Date of Award
Open Access Thesis
Blaine D Griffen
Many global fisheries are overexploited and working towards the development of sustainable fishing methods. Claw based crab fisheries, such as the Florida stone crab (Menippe mercenaria, M. adina, and hybrids) fishery, use unique fishing techniques that reduce the overall mortality of harvested organisms. For example, the Florida stone crab fishery is regulated by requiring that fisherman only harvest crab claws and requires that fishermen return the live crab to the water following harvesting. This process takes advantage of the ability of crabs to autotomize and regenerate their claws, and enables crabs to re-enter the fishery in subsequent years if they survive. Though this fishery is currently considered to be sustainable, fishery-related claw loss may negatively influence the population through multiple pathways. The objectives of this study were to demonstrate how fishery-related claw loss influences Florida stone crab diet choice, consumption over time, and energy allocation following simple dynamic energy budget theory, with the ultimate goal of determining how these factors influence the reproduction of harvested individuals. I demonstrated that one-clawed Florida stone crabs do not switch their diet to more easily managed food items, such as algae or sponge, following claw removal. However, I found that one-clawed crabs consume fewer bivalves than two-clawed crabs, and they do not improve in their ability to crack mussels over time, suggesting that decreased foraging capacity will remain until the regenerative molt. I found that one-clawed Florida stone crabs do not alter their energy storage patterns prior to the reproductive season, suggesting that the energy for both reproduction and claw removal will be derived from the same energy stores. Lastly, I found that regenerating a crusher claw has the potential to take energy away from reproduction; however, the energetic implications of decreased consumption following claw loss far outweigh the energetic costs of claw regeneration. The results of this study indicate that Florida stone crabs are likely to suffer from severe energetic constraints resulting from claw removal, which could limit growth, claw regeneration, reproduction and survival of harvested crabs.
Hogan, J. M.(2013). Evaluating the Impact of Fishery-Related Claw Removal On Diet, Consumption Rate, Energetics and Reproduction In the Florida Stone Crab (Menippe Spp.). (Master's thesis). Retrieved from http://scholarcommons.sc.edu/etd/1544