Food web model to assess the fishing impacts and ecological role of elasmobranchs in a coastal ecosystem of Southern Brazil

Rupp, Aurora; Bornatowski, Hugo

doi:10.1007/s10641-021-01120-9

Cited by 15 publications

(9 citation statements)

References 85 publications

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“…Stingrays are often described as keystone species, influencing invertebrate communities, and physical processes through bioturbation (O'Shea et al, 2011;Flowers et al, 2021;Crook et al, 2022). Therefore, S. mokarran predation may influence the spatio-temporal distribution of batoids and their feeding and bioturbation rates, shaping ecosystem processes in inshore habitats (Rupp and Bornatowski, 2021).…”

Section: Discussionmentioning

confidence: 99%

Trophic ecology shapes spatial ecology of two sympatric predators, the great hammerhead shark (Sphyrna mokarran) and bull shark (Carcharhinus leucas)

Lubitz,

Abrantes,

Crook

et al. 2023

Front. Mar. Sci.

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Information on how the trophic ecology of predators shapes their movement patterns and space-use is fundamental to understanding ecological processes across organisational levels. Despite this, studies combining spatial and trophic ecology to determine how prey preference and/or resource availability shape space use are lacking in marine predators as these can occur at low density and are often difficult to track over extended periods. Furthermore, many exhibit behavioural variability within species and among closely related, sympatric species adding further complexity. We applied a context-focused, multi-method approach to the understudied great hammerhead shark (Sphyrna mokarran) to test if movement and home ranges relate to prey preference and availability. Movement data from satellite and acoustic telemetry in Queensland, Australia, were combined with stable-isotope analysis, drone surveys, and videos of hunting behaviour. Limited dispersal, and small home ranges in S. mokarran were linked to trophic specialisation on stingray prey. Drone surveys and videos showed predation events on stingrays and demonstrated high, year-round availability of this prey in shallow, inshore habitats, which may allow the majority of S. mokarran to remain resident. This affinity for inshore habitats suggests that critical life-history requirements are performed over local or regional scales, although some larger movements were evident. These results were interpreted in comparison to the well-studied bull shark (Carcharhinus leucas), which showed reliance on pelagic food webs. Carcharhinus leucas had high individual variability in movement, with both large-scale migrations and residency. This could indicate that only some individuals are locally sustained on dynamic, pelagic food webs, while others undergo large-scale excursions over distant habitats. The specialised foraging of S. mokarran indicates they play an apex predator role in shallow, inshore habitats, potentially shaping space-use, and foraging behaviour of batoids. As inshore habitats are disproportionately affected by anthropogenic stressors, S. mokarran’s trophic specialisation and limited demographic connectivity may make the species particularly vulnerable to anthropogenic threats.

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Section: Discussionmentioning

confidence: 99%

Trophic ecology shapes spatial ecology of two sympatric predators, the great hammerhead shark (Sphyrna mokarran) and bull shark (Carcharhinus leucas)

Lubitz,

Abrantes,

Crook

et al. 2023

Front. Mar. Sci.

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“…In general, the tiger shark is among the least abundant shark species along the coast of different Brazilian states, such as Recife, Pernambuco [ 15 ], Rio de Janeiro itself [ 16 ], and near Mel Island in the state of Paraná [ 17 ]. This is possibly due to tiger sharks not being the main object of fishing unlike other shark species.…”

Section: Discussionmentioning

confidence: 99%

“…Currently, one-third of Brazilian shark species are threatened [ 14 ], although the true status of many species is unknown due to lack of information [ 13 ]. This is true for the tiger shark Galeocerdo cuvier (Péron & Lesueur, 1822) (Carcharhinidae), which, although one of the least representative species in northeast [ 15 ], southeast [ 16 ], and south [ 17 ] Brazil, has been classified as near threatened along the Brazilian coast, in line with its global categorization [ 14 , 18 ]. Australia has, in fact, recently identified declines in this species abundance [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

New Occurrences of the Tiger Shark (Galeocerdo cuvier) (Carcharhinidae) off the Coast of Rio de Janeiro, Southeastern Brazil: Seasonality Indications

Aximoff

Cumplido

Rodrigues

et al. 2022

Animals

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The tiger shark Galeocerdo cuvier (Péron & Lesueur, 1822) (Carcharhinidae) is classified as near-threatened along the Brazilian coast, in line with its global categorization. Although Rio de Janeiro, located in southeastern Brazil, is internationally identified as a priority shark conservation area, many shark species, including tiger sharks, are landed by both industrial and artisanal fisheries in this state. However, there is a lack of detailed information on the species capture pressures and records for the state of Rio de Janeiro. Therefore, the aims of this study were to expand the tiger shark record database and to improve upon future conservation and management strategies. Tiger shark records from four coastal Rio de Janeiro regions were obtained by direct observation. The information obtained from fishery colonies/associations, environmental guards, researchers, and scientific articles, totaling 23 records, resulted in an approximately 5-fold increase in the number of tiger shark records off the coast of the state of Rio de Janeiro. A possible seasonality pattern concerning the size of the captured/observed animals was noted, emphasizing the need to consider the coast of Rio de Janeiro as an especially relevant area for at least part of the life history of tiger sharks.

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“…Morphological anomalies recorded in this study for the Urobatis maculatus , Urotrygon chilensis , U. microphthalmum and U. rogersi individuals are most likely related to after‐birth injuries rather than genetic and anthropogenic issues, as has been proposed by other authors (Mejía‐Falla et al., 2011; Suresh & Raffi, 2012; Torres‐Huerta et al., 2015). For example, the majority of the American Batomorphi species are considered as mesopredators, connecting the lower trophic level with the higher levels (Bornatowski et al., 2014; Ehemann et al., 2019; González‐González et al., 2021; Navia et al., 2017; Olmo‐Gilabert et al., 2019; Oñate‐González et al., 2017; Restrepo‐Gómez et al., 2020; Rupp & Bornatowski, 2021; Serrano‐Flores et al., 2021), which supports the speculation of predation of the small‐bodied batomorphs found in this study. However, fishermen's causes, such as amputation, could not be ruled out as probable cause either.…”

Section: Discussionmentioning

confidence: 99%

Morphological abnormalities in seven American round ray specimens: A review of America's batomorph anomalies

Ehemann¹,

García‐Rodríguez²,

Cruz‐Agüero³

2021

Journal of Fish Diseases

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Although morphological abnormalities in several rays and skate species around the American continents have frequently mentioned, their numbers are unknown. The present work record morphological abnormalities in four Urotrygonidae species. Two anophthalmic specimens were detected (Urotrygon microphthalmum and Urobatis halleri). Two individuals lacked caudal fins (Urobatis maculatus and Urotrygon chilensis). Two round rays showed incomplete fusion of the pectoral fin to the head (U. microphthalmum and U. chilensis). Vertebral compression and fusion were found in a 6‐year‐old female Urotrygon rogersi. In addition, 118 abnormal batomorph specimens were gathered from the available bibliography, spanning the last six decades (1959–2021). Amblyraja doellojuradoi was the species with the highest number of abnormalities (18). The most common anomaly was an incomplete fusion of the pectoral fin with the head. Since 2010, at least 30 anomalous batomorphs have been recorded every 5 years. Sixty‐nine abnormal specimens occurred in the Northern Hemisphere (1.00–60.00 N). The Cortezian (Pacific) and Southeastern Brazil (Atlantic) marine ecoregions stood out with the highest number of these specimens. Mexico recorded 58 anomalous specimens, followed by Brazil (n = 36). Biological, abiotic and anthropogenic factors are probably the leading causes. However, additional studies are necessary to elucidate these speculations.

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Food web model to assess the fishing impacts and ecological role of elasmobranchs in a coastal ecosystem of Southern Brazil

Cited by 15 publications

References 85 publications

Trophic ecology shapes spatial ecology of two sympatric predators, the great hammerhead shark (Sphyrna mokarran) and bull shark (Carcharhinus leucas)

Trophic ecology shapes spatial ecology of two sympatric predators, the great hammerhead shark (Sphyrna mokarran) and bull shark (Carcharhinus leucas)

New Occurrences of the Tiger Shark (Galeocerdo cuvier) (Carcharhinidae) off the Coast of Rio de Janeiro, Southeastern Brazil: Seasonality Indications

Morphological abnormalities in seven American round ray specimens: A review of America's batomorph anomalies

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