Date of Award

Fall 12-2017

Degree Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Coastal Sciences, Gulf Coast Research Laboratory

Committee Chair

Zachary Darnell

Committee Chair Department

Coastal Sciences, Gulf Coast Research Laboratory

Committee Member 2

Robert T. Leaf

Committee Member 2 Department

Coastal Sciences, Gulf Coast Research Laboratory

Committee Member 3

Frank J. Hernandez

Committee Member 3 Department

Coastal Sciences, Gulf Coast Research Laboratory

Abstract

Temperature can exert impacts on many processes in ectotherms. With global temperatures rising due to climate change, many ectothermic species may exhibit changes in growth rates and size at maturity, and these changes can have population-level effects. Predicting responses of species to climate change will require not only knowledge of thermal tolerance limits, but also effects of temperature change on growth rates and other life history parameters. For arthropods that exhibit discontinuous growth (i.e., molting), this includes both intermolt period and growth per molt. Previous laboratory and field experiments suggest that temperature affects both intermolt period (IMP) and growth per molt (GPM) in many crustaceans, including blue crabs. Field surveys suggest that blue crabs reach maturity at larger sizes in cooler areas, and at smaller sizes in warm areas. In this study I investigate the effect of temperature on the growth process in blue crabs Callinectes sapidus and lesser blue crabs Callinectes similis, to examine differences in temperature sensitivity of growth rates across seasonal thermal regimes. Observed growth dynamics differed between species and were dependent on the time of collection and the temperature regime experienced by the crabs. Future research should examine the effect of temperature on growth in crabs from metamorphosis to maturity to determine if the response is consistent across all instars, and to directly assess effects of temperature on size at maturity.

ORCID ID

orcid.org/0000-0001-7789-8312

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