Matthew Kirkley is executive chef and partner at Chicago’s modern seafood restaurant, L20. A long-time supporter of sustainable seafood, Kirkley has been nominated for two James Bear awards and, in 2013, received two Michelin stars. Follow Kirkley and L20 on Twitter at @MattKirkleyL20 and @RestaurantL20. The views expressed herein are his and his alone.

There are a multitude of current threats to our planet’s interconnected ocean systems. Acidification, overfishing, pollution, and temperature increases are but a few major concerns regarding the health of the maritime environment. As the head of a kitchen whose primary focus is seafood, it is my hope that I am able to make positive decisions regarding our procurement of ocean species. In doing so, and by hopefully convincing others to do the same, I hope that I will be able to continue my passion of cooking fish for years to come.

It is a stretch for me to consider my kitchen at L20 to be unerringly sustainable in its practices of buying fish and shellfish from the world’s oceans, as my restaurant is located over 600 miles away from the nearest body of saltwater. Yet, while I cannot completely wash my hands of the damage that human consumption is exacting on our planet’s ocean systems, we do avoid purchasing specific species and sources that we believe to be particularly offensive.

This has two primary benefits. One is that we hope that by purchasing responsibly caught fish, and by paying a premium for that fish, we can set a precedent to encourage such practices through the means of our system of free enterprise. The fact that I will pay more for a fish that is caught responsibly will hopefully fuel the fisherman’s desire to fish in such a manner. Two, and perhaps more importantly, with few exceptions the best quality fish (gastronomically speaking) are obtained through good fishing practices. A line caught, wild Turbot will nearly always be of better flavor and texture than a farmed Turbot from Chilean sea pens. The variety of a wild fish’s diet, as opposed to homogenized fish meal mixed with vitamin compounds, as well as the struggle of wild life for survival as opposed to the controlled environments of a fish farm, account for this.

Fish to Care About

It would be difficult to synopsize the current problems facing our oceans into a few paragraphs. The issues are complex and international in scope: Pollution, acidification, overfishing, trawling. Instead, I hope that it will prove helpful to address a few specific fish — Atlantic farmed salmon, bluefin tuna, Chilean sea bass — that you will not see on our menus due to environmental concern:

1. Atlantic Farmed Salmon

While it seems natural to presume that a farmed animal would be beneficial to the wild stock of a species, there are negative consequences to salmon farming that render it a fish we avoid at L20. It takes 3 pounds of feed, typically derived from small fish lower in the food chain such as a sardine, to create 1 pound of farmed salmon flesh. That we are now clearing out the bottom of the food chain in the wild to farm a predatory species in captivity makes little caloric sense for our planet’s fish stocks. Overcrowded pens of farm salmon create a concentrated level of waste in the waters around the aquaculture, rendering the water toxic to other species. There is the continued concern that genetically modified farmed salmon escape from poorly maintained pens, thus allowing them to mate with wild stocks and diluate the natural gene pool. That is not to say that all farmed salmon should be avoided. An example of exemplary aquaculture practices is the Ora King Salmon of New Zealand.

2. Bluefin Tuna

No fish fetches higher prices than a bluefin tuna, particularly prized in Japan. The Bluefin Tuna is an incredibly beautiful animal, one which can grow to 1,500 pounds in weight and can reach speeds exceeding 45 miles/hour at full swim. It now faces extinction from overfishing, fueled by ever-increasing demand for sashimi grade fish. For tuna, we use Yellowfin (also known as Ahi) Tuna, caught off the island of Hawaii, which maintains a close watch on fishery stocks and has strict bycatch limits in place.

3. Chilean Sea Bass

Marketed as a Chilean Sea Bass, the commercial name is the Patagonian Toothfish, which is a deep water species fished off of the coast of Chile and Argentina in the Southern Ocean. While new regulation has been put in place to stabilize this species’ stock, the toothfish has been heavily overfished, rendering the population numbers still low. A Striped Bass would be a good alternative, as the species enjoys substantial controls in allowed catch.

Now What?

Sustainable seafood is important not just for restaurants but for anyone interested in having a nice piece of tuna 20 years from now. For more information on the topic, I usually recommend four stand-out books, listed below.

If you knew your dinner was endangered, would you still order it? Let us know in the comments below.