Sea Mullet (2018)
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Sea Mullet is a sustainable species occurring in all coastal regions of WA, and on the east coast of Australia.
Stock Status Overview
|Queensland||Eastern Australia||ECIFFF||Sustainable||Catch, CPUE, length and age frequencies|
- East Coast Inshore Fin Fish Fishery (QLD)
Sea Mullet was formerly regarded as a single species with a global distribution. However, recent genetic evidence indicates that ‘sea mullet’ is actually a complex of many cryptic species. Sea Mullet along the west and east coasts of Australia are now regarded as distinct species [Durand et al. 2012, Krück et al. 2013].
Extensive tagging studies [Kesteven 1953] suggest a single east coast biological stock of Sea Mullet, extending from central Queensland to eastern Victoria. The population structure within Western Australia is yet to be fully examined but given the extensive coastline and wide latitudinal range, it is possible that this jurisdiction hosts more than one biological stock (or species). Given this uncertainty, Sea Mullet within each Bioregion are currently managed as separate units. Limited tagging and genetic studies [Thomson 1951, Watts and Johnson 1994] suggest mixing of fish throughout the West Coast Bioregion (WCB), where the majority of the catch is taken.
Here, assessment of stock status is presented at the biological stock level—Eastern Australia; and the jurisdictional stock level—Western Australia.
This cross-jurisdictional biological stock has components in Queensland and New South Wales. Each jurisdiction assesses the part of the biological stock that occurs in its waters. The status presented here for the entire biological stock has been established using evidence from both jurisdictions.
The Queensland component of the Eastern Australian biological stock has a long history of stable commercial landings. In 2017, 1 730 t was reported landed, which is below the long-term average of around 2 000 t. Length frequency information from routine monitoring shows stable distributions of fish sizes harvested by the Queensland fishery [QDAF 2018]. Age frequency information shows fish from three to five years old dominate catches, but older fish are present. Recruitment has been consistent, with evidence of recent strong year classes. The above evidence indicates that the biomass of the Queensland component of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired.
Nominal effort in the Queensland component of the fishery has reduced from 7 563 days in 2015 to 7 252 in 2017, and the number of fishers reporting mullet (unspecified) catch has reduced from 250 fishers to 244 fishers over the same period [QDAF 2018]. Length frequency information shows an increase in the modes for the fishery, and catch is well above minimum legal size. Age frequency information shows continued recruitment to the fishery and evidence of strong year classes. Estimates of fishing mortality are high compared with estimates of natural mortality, but they show a stable trend in combination with consistent catches. The above evidence indicates that the current level of fishing pressure is unlikely to cause the Queensland component of the stock to become recruitment impaired.
The New South Wales component of the Eastern Australian biological stock is assessed annually in terms of landings and CPUE in both the estuary and ocean fisheries [Stewart et al. 2015]. The annual spawning run fishery on ocean beaches is also assessed in terms of fish sizes and ages in landings. Landings in New South Wales in 2016–17 (2 200 t) were below the long-term (10 year) annual average (around 3 000 t). The reported number of fisher days in the ocean and estuarine fisheries in 2016–17 were at historically low levels of approximately 417 and 13 000 respectively, down from around 1 000 and 15 000 days respectively in 2009–10. Typical length and age frequency compositions were found in landings in 2016–17, with most fish being between three and seven years of age [NSWDPI unpublished], suggesting no large changes in the stock. The above evidence indicates that the biomass of the New South Wales component of this stock is unlikely to be depleted and that recruitment is unlikely to be impaired.
Commercial median catch rates in the New South Wales component of the fishery have remained stable in the estuary fishery (kg per day of mesh netting) and increased slightly in the ocean fishery (kg per day of beach hauling) since the early 1980s [NSWDPI unpublished]. The size compositions of fish in ocean landings have remained stable, while the age compositions of fish in this fishery are generally between two and five years old, with some variations in year class strength [Stewart et al. 2015, NSWDPI unpublished]. Relatively high levels of fishing mortality have been documented on the spawning run ocean beach fishery [Stewart et al. 2018]; however when considered in combination with a complex life-history strategy that has evolved to promote population resilience and includes ‘skipped breeding’ partial migration, whereby a proportion of adult fish do not participate in the spawning run each year [Fowler et al. 2016], these periodic high levels of fishing mortality are sustainable. The above evidence indicates that the current level of fishing pressure is unlikely to cause the New South Wales component of the stock to become recruitment impaired.
On the basis of the evidence provided above, the entire Eastern Australia biological stock is classified as a sustainable stock.
|Species||Longevity / Maximum Size||Maturity (50 per cent)|
|Sea Mullet||Western Australia 12 years, 790 mm FL Eastern Australia 16 years, 640 mm FL||Western Australia Males and Females 370 mm TL Eastern Australia Males 300 mm TL, Females 330 mm TL|
Distribution of reported commercial catch of Sea Mullet
|Commercial||1.73Kt in ECIFFF|
- East Coast Inshore Fin Fish Fishery (QLD)
Queensland – Indigenous (management methods) In Queensland, under the Fisheries Act 1994, Indigenous fishers are able to use prescribed traditional and non-commercial fishing apparatus in waters open to fishing. Size and possession limits and seasonal closures do not apply to Indigenous fishers. Further exemptions to fishery regulations can be obtained through permits.
New South Wales – Indigenous (management methods) (a) Aboriginal Cultural Fishing Interim Access Arrangement—allows an Indigenous fisher in New South Wales to take in excess of a recreational bag limit in certain circumstances; for example, if they are doing so to provide fish to other community members who cannot harvest for themselves, (b) The Aboriginal cultural fishing authority is the authority that Indigenous persons can apply to take catches outside the recreational limits under the Fisheries Management Act 1994 (NSW), Section 37 (1d)(3)(9), Aboriginal cultural fishing authority, and (c) In cases where the Native Title Act 1993 (Cth) applies fishing activity can be undertaken by the person holding native title in line with S.211 of that Act, which provides for fishing activities for the purpose of satisfying their personal, domestic or non-commercial communal needs. In managing the resource where native title has been formally recognised, the native title holders are engaged with to ensure their native title rights are respected and inform management of the State's fisheries resources.
- Durand, JD, Chen, WJ, Shen, KN, Jamandre, BW, Blel, H, Diop K, et al. 2012, Systematics of the grey mullets (Teleostei: Mugiliformes: Mugilidae): molecular phylogenetic evidence challenges two centuries of morphology-based taxonomy. Molecular Phylogenetics and Evolution, 64 73–92.
- Fisheries Queensland 2016, Fisheries Queensland monitoring data 1999–2015, Monitoring our fisheries, Queensland Department of Agriculture and Fisheries.
- Fowler, AM, Smith, SM, Booth, DJ and Stewart, J 2016, Partial migration of grey mullet (Mugil cephalus) on Australia’s east coast revealed by otolith chemistry. Marine Environmental Research, 119: 238–244.
- Gaughan, D, Ayvazian, S, Nowara, G and Craine, M 2006, The development of a rigorous sampling methodology for a long-term annual index of recruitment for finfish species from south-western Australia, Final report, Fisheries Research and Development Corporation project 1999/153, Fisheries Research Report 154, Western Australian Department of Fisheries, Perth.
- Gaughan, D.J. and Santoro, K. (eds). 2018, Status Reports of the Fisheries and Aquatic Resources of Western Australia 2016/17: The State of the Fisheries. Department of Primary Industries and Regional Development, Western Australia.
- Kesteven, GL 1953, Further results of tagging sea mullet, Mugil cephalus Linnaeus, on the eastern Australian coast, Australian Journal of Marine and Freshwater Research, 4: 251–306.
- Krück, NC, Innes, DI and Ovenden, JR 2013, New SNPs for population genetic analysis reveal possible cryptic speciation of eastern Australian sea mullet (Mugil cephalus). Molecular Ecology Resources, 13: 715–725. doi:10.1111/1755-0998.12112.
- NSWDPI Unpublished. Status of Australian Fish Stocks 2018–NSW Stock status summary – Sea Mullet (Mugil cephalus).
- Queensland Department of Agriculture and Fisheries 2018, Queensland Stock Status Assessment Workshop Proceedings 2018. Species Summaries. 19–20 June 2018, Brisbane.
- Smith, KA and Deguara, KL 2002, Review of biological information and stock assessment for the NSW sea mullet resource, NSW Fisheries Resource Assessment Series No. 12, New South Wales Fisheries, Cronulla.
- Stewart, J, Hegarty, A, Young, C and Fowler, AM 2018, Gender-specific differences in growth, mortality and migration support population resilience in a heavily exploited migratory marine teleost, Mugil cephalus (Linnaeus 1758). Marine and Freshwater Research 69: 385–394.
- Stewart, J, Hegarty, A, Young, C, Fowler, AM and Craig, J 2015, Status of fisheries resources in NSW 2013–14, NSW Department of Primary Industries, Mosman, 391 pp.
- Thomson, JM 1951, Growth and habits of the sea mullet, Mugil dobula Gunther, in Western Australia, Australian Journal of Marine and Freshwater Research, 2: 193–225.
- Virgona, JL, Deguara, KL, Sullings, DJ, Halliday, I and Kelly, K 1998, Assessment of the stocks of sea mullet in New South Wales and Queensland Waters. Final Report Series No. 2. New South Wales Fisheries, Cronulla.
- Watts, RJ and Johnson, MS 2004, Estuaries, lagoons and enclosed embayments: habitats that enhance subdivision of inshore fishes, Marine and Freshwater Research, 55: 641–651.