thumbnail

An age-structured population model for horseshoe crabs in the Delaware Bay area to assess harvest and egg availability for shorebirds

Estuaries and Coasts

By:
, ,

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

The objective of this simulation study was to create an age-structured population model for horseshoe crabs (Limulus polyphenols) in the Delaware Bay region using best available estimates of age-specific mortality and recent harvest levels. Density dependence was incorporated using a spatial model relating egg mortality with abundance of spawning females. Combinations of annual female harvest (0, 50, 100, and 200 thousand), timing of female harvest (before or after spawning), and three levels of density-dependent egg mortality were simulated. The probability of the population increasing was high (> 80%) with low and medium egg mortality and harvest less than 200 thousand females per year. Under the high egg mortality case, the probability of the population increasing was < 50% regardless of harvest. Harvest occurring after spawning increased the probability of population growth. The number of eggs available to shorebirds was highest when egg mortality was lowest and female abundance was at its highest levels. Although harvest and egg mortality influenced population growth and food availability to shorebirds, sensitivity and elasticity analyses showed that early-life stage mortality, age 0 mortality in particular, was the most important parameter for population growth. Our modeling results indicate areas where further research is needed and suggest effective management will involve a combination of harvest management and actions to increase early juvenile survival. ?? 2007 Estuarine Research Federation.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
An age-structured population model for horseshoe crabs in the Delaware Bay area to assess harvest and egg availability for shorebirds
Series title:
Estuaries and Coasts
Volume
30
Issue:
2
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
277
Last page:
286
Number of Pages:
10