Habitat Use by Juvenile Gag, Mycteroperca microlepis (Pisces: Serranidae), in Subtropical Charlotte Harbor, Florida (USA)

Abstract

Estuaries playa key role in the juvenlle stage of gag (Myeteroperca microlepis). The use of estuarine habitats by juvenlle gag has been examined in temperate estuaries, which are at the northern limits of the range of this species, but the importance of subtropical estuaries during fue early life history of this species has not heen studied extensively. Gag were collected in subtropical Charlotte Harbor, Florida, during routine monthiy sampling from January 1996 to Decemher 2002. Juvenlle gag were collected using a 21.3-m seine, a 183-m haul seine, and a 183-m purse seine. A total of 738 individuals ranging from 30 to 489 rom standard length (SL) were collected in 4,480 samples. Most gag (96%) were probably young-of-the-year « 288 rom SL). The majority of juveniles were collected in polyhatine Gasparilla and Pine Island sounds from April to December, with a few larger individuals captured year-round. The observed period of gag settlement was similar to thet reported in other subtropical and temperate estuaries, but gag in Charlotte Harbor remained in fue estuary longer and egressed at a larger size 1han did gag in other estuaries. Relative abundance of juvenile gag within Charlotte Harbor was greatest on shallow seagrass shoals but was also high along flinging mangrove shorelines, which is a habitat not previously reported for gag.

Incorporating Ecology into Survey Design: Monitoring the Recruitment of Age‐0 Gags in the Eastern Gulf of Mexico

“…Age-0 Gag catch rates were demonstrably higher in the supplemental surveys than in the long-term surveys. It has been well documented that juvenile Gags frequent polyhaline seagrass beds throughout the eastern Gulf (Koenig and Coleman 1998;Fitzhugh et al 2005;Casey et al 2007), and our supplemental surveys incorporated information on habitat selection by age-0 Gags to focus sampling efforts on specific habitats that have not been adequately sampled during the ongoing long-term surveys conducted by the FWRI (Purtlebaugh and Rogers 2007;Winner et al 2010). This design approach is important for accurately assessing fish populations (Hilborn and Walters 1992) and provides cost-effective data from undersampled habitats, which can be integrated with data from long-term surveys to address a variety of emerging issues.…”

“…The eastern Gulf of Mexico (hereafter, Gulf) contains a productive, diverse reef fish assemblage, including several shallow-water grouper species (Epinephelidae) such as the Gag Mycteroperca microlepis, which has long supported lucrative commercial and recreational fisheries (Bullock and Smith 1991). Gags are relatively unusual among economically important groupers in the eastern Gulf because they spend most of their first year of life in estuarine nurseries (Koenig and Coleman 1998;Fitzhugh et al 2005;Casey et al 2007;Switzer et al 2012). Although some Gags may overwinter in the estuary (Heinisch and Fable 1999;Casey et al 2007;Switzer et al 2012), most migrate offshore en masse during the late fall (Ross and Moser 1995;Koenig and Coleman 1998).…”

“…Gags are relatively unusual among economically important groupers in the eastern Gulf because they spend most of their first year of life in estuarine nurseries (Koenig and Coleman 1998;Fitzhugh et al 2005;Casey et al 2007;Switzer et al 2012). Although some Gags may overwinter in the estuary (Heinisch and Fable 1999;Casey et al 2007;Switzer et al 2012), most migrate offshore en masse during the late fall (Ross and Moser 1995;Koenig and Coleman 1998). The ephemeral concentration of age-0 Gags in estuaries greatly facilitates the assessment of interannual variability in juvenile recruitment.…”

Reproductive Biology of the Cownose Ray in the Charlotte Harbor Estuarine System, Florida

“…The principal collecting gears were gill nets (45-183 m long, all with 152-mm stretched monofilament mesh) and center-bag haul seines (183 m long, with 38-mm stretched mesh). Details of these sampling techniques are given in Casey et al (2007) and Poulakis et al (2011). Following capture, all Cownose Rays were sexed and their maximum disk widths (DW; mm) were recorded.…”

Seagrass Habitats as Nurseries for Reef-Associated Fish: Evidence from Fish Assemblages in and Adjacent to a Recently Established No-Take Marine Reserve in Dry Tortugas National Park, Florida, USA

“…Although reef habitats in the DTNP are important centers for spawning of many exploited species (Ault et al 2002, Rogers et al 2007, little research has been done on the function of DTNP seagrass habitats, even though they serve as valuable nursery habitat in other coral reef systems (Nagelkerken et al 2001(Nagelkerken et al , 2002, Nagelkerken and van der Velde 2004, Unsworth et al 2008). It is well known that many reef fish juveniles settle into seagrass beds before moving into nearby reef habitats as adults (Chittaro et al 2005, Casey et al 2007, Nagelkerken et al 2012, Flaherty-Walia et al 2015, and this study documented smaller sizes of E. morio and H. plumierii in seagrass habitats than in reef habitats. Additional research is needed to confirm this result for E. morio due to small sample size (n = 8, ≤ 200 mm SL), however.…”