There are no large scale fisheries of thresher sharks in the Atlantic ocean however there is a very large recreational fishery industry surrounding the species from Virginia to Maine. While the fishery industry may not be targeting threshers they are often caught as bycatch in nets. From 1980s to the 2000s it was thought that thresher populations decreased by 63-80% in the Northern Atlantic. Since then the population has thought to have leveled off with periods of annual variability as seen through fishery dependent data. In spite of this the population is listed as vulnerable by the International Union for Conservation of Nature as it is thought there is an overall worldwide population decrease (Kneebone et al. 2020).

Many different gear types such as: commercial bottom long haul-line, pelagic longline, gill net (sink and floating), haul seine, purse seine, otter trawl, mid-water trawl, and recreational rod and reel are detrimental to thresher populations. The most detrimental to the species has been gill nets, pelagic longlines, and rod and reel which tend to catch threshers the most. There are no size restrictions in these waters which can be an issue due to the fact that juveniles are caught at a higher rate than adults. Due to the low fecundity of thresher sharks this is a detriment to the population (Kneebone et al. 2020).

They have been petitioned to be protected under the US endangered species act in order to protect their populations though they are still only listed as vulnerable. I’d say a large issue with this is that just not a lot of things are known about the thresher shark. It’s hard to protect their habitats or nurseries when their main habitats and nurseries may not be known. Another issue is that a place has to be proven to be a nursery according to policy definition of a nursery, which may be a hard and lengthy process to prove.

Something that has seemed to work in the past however is public knowledge. The more people know about thresher sharks and want to protect them the more likely they are to be protected. More recent research has started coming out to map their migration patterns in order to protect these areas.

More recent media coverage has also been given to thresher sharks, not for their declining populations, but for their loveable faces. If this keeps up they may be on their way to becoming a protected species.

(10. Image from Gina Zwicky on twitter)