Exploring Different Approaches to Improve Shark Fisheries Management in Resource-Limited Nations

Authors

Jessica R. Quinlan, Florida International UniversityFollow

Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Biology

First Advisor's Name

Demian D. Chapman

First Advisor's Committee Title

Co-Committee Chair

Second Advisor's Name

Heather Bracken-Grissom

Second Advisor's Committee Title

Co-Committee Chair

Third Advisor's Name

Yuying Zhang

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

John Carlson

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Mahadev Bhat

Fifth Advisor's Committee Title

Committee Member

Keywords

shark fisheries management, shark conservation, shark fins, shark fishers, shark relative abundance

Date of Defense

6-20-2023

Abstract

Overfishing continues to be the leading cause of decline in shark populations globally and although low- and mid- income nations are responsible for most global landings of sharks, there are no known examples of sustainably managed shark fisheries outside of high-income nations. Many countries struggle to collect the fundamental data needed to assess and report the status of their stocks, including species and size-specific catch data and species abundance. As more shark species become threatened, it is imperative that more cost-effective approaches are available for these nations to collect the data needed to monitor their shark catches and stocks.

In Chapter II, I outlined a widely applicable, cost-effective approach to reconstruct the species- and size-composition of the catch of a shark fishery in a middle- income Central American nation (Belize). Fisher-contributed secondary fins were submitted to fisheries managers, identified to species to determine species composition of the catch for one fishing season. Species-specific regressions equations were developed for key species in the fishery to infer the total lengths of the animals from which the fins came from, and length frequency data indicated whether sharks were being landed above or below the length at which they mature.

Chapter III extended our understanding of the catch of the Belize shark fishery by applying the approach outlined in Chapter II to four consecutive fishing seasons. There were marked changes in this fishery due to new management efforts and the COVID-19 pandemic, and so I tested for changes in overall species composition and average size of key species over time. Additionally, fisheries sustainability indicators were applied to length frequency data to determine what proportions of the catch fell within three indicator categories: 1.) the proportion of the catch that was mature, 2.) of optimum length and 3.) were mega-spawners. Tracking these indicators through time will provide guidance on the status of stocks and sustainability of this fishery.

Chapter IV, investigated a fisheries-independent survey method to investigate the relationship between environmental DNA sampling and drone-observed local shark densities, with the intention of using it as an alternative cost-effective survey method when other survey methods are unavailable or not practical (i.e., visual surveys in low visibility coastal water, fishing for scarce species.) Results supported a positive relationship between eDNA and shark density, and provided new insights into spatial and temporal precision of eDNA species detection in a dynamic coastal environment.

Identifier

FIDC011217

ORCID

0000-0002-5272-8867

Previously Published In

Chapter 2: Quinlan, J. R., O'Leary, S. J., Fields, A. T., Benavides, M., Stumpf, E., Carcamo, R., Cruz, J., Lewis, D., Wade, B., Amato, G., Kolokotronis, S.O., Chapman, D. D. (2021). Using fisher‐contributed secondary fins to fill critical shark‐fisheries data gaps. Conservation Biology, 35(3), 991-1001.

Recommended Citation

Quinlan, Jessica R., "Exploring Different Approaches to Improve Shark Fisheries Management in Resource-Limited Nations" (2023). FIU Electronic Theses and Dissertations. 5349.
https://digitalcommons.fiu.edu/etd/5349