HCNSO Student Theses and Dissertations

Defense Date

4-19-2018

Document Type

Thesis

Degree Name

M.S. Marine Biology

Second Degree Name

M.S. Biological Sciences

First Advisor

Paul Arena

Second Advisor

Dave Kerstetter

Third Advisor

Angela B. Collins

Abstract

Hogfish (Lachnolaimus maximus; Walbaum 1792) from Southeast Florida were aged using sectioned otoliths and growth rates were calculated using the von Bertalanffy growth equation. The samples were collected from Broward County (n=209); other regions of Southeast Florida (n=18), the Florida Keys (n=35) and Bahamas (n=43). Growth rates were determined for each of these areas and were then compared to previously reported growth rates from other regions including the eastern Gulf of Mexico and Florida Keys. There was significant separation at the 95% confidence level between growth rates from each reagion. The average maximum fork length increased, from the Florida Keys (336mm) to Southeast Florida (414-mm) by 78-mm. However, the annual survival rate was the same (S=61%) between these two regions and the maximum age of Southeast Florida (age 12) was still half that of the previously reported eastern Gulf (age 23). Broward County was divided into three reef zones each at different depths (5-m, 10-m, and 20-m) and growth rate and survival rate were compared between zones. Results showed a decrease in maximum fork length with reef depth (857-mm, 420-mm, 352-mm), as well as an increase in mean age (age 3, 4, 5), maximum age (9, 10, 12), and survival (42%, 65%, 73%), respectively. The decrease in observed growth rate of an area as a whole (e.g. Florida Keys) may represent an example of Lee’s phenomena caused by increased top-down selective fishing pressure. However, the growth rates of individual hogfish are most likely a result of differences in habitat and food resource availability. This study provides baseline age and growth information for hogfish in Southeast Florida prior to the recent changes to the fishery regulations, which will help fisheries management better understand the effects of alternative management strategies.

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