Grouper and snapper movements and habitat use in Dry Tortugas, Florida

Abstract

Home ranges, activity patterns, and habitat preferences in and around no-take marine reserves (NTMRs) were evaluated for 5 exploited snapper-grouper species in diverse coral reef habitats in the Dry Tortugas, Florida. Movements of ultrasonic tagged reef fish were determined using a calibrated array of omnidirectional hydroacoustic receivers. Average home range sizes were 2.09 ± 0.39 km 2 (n = 28; total length, TL = 45 to 66 cm) for red grouper Epinephelus morio, 4.17 ± 1.75 km 2 (n = 5, TL = 48 to 55 cm) for yellowtail snapper Ocyurus chrysurus, 1.44 ± 1.04 km 2 (n = 2, TL = 57 to 75 cm) for black grouper Mycteroperca bonaci, and 7.64 km 2 (n = 1, TL = 70 cm) for mutton snapper Lutjanus analis. Red grouper and yellowtail snapper moved moderate distances (from 700 to 900 m) with moderate frequency. Observed movements for black groupers were relatively small and infrequent. Mutton snappers appeared to make short, frequent movements. A tracked gray snapper L. griseus made long-distance nocturnal migrations. Several exploited-phase groupers and snappers crossed into and out of reserve boundaries. They were most likely to do so in locations where boundaries were positioned over contiguous coral reef and close to home-range centers. We found that home ranges for red grouper, black grouper, and yellowtail snapper were relatively small in comparison to NTMR area. Our observations suggest that the Dry Tortugas NTMRs may reduce exposure to exploitation for these and other species with limited home ranges, especially where NTMR boundaries do not overlie contiguous reef. KEY WORDS: Acoustic tracking · Snapper-grouper complex · Movement patterns · Home range · Marine reserves · Coral reef fishesResale or republication not permitted without written consent of the publisher reef habitats and helping to sustain the region's worldclass fisheries resources. Evidence has already emerged that they are reaching their intended goals (Ault et al. 2006b).Many marine fishes repeatedly use and move throughout particular areas, or home ranges (Burt 1943), for certain periods of the year or for particular life stages (Goeden 1978, Shapiro et al. 1994, Rooij et al. 1996, Zeller 1997, Kramer & Chapman 1999, Bell & Kramer 2000, Bolden 2001, Eristhee & Oxenford 2001, Baras et al. 2002, Lembo et al. 2002, Parsons et al. 2003. Occupation by marine fishes of a particular home range within a spatially heterogeneous landscape -given increased familiarity with key habitat features -may facilitate evasion of predators and increase foraging efficiency (review in Harris et al. 1990).Quantifying short-and longer-term fish movement patterns, home ranges, and habitat use is critical for advancing understanding of the dynamics of reef-fish community ecology and for informing intelligent NTMR design (Russ & Alcala 1996, Palumbi 2001, Meester et al. 2004, O'Dor et al. 2004. Unfortunately, data of this type are extremely limited (Kramer & Chapman 1999, Meyer et al. 2007. As a result, most reserves have been implemented with little quantitative desig...

Cross‐Shelf Habitat Occupancy Probabilities for Juvenile Groupers in the Florida Keys Coral Reef Ecosystem

“…Excess zeroes could have occurred if individual fish inhabiting a PSU moved into or out of the SSU, lowering the probability of their being observed by a diver. While many reef-associated fishes tend to exhibit low mobility, larger grouper species maintain home ranges considerably larger than the 200-m × 200-m PSU (Chapman and Kramer 2000;Farmer and Ault 2011). The areal extent of an SSU in relation to that of a PSU also suggests that finescale spatial environmental heterogeneity could influence the propensity for not being observed by divers.…”

Comparisons between abundance estimates from underwater visual census and catch-per-unit-effort in a patch reef system

“…Farmer & Ault (2011) reported that L. analis makes short, frequent (scales of minutes) movements of up to 500 m, and Lindholm et al (2005) showed that Ocyurus chrysurus also regularly moved back and forth from sites 500 m apart at 15 min intervals. As all 3 lutjanids appear to display similar movement abilities, differences in observed correlations between sampling methods may be affected by schooling behavior.…”

Home range and seasonal movements of Black Sea Bass (Centropristis striata) during their inshore residency at a reef in the mid-Atlantic Bight

“…These spatial and temporal scales of study may be suffi cient for elucidating the size of the home range of relatively sedentary fi shes that inhabit restricted areas, such as coral reefs. However, recent work indicates that estimates of home range may be larger when habitat use of a target fi sh is monitored over larger spatial scales and over longer time periods (Farmer and Ault, 2011). Furthermore, because movement behaviors may vary among individuals, large sample sizes could improve our understanding of the size of the home range for a given species.…”

“…Home range and movements of mobile species can be assessed with acoustic telemetry (e.g., Dawson and Starr, 2009;Douglas et al, 2009;Meyer et al, 2009;Farmer and Ault, 2011;Knip et al, 2012 intensive information, many acoustic studies of the home ranges of fi shes have been conducted on relatively small spatial scales (hundreds of meters to a few kilometers) or during brief periods of time (days to weeks) with few fi sh (typically 15 or less). These spatial and temporal scales of study may be suffi cient for elucidating the size of the home range of relatively sedentary fi shes that inhabit restricted areas, such as coral reefs.…”