Estimation of Survival of the Atlantic Horseshoe Crab, Limulus polyphemus, by Analysis of Mark-Recapture Data with Tag Loss

Abstract

The Atlantic Horseshoe crab, Limulus polyphemus, is a valuable resource along the Mid-Atlantic coast which has, in recent years, experienced new management paradigms due to increased concern about this species role in the environment. While current management actions are underway, many acknowledge the need for improved and updated parameter estimates to reduce the uncertainty within current management models. Specifically, updated and improved estimates of demographic parameters such as adult survival in the regional population of interest, Delaware Bay, could greatly enhance these models and improve management decisions. There is however, some concern that difficulties in tag resighting because of physical or behavioral differences between sexes or a complete loss of tags could be occurring. As defined in the assumptions of a Jolly-Seber model, any apparent loss of tags can bias results, by underestimating survival. Using data from a double tag mark-resight study conducted in Delaware Bay and Program MARK, we conducted three analyses to assess this system.