|Scientific Name:||Squalus montalbani Whitley, 1931|
|Taxonomic Notes:||Squalus philippinus was described from the west coast of Luzon Island, Philippines but was later renamed S. montalbani by Whitley (1931) as the previous name was already occupied by Squalus philippinus (= Heterodontus portusjacksoni) and was previously considered to be a likely junior synonym of S. mitsukurii (Last et al. 2007). Squalus montalbani was resurrected by (Last et al. 2007). Referred to as Squalus sp. 1 in White et al. (2006).|
|Red List Category & Criteria:||Vulnerable A2bd+4bd ver 3.1|
|Reviewer(s):||Valenti, S.V., Stevens, J. & Fowler, S.L. (Shark Red List Authority)|
The Philippines Spurdog (Squalus montalbani) is a recently described dogfish known from the Philippines, Indonesia and warm-temperate to tropical Australia at depths of 154-1,370 m. This species was previously considered to be con-specific with S. mitsukurii, which recent taxonomic work has revealed, does not occur in Australasian waters. It probably has limiting life history characteristics; similar to other deepwater Squalus species (three generation period may be ~70 years). The Philippines Spurdog has suffered documented declines of as much as 97% between 1976-77 and 1996-97 in a heavily trawled area off New South Wales, Australia. Fishing pressure is intensive on trawl grounds around south-east Australia, and lower in Western Australia where Philippines Spurdog was taken as bycatch in a small, short-lived demersal gillnet fishery for Centrophorus species in the mid-1990s, which ceased due to rapid catch declines. There may be some continuing bycatch in the Commonwealth-managed trawl fishery. This species is also caught in larger numbers at some landing sites from which deepwater fisheries operate in Indonesia and the Philippines. Although no specific information is available on population trends in these areas, deepwater dogfishes have been targeted by fisheries off the Philippines since 1967 which have generally collapsed, after 10 years of operation, due to over-exploitation. Given that unregulated deepwater fisheries are rapidly expanding off Indonesia and the Philippines, declines are only likely to continue. The species is assessed as Vulnerable based on global population declines considered >30%. The deeper extent of the species' depth range probably affords it refuge from fishing pressure, and this assessment reflects dramatic declines in parts of the range, as well as light fishing pressure in others. Catch levels and expanding fisheries should be monitored, and the assessment revisited if fishing pressure expands further throughout this species' geographic and depth range.
|Range Description:||Eastern Indian Ocean and western central Pacific: known from Philippines, Indonesia and warm-temperate to tropical Australia (Last et al. 2007).|
Native:Australia (New South Wales, Queensland, Western Australia); Indonesia; Philippines
|FAO Marine Fishing Areas:|
Indian Ocean – western; Indian Ocean – eastern
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Documented declines of approximately 97% of "greeneye dogsharks" between 1976-77 and 1996-97 between the Sydney area (central NSW) and the Eden-Gabo I. area (southern NSW/northern Victoria) were reported from a fishery independent survey (Graham et al. 2001). Total catches in the abovementioned areas at depths of 220-605 m declined from a mean of 44.8 kg/h in 1976/77 to a mean of 1.2 kg/h in 1996-97 (Graham et al. 2001). It is likely that Squalus chloroculus, S. montalbani and S. grahami were all caught during these surveys (K. Graham pers. comm. 2007). It is possible that S. montalbani was the worse affected of the species off Sydney and Ulladulla. In the Eden-Gabo Island area, only a single S. montalbani was caught in 1996-97. Elsewhere, no data are available on population trends. No specific information is available on population trends throughout the rest of the species' range, but there is no reason to suspect that similar declines will not occur in other areas of high exploitation.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Demersal on the continental slope at depths of 154-1,370 m. In Indonesia, attains at least 101 cm; males mature at 62-67 cm and females at ~80 cm; largest embryo observed was 24 cm. Viviparous, with yolk-sac dependency; gives birth to litters of 4-16 pups after an unknown gestation period. Diet consists primarily of small fishes, cephalopods and crustaceans (White et al. 2006).|
In southeast Australia, mature at ~65-70 cm TL (males), 80-82 cm TL (females), and have between seven and ten pups/litter (K. Graham pers. comm.). Maximum size ~81 cm TL (males) and 96 cm TL (females) (Last et al. 2007). The species is ovoviviparous with size at birth ~25 cm TL (Last et al. 2007). Across all populations the gestation period may be up to two years (Last et al. 2007). Maximum ages recorded from counting bands on dorsal fin spines (assuming annual bands) were 18 years (males) and 27 years (females) (Last et al. 2007). It reaches a maximum size of at least 96 cm TL (males) and ~125 cm TL (females) and size at birth is ~21-30 cm TL (Last et al. 2007).
A small number of vessels targeted dogfish (mainly Centrophorus "uyato" with a significant bycatch of Squalus montalbani) out of Esperance, Western Australia (WA) during the mid-1990s for squalene (Daley et al. 2002). This fishery was short-lived, due to dramatic declines in catch rates after two to three years, and had all but ceased by 1999 (R. McAuley pers. comm.). Catches were not reported to species level thus precise trends in S. montalbani catch rates cannot be determined. However, given the fate of the target stock and the similar life-history characteristics of S. montalbani, it is likely that the stock was impacted to some degree. There is currently a negligible catch of S. montalbani in the WA demersal gillnet fisheries, as its range is outside that of the fleet. There may be some continuing bycatch in the Commonwealth-managed trawl fishery (small quantities are sold in Australia under the marketing name of "Greeneye Dogfish").
Also caught commonly by demersal longline fisheries operating in deepwater in some parts of Indonesia and the Philippines. Although at present, deepwater fisheries are not operating below 600 m off Indonesia, this is unlikely to be the case for much longer (White et al. 2006). Future expansion of Indonesian deepwater fisheries for squaloid sharks is highly likely, and there is already anecdotal evidence to suggest squaloid shark catches have declined rapidly in the last ten or more years at one landing site, Cilacap, despite it being only a relatively restricted fishery (White et al. 2006). This species has a wide depth range, offering it some refuge from fisheries off Indonesia, Philippines,parts of Western Australia and at the deeper extent of its depth range at present.
The deep-sea fisheries resources of the Philippines are in many cases uncharted and unknown, and are believed to be relatively underexploited, however, dogfish sharks do have a documented history of wide-scale exploitation off this country, being targeted for their liver oil (Flores 2004, Gaudiano and Alava 2003). Fishing for dogfishes for their live oil began in 1967 in San Joaquin, Iloilo, and subsequently expanded and developed into nationwide fisheries. Mostly Centrophorus species are caught, but Squalus species also form part of the catch. They are mainly taken using bottomset multiple hook-and-line (Flores 2004). These fisheries appear to follow a typical "boom and bust" cycle, with heavy, unregulated exploitation resulting in increasing initial catches followed by collapse after about ten years (Flores 2004). Fisheries following this pattern have been conducted in Batangas Bay, waters off Marinduque and as far south as Sarangani Bay, and the Mindanao area (Flores 2004).
There are no species-specific measures in place for this species.
The below restrictions are in place within the Australian Southern and Eastern Scalefish and Shark Fishery (SESSF) in recent years, which may benefit this species:
Since 2003, vessels are required to land both the livers and carcasses of all dogfishes to enable accurate landing information to be recorded.
Since 2007, SESS Fishery was closed below 700 m to prevent targeting of deepwater species (see schedule 20 in the Southern and Eastern Scalefish and Shark Fishery (closures) direction 2007).
|Citation:||White, W.T. 2009. Squalus montalbani. The IUCN Red List of Threatened Species 2009: e.T161404A5416602.Downloaded on 17 November 2017.|
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