Scientists Discover Fish Sizes Getting Smaller in Oceans Globally

According to a fascinating new finding by ocean researchers, fish populations are getting smaller globally, even in areas where overfishing is not an issue. Although experts have proposed several theories, the actual reason is still a mystery.

Research published in the journal Science shows that the size of about 75% of marine fish globally decreased from 1960 to 2020.

Overfishing and warming are most likely contributors to the phenomena. 

Research into the mechanisms behind this evolutionary adaptation is of the utmost importance since over three billion people worldwide get a large portion of their daily calories from seafood, especially fish.

Fish catches must grow to keep calorie consumption constant since billions of people rely on fish as a protein source. This condition puts a heavy burden on coastal communities that depend on a healthy ocean for their survival and threatens fish species that are already struggling due to pollution, overfishing, and increasing ocean temperatures.

There has been observation of this occurrence in both protected and unprotected marine environments; scientists have dubbed it the “temperature-size rule,” according to Komoroske.

Evolutionarily speaking, a larger body is at a disadvantage due to the critical requirement for more oxygen as ocean temperatures rise.

Still, recent research by Komoroske and Joshua Lonthair found that brook trout bred in warm water had gills that could handle enough oxygen.

According to scientists, evolutionary pressures or the impact of organs other than the gills that cause stunted growth could be responsible for the fish’s shrinking size.

The decline in the fish population might severely affect fishermen’s earnings and marine ecosystems. Thus, it’s critical to understand why fish are becoming smaller.

The restoration of ocean ecosystem balance and the enforcement of prohibitions on commercial fishing and whaling globally have improved fish and other marine organisms’ chances of survival.

Renewable energy sources, such as solar and wind, are seeing a dramatic upturn. Because of this change, pollution will be reduced, and rising temperatures will affect wildlife, mainly fish. Lessening our reliance on oil will also reduce the likelihood of oil leaks, which endanger marine life.

Furthermore, there is a bright side to smaller fish. Ecologist Inês Martins said many of these fish are actually seeing population growth, even if they are smaller than average.