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Glyphis garricki

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES CARCHARHINIFORMES CARCHARHINIDAE

Scientific Name: Glyphis garricki
Species Authority: Compagno, White & Last, 2008
Common Name(s):
English New Guinea River Shark, Northern River Shark
Synonym(s):
Glyphis sp. [Compagno & Garrick] subspecies C
Taxonomic Notes: The taxonomy of Glyphis species is problematic, partly because of the lack of museum specimens. Glyphis garricki can be confused with the Bull Shark (Carcharhinus leucas) by non-specialists as the latter is known to occur in the same habitat and possibly occupies the known range of the former at some stages of its life cycle. Glyphis garricki can be distinguished from the Bull Shark by its taller second dorsal fin (about two-thirds the height of the first dorsal), the triangular shape of the first dorsal fin, and the small eye located on the grey-shaded part of the head as opposed to the white counter-shaded part. Additionally, when Glyphis garricki is alive it is steely grey in colour in comparison to the yellowish grey of the Bull Shark (Larson 2000 cited in Pogonoski et al. 2002). Glyphis garricki is also very difficult to distinguish from other Glyphis species and accurate identifications need to include x-rays of the vertebral column (see Taniuchi et al. 1991). It is possibly the same species that occurs in the Fly River of Papua New Guinea (Compagno 2002). Future research on Glyphis species is urgently required to solve the inherent taxonomic problems in the group.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered C2a(i) ver 3.1
Year Published: 2003
Date Assessed: 2003-04-30
Annotations:
Needs updating
Assessor(s): Pogonoski, J. & Pollard, D. (SSG Australia & Oceania Regional Workshop, March 2003)
Reviewer(s): Fowler, S. & Cavanagh, R.D. (Shark Red List Authority)
Justification:
Based on the very few specimens collected to date from northern Australia (records from Papua New Guinea are not yet confirmed as this species), this undescribed species is presumably very rare. Surveys targeting freshwater and estuarine elasmobranchs in northern Australia (Western Australia, Northern Territory, Queensland) in mid-late 2002 collected no Glyphis specimens, despite sampling in 136 sites in 38 rivers. It is inferred that the population contains fewer than 250 mature individuals and no subpopulation contains more than 50 mature individuals, further that it is presumably threatened by bycatch in commercial and recreational fishing activities and by possible habitat degradation. Future sampling in northern Australian and Papua New Guinea rivers may yet reveal this species to be more abundant than currently known. However, until a time when its abundance can be proven to be greater than current levels, the species is classified as Critically Endangered.

Geographic Range [top]

Countries:
Native:
Australia (Northern Territory)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population size is unknown, but is suspected to be small based on current knowledge and their apparent rarity. The number and size of subpopulations is also unknown. All populations need to be preserved to maintain the genetic diversity within this species. Kakadu National Park (NT) is probably an important site for this species as it may be afforded more protection here than in other areas.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: This species was thought to be confined to the turbid freshwater and brackish (6–26 ppt) reaches of rivers (Larson 2000), but a recent specimen provisionally identified as this species was taken from a salinity of 38 ppt in Western Autralia (W. White, Murdoch University, pers. comm. March 2003). Further research is required on its habitat preferences. The ecology (i.e., critical habitat, salinity tolerances) and life history parameters (age and size at maturity for males and females, litter sizes, longevity) of this species are little known and need further investigation. The small eyes and slender teeth of Glyphis species suggest that they are primarily fish eaters adapted to living in turbid waters with poor visibility (Compagno 1984, Fowler 1997).
Systems: Freshwater; Marine

Threats [top]

Major Threat(s): As with other species of the genus, Glyphis sp. C may be largely restricted to freshwater and brackish reaches of rivers. Some of the most threatened chondrichthyan species are those restricted to such habitats, and with naturally very small populations. In addition to all the biological constraints of the marine chondrichthyans, freshwater/brackish species are more seriously limited by threats (such as fisheries and habitat degradation) affecting their restricted populations than are more widely ranging marine species (Compagno 2002). Glyphis sp. C is likely to be threatened by both commercial and recreational fishing and possible habitat degradation. Commercial fishing may be in the form of gillnetting (legal or illegal) or longlining. Recreational fishing may be in the form of illegal gillnetting or hook and line fishing (using bait and/or lures). The potential impacts of fishing operations on this species need further investigation.

Conservation Actions [top]

Conservation Actions: This species is listed as Endangered on the Commonwealth Environment Protection and Biodiversity Conservation Act, 1999. A Recovery Plan is currently being drafted and will be completed by mid 2003 (S. Williams, Environment Australia, pers. comm. March 2003). It is also listed as an Endangered species under the Territory Parks and Wildlife Conservation Act 2000, but no management program was in place as of June 2002 (Stirrat and Larson 2002).

Citation: Pogonoski, J. & Pollard, D. (SSG Australia & Oceania Regional Workshop, March 2003) 2003. Glyphis garricki. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 30 July 2014.
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