Incidental capture of elasmobranchs by commercial prawn trawlers on the Tugela Bank, Natal, South Africa

Fennessy, S.T.

doi:10.2989/025776194784287094

Cited by 53 publications

(50 citation statements)

References 6 publications

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“…This disparity in birthing location is not typically considered for sharks in one geographic region, but both sheltered coastal lagoonal nurseries and exposed continental shelf nurseries have been observed for scalloped hammerhead sharks in Hawaii and South Africa, respectively (Fennessy 1994;Duncan and Holland 2006). Similarly, juvenile lemon sharks (Negaprion brevirostris) reside in sheltered lagoonal nurseries in Bimini, Bahamas (Feldheim et al 2002), while young sharks at Cape Canaveral, Florida, occupy the shallow LG-L SI-IF2 312 F H20…”

Section: Discussionmentioning

confidence: 96%

Juvenile Greenland sharks Somniosus microcephalus (Bloch & Schneider, 1801) in the Canadian Arctic

et al. 2014

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Life-stage-based management of marine fishes requires information on juvenile habitat preferences to ensure sustainable population demographics. This is especially important in the Arctic region given very little is known about the life histories of many native species, yet exploitation by developing commercial and artisanal fisheries is increasing as the ice extent decreases. Through scientific surveys and bycatch data from gillnet fisheries, we document captures of rarely reported juvenile Greenland sharks (Somniosus microcephalus; B200 cm total length [TL]) during the ice-free period in the Canadian Arctic. A total of 22 juvenile animals (42 % of total catch; n = 54), including the smallest reliably measured individual of 117 cm TL, were caught on scientific longlines and bottom trawls in Scott Inlet and Sam Ford Trough over three consecutive years. Molecular genetic nuclear markers confirmed species identity for 44 of these sharks sampled; however, two sharks including a juvenile of 150 cm TL were identified as carrying a Pacific sleeper shark (Somniosus pacificus) mitochondrial cytochrome b (cyt b) haplotype. This represents the first record of a Pacific sleeper shark genetic signature in Greenland sharks in Eastern Arctic waters. Juvenile sharks caught as bycatch in gillnet fisheries were only observed offshore in Baffin Bay surrounding a fishery closure area, while larger subadult and mature Greenland sharks ([200 cm TL) were caught in all fishing locations, including areas where juveniles were observed. The repeatable occurrence of juvenile Greenland sharks in a fjord and their presence at two offshore sites indicates that these smaller animals either reside in nurseries or have defined home ranges in both coastal and offshore regions or undertake large-scale inshoreoffshore movements.

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Section: Discussionmentioning

confidence: 96%

Juvenile Greenland sharks Somniosus microcephalus (Bloch & Schneider, 1801) in the Canadian Arctic

et al. 2014

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“…There is a notable imbalance ([80% of peerreviewed papers) between studies focussing on elasmobranchs in the industrial and semi-industrial fisheries e.g. (Fennessy 1994;Huang and Liu 2010;Kiszka and van der Elst 2015;Romanov 2002) and the small-scale fisheries (Molina and Cooke 2012). Published information for small-scale fisheries is generally sparsely quantified and limited to target species (e.g.…”

Section: Elasmobranch Interaction With Small-scale Fisheriesmentioning

confidence: 99%

Marine megafauna interactions with small-scale fisheries in the southwestern Indian Ocean: a review of status and challenges for research and management

Temple

Kiszka

Stead

et al. 2017

Rev Fish Biol Fisheries

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In developing regions, coastal communities are particularly dependent on small-scale fisheries for food security and income. However, information on the scale and impacts of small-scale fisheries on coastal marine ecosystems are frequently lacking. Large marine vertebrates (marine mammals, sea turtles and chondrichthyans) are often among the first species to experience declines due to fisheries. This paper reviews the interactions between small-scale fisheries and vulnerable marine megafauna in the southwestern Indian Ocean. We highlight an urgent need for proper documentation, monitoring and assessment at the regional level of small-scale fisheries and the megafauna affected by them to inform evidence-based fisheries management. Catch and landings data are generally of poor quality and resolution with compositional data, where available, mostly anecdotal or heavily biased towards easily identifiable species. There is also limited understanding of fisheries effort, most of which relies on metrics unsuitable for proper assessment. Management strategies (where they exist) are often created without strong evidence bases or understanding of the reliance of fishers on resources. Consequently, it is not possible to effectively assess the current status and ensure the sustainability of these species groups; with indications 123Rev Fish Biol Fisheries (2018Fisheries ( ) 28:89-115 https://doi.org/10.1007 of overexploitation in several areas. To address these issues, a regionally collaborative approach between government and non-governmental organisations, independent researchers and institutions, and smallscale fisheries stakeholders is required. In combination with good governance practices, appropriate and effective, evidence-based management can be formulated to sustain these resources, the marine ecosystems they are intrinsically linked to and the livelihoods of coastal communities that are tied to them.

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“…A crude estimate of the elasmobranch catch by the prawn and shrimp fishery in Africa can therefore be estimated from the following data: (i) a total catch of prawn and shrimp of 83 000 t (data reworked from Anon. 1997a); (ii) an estimated by-catch : landed catch weight ratio of 5 : 1; ratios ranged from 2.72 for Senegal (Alverson et al 1994) to 15.5 for South Africa (Fennessy 1994); (iii) a value of 7% for the elasmobranch component of the by-catch (Fennessy, unpublished). This gives a calculated value of some 23 000 t of elasmobranchs caught by this fishery in African waters.…”

Section: Landed and Discarded By-catchmentioning

confidence: 99%

Elasmobranch exploitation in Africa

Kroese¹,

Sauer²

1998

Mar. Freshwater Res.

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The impact of fisheries on elasmobranchs in Africa is not well documented. Available data suggest that there are no large shark fishing nations (> 10000 t year-1), reported landings for 1994 being around 39 000 t. This value is believed to be a underestimate, because of a lack of data on catches and landings from the various different fishing methods and the large number of nations fishing in African waters. Existing data are mostly linked to industrial fisheries, although the artisanal sector could be responsible for substantial catches. Landed by-catch and discard rates of elasmobranchs are unknown for most commercial fisheries targeting teleosts. Limited data sources allowed only crude estimates of catch. The artisanal fishery is calculated to land a minimum of 20 000 t of sharks, whereas the industrial trawl sector is likely to catch 23 000 t. A conservative estimate for the African continent and the surrounding islands is ~95 000 t. The quality of catch-and-effort data for both commercial and subsistence fisheries on the African continent needs to be improved, and the by-catch issue should be investigated through trained onboard observers.

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Incidental capture of elasmobranchs by commercial prawn trawlers on the Tugela Bank, Natal, South Africa

Cited by 53 publications

References 6 publications

Juvenile Greenland sharks Somniosus microcephalus (Bloch & Schneider, 1801) in the Canadian Arctic

Juvenile Greenland sharks Somniosus microcephalus (Bloch & Schneider, 1801) in the Canadian Arctic

Marine megafauna interactions with small-scale fisheries in the southwestern Indian Ocean: a review of status and challenges for research and management

Elasmobranch exploitation in Africa

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