Use of natural marks on population estimates of the nurse shark,Ginglymostoma cirratum, at Atol das Rocas Biological Reserve, Brazil

Castro, Alessandra Maia de; Rosa, Ricardo S.

doi:10.1007/s10641-004-1479-7

Cited by 72 publications

(88 citation statements)

References 21 publications

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“…through a longer period of time compared to Florida, where 27-30 cm TL offspring are born mainly during November and early December (Castro, 2000). However, Garla et al (2009) reported neonates visually-estimated at 30 cm TL to occur off FEN considerably earlier, mostly from July to September, which chronologically matches the observation of a 30-cm individual at the nearby Atol das Rocas in August (Castro & Rosa, 2005). The fact that the presence of yolk sac scars was not assessed, though, together with pigmentation distinctive of newborns persisting until ~55 cm TL (Castro, 2000), both bring uncertainty to the actual free-swimming age of these individuals.…”

Section: Discussionsupporting

confidence: 63%

Evasive mating behaviour by female nurse sharks, Ginglymostoma cirratum (Bonnaterre, 1788), in an equatorial insular breeding ground

Afonso

Cantareli²,

Levy

et al. 2016

Neotrop. ichthyol.

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Mating events and aggregations of vulnerable nurse sharks Ginglymostoma cirratum were recorded in the insular protected area of Fernando de Noronha (FEN), Brazil, between April and August 2015. Female sharks were observed clustering in groups of up to 14 individuals in shallow water adjacent to the shore. Several evasive mating behaviours in the presence of males were noticed, including shoreward movement, positioning ventral side up at the sea surface with emerged pectoral and pelvic fins, body rolling and caudal fin thrashing. Fresh bite marks indicative of male courtship and coupling attempts were visible in female's pectoral and caudal fins. Altogether, the observed behaviours match previous reports of noncooperative female nurse sharks during mating opportunities. An extended mating season coupled with a persistent use of inshore habitats result in nurse sharks being particularly vulnerable to human pressure during a most sensitive stage of their life cycle. The effective conservation of nurse shark populations from the western South Atlantic may thus depend on the protection of critical habitats where this species aggregates to reproduce. Explicitly addressing environmental requirements by vulnerable species in local management strategies is indispensable to ensure that human pressure, including ecotourism development, does not collide with stipulated conservation aims.Agregações e eventos reprodutivos do vulnerável tubarão-lixa, Ginglymosytoma cirratum, foram registrados na área insular protegida do Arquipélago de Fernando de Noronha (FEN), Brasil, entre Abril e Agosto de 2015. Grupos constituídos por até 14 fêmeas foram observados em águas rasas adjacentes à linha costeira. Perante a presença de machos, diversos comportamentos evasivos por parte das fêmeas foram identificados, incluíndo movimentação para águas ainda mais rasas, posicionamento na superfície do mar com a face ventral orientada para cima e emersão das nadadeiras peitorais e pélvicas, enrolamento do corpo e batimento da nadadeira caudal na superfície do mar. Foram identificadas marcas recentes de mordida nas nadadeiras peitorais e caudais das fêmeas, sugerindo interações de acasalamento com machos. No geral, os comportamentos observados coincidem com os comportamentos exibidos por fêmeas não aquiescentes à cópula reportados no hemisfério norte. Em FEN, a duração relativamente longa do período de acasalamento, juntamente com a utilização persistente dos habitats mais costeiros, promovem a vulnerabilidade do tubarão lixa às pressões antrópicas durante uma das fases mais sensíveis do seu ciclo de vida. A conservação efetiva das populações de tubarão-lixa do Oceano Atlântico Sul ocidental poderá, assim, depender da proteção dos habitats críticos de agregação onde esta espécie se reproduz. Por conseguinte, a abordagem explícita dos requisitos ambientais associados a espécies vulneráveis no âmbito dos planos de manejo locais deve ser considerada como indispensável para assegurar que as pressões antrópicas, incluíndo o desenvolvimento ecoturístico,...

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Section: Discussionsupporting

confidence: 63%

Evasive mating behaviour by female nurse sharks, Ginglymostoma cirratum (Bonnaterre, 1788), in an equatorial insular breeding ground

Afonso

Cantareli²,

Levy

et al. 2016

Neotrop. ichthyol.

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“…However, in white sharks, the trailing edge of the dorsal fin is analogous to a fingerprint, hence provides a unique identifying trait of individual sharks over long time periods (greater than 22 years) [10]. Similar identification techniques have been described to identify nurse sharks, Ginglymostoma cirratum [11], and marine mammals [12]. The goal of this study was to estimate the abundance of mature and sub-adult white sharks at seasonal aggregation sites in CCA, to serve as a baseline for future assessment and monitoring of this population.…”

Section: Introductionmentioning

confidence: 95%

A first estimate of white shark, Carcharodon carcharias , abundance off Central California

et al. 2011

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The decline of sharks in the global oceans underscores the need for careful assessment and monitoring of remaining populations. The northeastern Pacific is the home range for a genetically distinct clade of white sharks (Carcharodon carcharias). Little is known about the conservation status of this demographically isolated population, concentrated seasonally at two discrete aggregation sites: Central California (CCA) and Guadalupe Island, Mexico. We used photo-identification of dorsal fins in a sequential Bayesian mark-recapture algorithm to estimate white shark abundance off CCA. We collected 321 photographs identifying 130 unique individuals, and estimated the abundance off CCA to be 219 mature and sub-adult individuals ((130, 275) 95% credible intervals), substantially smaller than populations of other large marine predators. Our methods can be readily expanded to estimate shark population abundance at other locations, and over time, to monitor the status, population trends and protection needs of these globally distributed predators.

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“…Perkins and Whitehead 1977;Durban et al 2010). More recently, this technique has been applied successfully to examine aspects of the biology of several elasmobranch species, including the nurse shark Ginglymostoma cirratum (Castro and Rosa 2005), white shark Carcharodon carcharias (Domeier and Nasby-Lucas 2007), grey nurse shark Carcharias taurus (Bansemer and Bennett 2008), zebra shark Stegostoma fasciatum (Dudgeon et al 2008) and whale shark Rhincodon typus (Speed et al 2008). Much of the information available on manta ray movements and ecology has been obtained from photo-ID of individuals (e.g.…”

Section: Introductionmentioning

confidence: 99%

Distribution, site affinity and regional movements of the manta ray, Manta alfredi (Krefft, 1868), along the east coast of Australia

Couturier

Jaine

Townsend

et al. 2011

Mar. Freshwater Res.

100

150

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Abstract. Despite the increasing tourism interest worldwide for the manta ray, Manta alfredi, very little is known about its biology and ecology. Knowledge of its distribution and movement patterns is important for conservation purposes. Here we describe the distribution, site visitation and movements of M. alfredi along the east coast of Australia. Photographic identification techniques were used to identify individual manta rays at three study sites: Lady Elliot Island, North Stradbroke Island and Byron Bay. Of 388 M. alfredi individuals identified at Lady Elliot Island, 187 (48%) were subsequently re-identified at least once at the same site. In total, 31 individuals were identified at both Lady Elliot Island and North Stradbroke Island (,380 km to the south) and 4 at both Lady Elliot Island and Byron Bay (,500 km to the south). Manta alfredi was present all year around at Lady Elliot Island, although in higher numbers in winter, and was mainly observed at North Stradbroke Island and Byron Bay from mid-spring to mid-autumn. This is the first report of seasonal movements and site affinity for M. alfredi in eastern Australian waters and emphasises the value of photographic identification for monitoring the occurrence of individuals.

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Use of natural marks on population estimates of the nurse shark,Ginglymostoma cirratum, at Atol das Rocas Biological Reserve, Brazil

Cited by 72 publications

References 21 publications

Evasive mating behaviour by female nurse sharks, Ginglymostoma cirratum (Bonnaterre, 1788), in an equatorial insular breeding ground

Evasive mating behaviour by female nurse sharks, Ginglymostoma cirratum (Bonnaterre, 1788), in an equatorial insular breeding ground

A first estimate of white shark, Carcharodon carcharias , abundance off Central California

Distribution, site affinity and regional movements of the manta ray, Manta alfredi (Krefft, 1868), along the east coast of Australia

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