Environmental Science: Paul Greenberg: The four fish we're overeating -- and what to eat instead

Discussion Forum and Opinion on video:

Paul Greenberg: The four fish we're overeating -- and what to eat instead

Summary:

He discusses how we have moved from eating a multitude of animal species to only a few (four in fishing: salmon, cod, tuna, and shrimp). This trend has happened predominantly in the last 50 years. He also mentions how “we are currently taking between 80 and 90 million metric tons” (Greenberg, 2015) out of the sea every year and that with the advent of fish farming and aquaculture we are taking the equivalent of two of the human weight of China out of the seas every year.

In regards to the four species-shrimp, tuna, cod, and salmon-he starts out discussing shrimp. Between 5 and “15 pounds of wild fish are regularly killed to bring one pound of shrimp to the market and dragging for shrimp is one of the most carbon-intensive ways of fishing that you can find” (Greenberg, 2015). The shrimp’s natural habitat is also in mangrove forests, which is getting destroyed at an alarming rate, so there is an issue of ‘farming’ shrimp in habitats that are not natural.

Tuna is next on his list. Because Tuna is a global fish and current laws are limited to specific localities, as soon as the fish moves out of the area, the laws stop applying. So there is a law issue. In regards to farming them… “Tuna are warm-blooded. They can heat their bodies 20 degrees above ambient temperature and they can swim at over 40 miles an hour” (Greenberg, 2015). This makes keeping them in a pen problematic.

Salmon, which must swim up rivers to spawn, are one of the most widely caught and eaten fish in America. However, the U.S. has dammed up so many rivers that the fish are unable to get to their spawning grounds. Salmon is very good at being farmed though, with current numbers showing that we close to or below 2 lbs of fish feed to produce 1 lb of salmon, however, the feed is made up of ground fish (the trash fish caught in the shrimp nets in some instances) and ground chicken bi-products (blood, feathers, bones, etc). Here’s the kick, fish and pigs are also getting fed ground fish pellets, so you may have a fish that eats a chicken that’s eaten a fish. A bit strange. Still, that’s money going to grinding up fish that could be eaten just the way it is. Mr. Greenberg mentions that it’s “something between 20 and 30 million metric tons of wild creatures that are taken from the ocean and used and ground up” to make the pellets to feed the fish/chickens.

Lastly is cod, or ‘whitefish’, which also includes fish like halibut and Alaskan Pollock. Pollock is “the largest fin fish fishery in the United States, 2 to 3 billion pounds of fish taken out of the sea every single year.” After Pollock is Tilapia, which is a super energy efficient fish that many in developing nations use as it can go from an egg to an adult in nine months, it can be raised is less than ideal conditions and handles heat very well.

Greenberg ends the presentation by offering several possible solutions to the over fishing issue. Instead of eating shrimp and feeding the smaller ‘trash’ fish to salmon, why don’t we just eat the clupeids (the small fish that are the primary source of the fish feed [20 to 30 million metric tons])? According to Greenburg, “they are tremendously fuel efficient to bring to market, a fraction of the fuel cost of say, shrimp, and at the very top of the carbon efficiency scale. They also are omega-3 rich, a great source for EPA and DHA” (Greenberg, 2015). He also mentions mussels, seaweed, and a futuristic thought experiment of a vegetarian lab-created fish.

Opinion:

Cuttlefish for sale.

I think we are spoiled when it comes to seafood. I’ve lived in Asian communities where I was a little bit disturbed by what they had for sale and were eating and have had to ask what several species were in more than one store. We only want the best and that leads to inflated prices and demand that is destroying our supplies at a rate the planet cannot cope with. I do not think it’s simply an American issue, but a global issue and I don’t see it going away. I think farm raised fish like tilapia are a good idea, because the fish naturally congregate in areas like the pens and containers they are farmed in, so there is no undo stress or problems associated with farming to the fish. However, I think we need to put stricter laws on what types of fish should be farmed and what types of fish can be caught wild. We are allowing smaller juvenile fish to be caught wildly than ever before and that does nothing to help the species grow. Sustainable fisheries are a good alternative, but until everyone agrees to stop harmful wild fishing practices or changes up what types of fish are caught, bred, or served, nothing will change.

Personally, I’ve looked into backyard fish farming. Tilapia are a great backyard fish and can be grown in a smaller space. We also do not eat wild caught shrimp anymore and I try to only purchase farm raised or non-standard fish like monkfish and mullet.

References

Greenberg, P. (2015, October). The four fish we're overeating -- and what to eat instead. Retrieved October 1, 2016, from https://www.ted.com/talks/paul_greenberg_the_four_fish_we_re_overeating_and_what_to_eat_instead/transcript?language=en#t-211180