Habitat Partitioning by Blue Crabs

 

Post-mating behavior, intramolt growth, and onset of migration to Chesapeake Bay spawning grounds by adult female blue crabs, Callinectes sapidus Rathbun

Journal of Experimental Marine Biology and Ecology

Volume 295, Issues 1, 28 October 2003, Pages 107-130

Heather V. Turner 1, Donna L. Wolcott 1, Thomas G. Wolcott 1 and Anson H. Hines 2

1 Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina, USA
2 Smithsonian Environmental Research Center, Edgewater, Maryland, USA

Abstract

After molting to maturity, female blue crabs must rebuild muscles atrophied to permit molting and grow larger ones commensurate with the larger exoskeleton. They also must acquire energy for oogenesis and for migration to high-salinity spawning habitat, a distance of >150 km for females mating in the Upper Chesapeake Bay. Using telemetry and mark-recapture techniques, post-copulatory females in the upper bay were shown to forage at high rates, alternating between meandering and directed movement in the area of mating for weeks to months, and to begin migrating in October. Consequently, females from the Upper Chesapeake Bay probably do not spawn until the season after mating. Their priority seems to be to acquire energy before migrating. After molting, energy was allocated first into somatic tissue and eventually into hepatopancreas and gonads. Telemetry of feeding and movement showed that habitat utilization, traveling velocities, foraging patterns, and movements were similar to those already determined for males. However, females appeared to invest proportionally more energy (calories per gram dry weight) into their somatic and reproductive tissues than did males. A newly designed transmitter that telemetered depth showed that females moved during both ebbs and floods and remained at or near the bottom of the water column.