A Conversation With Demian Willette

Demian Willette, a biology instructor in the Frank R. Seaver College of Science and Engineering, does research that applies genetic testing to the problems of illegal fishing and species substitution — claiming a fish being supplied is one species but substituting another in its place. This past semester, he was named a Fulbright Global Scholar and will teach and conduct research during the next two summers on identifying fish caught near Thailand, Ecuador and the Philippines. By using a testing technique called Environmental DNA, Willette hopes to improve the identification and traceability of fish in the food supply chain that begins on fishing vessels and ends on restaurant tables in Los Angeles. Editor Joseph Wakelee-Lynch spoke with Willette about his research and his plans for future studies..

How does species substitution occur?
At the consumer end of the supply chain, there is intentional substitution — switching a less valuable fish for a more valuable one: You buy bluefin tuna but it ends up being skipjack tuna, a less valuable tuna, or albacore tuna, which is more abundant. That switching can also be accidental. At the other end of the supply chain, things are being swapped through labeling on the box: The label on the fish is different from what’s actually being delivered. Traceability is very difficult. These fish are caught in the ocean, they can move from boat to boat before they get to the port. In this supply chain, the paperwork and invoices can be lost.

How significant are the economic costs of species substitution?
It’s called illegal, unreported and unregulated fishing — IUU fishing — and its estimated cost to the fishing industry is $10 billion to $23 billion a year.

Is there a way to define illegal fishing?
Illegal, unreported and unregulated (IUU) fishing includes a broad range of concerns, including poaching and unlawfully taking fish to circumvent management or conservation regulations; misreporting fish by species, size or origin; and even human trafficking and slavery.

What questions arise about sustainability and illegal fishing?
One question, for example, is: Are there regulations to ensure that you are harvesting fish from the ocean in a sustainable way. In the United States, our fisheries are very well regulated. Most of the fish catch in U.S. waters is within what is known as maximum sustainable yield — a level at which the ocean can optimally replenish itself in terms of fish populations. Harmful fishing is when you’re fishing at high yields: The fish population drops to low levels and isn’t able to recover.

How will your research in Thailand, the Philippines and Ecuador illuminate traceability?

The goal is to use DNA barcoding. Environmental DNA relies on the fact that living organisms slough off skin cells, for example, as they move through an environment. Fish moving through the ocean are losing their scales. Their DNA can last from one to six days. For that period of time, you can get an idea of what is passing through the environment. So, you scoop up water and filter it, and then extract DNA from the materials you accumulated and match it to a database of fish. I’m curious about what fisherman say they are landing — what they’re off-loading at port — and what fish are being caught. Most countries have regulations saying that when fishermen come to port, they must declare what they’re landing. Realistically it’s hard to count all the fish. My plan is to jump into the bottom of a boat after its fish have been off-loaded, scoop up some of the slime at the bottom that contains DNA that has been shed, and test that to assess what was caught.

What is the benefit of knowing that?
You can keep tabs on what’s being caught, and on whether the fishermen are adhering to quotas. Most countries have regulations about how many tuna you can catch, for example. Additionally, most countries have regulations about “by-catch,” unintended things that are caught and how much by-catch is acceptable. Typically, if you’re using best practices, you’re reducing the amount of by-catch. If you’re catching a bunch of sea turtles and throwing them out before coming to port, using this Environmental DNA method would give us evidence.

View a diagram about fish fraud here.