What We Have Learned Studying Taunton Bay’s Horseshoe Crabs

Frank Dorsey

¨ They are at the extreme northern end of their range.

¨ They are slightly smaller than more southern horseshoes.

¨ They have adapted by remaining above Tidal Falls.

¨ Unlike horseshoes elsewhere, ours remain in the Bay, burying in the channel mud flats from October through April or May.

¨ We rarely see horseshoes except during mating.

¨ Distinct populations mate in Egypt Bay and on Shipyard Point.

¨ They rarely mate at a water temperature below 60F (16C).

¨ Mating begins in mid-May in Taunton Bay (earlier south of here).

¨ Mating has begun earlier each of the last four years.¨ Horseshoes seen mating during the most recent 4 years are about equal to the numbers seen in 2001- 2004.