A study has revealed some troubling news about the reproduction numbers of the North Atlantic right whale, one of the most endangered species of large whale, according to the World Wildlife Fund. The organization reports that there are just 366 individuals in the wild, and a study published in March in Proceedings of the Royal Society B Biological Sciences revealed an ongoing issue is having a major impact.

What's happening?

Joshua Reed, lead author of the study, found North Atlantic right whales becoming entangled in fishing lines to varying degrees caused them to skip calving, in addition to causing severe injury or death, as detailed by the Wildlife Society. 

The study rated entanglements in fishing lines along the lines of minor, moderate, and severe and found that even minor events were more likely to lead to females not breeding. Reed suggested that the amount of energy used to reproduce was being diverted to breaking free from the ropes. The researchers also noted that whales that become entangled (or that have mothers who were while nursing), tend to be smaller than average.

"This induced stunting affects the individuals' ability to accumulate energy reserves, which impacts calf production," the researchers stated in the report.

Moderate and severe entanglements also impacted reproduction, with females who had given birth before but later became entangled becoming less likely to have another calf.

Why are North Atlantic right whales important?

According to NOAA Fisheries, the North Atlantic right whale only has around 70 "reproductively active" females in its limited population. The species has been on the endangered list since 1970, and while whaling is no longer under threat (at least not by law), commercial fishing, boat strikes, ocean noise, and climate change continue to impact the whales. 

The extinction of the right whale, or indeed any other whale species, would have significant environmental impacts. According to the Animal Welfare Institute, whales contribute to carbon sequestration, helping fight global warming. There's also the economic benefit of (safe) tourism, environmental education, and conservation fundraising through whale watching.  

What's being done about the entanglements?

NOAA Fisheries shared several changes being made, including reducing rope strength to help whales break free more easily, imposing seasonal closures in areas where the whales are known to gather, and implementing rules to reduce boat strikes. 

The Wildlife Society also noted Reed said ropeless fishing gear is an option, but it's an expensive one for most fishermen at the current time. 

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