Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Biology

First Advisor's Name

Michael Heithaus

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Yuying Zhang

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Joel Trexler

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Pallab Mozumder

Fourth Advisor's Committee Title

Commitee member

Fifth Advisor's Name

Maureen Donnelly

Fifth Advisor's Committee Title

committee member

Keywords

elasmobranchs, sharks, rays, fisheries, small-scale, artisanal, caribbean

Date of Defense

11-15-2019

Abstract

Although 95% of fishers are artisanal, little is known about the magnitude of their catches and impacts on marine ecosystems at a global scale. I used a rapid assessment framework to study elasmobranch occurrence, elasmobranch fisheries, and use in coastal small-scale fisheries in the Caribbean, combining observational data and fisher’s knowledge. A total of 800 Baited Remote Underwater Videos were deployed in addition to 660 interview surveys that were collected in Colombia, Guadeloupe, Martinique, Tobago and the Florida Keys. In Colombia, I compared elasmobranch and teleost species richness and relative abundance within four coral reef habitats, where species targeted by fishers occur. Elasmobranch abundances were low and I detected no difference between the protected and unprotected reefs. Fishers reported Lutjanidae, Carangidae and barracuda as the main taxa they target, and although teleost abundances were also low, Tesoro Island was significantly higher in relative abundance of Lutjanidae, Carangidae and barracuda from the other islands. My data revealed that artisanal fishers continue to exploit coral reef resources inside MPAs, retain almost all of the species they catch, perceive less elasmobranchs than when they started fishing and the only island that enforced protection had a significantly higher teleost relative abundance. In the Lesser Antilles, the fate of artisanal fishers’ catches of elasmobranchs varied by island, with Martinique reporting the highest proportion of keeping catch only for subsistence, Guadeloupe having the highest proportion of keeping catch only to sell, and Tobago reporting the highest proportion for both sustenance and catch. I also found that fishers retain almost all animals caught, and perceive less elasmobranchs than when they started fishing. Fishers reported catching far more species of sharks (n= 22) and rays (n = 4) than were observed on BRUVs (n = 5 and 2, respectively). In the Florida Keys, recreational ocean activities such as fishing and diving are a lucrative businesses, and individuals in these industries represent potentially valuable sources of insight and knowledge on the current state of, and recent changes in, coastal oceans. I investigated perceptions of elasmobranch abundance and diversity, as well as attitudes towards management practices, in these industries in the Upper Florida Keys, USA using a rapid assessment framework. Fishers reported capturing seven sharks species, while underwater users reported four shark species and BRUVs captured six sharks species. From BRUVs, elasmobranch relative abundances were comparable to my other sites in previous chapters and I found that there are significantly more elasmobranch species captured on camera on the southern portion of the Upper Florida Keys, even though the relative abundance of elasmobranchs was significantly different across all three sampling blocks. These data revealed that fishers and divers agree on the need for protected areas and do not have a conflicting opinion with regards to elasmobranch conservation policies.

Identifier

FIDC008859

Available for download on Thursday, October 28, 2021

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