|Scientific Name:||Zapteryx exasperata|
|Species Authority:||(Jordan & Gilbert, 1880)|
|Taxonomic Notes:||There are possible taxonomic problems in tropical latitudes (possible confusion with Zapteryx xyster), which may severely limit its functional range (Ebert 2003).|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Bizzarro, J.J. & Kyne, P.M.|
|Reviewer(s):||Heupel, M.R. & Simpfendorfer, C.A.|
A very poorly known guitarfish of the eastern Pacific. Range is not well defined; reported from central California south to Peru, however its occurrence south of Mazatlán, México is questionable due to possible confusion with Zapteryx xyster, a more tropically distributed species. Zapteryx exasperata may therefore have a relatively restricted occurrence in the Eastern Central Pacific. Inhabits rocky reefs, shallow, sandy lagoons and nearshore waters, from the intertidal zone down to 200 m depth, but mostly at depths of 2.5 to 10 m. This species is taken in artisanal fisheries in the Gulf of California and Bahia Almejas, Baja California, México. In the directed batoid fishery in Bahía Almejas, Baja California, fishermen target aggregations of primarily gravid females during late spring and early summer months in nearshore and inshore nursery grounds. Within the Gulf of California (GOC), landings information is scarce outside of Sonora. It is not a primary fishery target, however, and is apparently rarely taken in the GOC. Exceptions may be during reproductive aggregations and possible large catches by shrimp trawlers, although information on indirect landings by commercial trawls and gillnets is lacking. It is not known if this is a relatively uncommon species, as landings would suggest, or (other than during breeding aggregations) it simply occupies areas that are not heavily fished. In the first instance the distribution of the species needs to be accurately documented and catch information obtained. This species is potentially at threat due to targeting of reproductive aggregations and generally unregulated artisanal fishing across its Mexican range. When further information is obtained the species' conversation status should be reassessed with priority.
|Range Description:||Southern extent of range is not well defined. Known to occur at least to Mazatlán, México with records further south (through Central and South America to Peru) probably the closely-related Z. xyster. May therefore have a relatively restricted range.|
Native:Mexico (Baja California, Baja California Sur, Sinaloa, Sonora); United States (California)
|FAO Marine Fishing Areas:||
Present - origin uncertain:
Pacific – eastern central; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are several lagoons along the Pacific coast of Baja California, which likely serve as important nursery grounds (Ebert 2003). Neonates were recorded at San Ignacio Lagoon, Baja California Sur, but only gravid females have been noted in other embayments (though their function as nursery grounds is almost assured) (Villavicencio-Garayzar 1995). Near-term embryos were spontaneously aborted from landings taken in shallow, nearshore waters off central Sonora during late May (R. Hueter et al. unpublished data).
The population size is completely unknown and it is not known if this is a relatively uncommon species, as landings would suggest, or (other than during breeding aggregations) it simply occupies areas that are not heavily fished.
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Inhabits rocky reefs, shallow, sandy lagoons and nearshore waters, from the intertidal zone down to 200 m depth, but mostly at depths of 2.5 to 10 m (Feder et al. 1974, Villavicencio-Garayzar 1995, de la Cruz-Aguero et al. 1997, Ebert 2003).
Reaches a maximum size of 97 cm TL (Villavicencio-Garayzar 1995). Very little information is available for this species outside of its breeding grounds. Aplacental yolksac viviparous with litter sizes of 4 to 11 young produced annually. Gestation is 3 to 4 months and birthing occurs during July and August after mating at the end of March and beginning of April (Bahía Almejas, Baja California Sur, México). Other than during the mating period, sexes may be segregated (Villavicencio-Garayzar 1995). Females congregate in shallow bays and lagoons (Villavicencio-Garayzar 1995, Ebert 2003). In Bahía Almeja, México, females are resident from January to August, after which they migrate, likely to deeper waters. However, almost no information exists on this species outside its breeding/pupping cycle and its whereabouts and possible sexual segregation during these times is purely speculative. Males are present in embayments and probably nearshore waters during early spring for copulation, then emigrate while females remain until parturition during July or August (Villavicencio-Garayzar 1995). No specific age and growth or feeding studies have been conducted and only limited reproductive information is available. Larger females may produce larger litters (Villavicencio-Garayzar 1995).
Benthic invertebrates, including crabs and shrimp, have been noted among stomach contents (Ebert 2003).
Life history parameters
Age at maturity (years): Unknown.
Size at maturity (total length): Female: 57 to 77 cm TL (Ebert 2003); Male: 64 to 70 cm TL (Ebert 2003).
Longevity (years): Unknown.
Maximum size (total length): 97 cm TL.
Size at birth: 15 to 18 cm TL.
Average reproductive age (years): Unknown.
Gestation time: 3 to 4 months.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: 4 to 11 young per litter.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
This species is taken in artisanal fisheries in the Gulf of California and Bahia Almejas, Baja California, México. In the directed batoid fishery in Bahía Almejas, Baja California fishermen target aggregations of primarily gravid females during late spring and early summer months in nearshore and inshore nursery grounds (Villavicencio-Garayzar 1995, Bizzarro and Smith in press, Hueter et al. unpublished data). Within the Gulf of California (GOC), landings information is scarce outside of Sonora (Marquez-Farias 2002). It is not a primary fishery target, however, and is rarely taken in the GOC. Exceptions may be during reproductive aggregations and possible large catches by shrimp trawlers. Information on indirect landings by commercial trawls and gillnets is lacking.
Habitat modification. Many embayments and estuaries in Sinaloa, México are being modified to accommodate shrimp farming. This practice may also be occurring in the southern portion of its range, but no data is available.
In México, a moratorium on the issue of elasmobranch fishing permits was enacted in 1993, but no formal management plan has been implemented for Z. exasperate specifically or most other chondrichthyans in México. Legislation is currently being developed in México to establish national elasmobranch fishery management, but progress has been seriously delayed. Elasmobranch fisheries are unmanaged throughout Central America, and attempts to regulate these fisheries would greatly improve conservation of Z. exasperata and other chondrichthyans.
Elasmobranch landings in México and Central America are poorly monitored and lack species-specific details. All batoids are generally broadly termed "manta raya". Improved clarity in catch records would provide an essential basis for detecting fishery trends. Expanded monitoring of elasmobranch catches in México, Central and South America are necessary to provide valuable species- and sex-specific information and improve our limited knowledge of the extent of these fisheries.
In addition to the much-needed species-specific catch details, life history information including age, growth, longevity, movement patterns, habitat use, and further reproductive studies throughout its range. Fishery-independent surveys of this and other demersal elasmobranchs are necessary to provide estimates of abundance and biomass.
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 Z. exasperata.
|Citation:||Bizzarro, J.J. & Kyne, P.M. 2006. Zapteryx exasperata. The IUCN Red List of Threatened Species 2006: e.T60177A12301734. http://dx.doi.org/10.2305/IUCN.UK.2006.RLTS.T60177A12301734.en . Downloaded on 13 October 2015.|
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