Limits on the global distribution of horseshoe crabs (Limulacea): Lessons learned from two lifetimes of observations: Asia and America

Abstract

This paper is based on the premise that understanding the natural history and ecology of the horseshoe crabs (Limulacea) is paramount to conservation of the species. Our objective has been to select those large-scale, global parameters that help to define the opportunities for, and the limits on, their distribution. Essentially, we have selected the big-picture type of conditions pertinent to considerations of the conservation of the species. This has led to an examination of potential biotic and environmental parameters. Of these we have selected eight, four in each category. The biotic aspects are: who they are (taxonomically), whether they are living fossils, what they are (ecologically), and the significance of discrete populations in conservation of the species. Four large-scale environmental parameters that limit their global distribution are geologic (estuarine environments, continental shelves as avenues of distribution, ocean deeps as deterrents), temperature which sets boundaries, tidal types that define predominant potential spawning sites, and the influence of benthic currents. © Springer Science+Business Media, LLC 2009. All rights reserved.