|Scientific Name:||Scyllarides astori|
|Species Authority:||Holthuis, 1960|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Butler, M., Cockcroft, A. & MacDiarmid, A.|
|Reviewer(s):||Collen, B., Livingstone, S. & Richman, N.|
|Contributor(s):||Batchelor, A., De Silva, R., Dyer, E., Kasthala, G., Lutz, M.L., McGuinness, S., Milligan, H.T., Soulsby, A.-M. & Whitton, F.|
Scyllarides astori has been assessed as Data Deficient. This species is harvested across much of its range but the status of the global stock is unknown. Landings of this species have increased in response to the loss of stocks of other species, though due to a lack of data on effort it is unclear if the stock is stable or in decline. Monitoring of the stock status is needed before a more accurate assessment of conservation status can be made.
|Range Description:||This species is distributed in the eastern Pacific including: the Gulf of California in Mexico, the Galápagos Archipelago, and Ecuador. There is a report of larva probably belonging to this species, at 200 miles north of Clipperton Island, to the south-west of Mexico (Holthuis 1991). This species is likely to occur along the scattered islands running from Baja California, to the Galápagos e.g. Clipperton Is, Cocos Is., Roca Partida (M. Butler pers. comm. 2009).
The type locality for this species is 'Post Office Bay, Charles Island, Galapagos Archipelago' (Holthuis 1991).
Native:Cocos (Keeling) Islands; Colombia (Malpelo I.); Ecuador (Galápagos); France (Clipperton I.); Mexico (Baja California, Baja California Sur, Revillagigedo Is., Sinaloa, Sonora); Panama
|FAO Marine Fishing Areas:||
Pacific – eastern central; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
There is little population data available for this species. In the north and far north of the Galapagos archipelago, where sea surface temperatures are highest, this species has been found to be rare (less than one individual observed per diver hour). In other areas of the archipelago this species showed higher levels of abundance; ranging between two and four individuals observed per diver hour (Hearn et al. 2007). This species is less abundant in the immediate subtidal zone, where approximately 5 individuals have been observed per diver hour. This abundance more than doubled at depths greater than 10 m (Hearn et al. 2007). Population data for Mexico is not available.
|Habitat and Ecology:||
This nocturnal, mostly solitary species forages during the night and shelters during the day. It can be found on platforms, crevices, and on vertical walls down to a depth of 20 m (Holthuis 1991, Lavalli et al. 2007). This is a diver fishery and so this species has only been collected to 20 m, however it may extend down to about 50 m (M. Butler pers. comm. 2009). Its diet consists mainly of bivalves (Lavalli et al. 2007).
This is a relatively slow growing species, with sexual maturity being reached at more than 6 years (Lavalli et al. 2007) or at a total length of 20 to 25 cm (Hearn et al. 2007). The species has a clear seasonal breeding pattern, with ovigerous females occurring in the warmer months from December to May (Hearn and Toral-Granda 2007). This species is likely to reproduce once a year at the most, and the fecundity is between 87,000 - 360,000 eggs per female (Hearn et al. 2007).
|Use and Trade:||
Fishing is currently restricted by law to the local artisanal fleet for which the lobster fishery is one of the major sources of income. In the past, this species was viewed as a minor resource associated with the Spiny Lobster fishery. In recent years, landings have increased and there is mounting pressure to allow large-scale export to the continent (Hearn et al. 2007).
In 1999, the total lobster catch recorded was 54.4 tonnes. This increased to 85.3 tonnes in 2000, of which 0.9 % of the total catch comprised of this species. The majority, at 76.3 %, of the total catch was the Red Lobster (Panulirus penicillatus), and 22.9 % of the catch was the Green Lobster (P. gracilis) (based on a sample size of 60,000) (Baine et al. 2007: 162). It is estimated that ~70 % of the total volume of this species landed is caught during the Spiny Lobster season between September and December (Hearn et al. 2007).
Only the tails of the lobsters are marketed and most of them are frozen and exported. Although there are very few catch statistics specifically for this species, it is estimated that landings have risen from insignificant amounts in the 1970s to 12-14 tonnes of whole animal (which corresponds to approximately 5 tonnes of tails) in 2002 and 2003 (Hearn and Toral-Granda 2007, Sonnenholzner et al. 2009). The catch-per-unit-effort (CPUE) data, expressed in terms of live weight removed per diver day was 19 kg/diver day in 2002, and declined to 10.7 kg/diver day in 2003 (Hearn et al. 2007).
In comparison with the Spiny Lobster (US$10 per lb tail), this species has a relatively low value and does not exceed US$3 per whole individual or US$2 per lb of tail. For this reason, and due to its low abundance when compared with the Spiny Lobster, the expectation that this species could be a lucrative alternative resource seems unfounded (Hearn et al. 2007).
The main threat facing this species is the increase in the catch and demand within the fisheries sector as described in the Use and Trade section. The decline in the catches of the predominantly harvested Spiny Lobsters (Panulirus penicillatus and P. gracilis) from a maximum of 85 tonnes of tail in 2000 to 25.7 tonnes in 2005, has coincided with an increase in catch and demand for this species (Hearn and Toral-Granda 2007). The decrease in Spiny Lobster catch together with the progressive and severe depletion of the Sea Cucumber population since 2000, raises concerns as to the sustainability of fisheries as a whole within the GMR (Hearn et al. 2007).
Hearn and Toral-Granda (2007) encourage a cautious approach to the development of a Slipper Lobster fishery. This species exhibits characteristics such as low fecundity, slow growth, and relatively easy catchability. These factors together with the species possible endemic status, low abundance, its value in relation to the Spiny Lobsters, plus the track record of the local fishing sector in overexploiting their resources all mean that this species is at potential risk of overexploitation.
There are no clearly identified threats from the Mexico part of this species' range, though it should be noted that there are significant fishing industries in this area (FAO 2010). Although these are often specialised for other species, such as sardines or tuna, lobsters could potentially be taken as by-catch.
As a World Natural Heritage Site and multi-use marine reserve, the Galapagos must ensure sustainability and minimize the ecological impact of all of its activities. The fishery for this species is open all year round. Besides a ban on landing ovigerous females, and the implementation of No-Take Zones, the fishery is essentially unregulated. A maximum of 5 kg of tails per person may be exported upon application for a permit (Hearn and Toral-Granda 2007, Viteri and Chavez 2007). There is a preliminary (as yet not enforced) zonation scheme within the GMR which prohibits extractive activities in a further 18 % of the coastal waters (Hearn et al. 2007). The GMR Five-Year Fishing Calendar recognized the need to incorporate a closed season, minimum landing size, and identification of nursery areas for this species by the end of 2004. As of July 2006 that was still pending (Hearn et al. 2007).
Further research should target the early life history of this species including the identification of nursery areas, more knowledge about population status and threats across it's range, and also if it has a wider distribution than formally attributed to it.
Recommended conservation strategies include the creation of a minimum landing size and the implementation of an appropriate closed season for the harvesting of this species is necessary in order to protect the population, and in particular ovigerous females (Hearn and Toral-Granda 2007).
|Citation:||Butler, M., Cockcroft, A. & MacDiarmid, A. 2013. Scyllarides astori. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 October 2014.|
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