|Scientific Name:||Elops machnata|
|Species Authority:||(Forsskål, 1775)|
Argentina machnata Forsskål, 1775
Elops capensis Smith, 1838-47
|Taxonomic Notes:||E. machnata and E. hawaiensis occur sympatrically in the Western Pacific and possibly the Hawaiian Islands, so further research appears warranted. In the northern south China Sea, for example, Shao et al. (2008) claim that E. hawaiensis historically reported in the region are misidentifications of E. machnata. Wang et al. (2002) state that genetic data is now available to discriminate between E. machnata and E. hawaiensis.
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Adams, A., Guindon, K., Horodysky, A., MacDonald, T., McBride, R., Shenker, J. & Ward, R.|
|Reviewer/s:||Harwell, H. & Raynal, M.|
Elops machnata is distributed in the Indo-West Pacific from the Red Sea to East Africa, South Africa, Seychelles, Madagascar and western Mascarenes east to Philippines. The unknown extent of commercial fisheries and the magnitude of harvest suggest a potential threat to this species. Its early stages use estuary and lagoonal habitats, which are prone to anthropogenic alterations but this species exhibits a broad range of habitat plasticity. Population trends are currently stable in eastern Africa, Indian Ocean but are unknown throughout the rest of its expansive range. We therefore globally consider this species as Least Concern in the absence of known threats. However, a number of questions remain regarding its taxonomic uncertainty, population status, fisheries interactions and potential threats in the eastern part of its range. Future monitoring is needed, particularly in the Coral Triangle, where significant declines in other Elopiformes has been inferred.
Elops machnata is distributed in the Indo-West Pacific from the Red Sea to East Africa, South Africa, Seychelles, Madagascar and western Mascarenes (extinct in Réunion) east to Philippines; possibly Hawaiian Islands (Eschmeyer and Fong 2008).
Native:Australia; Bangladesh; Cambodia; China; Djibouti; Egypt; Eritrea; India (Andaman Is., Nicobar Is.); Indonesia; Israel; Japan; Jordan; Kenya; Malaysia; Maldives; Mozambique; Myanmar; Philippines; Saudi Arabia; Singapore; Somalia; South Africa; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Viet Nam; Yemen
|FAO Marine Fishing Areas:||
Atlantic – southeast; Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
Overall population trends are currently stable in eastern Africa, Indian Ocean but are unknown throughout the rest of its expansive range.
Elops machnata was dominant in mangrove clear-cut areas in Tanzania, but was found in relatively low abundances compared to the undisturbed areas. Results of the study done by Mwandya et al. (2009) indicate that mangrove habitat loss and changes in environmental conditions caused by salt farm developments will decrease fish densities, biomass and species numbers as well as alter the overall fish assemblage composition in the salt farm area but not downstream in the creek. Also in the St. Lucia Estuary, South Africa, Mann et al. (2002) ranked E. machnata eigth by numbers and fifth by weight in the recreational catch. Catch per unit effort (CPUE) was stable from 1986 to 1989.
In Thukela Estuary, South Africa, a trend of declining fish abundance with increasing river flow was observed. CPUE (average number of fish sampled per seine haul) for E. machnata was recorded at 28 individuals per haul in 1997 and 0 in 1999. This decline is probably due to a combination of high river discharge and zero salinities throughout the system, with many marine species then finding temporary refuge in the sea. The pattern observed in Thukela Estuary of declining fish abundance and lack of colonization of the estuary during high river flow conditions has been observed in other estuaries and river mouths of southern Africa (Whitfield and Paterson 1995, Ter Morshuizen et al. 1996, and South America (Garcia et al. 2001, Garcia and Vieira 2002).
There was an increase in gill net CPUE in the Sundays and Swartkops estuaries of South Africa between late 1970s and 1992–1993. There was also an increase in percentage composition of anglers' catches from 1.9% in 1972–78 to 2.2% in 1988–93 in Swartkops estuary (Mann and Radebe 1999).
Pradervand and Baird (2002) report a creel survey for one year (1996–1997) in Eastern Cape, South Africa.
|Habitat and Ecology:||
Elops machnata adults inhabit shallow coastal areas and commonly enter estuaries, particularly larger subtropical estuaries which are permanently open. Harrison and Whitfield (2006) categorized E. machnata as a eurythermic tropical species found widely into subtropical and warm temperate regions. Whitfield (2005) reports no Elops spp. in cool-temperate estuaries. It may be found in turbid water and has a wide salinity tolerance. Juveniles are common in warm, turbid estuaries on which they are dependent as nursery areas (Mann and Radebe 1999). Elops machnata was recorded from 0–90 ppt in St. Lucia Estuary, South Africa (Whitfield et al. 2006). Maximum size recorded is 118 cm FL (International Game Fish Association 2001).
Elops machnata is piscivorous (Marais 1984). Whitfield and Blaber (1978) report that crustaceans and molluscs are also consumed.
Alikunhi and Rao (1951) describe leptocephalus metamorphosis and early growth of E. machnata (erroneously called E. saurus) in an estuary of the Bay of Bengal in India.
Results of the study done by Mwandya et al. (2009) indicate that mangrove habitat loss and changes in environmental conditions caused by salt farm developments will decrease fish densities, biomass and species numbers as well as alter the overall fish assemblage composition in the salt farm area but not downstream in the creek. The unknown extent of commercial fisheries and the magnitude of harvest suggest a potential threat to this species. Its early stages use estuary and lagoon habitats, which are prone to anthropogenic alterations. However, population trends are currently stable in St. Lucia Estuary, South Africa and this species is exhibits a broad range of habitat plasticity.
In South Africa, this species is an important component of estuarine sport anglers' catches. It is also taken by rock and surf anglers, recreational skiboat anglers and spearfishers. It is particularly popular with saltwater fly anglers. It is caught by subsistence and artisanal fishers using fish traps and gill-nets (Mann and Radebe 1999).
In South Africa, there is a bag limit of five fish/per person/day. There is no sale for this species (Crook and Mann 2002).
Its distribution overlaps with a number of marine reserves in parts of its range.
|Citation:||Adams, A., Guindon, K., Horodysky, A., MacDonald, T., McBride, R., Shenker, J. & Ward, R. 2012. Elops machnata. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 07 March 2014.|
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