Larger sea creatures at greater risk of extinction

A new study published in “Science” reveals that the greater the size of a sea creature, the greater the chances are of it becoming extinct. As one might expect, human action, especially fishing, is the most likely culprit.

The study’s authors compared nearly 2,500 species of both living and extinct marine vertebrates to determine how traits of the extinct line up with those of the living. Living species considered in the study include the great white shark, blue whale and Pacific bluefin tuna. According to the Canary, “The results reveal a strong association of body size to the probability of of being threatened by extinction,” and the association holds up in a variety of data treatments.

Jonathan Payne, the lead researcher in the study, explains:

“What our analysis shows is that for every factor of of 10 increase in body mass, the odds of being threatened by extinction go up by a factor of 13 or so. The bigger you are, the more likely you are to be facing extinction.”

Perhaps the most concerning part of the study’s results is that this pattern is unlike the previous five known extinction events in Earth’s history. Before, smaller animals were the ones at higher risk for extinction. Additionally, the association is recent. Neil Heim, one of the study’s co-authors, sheds some light on why:

“We see this over and over again. Humans enter into a new ecosystem, and the larger animals are killed off first. Marine systems have been spared up to now, because until relatively recently, humans were restricted to coastal areas and didn’t have the technology to fish in the deep ocean on an industrial scale.”  

Similar to how lions, elephants, tigers, rhinos and many apes are at risk because of habitat destruction and hunting, large marine creatures are suffering because of overfishing.

Because larger animals are often found at the top of food webs, their extinctions would be catastrophic to marine ecosystems. However, researchers do have hope of reversing the current size/extinction association. Restoring fish populations is a task that could be attained far more quickly and realistically than reversing ocean acidification, which still must be addressed as well.

“We can change how we hunt and fish,” Payne appeals to readers of the study, “We can turn this situation around relatively quickly with appropriate management decisions at the national and international levels.”