|Scientific Name:||Mobula munkiana Notarbartolo-di-Sciara, 1987|
|Taxonomic Notes:||The relatively recent description of this species and similarity of morphology among mobulids may account for common misidentifications of this ray.|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Bizzarro, J.J., Smith, W.D. & Clark, T.B.|
|Reviewer(s):||Kyne, P.M., Notarbartolo-di-Sciara, G., Fowler, S.L. & Compagno, L.J.V. (Shark Red List Authority)|
Mobula munkiana is a recently described inshore devil ray which is known to form large aggregations. It is endemic to the Eastern Pacific from the Gulf of California, México to Peru and reaches 110 cm disc width. It is listed as Near Threatened due to its episodically high catch rates from gillnet fisheries, restricted range and low reproductive potential. The large schools, migratory nature, and demersal feeding of M. munkiana make it highly susceptible to coastal demersal gillnet fisheries throughout its range. Fishery information for this species is limited to the Gulf of California, México, where it is landed in a mixed mobulid fishery south of La Paz, México and in nearshore artisanal elasmobranch fisheries throughout the Gulf of California. A fecundity of one pup per female emphasizes the limited reproductive potential and low productivity of this species. Sporadically high landings (>60 per gillnet) in the northern Gulf of California stress the vulnerability of M. munkiana to bottomset gillnets and the extreme fluctuations in its local abundance. Life history characteristics, limited distribution, and exposure to many fisheries due to its highly migratory nature will likely result in designation of the species as Vulnerable should additional fisheries details become available.
|Range Description:||Eastern Pacific from the Gulf of California, México to Peru, including the Galapagos, Cocos, and Malpelo Islands (Robertson and Allen 2002).|
Native:Colombia; Costa Rica; Ecuador; El Salvador; Guatemala; Honduras; Mexico (Baja California, Baja California Sur, Chiapas, Colima, Guerrero, Jalisco, Michoacán, Nayarit, Oaxaca, Sinaloa, Sonora); Nicaragua; Panama; Peru
|FAO Marine Fishing Areas:|
Pacific – eastern central; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||No information is available on its population biology.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Mobula munkiana is a recently described schooling species typically of shallow coastal waters, known to form large, highly mobile aggregations (Notarbartolo-di-Sciara 1987, 1988). Specifics of its migratory patterns are largely unknown or speculative (Notarbartolo-di-Sciara 1988, J. Bizzarro pers. obs). |
Most of the fragmentary information available on the species is derived from the work of Notarbartolo-di-Sciara (1987, 1988) in the southern Gulf of California, México, though this species has been recently observed during artisanal fishing camp surveys throughout the Gulf of California (R. Hueter et al. unpublished data, Bizzarro 2001). Migrations are likely driven by temporal changes in water temperature with local movements presumed to be associated with the distribution and abundance of planktonic crustaceans, especially mysid shrimp (Mysidium spp.). Mysids are believed to be the dominant prey item of this species, at least during winter months. However, these conclusions are drawn from a very limited sample size (n=3) and through inference with a closely related, similar-sized mobulid from Africa (M. rochebrunei) and as such should be considered speculative (Notarbartolo-di-Sciara 1988, J. Bizzarro pers. obs). Gastropod shells and coral fragments have been found in stomach contents (presumed taken incidentally), indicating that unlike other eastern Pacific mobulids, benthic foraging may be common (Notarbartolo-di-Sciara 1988). This species may live in large aggregations consisting of several schools that move locally or regionally between prey patches. Occurrence of large schools in the northern Gulf of California are likely confined to summer months, though it has been reported in low numbers throughout the year in the southern Gulf of California (Notarbartolo-di-Sciara 1988, Bizzarro 2001, J. Bizzarro unpublished data). Mobula munkiana is not thought to segregate by gender, but may segregate by size (Notarbartolo-di-Sciara 1988). Observations and catches of the species often occur in pulses as it may be abundant in an area for only a few days and then not be observed locally for weeks or months (Notarbartolo-di-Sciara 1988, Villavicencio-Garayzar 1991, J. Bizzarro pers. obs). These movements have likely influenced the contrasting conclusions of M. munkiana abundance in the southern Gulf of California (Notarbartolo-di-Sciara 1988, Villavicencio-Garayzar 1991). Frequent benthic association of this species would also account for its irregularity in pelagic gillnet landings.
Location of copulation is unknown, but partruition has been reported in Bahía de La Paz during May and June (Villavicencio-Garayzar 1991). Although data is limited, sexual maturity of males is thought to occur at ~87cm DW based on an increase in clasper size and hardening of the clasper cartilage (Notarbartolo-di-Sciara 1988), with females maturing at 97cm DW (Villavicencio-Garayzar 1991). The reproductive mode is aplacental viviparity and embryos feed initially on yolk, then through absorption of enriched uterine fluid from the mother (Wourms 1977). Only the left ovary is functional and reports indicate that a maximum of one pup is estimated to be produced (Villavicencio-Garayzar 1991). Reproductive periodicity is unknown and there is no information on age and growth for this species.
Life history parameters
Age at maturity (years): Unknown.
Size at maturity (disc width): Female: 97 cm DW (Villavicencio-Garayzar 1991); Male: ~87 cm DW (Notarbartolo-di-Sciara 1988).
Longevity (years): Unknown.
Maximum size (disc width): 110 cm DW (Notarbartolo-di-Sciara 1987).
Size at birth: 35 to 36 cm DW (estimated from related species by Notarbartolo-di-Sciara (1988), verified by Villavicencio-Garayzar (1991).
Average reproductive age (years): Unknown.
Gestation time (months): Unknown.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: 1 pup/litter (Villavicencio-Garayzar 1991).
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
Mobula munkiana is highly susceptible to demersal and pelagic gillnets due to its consistent schooling nature and benthic feeding ability. Juveniles could also be incidentally captured in trawl fisheries. The species is landed in directed artisanal elasmobranch fisheries in the Gulf of California and it is possibly taken as bycatch in many nearshore gillnet and trawl fisheries throughout its range. The relatively recent description of this species and similarity of morphology among mobulids may account for common misidentifications of this ray making it underrepresented among available records.
In northern Gulf of California artisanal fishery surveys during 1998 and 1999, M. munkiana were observed to be landed in large numbers at several camps. As catches in the more southerly camps decreased, those in the north increased, suggesting that large portions of the schools may be taken during the unknown movement patterns of this highly mobile species. The species was directly targeted during these times and dominated the elasmobranch landings (J. Bizzarro and W. Smith unpublished data, Bizzarro 2001). However, although catches consist of hundreds of individuals per day when the species is present, artisanal fishermen indicate that the presence of the ray is somewhat unpredictable.
Notarbartolo-di-Sciara (1988) described an active mobulid fishery operating from several artisanal fishing camps in and around Bahía la Ventana, Baja California Sur, México. Mobula munkiana, though taken, was not an abundant species in landings (9% of observed mobulid catches). Recent fieldwork in this region (June 2001), however, showed that this fishery is still active and that M. munkiana was the dominant mobulid landed, at least at the time of surveys (J. Bizzarro unpublished data). This species was landed with gillnets of 10-12", typically set at the surface, but also throughout the water column.
Mobula munkiana is not likely to be able to tolerate high catch levels, given its low reproductive potential. Increasing demand for mobulid products in Asia, which may result in increased targeting in Central America, is of great concern.
Additional research is needed to quantify the extent of target and non-target fisheries take for this species throughout its range. Most current information is derived from the Gulf of California, México, but this represents a very small portion of the overall range of M. munkiana. Because of its moderate to large size, schooling and migratory behavior, extremely low fecundity and large size at maturity, this species is likely highly vulnerable to fishing pressure. However, available life history information is limited and more research is required to make a more accurate assessment of the threat posed by fisheries.
In México, a moratorium on the issue of elasmobranch fishing permits was issued in 1993, but no formal management plan has been implemented for Mobula munkiana specifically or most other chondrichthyans. However, legislation is currently being developed in México to establish national elasmobranch fishery management. Elasmobranch fisheries are unmanaged throughout Central America, and attempts to regulate fisheries in Central America would greatly improve conservation of M. munkiana and other chondrichthyans.
Elasmobranch landings in México and Central America lack species-specific details with batoids broadly grouped as "manta raya". Improved clarity in catch records would provide a basis for detecting potential trends in effort and landings.
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 Central America.
The vulnerability of mobulids and increasing demand/catches requires urgent international conservation measures. These will need to focus on harvest and trade management.
|Citation:||Bizzarro, J.J., Smith, W.D. & Clark, T.B. 2006. Mobula munkiana. The IUCN Red List of Threatened Species 2006: e.T60198A12309375.Downloaded on 18 November 2017.|