Female Delaware Bay horseshoe crabs have spared commercial fishing

Cottrell of the Delaware Audubon Society supports the use of artificial horseshoe crab blood, which was developed as an alternative to harvesting horseshoe crabs for biomedical purposes. However, its use has not been considered in the United States

“One of the goals of the environmental groups moving forward is to try to put pressure on those groups that are resisting conversion,” he said. “There is going to be a battle, because this industry is well funded. They have lobbyists who are influential.

A highly controversial change in the calculation of horseshoe crab harvests

Larry Niles, a biologist formerly with New Jersey’s Fish and Wildlife Division, said he’s glad females aren’t included in next year’s commercial harvest. However, he opposes the commission’s decision to adopt the new framework. Niles and other naysayers believe he is using data points that do not paint a complete picture of horseshoe crab health and overestimates crab and red knot populations.

The ASMFC reports that Delaware Bay horseshoe crab populations have steadily increased to 21.9 million males and 9.4 million females. However, Niles argues that egg density is a more important number. He and his colleagues at the Delaware Bay Shorebird Project found that the density of horseshoe crab eggs in Delaware Bay was around 7,000 eggs per square meter in May 2022. For comparison, eggs reached almost 50,000 per square meter in the 1990s.

“Egg densities haven’t improved since this agency started managing crabs,” Niles said, adding that “there are as many crabs dying as there are in the population.”

Project reports red nodes remained at historically low levels in 2022. Although the number has increased from 6,800 in 2021 to over 12,000 this year, it is less than half the peak number of 30,000 in 2019 – and a fraction of the peak population of over 94,000 in 1989. The US Geological Survey estimates that 40,000 to 50,000 red knots stop and feed each spring along Delaware Bay.

But Niles argues that the survey is flawed. He says it’s an overcount, as it includes birds flying overhead looking for food they may never find, rather than just birds stopping at the shore. to eat and successfully make their way to the Arctic to breed.

Proponents of the new framework say it’s more accurate than the previous one, in part because it’s based on empirical data collected directly from the Delaware Bay. In the previous setting, most of the information used to formulate the horseshoe crab population model came from Pleasant Bay, Massachusetts, because information from Delaware Bay was not available.

Volunteer Karen Longo holds a marked horseshoe crab during a population survey at James Farm Ecological Preserve in Ocean View, Del. (Emma Lee/WHYY)

The new framework also includes new data on mortality, including horseshoe crabs that die after being bled and released for biomedical purposes, and deaths caused by catches in other fisheries. This offers a better estimate of the number of crabs in the population, proponents say.

Another concern with the old framework is that if the horseshoe crab and red knot populations reached a certain threshold, the catch quota for females would automatically increase from zero to 210,000. Under the new method, the quotas will increase gradually if the abundance of female horseshoe crabs continues to increase.

The US Fish and Wildlife Service has endorsed the model, saying it uses the most advanced data.

“It reflects the best available science available to us today,” said Rick Jacobson, deputy regional director of the Fish and Aquatic Resources Conservation Service, after Thursday’s vote.

However, he added that in order to gain the public’s trust, it is important for the ASMFC to be more transparent.

“We are delighted that the commission has chosen to prevent the harvest of female horseshoe crabs…by preventing a harvest of female horseshoe crabs for 2023, it will give the public a further opportunity to explore this model to develop more self-confidence,” Jacobson said.

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