Date of Award

Summer 2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

Committee Director

Mark Butler

Committee Member

Richard Zimmerman

Committee Member

Kent Carpenter

Committee Member

Holly Gaff

Committee Member

John McConnaugha

Abstract

“Casitas” (artificial table-like structures) are a commercial fishing gear used to harvest Caribbean spiny lobster (Panulirus argus) in the Caribbean and in The Bahamas, where lobster is the most valuable fishery. Yet, casitas are largely unregulated in The Bahamas and they may threaten fishery sustainability through alteration of lobster growth, disease, or mortality rates and due to insufficient information concerning their number and location. Focusing on the lobster fishery in The Bahamas, my objectives were to: (1) investigate the mortality, growth, and susceptibility to disease of lobsters collected in casitas compared to wooden traps and those living in natural shelters; (2) evaluate lobster size-structure and the bycatch of undersized lobster and other taxa from casitas compared to traps; and (3) ascertain whether remote sensing can be used to estimate the distribution and density of casitas.

Using tethering and time-lapse photography, I compared predation on lobsters at casitas and natural locations. I also compared the growth, frequency of injury, and prevalence of disease of lobsters collected from casitas and traps, as well as lobster size structure and the bycatch of other taxa and of undersized lobsters from traps and casitas. Fishermen use hooks to remove lobsters from casitas, so I also tested if hooking increased the mortality of under-sized lobsters released after capture. In situ measurements of the reflectance of casitas relative to background habitats along with the analysis of remote sensing images were used to explore the feasibility of using remote sensing to detect and census casitas in Bahamian waters.

Predation of lobsters at casitas and natural shelters did not differ, nor was the survival of sub-legal sized lobsters affected when impaled by a hook during removal from casitas. A larger size range of lobsters occurred under casitas than were caught in traps. However, lobsters in traps were in poorer health than those in casitas. Casitas were detectable using remote sensing but refinement of detection methods is needed before the technology can be employed by fishery managers. All in all, there is no evidence that casitas have a negative ecological effect on lobsters in The Bahamas.

Available for download on Friday, October 11, 2019

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