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A Fan Favorite Menu Item Might Be Off the Menu Soon

Isabella Deza

Ever wonder what foods might be off the menu soon due to climate change? A fan favorite item may be at risk if you’re a fellow seafood lover. In a recent study, it’s been found that some crabs are losing their sense of smell. New research from the University of Toronto Scarborough has found that a commercially important marine species, the Dungeness crab, is being impacted specifically. The detrimental perpetrator to this is carbon dioxide, as more is seeping into the ocean and causing the water to become more acidic. This discovery shed light as to why their populations are thinning and how it will cause significant consequences for the marine ecosystem since smell is vital to finding food.

This specific species is an important species to the economy since it defines the waters of the West Coast of North America and generated over $250 million in revenue from fisheries in 2019. It’s a crab that is valuable to a number of fisheries on the Pacific Coast, including California, Oregon, Washington and Alaska. However, it’s been in decline and the discovery found the reason as to why this specific species' population has been diminishing. The culprit to their reduction is ocean acidification. it “causes them to physically sniff less, impacts their ability to detect food odors, and even decreases activity in the sensory nerves responsible for smell.” Not only do Dungeness crabs rely heavily on their sense of smell for food but also for mates, suitable habitats, and being able to avoid predators since their vision is limited.

However, carbon dioxide isn’t the only factor – NOAA scientists have more to blame, “an increase in algae blooms, low-oxygen water conditions and marine heat waves, among other factors. These stressors can be worsened by the influence of climate change.” Yet, in the study it was found that ocean acidification specifically interferes with their ability to process a scent. When crabs sniff, it goes through a process called flicking. They will begin to flick their antennules (small antenna) through the water to help process the detection of the odor. The assistant professor in the Department of Biological Science at the University of Toronto Scarborough says, “crabs increase their flicking rate when they detect an odor they are interested in, but in crabs that were exposed to ocean acidification, the odor had to be 10 times more concentrated before we saw an increase in flicking.”

The study discovered that crabs were flicking less and their sensory neurons were 50% less responsive to odors, when the crabs were exposed to ocean acidification. Porteus also says, “losing their sense of smell seems to be climate-related, so this might partially explain some of the decline in their numbers...if crabs are having trouble finding food, it stands to reason females won’t have as much energy to produce eggs.” Researchers revealed that it’s some of the first evidence on how ocean acidification can affect a crustacean’s olfactory system. The decrease of food detection could lead to implications for other species such as the Alaskan king and snow crabs since their sense of smell is the same as the Dungeness crab. If the number of crabs continues to drop because of their loss of smell due to climate change damages, we might lose the option of ordering delicious crab cakes…


  1. Toronto, U. of. (2023, May 13). Crab crisis: Is a lost sense of smell decimating populations?. SciTechDaily.;

  2. Harvey, C. (2023, May 10). Some crabs are losing their sense of smell as oceans acidify. Scientific American. https://www.scientificamerican...;

  3. Crabs are losing their sense of smell and vanishing due to ocean acidification. (2023, May 9).


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