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CHARACTERIZATION OF THE STRIPED MULLET (MUGIL CEPHALUS) IN SOUTHWEST FLORIDA: INFLUENCE OF FISHERS AND ENVIRONMENTAL FACTORS

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Date Issued:
2018-08-21
Abstract/Description:
Striped mullet (Mugil cephalus) make up a significant portion of Florida’s commercial fishery, with 80% of the landings coming from Southwest Florida between Tampa Bay and Charlotte Harbor. The Gill Net Ban of 1995 marked a significant moment in the history of mullet fishing in the state, and its affects on the industry, particularly the shift of gear usage from primarily gill nets to cast and seine nets have not been fully evaluated. Although the program for collecting data onboard larger offshore vessels has been in place for several decades, little work has been done to collect similar information onboard smaller, inshore vessels. The approach of this study was an attempt to see if it was feasible to collect quality data onboard small commercial vessels fishing in Florida state waters. The goal of this project was to collect relevant data useful for fisheries management, including comprehensive onboard observations for characterizing the spatial and temporal patterns in fishing activities and effort in the mullet fishery. The project collected data to qualitatively and quantitatively describe a typical mullet fishing trip on the southwest coast of Florida (Sarasota Bay and Charlotte Harbor), including effort information and gear types. Catch composition, including target and bycatch species, fish size, and sex were recorded, and the influence of various environmental factors was analyzed. Results indicated that air temperature and catch of Striped Mullet Mugil cephalus and Silver Mullet M. curema were inversely related. Water temperature and M. curema were also inversely correlated. These results reflect the consideration of the more profitable winter mullet roe season by fishers in directing their fishing effort. Total catch and dissolved oxygen concentration were inversely correlated. Striped Mullet are known to undertake surface respiration under conditions of hypoxia encountered during feeding. The relationship between dissolved oxygen and total fish catch may therefore have been shaped by the dominance of M. cephalus (63.5%) in the total catch. More fish were caught during crepuscular hours, suggesting that reduced light may alter swimming behavior or increase net avoidance. In further support of this, M. curema catch was greatest during a new moon. More fish were caught over seagrass, and more M. curema were caught over sand, indicating the importance of habitat type on species distribution. The simultaneous use of cast nets and seine nets was more effective than either net alone and resulted in less bycatch—information that may prove useful in the management of the fishery. Overall results indicate that fishing techniques and behavior had more of an effect on catch rates than variability in environmental conditions.
Title: CHARACTERIZATION OF THE STRIPED MULLET (MUGIL CEPHALUS) IN SOUTHWEST FLORIDA: INFLUENCE OF FISHERS AND ENVIRONMENTAL FACTORS.
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Name(s): Marin, Charlotte, author
Type of Resource: text
Genre: Thesis
Issuance: single unit
Date Issued: 2018-08-21
Physical Form: PDF
Extent: 147 pgs.
Language(s): English
eng
Abstract/Description: Striped mullet (Mugil cephalus) make up a significant portion of Florida’s commercial fishery, with 80% of the landings coming from Southwest Florida between Tampa Bay and Charlotte Harbor. The Gill Net Ban of 1995 marked a significant moment in the history of mullet fishing in the state, and its affects on the industry, particularly the shift of gear usage from primarily gill nets to cast and seine nets have not been fully evaluated. Although the program for collecting data onboard larger offshore vessels has been in place for several decades, little work has been done to collect similar information onboard smaller, inshore vessels. The approach of this study was an attempt to see if it was feasible to collect quality data onboard small commercial vessels fishing in Florida state waters. The goal of this project was to collect relevant data useful for fisheries management, including comprehensive onboard observations for characterizing the spatial and temporal patterns in fishing activities and effort in the mullet fishery. The project collected data to qualitatively and quantitatively describe a typical mullet fishing trip on the southwest coast of Florida (Sarasota Bay and Charlotte Harbor), including effort information and gear types. Catch composition, including target and bycatch species, fish size, and sex were recorded, and the influence of various environmental factors was analyzed. Results indicated that air temperature and catch of Striped Mullet Mugil cephalus and Silver Mullet M. curema were inversely related. Water temperature and M. curema were also inversely correlated. These results reflect the consideration of the more profitable winter mullet roe season by fishers in directing their fishing effort. Total catch and dissolved oxygen concentration were inversely correlated. Striped Mullet are known to undertake surface respiration under conditions of hypoxia encountered during feeding. The relationship between dissolved oxygen and total fish catch may therefore have been shaped by the dominance of M. cephalus (63.5%) in the total catch. More fish were caught during crepuscular hours, suggesting that reduced light may alter swimming behavior or increase net avoidance. In further support of this, M. curema catch was greatest during a new moon. More fish were caught over seagrass, and more M. curema were caught over sand, indicating the importance of habitat type on species distribution. The simultaneous use of cast nets and seine nets was more effective than either net alone and resulted in less bycatch—information that may prove useful in the management of the fishery. Overall results indicate that fishing techniques and behavior had more of an effect on catch rates than variability in environmental conditions.
Identifier: fgcu_ETD_0257 (IID)
Note(s): Degree Awarded: Master of Science
Subject(s): Environmental affects mullet fishing catch rates
Florida commercial fishing
Gill Net Ban Florida
history striped mullet (Mugil cephalus) Florida
striped mullet habitat conditions
striped mullet (Mugil cephalus) fishing
Persistent Link to This Record: http://purl.flvc.org/fgcu/fd/fgcu_ETD_0257
Use and Reproduction: Creator holds copyright.
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FGCU