Age and growth estimates of the bull shark, Carcharhinus leucas, from the northern Gulf of Mexico

Branstetter, Steven; Stiles, Robert

doi:10.1007/bf00004952

Cited by 116 publications

(124 citation statements)

References 18 publications

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Section: Methodsmentioning

confidence: 86%

“…We regarded the change of angle caused by differences in growth rate from intra-uterine to post-natal life history stages as the point of birth, or birth mark and recorded it as year zero (Cailliet & Goldman 2004). Annual growth band deposition has been confirmed for bull sharks (Branstetter & Stiles 1987, Neer et al 2005) and pig-eye sharks (Tillett et al 2011a).Preliminary study. Initial analyses determined (1) the concentric manner in which the calcareous vertebral matrix was deposited and the corresponding 3-dimensional structure of the sagittal section, and (2) inter-vertebral variation in chemical composition of the matrix.…”

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confidence: 75%

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Decoding fingerprints: elemental composition of vertebrae correlates to age-related habitat use in two morphologically similar sharks

Tillett¹,

Meekan²,

Parry³

et al. 2011

Mar. Ecol. Prog. Ser.

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We compare vertebral microchemistry with previously described age-related movement patterns of bull sharks Carcharhinus leucas and pig-eye sharks C. amboinensis within coastal waters of north Australia. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) quantified the chemical signatures of nursery habitats within the vertebrae of juvenile and adult sharks. We examined evidence for adults returning to these habitats by applying LA-ICP-MS along a growth axis of their vertebrae. We transposed chemical signatures with growth increments in adult vertebrae to correlate with age estimates. Unique elemental signatures were identified in each of the freshwater nurseries, but we did not find them in adult vertebrae. Age-specific changes in vertebral microchemistry in mature female bull sharks correlate with periodic returns every 1 to 2 yr to less saline environments to pup. We were unable to discriminate among natal habitats of pig-eye sharks using elemental fingerprints, and age-specific changes in vertebral microchemistry were also absent. We conclude that changes in vertebral microchemistry correlate with known habitat use patterns of the bull and pig-eye sharks, showing the potential of vertebral microchemistry to discern movement patterns in sharks. KEY WORDS: Vertebral microchemistry · LA-ICP-MS · Movement · Long-term · Resource partitioning · CarcharhinidaeResale or republication not permitted without written consent of the publisher Mar Ecol Prog Ser 434: 133-142, 2011 Speed et al. 2010) that are critical to the maintenance of genetic diversity and replenishment of populations (Hueter et al. 2005).Studies tracking shark movements and identifying patterns of habitat use in coastal regions typically involve tagging with standard (numerical), satellite or sonar tags (Speed et al. 2010). Such an approach is often logistically difficult and expensive because it first involves the capture, tagging and release (in good condition) of the shark. Furthermore, the animals must either be recaptured (standard tags), or tags must report to satellites or arrays of listening stations (sonar tags) for data acquisition (Voegeli et al. 2001, Simpfendorfer & Heupel 2004. Rates of recapture are usually low, while failure of expensive satellite tags to report is commonplace (Hays et al. 2007). Arrays of listening stations require considerable effort to deploy, download and maintain, which can limit the duration and spatial extent of a study using this approach. Despite these problems, studies using these techniques have mapped fine-scale (25 km) movements of different-age cohorts of sharks in shallow coastal waters (Simpfendorfer et al. 2005, Yeiser et al. 2008, Heithaus et al. 2009, Ortega et al. 2009, but the logistics, cost and limited life span of tags have restricted the number of target individuals and species and, in the case of sonar tags, the spatial extent of the sampling area.To overcome the limitations associated with conventional tracking, natural chemical fingerprints are a developing ...

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Section: Methodsmentioning

confidence: 86%

mentioning

confidence: 75%

Decoding fingerprints: elemental composition of vertebrae correlates to age-related habitat use in two morphologically similar sharks

Tillett¹,

Meekan²,

Parry³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…Because size at birth is quite variable in bull sharks (Neer et al 2005) and growth rate among individuals is also variable, especially for smaller animals (Branstetter & Stiles 1987), it is possible that individuals that fall between 60 and 80 cm total length (in Fig. 4) may represent sharks whose isotopic compositions are both completely dependent and increasingly or completely independent of maternal composition (see Olin et al 2011).…”

Section: Discussionmentioning

confidence: 99%

“…Similarly, temporal and spatial variability in shark diet may also be affecting our ability to fully resolve the early-life feeding ecology of bull sharks. Our data encompassed individuals collected in both wet and dry seasons over multiple years, but was not large enough to adequately address changes in shark diet on spatial and temporal scales.Because size at birth is quite variable in bull sharks (Neer et al 2005) and growth rate among individuals is also variable, especially for smaller animals (Branstetter & Stiles 1987), it is possible that individuals that fall between 60 and 80 cm total length (in Fig. 4) may represent sharks whose isotopic compositions are both completely dependent and increasingly or completely independent of maternal composition (see Olin et al 2011).…”

mentioning

confidence: 99%

Fatty acids and stable isotopes as indicators of early-life feeding and potential maternal resource dependency in the bull shark Carcharhinus leucas

Belicka¹,

Matich²,

Jaffé³

et al. 2012

Mar. Ecol. Prog. Ser.

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The degree of reliance of newborn sharks on energy reserves from maternal resource allocation and the timescales over which these animals develop foraging skills are critical factors towards understanding the ecological role of top predators in marine ecosystems. We used muscle tissue stable carbon isotopic composition and fatty acid analysis of bull sharks Carcharhinus leucas to investigate early-life feeding ecology in conjunction with maternal resource dependency. Values of δ 13 C of some young-of-the-year sharks were highly enriched, reflecting inputs from the marinebased diet and foraging locations of their mothers. This group of sharks also contained high levels of the 20:3ω9 fatty acid, which accumulates during periods of essential fatty acid deficiency, suggesting inadequate or undeveloped foraging skills and possible reliance on maternal provisioning. A loss of maternal signal in δ 13C values occurred at a length of approximately 100 cm, with muscle tissue δ 13 C values reflecting a transition from more freshwater/estuarine-based diets to marine-based diets with increasing length. Similarly, fatty acids from sharks >100 cm indicated no signs of essential fatty acid deficiency, implying adequate foraging. By combining stable carbon isotopes and fatty acids, our results provided important constraints on the timing of the loss of maternal isotopic signal and the development of foraging skills in relation to shark size and imply that molecular markers such as fatty acids are useful for the determination of maternal resource dependency. KEY WORDS: Essential fatty acid deficiency · Fatty acids · Food webs · Maternal investment · Stable isotopes · Sharks Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 455: [245][246][247][248][249][250][251][252][253][254][255][256] 2012 man et , Torres-Rojas et al. 2010, to molecular tools including stable isotope and lipid biomarker analysis (MacNeil et al. 2005, Pethybridge et al. 2010, Wai et al. 2011. Although stomach content analysis can provide evidence for specific dietary items, biochemical approaches have the advantage of providing information on assimilated organic substrates and can be especially helpful in complex ecosystems with multiple organic carbon substrates (Dalsgaard et al. 2003, Iverson et al. 2004, Whiles et al. 2010. Bulk δ 13 C has been widely used for food web studies, providing information on the source of organic matter in food webs (Fry et al. 1978, Fry & Sherr 1984, McCutchan et al. 2003. Furthermore, stable isotopic composition of neonatal animals has been demonstrated to reflect maternal diet and foraging location instead of neonatal diet, and this complication must be considered when interpreting isotope values in neonates and juveniles, especially for tissues with slow isotopic turnover times (e.g. muscle tissue in elasmobranchs; MacNeil et al. 2005, Olin et al. 2011. Fatty acid signatures are particularly useful for dietary studies because fatty acids from a prey item are taken up i...

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“…Bull sharks encountered in the SRMR are predominantly large animals with the majority being around 2.8 m (Brunnschweiler & Baensch, 2011). This mean length corresponds to an estimated weight of 200 kg (Branstetter & Stiles, 1987). They spend the majority of their time below 20 m in water with an average temperature of 27°C (Brunnschweiler, Queiroz & Sims, 2010).…”

Section: Methodsmentioning

confidence: 99%

Hand feeding can periodically fuel a major portion of bull shark energy requirements at a provisioning site in Fiji

Brunnschweiler

Payne

Barnett

2017

Animal Conservation

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Wildlife tourism is often extolled for its contribution to conservation. However, understanding the effects of tourism activities on the health of target animals is required to fully assess conservation benefits. Shark tourism operators often use food rewards to attract sharks in close proximity to tourists, but nothing is known about the contribution of these food rewards to the energetic requirements of target species. In this study, hand feeding of bull sharks Carcharhinus leucas was directly observed on 36 commercial shark watching dives in the Shark Reef Marine Reserve (SRMR), Fiji. Mean number of tuna heads consumed per dive by focal individuals ranged from 1.3 to 3.7. Monitored bull sharks consumed an average of~0.74 heads per provisioning day, and bioenergetics modelling suggests that some sharks might periodically be meeting their full energy requirement from provisioning at the SRMR. Knowing how much individual sharks consume at provisioning sites and how this relates to their energy requirements is crucial in order to better understand the effects of wildlife tourism and its contribution to conservation.

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Age and growth estimates of the bull shark, Carcharhinus leucas, from the northern Gulf of Mexico

Cited by 116 publications

References 18 publications

Decoding fingerprints: elemental composition of vertebrae correlates to age-related habitat use in two morphologically similar sharks

Decoding fingerprints: elemental composition of vertebrae correlates to age-related habitat use in two morphologically similar sharks

Fatty acids and stable isotopes as indicators of early-life feeding and potential maternal resource dependency in the bull shark Carcharhinus leucas

Hand feeding can periodically fuel a major portion of bull shark energy requirements at a provisioning site in Fiji

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