Proposed Changes to Horseshoe Crab Harvest Regulations Would Better Protect Spawning Crabs

By TODD McLEISH/ecoRI News contributor

Rhode Island horseshoe crabs spawn in April and May. (USFWS)

Rhode Island horseshoe crabs spawn in April and May. (USFWS)

The Rhode Island Department of Environmental Management (DEM) has proposed a series of changes to regulations governing the commercial harvest of horseshoe crabs in Rhode Island waters, but the environmental advocacy group Save The Bay says the proposal doesn’t go far enough to protect the state’s horseshoe crab population.

At a Dec. 5 hearing before the Rhode Island Marine Fisheries Council, DEM proposed to implement daily catch limits, minimum size requirements, tighter reporting rules and a closure of the fishery during the peak spawning period in the first three weeks of May. While Save The Bay agrees with most of the changes DEM proposed, the group says that climate change should be considered in the new regulations.

“The director should recognize that spawning can occur in April due to warming water temperatures and close the fishery to protect early spawning,” Jonathan Stone, executive director of Save The Bay, said.

Horseshoe crabs are familiar to anyone who spends time around Rhode Island’s salt marshes and beaches. Ancient creatures that evolved about 300 million years ago, they have 10 eyes, blue blood, and are more closely related to spiders and scorpions than to most marine life.

DEM issues between 40 and 60 permits each year allowing fishermen to capture horseshoe crabs. A quota of 14,466 horseshoe crabs were allowed to be harvested in Rhode Island waters in 2016, for use as bait, primarily in the eel and conch fisheries. Another 34,000 can be harvested annually for the biomedical industry, which uses the crabs’ copper-based blood in tests to ensure that medical devices, vaccines and intravenous solutions are free of harmful bacteria. Most of those captured for the biomedical industry are returned to the water unharmed.

According to Scott Olszewski, a marine fisheries biologist at DEM, a horseshoe crab management plan has been in effect since 2000, after crab populations were found to be at low levels.

“Based on our assessment, we had a total allowable catch that should have equated to a rebuilding schedule to rebuild the stock,” he said. “But the abundance indices we use to manage the population have continued to show the same signal — relatively low abundance and no upward trend in the population.”

As a result, DEM initiated the process to amend the regulations. A workshop and public hearing in November resulted in proposals from DEM, the horseshoe crab fishing industry and Save The Bay.

It has long been believed that horseshoe crabs crawl up onto beaches to lay their eggs at high tide on days when the moon is new or full in May, June and July. To allow the crabs to spawn, the fishery has been closed for the 48 hours before and after the full and new moon. But new research suggests that water temperature may be a more important spawning trigger, so DEM proposed closing the fishery from May 1-21, while Save The Bay recommended a closure from April 15 to May 31.

“Horseshoe crabs are spawning prior to the closure periods, and that’s when the harvest pressure is occurring as well,” said Wenley Ferguson, Save The Bay’s director of habitat restoration who conducts annual spawning surveys in Warwick and Cranston. “The bait fishery quota is often exceeded before any lunar closure even takes place because the crabs are spawning early because of water temperatures.”

DEM also proposed that each permitted fisherman be limited to possessing up to 60 horseshoe crabs per day, a strategy that would spread out the catch among the fishermen and extend the length of the fishing season. In addition, it proposed that harvested crabs must have a shell size of at least 7 inches.

At the Dec. 5 meeting, the Rhode Island Marine Fisheries Council — which will make a recommendation to DEM director Janet Coit, who will make the final decision — agreed with the proposals for daily possession limits and minimum crab size. The daily possession limits wouldn’t apply to the biomedical industry. But it decided to recommend that the bait fishery be closed during the entire month of May, a compromise between the DEM and Save The Bay proposals. The biomedical fishery will retain the lunar closures in May.
Olszewski said the recommended changes to the regulations will enable DEM to better manage the fishery.

“We have a relatively small bait fishery, and what usually happens is the landings come in at a very rapid pace,” he said. “We try to anticipate when we’re going to reach the threshold, but you get harvesters that land a large number of crabs in a short period of time, so it’s been hard to manage the quota.

“The idea [with the proposed regulations] is to promote equity among the participants in the fishery and allow Marine Fisheries to better manage the allowable catch.”

Ferguson agreed with DEM’s objectives, but noted that “we should at least protect the horseshoe crabs during the spawning period so they have a chance to spawn before they’re harvested.”

To do that, she said, “we should really be considering climate change.”

Coit is expected to make a decision soon. The regulations would go into effect Jan. 1.

Rhode Island resident and author Todd McLeish runs a wildlife blog.