Fine‐Scale Movements and Home Ranges of Red Snapper around Artificial Reefs in the Northern Gulf of Mexico

Abstract

Red Snapper Lutjanus campechanus are generally associated with artificial reef habitats in the northern Gulf of Mexico, but whether this association results in fish production is still controversial. Information on fine‐scale habitat use patterns would be helpful in evaluating this. Little is known about the fine‐scale movement patterns of Red Snapper around artificial reefs. The present study examined fine‐scale (∼1‐m accuracy) movements of Red Snapper with the Vemco VR2W Positioning System. This system enabled continuous monitoring of tagged fish from 100 to 694 d. Locations of individual fish were recorded approximately every 10 min and totaled over 1.9 million accurate locations of Red Snapper from August 2010 through May 2012. Red Snapper showed close association with the reef structure (mean ± SD distance = 26.3 ± 35.4 m) but differential habitat use in relation to both diel and seasonal periods. Home range areas (95% kernel density estimates [KDE]) were significantly larger during day than night periods and showed the lowest area use at dawn and dusk. Monthly home ranges (95% KDE) and core areas (50% KDE) were significantly larger in spring, summer, and fall than in winter and were significantly correlated with water temperature, suggesting colder winter temperatures reduced Red Snapper movement. Home range area was significantly correlated with fish size (407–590 mm standard length), and the fish in this study showed the highest site fidelity (88% still present after >10 months) of any Red Snapper in other previous studies. Red Snapper also showed use of multiple reefs within the monitoring area, as home ranges (95% KDE) showed a second peak around other artificial reefs. The high site fidelity, long‐term use, and concentrated use of multiple artificial reefs confirm the importance of structured habitat for Red Snapper. Received September 1, 2013; accepted February 27, 2014

A cage release method to improve fish tagging studies

“…All tagged fish were released on artificial reefs surrounded by an acoustic array (VEMCO, VR2W Positioning System, Vemco Ltd, Nova Scotia; Piraino and Szedlmayer, 2014) and their fine-scale positions (∼1 m accuracy) were monitored for extended time periods (up to 2 years). Survival was evaluated based on the fine-scale movements of tagged fish within the VPS array.…”

“…In both conventional and acoustic tagging studies, increased stress, emigration, and mortality of fish after tag and release has been reported for several different release methods (Szedlmayer, 1997;Starr et al, 2000;Humston et al, 2005;Szedlmayer and Schroepfer, 2005;McDonough and Cowan, 2007;Westmeyer et al, 2007;Szedlmayer, 2011b, 2013;Piraino and Szedlmayer, 2014). Immediate and prolonged tagging mortalities due to barotrauma and stress from the tagging procedure have been examined in multiple species (Parrish and Moffitt, 1992;Davis, 2002;McGovern et al, 2005;Jarvis and Lowe, 2008;Diamond and Campbell, 2009;Pribyl et al, 2009;Campbell et al, 2010;Sumpton et al, 2010;Hannah and Rankin, 2011;Hannah et al, 2012;Pribyl et al, 2011).…”

“…For example, the drop weight release method was quick, inexpensive, and returned fish to their depth of capture (Szedlmayer and Schroepfer, 2005;Szedlmayer, 2011a, 2011b;Piraino and Szedlmayer, 2014). However, during descent tagged fish were not protected against predators.…”

“…Methods of release include surface release (Fable, 1980;Szedlmayer and Shipp, 1994;Gitschlag and Renaud, 1994;Patterson et al, 2001;McDonough and Cowan, 2007;Hannah and Rankin, 2011), drop weights (Szedlmayer and Schroepfer, 2005;Szedlmayer, 2011a, 2011b;Piraino and Szedlmayer, 2014), underwater tagging and release by SCUBA divers (Tong, 1978;Gitschlag, 1986;Parrish and Moffett, 1992;Szedlmayer, 1997;Starr et al, 2000;Sigurdsson et al, 2006), surface tagging and underwater release by divers (Szedlmayer, 1997;Nemeth et al, 2007), and surface tagging, caging, and delayed release by divers (Piraino and Szedlmayer, 2014).…”

“…The early escape of disoriented fish during decent at mid-depths can substantially increase emigration and predation. In an effort to reduce predation effects, cage release methods were tested for transmitter tagged red snapper (Lutjanus campechanus; Piraino and Szedlmayer, 2014 doors on the bottom and released the fish close (2-3 m) to the reef. This cage release method required more time and training, but successfully reduced tag induced emigrations and predation mortality of tagged red snapper from 85% to 8%.…”