Accuracy of species identification by fisheries observers in a north Australian shark fishery

Tillett, Bree J.; Field, Iain C.; Bradshaw, Corey J. A.; Johnson, Grant; Buckworth, Rik C.; Meekan, Mark G.; Ovenden, Jennifer R.

doi:10.1016/j.fishres.2012.04.007

Cited by 66 publications

(68 citation statements)

References 42 publications

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“…One likely source of error is misidentification, particularly of Glyphis sharks due to morphological similarities among carcharhinids (Tillett et al 2012). Genetic techniques provide a proven means to remove such uncertainty from catch data (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…Genetic techniques provide a proven means to remove such uncertainty from catch data (e.g. Tillett et al 2012), allowing better monitoring of impacts on these threatened species.…”

Section: Discussionmentioning

confidence: 99%

“…In the Northern Territory, the offshore net and line and the barramundi Lates calcarifer fisheries are the 2 principal commercial fisheries where by-catch of Glyphis sharks and sawfishes have been recorded (Northern Territory Department of Primary Industry Fisheries and Mines 2010). Although the reporting of by-catch in commercial logbooks is a requirement of fishing licences (Northern Territory Department of Primary Industry Fisheries and Mines 2010), reporting is often inaccurate, incomplete and compromised by misidentification, hindering effective management of fishery interactions with these threatened species (Tillett et al 2012). Many fisheries now employ trained scientific observers to improve identification of by-catch (Tillett et al 2012), but overall coverage is low.…”

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confidence: 99%

“…Although the reporting of by-catch in commercial logbooks is a requirement of fishing licences (Northern Territory Department of Primary Industry Fisheries and Mines 2010), reporting is often inaccurate, incomplete and compromised by misidentification, hindering effective management of fishery interactions with these threatened species (Tillett et al 2012). Many fisheries now employ trained scientific observers to improve identification of by-catch (Tillett et al 2012), but overall coverage is low.We use a combination of catch records, observer data and fishery-independent survey data to improve the knowledge of distribution and relative abundance of Glyphis sharks and sawfishes in the Northern Territory, Australia, and investigate the potential threat to populations posed by commercial fisheries. …”

mentioning

confidence: 99%

“…Genetic techniques provide a proven means to remove such uncertainty from catch data (e.g. Tillett et al 2012), allowing better monitoring of impacts on these threatened species.The diversity of reported interactions in the barramundi fishery lends support to the call to introduce species-specific reporting of elasmobranch by-catch. The by-catch problem is further confounded by the high mortality among caught sawfish in the barramundi fishery, suggesting that changes in fishing effort (such as banning bottom set nets) to reduce bycatch of threatened species are also necessary.…”

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confidence: 99%

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Distribution, relative abundance and risks from fisheries to threatened Glyphis sharks and sawfishes in northern Australia

Field¹,

Tillett²,

Charters³

et al. 2013

Endang. Species. Res.

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Glyphis sharks and pristid sawfishes are globally threatened. While some populations still exist in northern Australia, their distributions are poorly quantified. We used catch records from commercial fisheries and independent surveys to estimate the broad distribution and relative abundances of 2 Glyphis sharks (G. glyphis and G. garricki) and 4 pristid sawfishes (Pristis pristis, P. zijsron, P. clavata and Anoxypristis cuspidata) along the coast, estuaries and river systems of the Northern Territory, Australia. Coarse-scale catch data and records from commercial fishing logbooks that report encounters with Threatened, Endangered and Protected species confirm that small, fragmented populations are distributed across the Northern Territory coastline and suggest limited fishery interactions, although underreporting might occur.KEY WORDS: Sharks · Habitat · Fishing · Conservation · Management · Pristis spp. · Anoxypristis spp. Resale or republication not permitted without written consent of the publisherEndang Species Res 21: [171][172][173][174][175][176][177][178][179][180] 2013 tions, thus hindering conservation planning (IUCN 2010). Two species of Glyphis sharks have been described in northern Australia, G. glyphis (the speartooth shark, previously known as Glyphis sp. A) and G. garricki (the northern river shark, previously known as Glyphis sp. C) (Larson 2002, Martin 2005, Peverell et al. 2006, Compagno et al. 2008, Wynen et al. 2009). Both species have restricted distributions; G. glyphis has only been recorded in the Northern Territory (Adelaide River, East, South and West Alligator Rivers, Murganella Creek and Marrakai Creek) and in Queensland (Wenlock and Ducie Rivers, Port Musgrave and the Bizant River) (Peverell et al. 2006, Compagno et al. 2008. The only other record of this species globally is from Papua New Guinea (Compagno et al. 2008). G. garricki is also found in Australia in the Northern Territory (Adelaide, East and South Alligator and Mary Rivers) but unlike G. glyphis, it has also been recorded in Western Australia (King Sound in the Kimberley region) (Taniuchi et al. 1991, Thorburn & Morgan 2004. Similar to G. glyphis, the only other place where this species has been recorded is Papua New Guinea (Taniuchi et al. 1991, Compagno et al. 2008. Both Glyphis spp. are considered extremely rare, although no population estimates are available for either species. G. glyphis and G. garricki are currently listed as Critically Endangered in the IUCN Red List (www. iucn redlist .org), and critically endangered and endangered under the Australian Commonwealth Environment Protection and Biodiversity Conservation (EPBC) Act 1999, respectively. Due to these classifications, both species are identified as 'key' species for conservation planning (National Oceans Office 2004).There are 4 sawfishes in Australia: the freshwater sawfish Pristis pristis (previously known as P. microdon), green sawfish P. zijsron, dwarf sawfish P. clavata and narrow sawfish Anoxypristis cuspidata (Thorburn et al. 2003, ...

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Section: Discussionmentioning

confidence: 99%

“…Genetic techniques provide a proven means to remove such uncertainty from catch data (e.g. Tillett et al 2012), allowing better monitoring of impacts on these threatened species.…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Distribution, relative abundance and risks from fisheries to threatened Glyphis sharks and sawfishes in northern Australia

Field¹,

Tillett²,

Charters³

et al. 2013

Endang. Species. Res.

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Untangling the Indonesian tangle net fishery: Describing a data‐poor fishery targeting large, threatened rays (Superorder Batoidea)

D’Alberto

White

Chin

et al. 2021

Aquatic Conservation

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Shark‐like rays (Order Rhinopristiformes) are among the most threatened families of marine fish, yet little is known about their populations. These rays are normally taken as opportunistic catch in fisheries targeting other species and are thus poorly reported. One exception is the Indonesian tangle net fishery, which targets shark‐like rays. Market surveys of Muara Angke landing site in Jakarta, north‐western Java were conducted between 2001 and 2005, and the landed catch from the tangle net fishery was recorded (the Muara Angke landing site includes landings from more than one fishery). In total, 1,559 elasmobranchs (sharks and rays) were recorded, comprising 24 species of rays and nine species of sharks. The most abundant species landed were the pink whipray Pateobatis fai and the bottlenose wedgefish Rhynchobatus australiae, the latter being the main target species. Catch composition varied based on differences in species catchability and may also be indicative of localized declines. The fishery was highly selective for larger sized individuals, while smaller size classes of many ray species, including the target species, were also caught in other Indonesian fisheries, resulting in fishing pressure across all age classes. The decline of tangle net vessels in the fishery and the potential shift in catch composition in the Indonesian tangle net fishery increase concerns about the status of shark‐like rays and stingrays in Indonesia.

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Counting Cats: The integration of expert and citizen science data for unbiased inference of population abundance

McDonald¹,

Hodgson

2021

Ecology and Evolution

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Accuracy of species identification by fisheries observers in a north Australian shark fishery

Cited by 66 publications

References 42 publications

Distribution, relative abundance and risks from fisheries to threatened Glyphis sharks and sawfishes in northern Australia

Distribution, relative abundance and risks from fisheries to threatened Glyphis sharks and sawfishes in northern Australia

Untangling the Indonesian tangle net fishery: Describing a data‐poor fishery targeting large, threatened rays (Superorder Batoidea)

Counting Cats: The integration of expert and citizen science data for unbiased inference of population abundance

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