Activity in the pallial nerve of knobbed (Busycon carica) and channeled (Busycotypus canaliculatum) whelks recorded during exposure of the osphradium to odorant solutions

Adult horseshoe crabs (Limulus polyphemus) are the preferred bait in the U.S. east coast whelk pot fishery, but their harvest is being restricted because of severe population declines in the Chesapeake and Delaware bays. To identify other baits, the activity in the pallial nerve of whelks was determined during exposure of the osphradium to odorant solutions prepared from horseshoe crab eggs, horseshoe crab hemolymph, and hard clam (Mercenaria mercenaria) tissue. All three elicited significant responses; bait based on them may provide an alternative to the use of adult horseshoe crabs, although extensive behavioral testing remains to be done. Channeled whelk did not respond to molecular weight fractions (>3 kDa and <3 kDa) prepared from horseshoe crab egg odorant solutions but did respond when the molecular weight fractions were recombined. Whelks appear to have broadly tuned chemoreceptors and manufactured baits may need to mimic the complex mixture of odorants derived from natural sources.