“Urbanite” rays and sharks: Presence, habitat use and population structure in an urban semi-enclosed lagoon

Tuya, Fernando; Asensio, Maite; Navarro, Alberto

doi:10.1016/j.rsma.2020.101342

Cited by 10 publications

(10 citation statements)

References 29 publications

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“…The importance of more complex habitats is also noted for S. squatina, with Lapinski & Giovos 2019 Whilst disturbance to, and degradation of, important angel shark habitats are also considered potentially important threats to populations of Squatina spp., especially those species using coastal waters (e.g., Barker et al, 2016;Gordon et al, 2019;Tuya et al, 2020), there is no published information with which to fully assess this and further studies are required.…”

Section: Habitatmentioning

confidence: 99%

Angel sharks (Squatinidae): A review of biological knowledge and exploitation

Ellis

Barker

Phillips

et al. 2021

Journal of Fish Biology

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Angel sharks (Squatina spp.) are distributed in warm temperate to tropical waters around the world. Many species occur in shelf seas and exhibit seasonal inshoreoffshore migrations, moving inshore to give birth. Consequently, there can be high spatial overlap of angel shark populations with fisheries and other human activities. Their dorso-ventrally flattened body shape, large size (most species attain >100 cm total length, L T) and demersal nature means that they may be taken in a variety of demersal fishing gears from birth. Available data indicate that angel sharks typically have a biennial reproductive cycle, with litter sizes generally <20 and the young born at c. 20-30 cm. The biological characteristics of angel sharks render them susceptible to overexploitation, as exemplified by the decline of Squatina squatina from many parts of its former range in the northeast Atlantic and Mediterranean Sea. Currently, half of the 22 recognized extant species of angel shark are classed as Threatened on the International Union for Conservation of Nature (IUCN) Red List (with a further three classified as Data Deficient). Given the biological vulnerability of angel sharks, and that many species are data-limited, the current paper provides a review of available biological information and fisheries data pertaining to this family.

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Section: Habitatmentioning

confidence: 99%

Angel sharks (Squatinidae): A review of biological knowledge and exploitation

Ellis

Barker

Phillips

et al. 2021

Journal of Fish Biology

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“…Large aggregations of elasmobranchs are spotted near the shore, including urban beaches (Escánez et al, 2016;Jiménez-Alvarado et al, 2020;Tuya et al, 2020). Importantly, sea-cage fish farms act as aggregating structures for a range of rays across times and islands (Dempster et al, 2005;Tuya et al, 2005Tuya et al, , 2006.…”

Section: Introductionmentioning

confidence: 99%

“…For example, the archipelago is considered a unique stronghold of the iconic angelshark, Squatina squatina (Linnaeus, 1758) (Barker et al, 2016; Lawson et al, 2019; Meyers et al, 2017). Large aggregations of elasmobranchs are spotted near the shore, including urban beaches (Escánez et al, 2016; Jiménez‐Alvarado et al, 2020; Tuya et al, 2020). Importantly, sea‐cage fish farms act as aggregating structures for a range of rays across times and islands (Dempster et al, 2005; Tuya et al, 2005, 2006).…”

Section: Introductionmentioning

confidence: 99%

Differences in the occurrence and abundance of batoids across an oceanic archipelago using complementary data sources: Implications for conservation

Tuya

Aguilar²,

Espino

et al. 2021

Ecology and Evolution

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Batoids, distributed from shallow to abyssal depths, are considerably vulnerable to anthropogenic threats. Data deficiencies on the distribution patterns of batoids, however, challenge their effective management and conservation. In this study, we took advantage of the particular geological and geomorphological configuration of the Canary Islands, across an east-to-west gradient in the eastern Atlantic Ocean, to assess whether patterns in the occurrence and abundance of batoids varied between groups of islands (western, central, and eastern). Data were collected from shallow (<40 m, via underwater visual counts and by a local community science program) and deep waters (60-700 m, via ROV deployments). Eleven species of batoids, assessed by the IUCN Red List of Threatened Species, were registered, including three "Critically Endangered" (Aetomylaeus bovinus, Dipturus batis, and Myliobatis aquila), three "Endangered" (Gymnura altavela, Mobula mobular, and Rostroraja alba), two "Vulnerable" (Dasyatis pastinaca and Raja maderenseis), and two "Data Deficient" (Taeniurops grabata and Torpedo marmorata). Also, a "Least Concern" species (Bathytoshia lata) was observed. Overall, batoids were ~1 to 2 orders of magnitude more abundant in the central and eastern islands, relative to the western islands. This pattern was consistent among the three sources of data and for both shallow and deep waters. This study, therefore, shows differences in the abundance of batoids across an oceanic archipelago, likely related to varying insular shelf area, availability of habitats, and proximity to the nearby continental (African) mass. Large variation in population abundances among islands suggests that "whole" archipelago management strategies are unlikely to provide adequate conservation. Instead, management plans should be adjusted individually per island and complemented with focused research to fill data gaps on the spatial use and movements of these iconic species.

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“…These “nursery” sites correspond to some semi‐enclosed bays in very shallow waters, as those reported from the nearby Madeira Island for this species (Biscoito et al, 2018). In this type of habitats, the presence of potential predators is low, but feeding resources are abundant, as it has been reported for other nearshore sharks, also in the Canary Islands, such as the angelshark, Squatina squatina (Jiménez‐Alvarado et al, 2021) and several rays (Tuya et al, 2020). This species would stand to benefit from protection of these sites, which seems to play a key role in a critical life stage of M. mustelus in the Canary Islands, particularly since this species has a high degree of site fidelity, at least in other regions (da Silva et al, 2013; Klein et al, 2021) and observations of juvenile and subadults occur in successive years (da Silva, 2018).…”

Section: Discussionmentioning

confidence: 62%

Distribution and population structure of the smooth‐hound shark, Mustelus mustelus (Linnaeus, 1758), across an oceanic archipelago: Combining several data sources to promote conservation

Espino

González

Bosch

et al. 2022

Ecology and Evolution

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Sharks play a key role in the structure and functioning of marine ecosystems. More ecological information is essential to implement responsible management and conservation actions on this fauna, particularly at a regional level for threatened species. Mustelus mustelus is widely found in the eastern Atlantic Ocean and catalogued as “Vulnerable” by the IUCN European assessment. In this study, data on the distribution and population structure of this species across the islands of the Canarian archipelago, located along an east to west gradient in the north‐eastern Atlantic, were collected by taking advantage of “Local Ecological Knowledge,” in terms of sightings in coastal waters and long‐term imprints on the local gastronomic heritage, and decadal fisheries landings. Both sources of quantitative data (sightings and fisheries landings) demonstrated that adults of M. mustelus has a significantly larger presence in the eastern and central, than in the western islands of the archipelago. This is also reflected on local gastronomic legacies, with a larger number of recipes in the eastern and central islands. Adult smooth‐hound sharks were significantly more observed in sandy and sandy‐rocky bottoms, with individuals seen throughout the entire year, whereas juveniles aggregate on very shallow waters in spring and summer. Such aggregations require a special management strategy, as they play a key role in critical life stages; these sites should be protected from human perturbations. We also suggest a temporal fishing ban between April and October, when individuals tend to concentrate on nearshore waters. Because of the large differences in presence of this shark among the Canary Islands, management of the species should be adapted to the specific peculiarities of each island, rather than adopting a management policy at the entire archipelago‐scale. Overall, this study sets the basis for further investigation to promote conservation of this vulnerable shark in the study region.

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“Urbanite” rays and sharks: Presence, habitat use and population structure in an urban semi-enclosed lagoon

Cited by 10 publications

References 29 publications

Angel sharks (Squatinidae): A review of biological knowledge and exploitation

Angel sharks (Squatinidae): A review of biological knowledge and exploitation

Differences in the occurrence and abundance of batoids across an oceanic archipelago using complementary data sources: Implications for conservation

Distribution and population structure of the smooth‐hound shark, Mustelus mustelus (Linnaeus, 1758), across an oceanic archipelago: Combining several data sources to promote conservation

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