| Citation |
Finucci, B., Cheok, J., Cotton, C.F., Kulka, D.W., Neat, F.C., Pacoureau, N., Rigby, C.L., Tanaka, S. & Walker, T.I. 2020. Zameus squamulosus. The IUCN Red List of Threatened Species 2020: e.T60215A3093577. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T60215A3093577.en. Accessed on 07 March 2022. |
Description |
JUSTIFICATION
The Velvet Dogfish (Zameus squamulosus) is a small (to 109.4 cm total length) deep-water shark know from a widespread yet patchy global distribution in the Atlantic and Indo-Pacific Oceans (excluding the eastern Pacific Ocean). It has been recorded from the continental slope and oceanic ridges, and as epipelagic over deep water, from the surface to 1,511 m. The Velvet Dogfish may be subject to local variability in its susceptibility to capture and likely has refuge at depth. It is infrequently reported from surface longline, as well as demersal longline and trawl fisheries. The species is not suspected to be close to reaching the population reduction threshold. There is nothing to suspect or infer population reduction at this time, and the Velvet Dogfish is assessed as Least Concern.
RANGE DESCRIPTION
The Velvet Dogfish has a widespread, yet patchy, global distribution in the Atlantic and Indo-Pacific Oceans (Ebert et al. 2013).
DESCRIPTION
Population size and trends for this species across its entire range are unknown. Global population trend is suspected to be stable based on levels of fishing effort in its range and refuge in deep water outside of current fishing activities.
Unstandardised catch-per-unit-effort (CPUE) data from longline fisheries reporting to the Western and Central Pacific Fisheries Commission (WCPFC) from 1995–2015 (Tremblay-Boyer and Brouwer 2016) were analyzed over three generation lengths (111 years) using a Bayesian state-space framework (Winker et al. 2020). This analysis yields an annual rate of change, a median change over three generation lengths, and the probability of the most likely IUCN Red List category percent change over three generations (see the Supplementary Information). The CPUE fluctuated considerably over the 21 years and the trend analysis revealed an annual rate of increase of 0.1 %, an estimated decline of 15.6% over three generation lengths (111 years), with the highest probability (51%) of no major reductions in population over the past three generation lengths. Surface longline fishing effort (number of hooks) reported from this region has nearly tripled over the same time period (Francis and Hoyle 2019).
HABITAT AND ECOLOGY
The Velvet Dogfish has been recorded from the continental slope and oceanic ridges, and as epipelagic over deep water, from the surface to 1,511 m (Ebert et al. 2013, Weigmann 2016). It reaches a maximum size of 109.4 cm total length (TL) (Pajuelo et al. 2010). Males mature at 47–51 cm TL and females mature at 59–69 cm TL (Ebert et al. 2013). Reproduction is likely aplacental viviparous with litter sizes of 3–10 pups and size-at-birth is 20 cm TL (Ebert et al. 2013). Nothing else is known of its biology. Age parameters are unknown but can be inferred from a related species, the Longnose Velvet Dogfish (Centroselachus crepidater) that has a female age-at-maturity of 20 years and a maximum age of 54 years, resulting in a generation length of 37 years (Irvine et al. 2006).
THREATS
The Velvet Dogfish may be subject to local variability in its susceptibility to capture and likely has refuge at depth. It is infrequently reported from surface longline fisheries targeting pelagic fishes, such as tunas and swordfish (e.g. Piovano and Gilman 2017, Crow et al. 2018), as well as demersal longline and trawl (e.g. Akhilesh et al. 2013, Romanov et al. 2013, Fauconnet et al. 2019). The species was caught in relatively high numbers in an experimental midwater drifting longline fishery targeting Black Scabbardfishes (Aphanopus spp) off the Canary Islands at depths of 800–1,200 m (Freitas et al. 2018). When caught, the Velvet Dogfish is likely to be discarded. Post-release mortality is unknown, however, in surface longline fisheries, the species is likely to be alive when landed (Griggs and Baird 2013).
Deep-water sharks have been targeted in demersal longline and gillnet fisheries operating in areas managed under the Southern Indian Ocean Fisheries Agreement (SIOFA); the latter of these fisheries ceased in 2015 (Georgeson et al. 2019). An ecological risk assessment framework for deep-water sharks found the Velvet Dogfish to have high or extreme vulnerability to all fisheries in Southern Indian Ocean and extreme vulnerability to demersal trawl in the South Pacific Ocean (Georgeson et al. 2019).
USE AND TRADE
This species is not known to be utilized, but like other deep-water sharks, it may be processed for its liver oil while the meat would be sold at local markets (Akhilesh et al. 2011).
CONSERVATION ACTIONS
There are no species-specific measures in place for the Velvet Dogfish. Targeted deep-water shark fishing is not permitted in the South East Atlantic Fisheries Organization (SEAFO) Convention Area or under the Southern Indian Ocean Fisheries Agreement (SIOFA) (SIOFA 2019, SEAFO 2016). The species is considered a "key species of concern" within the SIOFA area (SIOFA 2019). Further information is required on its distribution, ecology and life history, and interactions with fisheries. |
