Study shows rising ocean acidification likely to cause shrimp to taste bad

A deep sea shrimp out in open water. Credit: National Oceanic and Atmospheric Administration

(—A study conducted by a small team of researchers with members from the U.K., Sweden and Canada has revealed that in the future as the oceans become more acidic, it appears likely that the taste of shrimp will become less appealing. In their paper published in the Journal of Shellfish Research, the team describes how they raised test shrimp in higher than normal acidic water and then held taste tests with volunteers.

Shrimp, as most everyone knows, is wildly popular the world over—but that popularity may be in jeopardy in the future if findings by the team with this new research prove true. Prior research has suggested that the oceans are growing more acidic as they absorb more from the atmosphere. That increase, the team suggests, along with an increase in temperatures is likely to cause stress to shrimp, which it now appears, will likely cause them to be less pleasurable to the human palate.

It is no secret that animals living under stressful conditions wind up suffering degradations in taste—slaughterhouses, for example, attempt to surprise cows, pigs, chickens, etc., with a sudden isolated swift death so that they (and the other livestock) will not stress about their fate beforehand. Now it appears that creatures living in the sea may surprise us in the future with how they taste if they are forced to live under increasingly .

The researchers raised shrimp for three weeks in water with a pH level of 7.5 (the level predicted for the oceans by 2100) rather than the normal 8—the water temperature was slightly higher than normal as well to reflect a gradual warming of the oceans by the end of this century. Other shrimp were raised under current normal conditions. All of the shrimp were cooked by professional chefs and fed to volunteer shrimp lovers who rated the shrimp on how well they tasted.

The researchers found that the shrimp raised under normal current conditions were 3.4 times as likely to be deemed the tastiest among all the shrimp, while those raised in acidic/warm water were found to be 2.6 times as likely to be described as the worst tasting. The researchers also found that the fish raised in the more acidic/warmer were 1.6 times as likely to die during the three week test. Thus, unless learn to adapt to the new conditions so they will not feel stressed, they might just find their numbers increasing as people find them less tasty.

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More information: First Evidence of Altered Sensory Quality in a Shellfish Exposed to Decreased pH Relevant to Ocean Acidification, Journal of Shellfish Research 33(3):857-861. 2014

Understanding how seafood will be influenced by coming environmental changes such as ocean acidification is a research priority. One major gap in knowledge relates to the fact that many experiments are not considering relevant end points related directly to production (e.g., size, survival) and product quality (e.g., sensory quality) that can have important repercussions for consumers and the seafood market. The aim of this experiment was to compare the survival and sensory quality of the adult northern shrimp (Pandalus borealis) exposed for 3 wk to a temperature at the extreme of its thermal tolerance (11°C) and 2 pH treatments: pH 8.0 (the current average pH at the sampling site) and pH 7.5 (which is out of the current natural variability and relevant to near-future ocean acidification). Results show that decreased pH increased mortality significantly, by 63%. Sensory quality was assessed through semiqualitative scoring by a panel of 30 local connoisseurs. They were asked to rate 4 shrimp (2 from each pH treatment) for 3 parameters: appearance, texture and taste. Decreased pH reduced the score significantly for appearance and taste, but not texture. As a consequence, shrimp maintained in pH8.0 had a 3.4 times increased probability to be scored as the best shrimp on the plate, whereas shrimp from the pH 7.5 treatment had a 2.6 times more chance to be scored as the least desirable shrimp on the plate. These results help to prove the concept that ocean acidification can modulate sensory quality of the northern shrimp P. borealis. More research is now needed to evaluate impacts on other seafood species, socioeconomic consequences, and potential options.

© 2014

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Dec 23, 2014
It has nothing to do with the fact they are bottom feeders and eat fish feces and rotting matter?

Dec 23, 2014
As reducing human consumption of shrimp would be a boon for shrimp populations, is climate change actually beneficial for them?

Dec 23, 2014
A small team of researchers studying . . . shrimp - that does make sense!

Dec 23, 2014
A potentially significant and major flaw in this study appears to be that they did not feed the shrimp their native, omnivorous diet. They fed them a steady diet of chopped herring, blue mussel, brine shrimp, and Marine Flake (if it is what I think it is, it is processed feed for tropical aquarium fish). This definitely is not their natural diet. Might not that make a difference in the flavor and composition of their meat independent of other considerations? Right idea on bubbling CO2 into the water. Maybe not so much the rest? Time for a redo. Feel free to one-rank accordingly...

Dec 23, 2014
@Skeptcus Rex

You make some very good points. I've stopped buying shrimp because only wild caught shrimp are delicious, the farm raised (most of the market) are flavorless.

Dec 23, 2014
Skepticus, as long as the diet is the same between the two groups, it's a non factor because they are making what they can out of the same nutrients.
Although they probably could of tasted better with a better diet, I don't think the point of this study was to make the best shrimp platter ever made.

Dec 24, 2014
No, it is a factor still. Certain kinds of foodstuffs will change chemical composition in higher levels of CO2 when they come from areas containing less CO2. But, this isn't necessarily the case with the native diet of these shrimp.

Most of their native diets are located where CO2 levels are higher in their food on the ocean floor already. But, if you feed things outside of their native diet to the shrimp that come from regions with lower CO2, and add higher CO2 to them, it will modify the flavor of that group because those forms of food from the upper ocean will be different by nature anyway.

Remember, many of the things these shrimp eat already have higher CO2 inherent in them, bringing it to the ocean floor.

The experiment still needs to be redone with their native diets as they occur on the ocean floor (where CO2 levels already are higher than nearer the surface), not fish flakes and shallows-located foods.

Dec 28, 2014
We have noticed the taste of shrimp here in Vancouver to be especially bad. Also our kids have complained of stinging when they go swimming here in the ocean and they develop skin rashes. We won't let our kids swim here anymore. The acidity is also killing our salmon runs. Here is a picture link.

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