The researchers found that for approximately two weeks after the bleeding procedure, the crabs' behavior differed from their behavior prior to the bleeding they moved less frequently and with different patterns and rhythms, indicating they may have been disoriented. The researchers hope to track the movements of bled horseshoe crabs in their native environments to verify that their lab findings apply to real life behavioral changes.
One of the concerns, Anderson explains, is that the crabs are collected for bleeding during their breeding cycle when it's easiest to capture them on beaches. If the crabs are bled and then returned to the beach in a disoriented condition, they might be less likely to breed. This has the potential to exacerbate the population declines that are already occurring in parts of the east coast, including Delaware and Cape Cod. The populations in N.H. seem to be holding steady at the moment.
"If the biomedical industry could delay the blood harvest, it would probably help these animals," Chabot says. "For example, if they are bled after the breeding season, then they could recover in the subsequent months, fatten up and survive the winter without any problems to be able to breed again the following year," he said.
Watson suggests that the conditions under which they are transported could be improved as well. Fishermen capture the horseshoe crabs and often place them on a hot boat deck until they are transported by truck to the biomedical facility, all the while out of water and unable to breathe. If instead they were kept in cold, well-aerated water and perhaps fed, their stress levels might decrease and thus improve their chances of survival and ability to breed upon return to their native habitat.
Watson also notes that it is unclear which part of the process is the most detrimental the bleeding, the transporting, or simply keeping the crabs in the lab and
|Contact: Rebecca Zeiber|
University of New Hampshire