|Scientific Name:||Metanephrops boschmai (Holthuis, 1964)|
Nephrops boschmai Holthuis, 1964
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Butler, M., Chan, T.Y., Cockcroft, A., MacDiarmid, A. & Wahle, R.|
|Reviewer(s):||Collen, B., Livingstone, S. & Richman, N.|
|Contributor(s):||Batchelor, A., De Silva, R., Dyer, E., Kasthala, G., Lutz, M.L., McGuinness, S., Milligan, H.T., Soulsby, A.-M. & Whitton, F.|
Metanephrops boschmai has been assessed as Least Concern. Although this species is harvested commercially; there is no evidence that the fishery is being mined. Controls are in place, however should stock abundance show future declines then stricter controls are suggested for the fishery.
|Range Description:||This species occurs in the Eastern Indian Ocean region off the west and south coasts of Australia: from Port Hedland to Eucla in the Great Australian Bight (Holthuis 1991, Chan et al. 2009).|
Native:Australia (South Australia, Western Australia)
|FAO Marine Fishing Areas:|
Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species was the most common of the four Metanephrops species occuring off the northwest coast of Australia (George 1983). However, recent fisheries data suggest scampi populations might be declining, as both annual catch and catch per unit effort (CPUE) have decreased since the fishery opened in 1985 (M.J. Butler, A.C. Cockcroft, A.B. MacDiarmid and R.A. Wahle pers. comm.. 2008).|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||This species lives in mud or mud/rubble substrates at depths of 300-500 m (Holthuis 1991, Poore 2004). This species diet is largely comprised of fish (Wassenberg and Hill 1989). It is a strongly K-selected species, reaching maturity after three to five years, and living for up to 12 years (Rainer 1992). Females spawn annually, producing 100-900 larvae per brood (DEH 2004).|
|Generation Length (years):||4|
|Use and Trade:||
There is a small fishery involving this species (Wallner and Phillips 1988 in Poore 2004). It is a principal target species in the North West Slope Trawl Fishery (NWSTF) (DEH 2004).
The annual catch (in tonnes) in the NWSTF from 1985 to 2003 is as follows (data from Lynch and Garvey 2005):
1985 - 5.2; 1986 - 17.0; 1987 - 11.7; 1988 - 8.1; 1989 - 22.0; 1990 - 11.5; 1991 - 9.5; 1992 - 20.3; 1993 - 0.6; 1994 - 1.8; 1995 - 4.0; 1996 - 5.9; 1997 - 7.0; 1998 - 4.6; 1999 - 5.6; 2000 - 1.7; 2001 - 9.3; 2002 - 4.2; 2003 - 1.1
The proportion of this species caught within all Metanephrops species ranged from 2% to 22%, averaging 11.5%.
In the past this species was largely unexploited off the northwest Australian coast, partly due to its smaller size (compared to other Metanephrops species) which made it less marketable (Wallner and Phillips 1988). Holthuis (1991) stated that "more exploration [into fisheries potential of this species] remains necessary".
It is now a target species in the North West Slope Trawl Fishery (NWSTF), which may constitute a threat due to its slow life history (three to five years to maturity, six to eight years to attain commercial size, extended incubation period, and relatively small annual broods), meaning that sustainable yields are likely to be low (DEH 2004, Lynch and Garvey 2005).
Data collected by the Australian Fisheries Management Authority suggest that populations of this species are declining due to commercial trawling, although the severity of decline is unknown (Lynch and Garvey 2005). Fishing effort has decreased in recent years since peaking in the late 1980s, which may be allowing populations to recover. There appears to be no evidence of the fishery being "mined" (vessels continually moving to new areas of high abundance and depleting stocks locally, until the entire fishery has been exploited to such an extent that a sudden collapse may occur). The size frequency distribution of all Metanephrops species has not changed significantly over the period of exploitation (Lynch and Garvey 2005); this suggests that vessels are not having to shift their targets towards a greater number of smaller individuals due to over-harvesting of mature lobsters.
The North West Slope Trawl Fishery (NWSTF) is managed under a limited entry policy. Seven permits are granted, and several restrictions are placed on vessels: only one vessel is allowed on a permit at any one time, vessels cannot tranship product to another vessel, and vessels are only allowed to use trawling methods (Lynch and Garvey 2005).
It is recommended that populations of this species population and harvest levels continue to be monitored, and if declines continue then stricter controls on trawling are imposed.
|Citation:||Butler, M., Chan, T.Y., Cockcroft, A., MacDiarmid, A. & Wahle, R. 2011. Metanephrops boschmai. The IUCN Red List of Threatened Species 2011: e.T170050A6721425.Downloaded on 20 September 2017.|
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