|Scientific Name:||Megalops cyprinoides|
|Species Authority:||(Broussonet, 1782)|
|Red List Category & Criteria:||Data Deficient 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.|
The species is widely distributed in the Indo-Pacific from East Africa to the Society Islands, northward to Japan and southward to Australia. However, very little information is known regarding the life history, demographics, and harvest of this species. Given the reliance of this long-lived species on habitats susceptible to human disturbance and the unknown magnitude of commercial landings in the Philippines and Malaysia, this species is currently listed as Data Deficient. Future research and monitoring is warranted.
|Range Description:||The species is widely distributed in the Indo-Pacific from the eastern coast of Africa, the Arabian peninsula, throughout southern and southeastern Asia, to French Polynesia (the Society Islands), northward to Japan and southward to Australia.
Native:American Samoa (American Samoa); Australia (Coral Sea Is. Territory, New South Wales, Northern Territory, Queensland, Victoria, Western Australia); Bahrain; Bangladesh; Cambodia; China (Fujian, Guangdong, Hainan); Cook Islands; Djibouti; Egypt; Eritrea; Fiji; French Polynesia (Society Is.); Guam; Hong Kong; India (Andaman Is., Andhra Pradesh, Goa, Karnataka, Kerala, Nicobar Is., Orissa, Tamil Nadu, West Bengal); Indonesia (Irian Jaya, Kalimantan, Sulawesi, Sumatera); Iran, Islamic Republic of; Israel; Japan; Jordan; Kenya; Korea, Democratic People's Republic of; Korea, Republic of; Kuwait; Madagascar; Malawi; Malaysia (Peninsular Malaysia, Sabah, Sarawak); Mauritius (Mauritius (main island)); Micronesia, Federated States of ; Mozambique; Myanmar (Myanmar (mainland)); Nauru; New Caledonia; Niue; Northern Mariana Islands; Oman; Pakistan; Palau; Papua New Guinea; Philippines; Qatar; Réunion; Samoa; Saudi Arabia; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Swaziland; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Tonga; Tuvalu; United Arab Emirates; Vanuatu; Viet Nam; Wallis and Futuna; Yemen; Zimbabwe
|FAO Marine Fishing Areas:||
Atlantic – southeast; Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
The species is common in parts of its range, and over 300 museum records exist (accessed through the Fishnet2 Portal, www.fishnet2.net, 2011-05-14).
Larval recruitment occurs in strong seasonal peaks. In Australia, this species ranked third in abundance of all species sampled by Davis (1988) in Leanyer, Northern Territory. Larval M. cyprinoides was among the most abundant species collected on night time flood tides in Taiwan estuarine creek (Tzeng et al. 2002).
|Habitat and Ecology:||
The species is found in depths to 50 m in coastal waters and ranges inland to hundreds of kilometres upstream in rivers and floodplains (Pusey et al. 2004). It is commonly observed near the surface in shallow inshore waters (Shenker pers. comm. 2011). This species inhabits coral reefs, small lakes (billabongs), mangrove swamps, rivers, reservoirs, floodplains, coastal bays and canals. The favoured inshore habitat may be wave-dominated estuaries, having lower temperature and salinity but higher silicate levels (Ley 2005). It may be more common in systems with unmodified river flows. This species appears to be more active early in the night than during the day (Ley 2008).
In Papua New Guinea, it has been reported to occur under large mats of Salvinia molesta. It is one of the few fishes beside Ariidae reported to be caught under these mats (Coates 1987).
This species is believed to spawn offshore, but locations of spawning grounds and subsequent dispersal of larvae remain uncertain. In India, M. cyprinoides inhabit the estuary of the Waltair Coast as juveniles and progress to coastal areas for final maturity and spawning (Kulkarni 1983, Padmaja and Rao 2001), where spawning may occur twice a year (Padmaja and Rao 2001). A single larva was collected from the Great Barrier Reef approximately 25-45km off the mainland (Leis and Reader 1991). Larvae swim or drift with tidal currents and recruit to shallow coastal nurseries in 20-40 days post-hatching (Tsukamoto and Okiyama 1997, Tzeng et al. 1998). This species may be considered a marine transient species (Day et al. 1989) in tropical and sub-tropical estuaries.
Larval biology includes a leptocephalus stage, complete metamorphosis into juveniles occurs in approximately 10 days (Tsukamoto and Okiyama 1993,1997; Chen and Tzeng 2006). Pusey et al. (2004) suggest that M. cyprinoides acheives sexual maturity at age 2-years at length 30 cm, another study in Papua New Guinea by Coates (1987) suggest length at maturity at 40 cm. Systematic analyses of this species' reproductive biology is needed to provide important biological parameters such as length-at-maturity, fecundity, and related reproductive behavior (Ley 2008).
This species has been known to live up to 44 years (Kulkarni 1983). Maximum size of 1.5 m TL have been reported, however, this record needs to be verified. In South Africa, maximum size recorded is 0.5 m TL (Coates 1987). An average maximum size of 0.6 m TL seems probable (Ley 2008).
The diet of M. cyprinoides, summarized from four trophic studies, is highly diverse and consists of insects, fish, crustaceans, and even plants, though they are classified as opportunistic, intermediate carnivores (Ley 2008).
|Major Threat(s):||Potential effects of fishing in parts of its range remain unknown in the absence of catch records. Effective stock assessments in countries where this species is exploited (i.e., Philippines and India), are not possible given the current dearth of population information. Larvae and juveniles rely on mangrove and estuarine habitats, and loss of these habitats may limit production. Larger individuals are more abundant in wave-dominated systems (Ley 2005) where freshwater flow from riverine tributaries is both substantial and unaltered by diversions or dams. Changes to these freshwater delivery systems may reduce the habitat quality for this species. Declining water quality may significantly affect this species; heavy metals and industrial effluent have been shown to hamper gonadal growth and development (Padmaja and Rao 2001).|
|Conservation Actions:||There are no species-specific conservation measures in place for this species. Its distribution overlaps with marine protected areas in parts of its range. More research is needed on its population status, ecology, and the impacts of fishing on this species.|
|Citation:||Adams, A., Guindon, K., Horodysky, A., MacDonald, T., McBride, R., Shenker, J. & Ward, R. 2012. Megalops cyprinoides. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 11 March 2014.|
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