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Gledhill K.S.,South African Shark Conservancy | Kessel S.T.,University of Windsor | Guttridge T.L.,Bimini Biological Field Station Foundation | Hansell A.C.,University of Massachusetts Dartmouth | And 5 more authors.
Journal of Fish Biology | Year: 2015

A longline survey was conducted from 2004 to 2014 to investigate the demographic population structure and seasonal abundance of the blacktip shark Carcharhinus limbatus in the Bimini Islands, the Bahamas. All individuals sampled (n = 242) were sub-adult or adults [70·1-145·1 cm pre-caudal length (LPC) range] with no neonates or YOY recorded in Bimini. Carcharhinus limbatus abundance peaked in September, coincident with the largest ratio of female to male sharks and a peak in fresh mating wounds on females. Mitochondrial control region (mtCR) DNA sequences were obtained from C. limbatus at Bimini to test whether Bimini C. limbatus are most closely related to geographically proximate populations sampled on the south-eastern coast of the U.S.A., the closest known nursery areas for this species. Nine mtCR haplotypes were observed in 32 individuals sampled at Bimini [haplotype diversity (h) = 0·821, nucleotide diversity (π) = 0·0015]. Four haplotypes observed from Bimini matched those previously found in the northern Yucatan (Mexico)-Belize and two matched a haplotype previously found in the U.S.A. Four haplotypes were novel but were closely related to the northern Yucatan-Belizean haplotypes. Pair-wise ΦST analysis showed that Bimini was significantly differentiated from all of the populations previously sampled (U.S.A. Atlantic, U.S.A. Gulf of Mexico, northern Yucatan, Belize and Brazil). This indicates that C. limbatus sampled from Bimini are unlikely from the described, proximate U.S.A. nurseries. © 2015 The Fisheries Society of the British Isles. Source

Kessel S.T.,University of Windsor | Kessel S.T.,University of Cardiff | Chapman D.D.,State University of New York at Stony Brook | Franks B.R.,Bimini Biological Field Station Foundation | And 5 more authors.
Marine Ecology Progress Series | Year: 2014

Understanding how and why animals are distributed through time and space has always been a fundamental component of ecology and is an essential prerequisite for effective conservation and/or management. However, for highly mobile K-selected species, behavioural predictability is rarely considered over appropriate scales relative to life history. To address this point, a multidisciplinary approach combining telemetry, external tagging, physical assessment, environmental monitoring and genetic analysis was adopted to determine a spatial framework for the movements of adult lemon sharks Negaprion brevirostris at multiple spatial and temporal scales from 2007 to 2011. Lemon sharks (n = 83) were tracked with passive acoustic telemetry, revealing a winter residency in the southeast Florida region. Detections from individuals recorded within the core winter habitat for >20 d (n = 56) were incorporated into generalized linear mixedeffects models to investigate the influence of water temperature, photoperiod, moon phase, month and year on presence. The findings of this study suggest a temperature driven 'migrationresidency' model for mature lemon shark distribution across the USA eastern seaboard. Lemon sharks are distributed across a wide geographical area in the summer months and migrate south concentrating off southeast Florida in the winter, with this pattern repeated each year. From comparative genetic analysis and the absence of any evidence of mating behaviour during the winter residency period, mating and parturition most probably occur in May/June between northern Florida and the Carolinas. This study highlights the importance of determining the specific dynamics and proximate causes of animal movement and distribution over appropriate spatial and temporal scales relative to life history. © Inter-Research 2014. Source

Finger J.S.,Humboldt University of Berlin | Finger J.S.,Leibniz Institute of Freshwater Ecology and Inland Fisheries | Dhellemmes F.,Humboldt University of Berlin | Dhellemmes F.,Leibniz Institute of Freshwater Ecology and Inland Fisheries | And 6 more authors.
Animal Behaviour | Year: 2016

Personality differences are widespread throughout the animal kingdom and can have important ecological and evolutionary consequences. Despite a rapidly increasing body of literature, large (marine) vertebrates remain underrepresented in personality research. Given their unique life history traits (e.g. slow growth rate, slow reproduction rate, long life span) and their pivotal role in ecosystem processes, this is an important gap in our current knowledge. Here we investigated consistency and plasticity in movement behaviour of wild juvenile lemon sharks, Negaprion brevirostris, by repeatedly subjecting sharks to open field tests. First, we investigated the presence of interindividual differences in movement behaviour in a novel open field. Second, we investigated the effect of trial repetition on movement behaviour to understand whether movement in a novel open field reflects a reaction to novelty, or general activity. Third, we estimated individual differences in habituation/sensitization rates over trial repetition and studied how the habituation rate was predicted by the initial movement rate. We found consistent individual differences in movement behaviour during the open field tests. Sharks showed habituation in movement behaviour (i.e. decrease) over repeated trials indicating that the movement behaviour during the first trials is a reaction to novelty, and not general activity. Individuals, however, differed in their rate of habituation (i.e. plasticity) and this rate was negatively related to an individual's movement behaviour in the first open field trial. In addition to showing individual differences in consistency and plasticity in juvenile lemon sharks, our study emphasizes the importance of examining the validity of personality tests when adapting them to new species. © 2016 The Association for the Study of Animal Behaviour. Source

Guttridge T.L.,Bimini Biological Field Station Foundation | Gulak S.J.B.,Southeast Fisheries Science Center | Franks B.R.,Florida Southern College | Carlson J.K.,Southeast Fisheries Science Center | And 6 more authors.
Journal of Fish Biology | Year: 2015

This study documents and discusses recent (2002-2015) sightings and captures of smalltooth sawfish Pristis pectinata in the Bahamas. Movement patterns and habitat preferences of five P. pectinata are examined: two tracked with acoustic telemetry in Bimini and three tagged with pop-up archival transmitting tags in Andros. Historically, P. pectinata may have been distributed throughout the Bahamas; however, since 2002 only 61 encounters were recorded including: Andros (30), Bimini (19) and a handful across other Islands (12). In Bimini, all P. pectinata were >225 cm (stretched total length, LST) suggesting that it is not used as a nursery area. Pristis pectinata in Andros ranged from c. 80 to 450 cm (LST) indicating that this island might be an important nursery and breeding habitat. Pristis pectinata tracked in both islands remained at depths <3 m, often adjacent to mangrove habitats, displaying residency from 42 days (Bimini) to 180 days (Andros). These preliminary findings confirm the Bahamas as an important habitat for P. pectinata and emphasize the urgent need for national protection and management of this population. © 2015 The Fisheries Society of the British Isles. Source

Bullock R.W.,Bimini Biological Field Station Foundation | Bullock R.W.,University of Hull | Guttridge T.L.,Bimini Biological Field Station Foundation | Cowx I.G.,University of Hull | And 3 more authors.
Journal of Fish Biology | Year: 2015

Behavioural responses of lemon sharks Negaprion brevirostris to a fin-mounted tag package (CEFAS G6A tri-axial accelerometer with epoxied Sonotronics PT4 acoustic transmitter) were measured in a controlled captive environment (n = 10, total length, LT range 80-140 cm) and in free-ranging sharks upon release (n = 7, LT range100-160 cm). No changes were detected in behaviour (i.e. swimming speed, tailbeat frequency, time spent resting and frequency of chafing) between control and tagged captive shark trials, suggesting that the tag package itself does not alter behaviour. In the free-ranging trials, an initial period of elevated swimming activity was found in all individuals (represented by overall dynamic body acceleration). Negaprion brevirostris, however, appeared to recover quickly, returning to a steady swimming state between 2 and 35 min after release. Post-release tracking found that all sharks swim immediately for the shoreline and remain within 100 m of shore for prolonged periods. Hence, although N. brevirostris are capable of quick adaptation to stressors and demonstrate rapid recovery in terms of activity, tracking data suggest that they may modify their spatial use patterns post release. This research is important in separating deviation in behaviour due to environmental stressors from artefacts caused by experimental techniques. © 2015 The Fisheries Society of the British Isles. Source

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