Discovery of a putative scalloped hammerhead shark Sphyrna lewini (Carcharhiniformes: Sphyrnidae) nursery site at the Galapagos Islands, Eastern Tropical Pacific

Chiriboga-Paredes, Yasuní; Palomino, Ángela; Goodman, Lauren; Córdova, Florencia; Páez, Viviana; Yépez, Manuel; Armijos, Daniel; Pazmiño, Diana A.; Hearn, Alex

doi:10.1007/s10641-021-01207-3

Cited by 6 publications

(2 citation statements)

References 29 publications

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“…The functions of such aggregation behaviors have been hypothesized to include reproduction (Klimley, 1987;Chaikin et al, 2020;Sims et al, 2022), feeding (De-la-Parra-Venegas et al, 2011), energy conservation, (Klimley and Nelson, 1984;Economakis and Lobel, 1998;Hight and Lowe, 2007), refuge from predators (Heupel et al, 2007;McAllister et al, 2017) and social learning (Sih et al, 2009;Brown and Laland, 2011). The formation of these aggregations can be seasonal and is often linked to environmental factors and life history stages (Rohner et al, 2013;Kajiura and Tellman, 2016), food abundance (Clua et al, 2013;Hacohen-Domenéet al, 2015), critical habitats (Oh et al, 2017;Chiriboga-Paredes et al, 2022) and reproduction (Heupel and Simpfendorfer, 2005;Reyier et al, 2008). The seasonality of these aggregation events, along with the large number of individuals at specific areas (i.e., coastal areas, productive systems) can also increase the likelihood and intensity of exposure to anthropogenic threats such as targeted fishing (Litvinov, 2006;Croll et al, 2016), bycatch (Watson et al, 2009;Hall and Roman, 2013), habitat degradation (Cattano et al, 2021), irresponsible tourism (Venables et al, 2016;Zemah-Shamir et al, 2019), boat strikes (Lester et al, 2020;Allen et al, 2021;Womersley et al, 2022) or climate change (particularly if mismatches in the timing of migration, reproduction or foraging interactions occur).…”

Section: Introductionmentioning

confidence: 99%

Manta and devil ray aggregations: conservation challenges and developments in the field

et al. 2023

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Manta and devil rays (mobulids) are filter feeding elasmobranchs with extreme K-selective life histories found circumglobally from temperate to tropical waters. Their vulnerability to fisheries exploitation, bycatch, boat collisions, entanglement and unregulated tourism is exacerbated by their aggregative behavior. Studies have identified aggregation sites around the world for all nine mobulid species, with these groupings varying from a few individuals to thousands. However, the terminology used to define these aggregations and the drivers underpinning them remain unclear, hindering the development of effective management and conservation strategies. Here, we analyze aggregation behavior for mobulid species, providing consistent definitions for grouping events and summarizing the existing research on drivers and environmental factors triggering these events. We find that aggregation behaviors facilitate socializing and key life history functions in mobulids, including feeding, courtship and mating, predation avoidance, cleaning, and thermoregulation. Conservation threats and management mitigation opportunities associated with aggregations sites include fisheries, tourism, spatial protection, and climate change. Finally, we highlight knowledge gaps for future research prioritization and developments in the field for the identification of aggregation sites, the study of aggregation size and demographics and the functions and timing of aggregations.

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Section: Introductionmentioning

confidence: 99%

Manta and devil ray aggregations: conservation challenges and developments in the field

et al. 2023

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“…Larger‐bodied coastal sharks are hypothesized to use shallow, nearshore waters as nursery habitats in many contexts (Knip et al , 2010). Yet testing this hypothesis has been difficult given the inherent obstacles of studying wide‐ranging, highly mobile juveniles that are often found in physically and/or geographically inaccessible areas ( e.g ., Chiriboga‐Paredes et al , 2022; Garla et al , 2006; Llerena et al , 2015; Weideli et al , 2019). Indeed, while nursery areas have been defined for some populations, the criteria proposed to identify shark nurseries (Heupel et al , 2007) have yet to be rigorously tested for most coastal sharks in part due to inaccessibility and data limitations, hindering conservation and management efforts (Heupel et al , 2019).…”

Section: Introductionmentioning

confidence: 99%

Delineation of blacktip shark (Carcharhinus limbatus) nursery habitats in the north‐western Gulf of Mexico

Matich

Bigelow

Chambers

et al. 2022

Journal of Fish Biology

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Coevolution with predators leads to the use of low‐risk habitats by many prey species, which promotes survival during early developmental phases. These nurseries are valued by conservation and management agencies because of their contributions to adult populations. However, the physical and geographic characteristics, like shallow depths and isolation from other marine habitats, that restrict access to predators and thereby reduce risk to juvenile animals can also limit scientific research. Consequently, many nursery habitats are still unidentified and understudied. Here we used gillnet monitoring from 1982 to 2018 to delineate blacktip shark (Carcharhinus limbatus) nurseries in the north‐western Gulf of Mexico and elucidated their physical, environmental and biological characteristics. Nursery habitats within estuaries (<2% of spatial area) were proximate to the Gulf of Mexico and exhibited significantly lower variability in salinity than non‐nurseries. However, relative abundances of predators and prey were not significant delineators of nursery habitats. As such, food and risk may not influence juvenile blacktip habitat use as expected. Alternatively, reduced osmoregulatory stress attributed to predictable environments likely provides advantageous conditions for blacktips to develop foraging and antipredator tactics, which is vital prior to the winter migration of juvenile sharks into the Gulf of Mexico.

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The bumpy road to conservation: Challenges and opportunities in updating the Galapagos zoning system

Castrejón,

Moity,

Charles

2024

Marine Policy

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Discovery of a putative scalloped hammerhead shark Sphyrna lewini (Carcharhiniformes: Sphyrnidae) nursery site at the Galapagos Islands, Eastern Tropical Pacific

Cited by 6 publications

References 29 publications

Manta and devil ray aggregations: conservation challenges and developments in the field

Manta and devil ray aggregations: conservation challenges and developments in the field

Delineation of blacktip shark (Carcharhinus limbatus) nursery habitats in the north‐western Gulf of Mexico

The bumpy road to conservation: Challenges and opportunities in updating the Galapagos zoning system

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