|Scientific Name:||Scomberomorus munroi|
|Species Authority:||Collette & Russo, 1980|
This species was confused with S. niphonius from Munro (1943) until it was described by Collette and Russo (1980).
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Collette, B., Di Natale, A., Fox, W., Juan Jorda, M. & Nelson, R.|
|Reviewer(s):||Russell, B., Carpenter, K.E. & Begg, G.|
This species is only known from Australia and southern Papua New Guinea, and has been an important line-fished species since 2004. An earlier assessment for the eastern Australia stock estimated biomass declines to be approximately 33–63% from 1992 to 2002 (within three generation lengths). In the most recent (2009–2010) stock assessment, it was recorded as sustainably fished with total mortality estimates indicating fishing is occurring at upper levels (SS 2011). Estimates are not available for the remaining portion of its range. Early declines in catch and the lack of information on the stock structure and fisheries in the northern and western portion of this species range indicate that the status of this species should be carefully watched. Currently it is listed as Near Threatened instead of Vulnerable as recommended by Collette et al. (2011).
|Range Description:||This species is restricted to the northern coast of Australia, from the Abrolhos Islands region of Western Australia to Coffs Harbour and Kempsey in central New South Wales; also occurring in southern Papua New Guinea from Kerema to Port Moresby.|
Native:Australia; Papua New Guinea
|FAO Marine Fishing Areas:||
Indian Ocean – eastern; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
A stock assessment (Begg et al. 2005) for this species' population off the Australian east coast (northern Queensland to northern New South Wales), based on data from 1960–2002, showed 2002 biomass levels to be between 33% and 63% of pre-1960 unfished or virgin biomass levels. This assessment indicated that the estimated 2002 biomass was above BMSY. Model projections suggest catches of greater than 300–350 tonnes in 2003 have a high risk of reducing the population in relation to maximum sustainable yield (MSY). Annual landings in 2009–2010 reached 71% of the total allowable catch (TAC) (ASR 2011).
This Queensland stock in 2004 was considered fully fished, with commercial landings of 60–120 t and a recreational catch of about 150 t (Begg et al. 2005). Commercial landings in New South Wales have fluctuated, and averaged around 20–30 t between 1990 and 2009, with a high of 60 t in 2000 and a low of around 10 t in 2009. However, catches are not considered a robust indicator of abundance (Queensland Fisheries 2010).
There is no information available for the remaining parts of this species' range. This may be because the Queensland portion of the range represents the most important part of the fishery.
|Habitat and Ecology:||
This species is pelagic, oceanodromous, and found more commonly in offshore, open waters away from reefs and shoals. It forms large schools which move close inshore along the coast of Queensland, where it is commonly taken between December and April or May. It feeds largely on fishes, particularly anchovies and sardines, with smaller quantities of shrimps and squids (Begg and Hopper 1997). Common fork length ranges 50–80 cm.
Spotted Mackerel spawn between August and October in northern Queensland waters with peak spawning occurring in September (Begg 1998). They grow quickly for the first three years of life, and demonstrate sex-specific growth rates, with females tending to grow faster and to larger sizes (Begg and Sellin 1998). Considerable variation in length is found for any given age of Spotted Mackerel, where they have been aged up to seven years and observed to 105 cm total length (TL) and 7.4 kg. Female and male Spotted Mackerel reach maturity at about 60 cm and 52 cm TL, respectively, within 1–2 years of age (Begg et al. 2005). Generation length is estimated to be between 3–4 years.
Tagged Spotted Mackerel move long distances, with about 39% recaptured over 100 km from the release site (Begg et al. 1997). The longest movement was 1,100 km over 228 days. These movements, together with spatial and temporal patterns of tagging effort and commercial fishing harvest, indicate a single eastern stock that undertakes a seasonal migration associated with spawning and feeding along the Queensland and New South Wales coasts (Begg et al. 1997, Staunton-Smith et al. 2005).
The all-tackle angling record is of a 9.25 kg fish caught off South West Rocks, New South Wales, Australia in 1987 (IGFA 2011).
|Use and Trade:||This is a commercial species in Australia.|
This is an important species for recreational and commercial fishers in Queensland, Australia. It was a major part of the set gillnet and ring-net commercial fisheries (Begg et al.1998), but since 2004 it has been predominantly a line-fished species. The highly aggregated, near-surface schooling behaviour of the stock coupled with its predictable seasonal movements along the east coast allows ease of targeting by both the commercial and recreational sectors; thereby making the stock susceptible to over-fishing. In 1999–2000, commercial catches of Spotted Mackerel increased significantly in response to the development of valuable overseas export markets. The 2009–10 SS and ASR reports that the east coast harvest was 100 tons of commercial catch (12 t net and 88 t line), 11 t of charter and 305 t recreational (A. Garland, pers. comm. 2011). The Gulf of Carpentaria commercial sector has not reported any harvest since 2008 (the catch between 2003 and 2008 was less than 400 t).
More information is needed to determine the status of the western population, and if the assessment conducted on the East coast are inclusive.
There are bag and size limits for this species. The Queensland Fishery is regulated under Queensland's Fisheries Regulations 1995. In response to concerns about sustainability, some major changes in management were made in 2002 and 2003 that apply to both commercial and recreational fishers (Staunton-Smith et al. 2005). The minimum legal size was increased from 50 to 60 cm total length, the recreational bag limit was reduced from 30 to five fish per person, and the use of nets to target spotted mackerel was prohibited. Since these changes to management, line fishing has become the main commercial method to catch Spotted Mackerel.
To improve and develop the stock assessment there is a need for: 1) a more comprehensive and structured monitoring approach to the collection of appropriate age-structured data from both the commercial and recreational sectors; 2) the recording of a better measure of effort and species identification in the commercial logbooks and recreational diaries to provide a more reliable indicator of CPUE; 3) a review of the historical catch data to confirm the assumed commencement of the fishery and magnitude of the catches; 4) a robust evaluation of the selectivity functions for the different fishing gears;
5) an appraisal of the protocols used to age spotted mackerel; 6) a fishery-independent measure of changes in stock size; 7) investigations into the fecundity, spawning, recruitment processes and environmental-catch distributions of Spotted Mackerel; and 8) a periodic review and update of the data and models used in the assessment via a systematic and transparent stock assessment review process (Begg et al. 2005). Furthermore, recent management measures also need to be assessed in the future, and more prudent actions may be needed, if fishing pressure increases in the recreational sector or the commercial catch quota is exceeded.
|Citation:||Collette, B., Di Natale, A., Fox, W., Juan Jorda, M. & Nelson, R. 2011. Scomberomorus munroi. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 05 August 2015.|
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