Something fishy? Better hope that it is

by Jagath – This weekend me and a few friends decided to get something fancy for dinner. We decided to dine at a well-known sushi restaurant in the city. My experience with sushi has been very limited. Actually, my experience with seafood in general has been very limited because I grew up vegetarian (which I still identify as, shhh…).

So there I was- savoring the maki that we’d ordered- the subtle flavor of the fish and the creamy texture of the rice undercut by the pungent soy sauce and piquant wasabi nibbling away at my taste buds. My sushi-connoisseur friend, on the other hand, was staring blankly at a piece of half eaten Hamachi nigiri – thin slice of yellowtail fish on vinegar rice. “This isn’t yellowtail; This doesn’t taste like yellow tail at all” they said.

Hamachi nigiri (or is it?)

Another friend added, “Fish in sushi is often wrongly labelled apparently, I think there was a study about that”. “Ha! There’s a study about anything and everything” remarked my sushi-expert friend. And indeed there was- A quick internet search led us to a twitter thread from April this year by a biology professor Jennifer McDonald. As a part of a lab experiment, she asked undergraduate students to collect fish from different sushi joints and supermarkets. The fish samples were then DNA-barcoded to find out if the fish was what it was claimed to be. DNA-barcoding is a technique where certain segments of DNA are matched with reference DNA to identify species of the organism.

The study revealed that only 2 of the 9 fish that they were able to barcode were correctly labelled. What was sold as rainbow trout was actually salmon and what was sold as red tuna was actually tilapia. More concerning is that escolar (which can cause gastrointestinal distress) was labelled as white tuna.

Later that night I fell down the internet rabbit hole. Reports from more rigorous studies in the past also show that seafood mislabeling is common. For example, a paper by K Nagalakshmi and others looked at seafood mislabeling in the Indian context. They found that 13% of seafood in local markets were mislabeled and 9% in supermarkets. Seafood from restaurants fared worse, the samples showed 32% mislabeling. What really stood out to me from the study was that certain fish are more likely to be mislabeled than others and that less expensive fish are more likely to be mislabeled as more expensive ones.

Despite this, I don’t think it’s likely that I will stop eating seafood. But, until there is a change in our policies and practices, it is better to be cautious about our seafood consumption.


Just some food for thought.

References:
1)  Mislabelling in Indian seafood: An investigation using DNA barcoding, K Nagalakshmi et al, 2016
2) https://twitter.com/AwesomeBiota/status/1114262375446663168

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