|Scientific Name:||Gymnura micrura|
|Species Authority:||(Bloch & Schneider, 1801)|
|Taxonomic Notes:||Records referring to G. micrura from off Sri Lanka, India, Malaysia, Singapore, Viet Nam, Borneo and Sumatra in Indonesia, and the Philippines refer to other taxa (L.J.V. Compagno, pers. comm.).|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor/s:||Grubbs, R.D. & Ha, D.S.|
|Reviewer/s:||Compagno, L.J.V., Fowler, S.L., Kyne, P.M. & Cavanagh, R.D. (Shark Red List Authority)|
Gymnura micrura is reasonably widespread in inshore waters (to 40 m depth) in the Eastern and Western Atlantic. Little known of its biology, although reported to have litter sizes of 6 to 8 pups. There is no information available on the species throughout its Central and South American and West African range, but it is likely taken as bycatch in various (often intensive) inshore fisheries in these regions. Gymnurids are susceptible to a variety of fishing gear, are commonly taken in inshore fisheries and heavy fishing pressure appears to be impacting populations of some Indo-West Pacific gymnurids (i.e., G. poecilura and Aetoplatea zonura), thus raising concerns for G. micrura. Due to lack of information it is assessed as Data Deficient globally, but given the vulnerability of gymnurids to inshore fishing, combined with limited biological characteristics, an immediate effort should be made to gather data to accurately assess catches of G. micrura throughout its range. In US waters, where it is locally common in estuaries and nearshore waters, the species is not commercially targeted. Although taken as bycatch in shrimp trawl fisheries it is typically released alive (post-release survivorship is probably high). With no major threats affecting the species in the US, it is assessed as Least Concern in that country.
|Range Description:||Reasonably widespread in the Eastern (Senegal, Gambia, Sierra Leone, Cameroon and Democratic Republic of the Congo) and Western Atlantic (from Chesapeake Bay, US through the Gulf of Mexico to Brazil; not recorded from the Greater or Lesser Antilles).|
Native:Belize; Brazil; Cameroon; Colombia; Congo, The Democratic Republic of the; Costa Rica; French Guiana; Gambia; Guatemala; Guyana; Honduras; Mexico; Nicaragua; Panama; Senegal; Sierra Leone; Suriname; Trinidad and Tobago; United States (Alabama, Florida, Georgia, Louisiana, Maryland, Mississippi, North Carolina, South Carolina, Texas, Virginia); Venezuela
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – northwest; Atlantic – southwest; Atlantic – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||No estimates of population size exits. Can be locally common in estuaries and nearshore waters along the Atlantic coast of the US and in the Gulf of Mexico.|
|Habitat and Ecology:||
Prefers neritic waters of the continental shelf to 40m depth and usually found on soft bottoms. Enters brackish estuaries or hyper-saline lagoons. Aplacental viviparous, but little information available on its biology. Reported litter sizes of 6 to 8 pups. Parturition is known to occur in Chesapeake Bay and seaside lagoons along Virginia?s eastern shore (Grubbs, unpubl. data).
Food consists of bivalve molluscs, crustaceans including mysids, shrimps, crabs, and ray-finned fishes (McEachran and de Carvalho 2002, Schmid et al. 1988). Also feeds on sedentary polychaetes in soft sediments (Grubbs, unpubl. data). Life history parameters taken from McEachran and de Carvalho (2002), unless otherwise stated.
Life history parameters
Age at maturity (years): Unknown.
Size at maturity (disc width): 50 cm DW (female); 42 cm DW (male).
Longevity (years): Unknown.
Maximum size (disc width): 120 cm DW.
Size at birth: 16 to 22 cm DW.
Average reproductive age (years): Unknown.
Gestation time (months): Unknown.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: Unknown.
Annual rate of population increase: 6 to 8 per litter based on 4 females (Grubbs, unpubl data).
Natural mortality: Unknown.
There are no directed fisheries for this species in the USA. However, G. micrura is commonly taken as bycatch in shrimp trawl fisheries in the Gulf of Mexico. It is also likely taken as bycatch in various inshore fisheries throughout its Central and South American and West African ranges. Gymnurids are susceptible to a variety of fishing gear and are commonly taken in inshore fisheries, although no specific data is available on catches of G. micrura in the region. Heavy fishing pressure appears to be impacting populations of some Indo-West Pacific gymnurids (i.e., G. poecilura and Aetoplatea zonura) and so this raises concerns for G. micrura in parts of its Central and South American and West African ranges where inshore fishing can be intensive.
Individuals taken by shrimp trawl in the USA are typically released and post-release survivorship is probably high.
There are no conservation measures in place for this species throughout its range. Catches in artisanal and commercial fisheries throughout its Central and South American and West African distributions need to be documented.
The development and implementation of management plans (national and/or regional e.g. under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA?Sharks) are required to facilitate the conservation and sustainable management of all chondrichthyan species in the region. See Anon. (2004) for an update of progress made by nations in the range of G. micrura.
|Citation:||Grubbs, R.D. & Ha, D.S. 2006. Gymnura micrura. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 June 2013.|
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