Myliobatis longirostris is a distinctive eagle ray reported from the surface to depths of at least 64m (Fitch and Schultz 1978). It is often landed in areas with sand or soft bottoms (McEachran and Notarbartolo di Sciara 1995). Information on the biology and distribution of this ray is sparse. As in other myliobatid rays, the reproductive mode is aplacental viviparity, and fecundities are generally low. Reaches a maximum size of 95 cm DW (McEachran and Notarbartolo di Sciara 1995). Villavicencio-Garyazar (1996) estimated the size at maturity to be ~74 cm DW and ~54 cm DW for males and females, respectively. These observations are based on a sample size of less than 70 individuals and no other details on the ecology of this ray are available.

Life history parameters
Age at maturity (years): Unknown.
Size at maturity (disc width): ~74 cm DW (Villavicencio-Garyazar 1995, Villavicencio-Garyazar 1996 (female); ~54 cm DW (Villavicencio-Garyazar 1995, Villavicencio-Garyazar 1996) (male).
Longevity (years): Unknown.
Maximum size (disc width): 95 cm DW (McEachran and Notarbartolo di Sciara 1995).
Size at birth (cm): Unknown.
Average reproductive age (years): Unknown.
Gestation time (months): Unknown.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: Unknown.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.

Red List Category

Red List Criteria

Year Assessed

Assessor/s

Reviewer/s

Justification

Unknown.

Unknown

This species is a minor component of directed artisanal elasmobranch fishery landings in Bahía Almejas (Bizzarro 2005) and Sonora (Márquez-Farías unpub. data), México.

Myliobatids are highly susceptible to capture by a variety of fishing gear and as such M. longirostris is taken as incidental catch among trawl and other artisanal fisheries using gillnets and longlines. Mexican shrimp trawlers have long been known to take this species, among others (Fitch and Schultz 1978).

Although M. longirostris are not directly targeted, they are landed in artisanal elasmobranch fisheries throughout their Mexican range and likely in other areas. Fishery surveys conducted in the Gulf of California (Notarbartolo di Sciara 1987, Hueter et al. unpubl. data) and Bahía Magdalena lagoon complex (Villavicencio-Garyazar 1995, Bizzarro and Smith unpubl. data) indicate that this species is not a common component of artisanal landings. Fitch and Schultz (1978) reported M. longirostris taken annually by shrimp trawlers, the majority of which were discarded. When landed, the meat is sold fresh, or dried and salted for local or regional resale or subsistence use.

Myliobatis longirostris fisheries and bycatch are unmanaged throughout the species range. In México, a moratorium on the issue of elasmobranch fishing permits was enacted in 1993, but no formal management plan has yet been implemented. Legislation is currently being developed in México to establish national elasmobranch fishery management and this should be implemented as a matter of urgency. 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. Some countries in the potential range of this species (e.g., Costa Rica, El Salvador and Ecuador) were working towards their NPOA?Sharks development and implementation at the time of writing (Anonymous 2004), action is required throughout the region without further delay.

Elasmobranch landings in México are poorly reported and generally lack species-specific details. Typically batoids are grouped as ?manta raya?. Improved clarity in catch records would provide an essential and lacking basis for detecting fishery trends. Improved monitoring of elasmobranch catches in México is necessary to provide valuable species- and sex-specific information and expand our limited knowledge of the extent of these fisheries. Improved catch records from Central America are necessary to confirm the assumption that this species indeed ranges throughout the tropical eastern Pacific.

In addition to species-specific catch details, biological information including age, growth, longevity, movement patterns, diet, habitat use, and further reproductive studies are necessary. Additional information on the range of the species is also necessary.