scholarly journals Habitat preferences and site fidelity of juvenile red snapper (Lutjanus campechanus)

2002 ◽  
Vol 59 ◽  
pp. S43-S50 ◽  
Author(s):  
I WORKMAN

<em>Abstract.</em>—Red snapper, <em>Lutjanus campechanus</em>, (<em>n </em>= 4,317) were captured and tagged at 14 experimental artificial reefs of two designs during quarterly research cruises (<em>n </em>= 17) off coastal Alabama between January 1999 and October 2002. Six-hundred and twenty nine recaptures were reported, representing 578 tagged red snapper. Sixty-five percent of recaptures (<em>n </em>= 412) were made at the site of release on subsequent research cruises, while 217 recaptures were reported by fishers. Eighty-six percent of individuals with known recapture locations moved 2 km or less from the site of release; mean and maximum distances moved were 2.1 km and 201 km, respectively. Nine red snapper moved greater than 80 km. Mean dispersion rate from release sites was 8.6 m d<sup>⁻1</sup>. Annual site fidelity of tagged fish was estimated using nonlinear decay models. Estimated annual site fidelity ranged from 48% to 52% year<sup>⁻1</sup> and was not significantly affected by artificial reef design, reef fish biomass at the site of release, or artificial reef densities surrounding each tagging site. Growth rates were estimated by regressing the change in red snapper total length versus the days a fish was at liberty. Mean growth rate for all recaptured fish was 0.206 mm d<sup>⁻1</sup>. Growth rates were significantly affected by reef size (faster at larger experimental reefs) and reef fish biomass (slower at tagging sites supporting low reef fish biomass), but were not affected by artificial reef density. Moderate site fidelity and low dispersion rates during our study provide support for the hypothesis that artificial reefs off Alabama are suitable habitat for adult red snapper. However, characteristics of artificial reefs, such as reef size and standing stock biomass, may affect red snapper growth. Furthermore, ratios of instantaneous growth in weight to total mortality (<EM>G/Z</EM>) suggest artificial reefs off Alabama serve as net sinks (i.e., <EM>G/Z </EM>< 1) of red snapper biomass under current fishing mortality rates.


<em>Abstract.</em>—Site fidelity and movements of red snapper <em>Lutjanus campechanus </em>off the coast of Texas were estimated from two tagging programs conducted aboard recreational boats. In one program, we tagged 5,614 red snapper at over 200 fishing sites between July 2002 and August 2005 using hook-and-line gear; fishermen and others reported 130 recaptured fish (a 2.3% return rate), 82 of which included location data. About 54% of the recaptured fish had moved, with an average movement of 20.4 km. In the other program, over 9,000 fish were tagged between 1983 and 2006, but only 68 records of fish tagged between 1986 and 2000 could be analyzed due to computer problems. Of the recaptured fish, 60 could be analyzed for movement, and 17 fish (28%) had moved an average of 19.1 km. Important predictors of movement in at least one program or analysis were depth, habitat type, isolation of the initial capture location, time at liberty, and fish size. Red snapper showed a higher probability of movement from capture sites that were in deep water (>40 m), natural rather than artificial structures, and isolated from other sites rather than clustered. Differences in movement from natural versus artificial sites may have been related to red snapper ‘sub-cohort’ behavior, (the tendency of small groups of red snapper to associate together), as the majority of fish that moved were members of sub-cohorts. Larger fish had a higher probability of movement than smaller fish. In one program, fish movements increased with increasing time at liberty, which is similar to past studies on red snapper site fidelity. In the other program, movements decreased with increasing time at liberty, but this was probably a bias caused by the spatial and temporal scale of the recapture effort. Red snapper that moved showed a higher average daily growth rate between capture and recapture than fish that were stationary, suggesting that movements may be beneficial for red snapper. The spatial scale of fish movements in this study, although larger than in other studies without hurricanes or translocation of fish, was still small enough to support the idea that red snapper populations in the northern Gulf of Mexico are relatively isolated, and that there may be a separate demographic stock off Texas.


<em>Abstract.</em>—The habitat value of petroleum platforms for red snapper, <em>Lutjanus campechanus</em>, is poorly understood. However, it is widely recognized that the presence of thousands of platforms in the northern Gulf of Mexico (GOM) has affected the distribution of red snapper by the addition of hard substrate habitat. We evaluated the habitat value of petroleum platforms by monitoring the fidelity of red snapper to these structures with acoustic telemetry. In May 2003, 125 red snapper were captured with hook and line at several platforms in a 35-km<sup>2</sup> portion of the South Timbalier oil and gas lease blocks, 50 km south of Port Fourchon, Louisiana. Following anaesthetization with MS-222, an individually coded acoustic pinger was surgically implanted into the peritoneal cavity of each specimen. After a short recovery period fish were released at five platforms in the study area. Presence of individual snapper was recorded with omnidirectional acoustic receivers attached to eight platforms. Red snapper exhibited little movement among platforms in the study area; however, logistic regression showed a high initial fidelity to release location which subsequently decreased over time. Therefore, site fidelity was estimated to be high in the short-term, but much lower in the long-term. However, study results were confounded by tag detection issues that may have resulted in long-term site fidelity being underestimated. Overall, estimates provided of red snapper fidelity to petroleum platforms should lead to more effective management of this species by adding to the knowledge of the function of platforms as habitat and their importance to the GOM red snapper population.


2009 ◽  
Vol 17 (2) ◽  
pp. 149-155 ◽  
Author(s):  
R. P. Phelps ◽  
N. Papanikos ◽  
B. D. Bourque ◽  
F. T. Bueno ◽  
R. P. Hastey ◽  
...  

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