are caught by small-scale fishermen in the North Pacific Ocean, South Pacific Ocean, Central Pacific Ocean, and Indian Ocean. By using sustainable methods, they are catching juvenile migratory fish that are from 3 to 5 years old, weighing 9 to 25 pounds as opposed to the fish caught with the longline system which typically catches 6- to 12-year-old fish weighing 30-70 pounds. There are two advantages of focusing on younger fish. One has to do with flavor, and this is something that many consumers notice. That characteristic along with the responsible fishing feature is apparently what drove the decision by Costco to start carrying the brand in 2010.

The other advantage of the 3 to 5-year-old fish has to do with methyl-mercury which is something that a “top predator” like tuna can bio-accumulate over time. Mercury isn’t as much of an issue for tuna as it is for some other species, but the FDA set a recommend “action level” safety threshold of 1.0 ppm. The average US albacore market mercury level is 0.358 ppm, about three times lower than the FDA action level. Wild Planet’s tests average 0.17ppm or about two times lower than the US category average and six times lower than FDA action level.

Conclusions

Ocean-based food production continues to make a significant contribution to global food security, particularly as a source of protein. Fisheries management is important to the sustainability of the sector, but it is also important to mitigate collateral impacts such as “bycatch.” Wild Planet has demonstrated that retailers and consumers are receptive to a message about responsible sourcing based on a fishing method that reduces impacts on desirable species. That is particularly true when that is paired with flavor quality.