Date of Award

Spring 5-12-2018

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)


Ocean Science and Technology

Committee Chair

Zachary Darnell

Committee Chair Department

Ocean Science and Technology

Committee Member 2

Frank Hernandez

Committee Member 2 Department

Ocean Science and Technology

Committee Member 3

Wei Wu

Committee Member 3 Department

Ocean Science and Technology


The overarching goal of this research was to better understand the structure and boundaries of the blue crab stock(s) in the Gulf of Mexico, focusing on large-scale movements of spawning female crabs. Because spawning location is a primary determinant of larval transport pathways, understanding spawning locations and offshore movements of female blue crabs can inform stock identification and potentially clarify the somewhat conflicting population genetic information available for blue crabs. A large-scale mark-recapture study was conducted through the partnership of state/federal management agencies, the commercial fishing industry, recreational fisherman, tourists, and numerous academic institutions to shed light on the timing and movements of mature female blue crabs in the Gulf of Mexico. The direction of travel, travel distances, and travel rates were estimated for each region in the study area using novel analytical techniques. Crabs regularly migrated beyond the borders of their home state, providing further evidence of mixing of the different state-managed stocks. The endpoint of the spawning migration in the offshore Gulf of Mexico, and the importance of the offshore spawning stock has come into question. Offshore female blue crabs collected during the SEAMAP groundfish survey were found to be actively spawning, with fecundity estimates in a similar range to the inshore population. Higher offshore abundances were observed off the coast of Texas and Louisiana across all study years from 2001-2016. Increasing temperature and dissolved oxygen were positively correlated with higher abundance, and offshore abundance was consistently higher in the summer sampling period than the fall.