Publication Date

2018-12-05

Availability

Open access

Embargo Period

2018-12-05

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Marine Biology and Fisheries (Marine)

Date of Defense

2018-10-29

First Committee Member

Jerald S. Ault

Second Committee Member

Juan J. Agar

Third Committee Member

James A. Bohnsack

Fourth Committee Member

R. Stephen Cantrell

Fifth Committee Member

Nelson M. Ehrhardt

Sixth Committee Member

Steven G. Smith

Abstract

The Florida reef ecosystem supports lucrative commercial and recreational industries that provide the state with billions of dollars annually. The goal of this study was to analyze the available demographic, fishery, and economic data for reef fishes, develop an age-structured bioeconomic production model, and assess the economic consequences of fisheries management. Key demographics data are required for the most basic assessment methodology, but just over half of these species had full parameter sets suitable for stock assessment, and less than a quarter had reliably estimated sets. Total mortality rates estimated from the average length of the commercial catch were combined with demographics models to assess the populations of principal species within numerical cohort models. Economic models were built linking commercial catch to revenues through inverse demand functions and nominal effort to costs through fleet-specific variable cost functions. Numerical cohort model outputs served as inputs to economic models, creating a dynamic bioeconomic production model that was validated with observed revenue and cost data. Four management strategies were simulated in this model: (1) a baseline simulation of no change since 1998; (2) actual management regulations; (3) maximizing revenue under actual fishing mortality rates, F, and adjusting age at first capture, ac; and (4) maximizing net revenue adjusting F and ac. Across all simulations, the strategies designed to optimize economic profitability were also the most sustainable, resulting in the highest SPR. Management measures that maximize commercial economic productivity would increase net benefits to the region while providing a more resilient ecosystem through healthier fish populations.

Keywords

age-structured models; bioeconomic simulations; fisheries economics; fish population dynamics; lifetime growth functions; management strategy evaluations

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