|Scientific Name:||Polyprion americanus|
|Species Authority:||(Bloch & Schneider, 1801)|
|Infra-specific Taxa Assessed:|
Amphiprion americanus Bloch & Schneider, 1801
Amphiprion americanus Bloch & Schneider, 1801
Polyprion americanum (Bloch & Schneider, 1801)
Polyprion cernium Valenciennes, 1824
Polyprion massiliense Costa, 1829
Sparus cernua Poggi, 1881
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Sadovy, Y. (Grouper & Wrasse Specialist Group)|
|Reviewer(s):||Sedberry, G. & Sadovy, Y. (Grouper & Wrasse Red List Authority)|
Polyprion americanus is assessed as Data Deficient. The RAMAS® Red List version 2.0 software package was used to make this assessment.
Since the species lives deep and offshore, there may well be significant stocks of wreckfish that have been little reported or yet to be discovered. To illustrate this point, the stocks off South Carolina were only discovered by chance in 1987 while exploratory fishing on the Mid-Atlantic ridge in 1996 also uncovered a new stock (Sedberry et al. 1999). The real possibility of unknown stocks of unknown size makes it very difficult to estimate population size and rates of decline for the global population. On the available information it seems that wreckfish would only be classified in one of the threatened categories under criterion A (high rate of population decline) but it is impossible to extend those instances where a subpopulation is in decline, as judged by falling catches, to the global population. It is possible that the species could also qualify under criterion B (restricted distribution and ongoing decline) if it is proven that there are specific spawning aggregation sites, which are vital for reproduction and which are of a small size. It is known that spawning aggregations occur in specific areas around the coast of Brazil (Peres 2000) but none have been reported elsewhere.
The available evidence of declining landings and life-history of this fish gives cause for concern. In addition, wreckfish fisheries are only managed in two countries and the use of landings and CPUE data to assess fish stocks is far from ideal. It seems to be assumed, in many but not all cases, that wreckfish stocks are exploitable until declining landings/CPUE/mean length proves otherwise. It may be too late to establish management plans once catch data have shown continual decline as there may be a substantial lag effect between the reproductive output etc. declining as the result of fishing and that manifesting itself in decreased catches (Sedberry et al. 1999). This is because it will be many years before the offspring from one year enter the demersal fishery (Sedberry et al. 1999). As subpopulations of wreckfish appear interlinked in the North Atlantic, effective management of the species may require collaborative efforts from both sides of the Atlantic (Sedberry et al. 1999). For this reason, regional assessments of the wreckfish may be of limited use although they may highlight localized threats to the wreckfish better than the current global assessment. A better approach may be to assess the three subpopulations (and any others that are discovered) separately. This will highlight the need for countries fishing each subpopulation to manage their fisheries collectively.
|Range Description:||The wreckfish has a widespread but discontinuous range, primarily in the Atlantic Ocean but also ranging into the Indian and Pacific Oceans.
In the Eastern Atlantic it ranges from Norway to South Africa including the Mediterranean, Canary Islands, Madeira, Cape Verde, and Tristan da Cunha. In the Western Atlantic it is found in Newfoundland, Canada and the Gulf of Maine to North Carolina, USA. In the Southern hemisphere it is known from South America (Uruguay, Argentina and Brazil) to New Zealand, including the St. Paul and Amsterdam Islands in the western Indian Ocean (data from Fishbase 2000, Peres 2000). The species shows an anti-tropical distribution (Ball et al. 2000).
The extent of occurrence could probably be estimated by calculating the area of potential habitat using the information in Sedberry et al. 1999. The area of occupancy would probably be the spawning grounds as this species aggregated to spawn (Peres 2000). However, there seems to be no more information than this available by which to estimate the area of spawning grounds.
Decline in extent or area of occupancy etc. is assumed to be none as wreckfish are pelagic or inhabit deep rocky reefs. Such rocky reefs are assumed not to fluctuate in size or quality, or be in decline. Indeed, suitable habitat is not believed to be in decline in Brazil (Peres, pers. comm. 2001).
Native:Argentina; Australia (New South Wales, South Australia, Victoria, Western Australia); Belgium; Brazil; Canada (Newfoundland I, Nova Scotia); Cape Verde; Denmark; France; Ireland; Italy; Netherlands; New Zealand (North Is., South Is.); Norway; Portugal; Saint Helena, Ascension and Tristan da Cunha (Tristan da Cunha); South Africa; Spain (Canary Is.); United Kingdom; United States (District of Columbia, Florida, Georgia, Maryland, New Jersey, North Carolina, South Carolina, Virginia); Uruguay
|FAO Marine Fishing Areas:|
Atlantic – eastern central; Atlantic – northeast; Atlantic – northwest; Atlantic – southeast; Atlantic – southwest; Atlantic – western central; Indian Ocean – western; Indian Ocean – eastern; Mediterranean and Black Sea; Pacific – southwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||It is not possible to estimate population size at present. A minimum figure could be reasonably derived by estimating numbers of fish from 1998 landings data for all countries for which is this data are available and using this figure but stating a sensible maximum figure is not possible as good data on wreckfish stocks is not available for many localities within the known range of the wreckfish. It also seems likely, as the species lives so deep, that there are also stocks yet to be discovered. It may be possible to make a crude approximation by working out the area of potential habitat based on bathymetry and the known range of the animal and multiplying this by population estimates from the better studied fishing grounds. However, calculating the area of potentially inhabitable areas will be extremely time consuming without the aid of a GIS or similar system.
Data from the US fishery (1985-97), Brazilian fishery (1989 to 98 with some missing years), and Portuguese and Spanish fisheries (1984-1998) shows no fluctuations above or approaching order of magnitude that cannot be explained by known fishing effort (data from FAO Fisheries Statistics, Capture Production 1998, Sedberry et al. 1999, Peres 2000). Large annual fluctuations would be unusual for an animal as long-lived and slow to reach sexual maturity as the wreckfish.
Evidence from mtDNA indicates that the subpopulation in the north Atlantic is probably isolated from that in the southern hemisphere (Sedberry et al. 1996). There may also be a subpopulation within the North Atlantic Subtropical Gyre (Sedberry et al. 1999). Subsequent genetic work using microsatellites has revealed that within the southern hemispheres, there are clear differences between the Brazilian and South Pacific subpopulations (Ball et al. 2000). Temperature profiles and current patterns are believed to prevent significant gene flow between these three subpopulations.
It seems extremely likely, given the continued and recent increases in exploitation, that the population of wreckfish will continue to decline in the near future, and that freshly discovered stocks will decline rapidly, if fishing is not controlled.
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Juveniles are pelagic to a length of around 50-60 cm and associate with floating seaweeds and wreckage (Sedberry et al. 1999). In the Mediterranean, pelagic juveniles occur from June-August (Deudero and Morales-Nin 2000). In Brazil, wreckfish are found on irregular substrate, late juveniles are found from 60-250 m depth while adults are deeper at 150-500 m (Peres 2000). On the Charlestone Bump off South Carolina, most wreckfish are taken over areas of extensive high relief but some are also taken over flat hard bottom (Sedberry et al. 1999). The extremes of depth range reported for demersal fish are 42-1,000 m (see Sedbury et al. 1994). Wreckfish inhabit demersal habitats where temperature ranges from 6.0 to 16.3 ºC (data from four localities, Sedberry et al. 1999).
Pelagic juveniles feed on teleost fishes, particularly Trachurus species and as well as other items (Deudero and Morales-Nin 2000). Adults feed on squids and mesopelagic fishes (Weaver and Sedberry 2001).
Generation time was calculated from age population structure data obtained from research cruises off Southern Brazil (Peres 2000) and other data about the fishery (Peres and Haimovici 1998, Peres 2000). This generation time is calculated from an exploited fishery, however, this is consistent with stocks in the USA which were monitored shortly after exploitation began and where most fish harvested have been between 8 and 12 years old (Sedberry et al. 1999).
The maximum observed age of wreckfish (through otoliths) from a study in Brazil was 81 years for males and 64 years for females Peres (2000). However, the oldest fish of more than 500 sampled from the US fishing grounds (Blake Plateau off South Carolina) was just 39 years (Vaughan et al. 2001). In the US fishery, most fish >100 cm total length (TL) were female (Sedberry et al. 1994). Different fisheries may consistently land fishes of differing size ranges (Sedberry et al. 1999).
The only known threats are from over-fishing.
The US fishery for wreckfish only started commercially following the chance discovery of stocks large enough to support commercial fishing off South Carolina in 1987. The numbers of fishing boats involved rose rapidly and there was concern by both biologists and fishermen that the fishery might not be sustainable (Sedberry et al. 1999). In general, large fish species that are slow to grow and mature are often poorly equipped to withstand intensive fishing. Although there was no obvious decrease in the length-frequency distributions of wreckfish caught off the US from 1989 to 1997 that would indicate stock declines, this may partly be due to the life-history of the animal. Juveniles are pelagic up to a large size (60 cm) before they descend and become demersal so it may be a number of years before fishing pressure would be reflected in decreasing fish sizes and by then it might be too late to initiate a management plan (Sedberry et al. 1999). Current management in the USA assumes that the wreckfish stocks on the US fishing ground will not be affected by fishing elsewhere, but as the source of the pelagic juveniles is not known, this may not be true (Sedberry et al. 1999). European fish hooks are frequently found in fish caught from US waters. This would seem to indicate the migration of large wreckfish across great distances (Sedberry et al. 1999). Finally, thousands of pelagic juveniles are being caught by pelagic tuna drift-net fisheries in the northern Atlantic (Sedberry et al. 1999) which may affect fisheries of adults in the future.
The case of Bermuda, where catches dropped rapidly after only being sustained for two years seems to show that high levels of fishing pressure (through use of bottom longlines in the case of Bermuda) can cause commercial extinctions of wreckfish, at least in island habitats (Sedberry et al. 1999).
The following data on wreckfish fisheries exist in the literature. Declines in landings and CPUE are assumed to reflect declines in wreckfish stocks unless it is known that fishing effort has decreased or other factors are involved.
1) The wreckfish fishery has existed in Brazil since 1973. The number of vessels involved increased from 10 in the 1970s to more than 35 in 1997 and there were technological advances in the gears used. The only estimated annual landings data available are 2,772 t (1989), 2,150 mt (1990), 1,674 t (1991), 2,291 t (1994) and 1,080 t (1995). CPUE declined 90% (0.72 to 0.073 kg/day/hook) off Southern Brazil from 1989/91 to 1997/98 (all data from Peres 2000). This fishery targets spawning aggregations thus increasing the susceptibility of the animal to overfishing.
2) Following a maximum Total Allowable Catch (TAC) of 2 million pounds annually, imposed by the South Atlantic Fishery Management Council in 1990/91, the estimated catch from the USA showed a relatively steady decline from 1,270,557 pounds (38,205 fish) in 1992 to 157,299 pounds (4,958 fish) in 2000 (Sedberry et al. 1999, Vaughan 2001). This is a drop of 87%. This is believed to be due to a decrease in fishing effort (Sedberry pers. comm. 2001) as the number of boats targeting wreckfish has declined (from 46 in 1992 to 3 in 2000, a drop of 93%) while the catch per hour has not (Hardy 2001) and the mean lengths of caught fish have not declined (Vaughan 2001). Fishing for wreckfish off the USA requires considerable skill and only the most dedicated fishers have remained. Wreckfish stocks seem large enough to maintain the current fishery (Sedberry et al. 1999).
3) A small wreckfish fishery off Bermuda developed rapidly from 1979 (25 fish) to 1981 (369 fish) and 1982 (311) fish. Catches declined sharply from 1982 (311 fish weighed roughly 4.7 mt) to 1983 (1.2 mt) and remained below 1.5 mt over the 13 years. In 1996 and 1997, just 6 and 9 fish were caught. The decline in landings from 1981 to 1996 (roughly 5.1 mt to 0.2 t) is a drop of 96% (all data from Sedberry et al. 1999). Rapid declines were associated with the introduction of longlines into what had been a vertical line fishery.
4) Annual landings of wreckfish from the Azores (off Portugal) climbed slowly from around 50-100 mt in the 1970s and 1980s to a peak of 425 mt 1994. In 1995 the catch dropped rapidly to 246 mt and was down to 139 mt by 1998. As the wreckfish is an incidental catch for a mixed-species demersal fishery which has continued to produce increased landings, it seems the decline is a reflection of decreasing wreckfish stocks. The decline from 1994 to 1998 was 67% (data from Sedberry et al. 1999, ICES Marine Data Centre 2001).
5) In Madeira (off Portugal) the wreckfish fishery developed slowly with landings rising from 5 metric tonnes in 1988 to a peak 55 mt in 1994. Landings then dropped 51% to around 27 mt in 1996. This was at least partly due to a drop in the number of fishing trips (by around 45%) but as the catch per trip also dropped (by around 15%) there may have been an actual drop in wreckfish stocks. For this location the reduction in wreckfish stocks is assumed to be 15%.
6) Annual landings data are also available for Northeast Portuguese waters (FAO Area 27). As Area 27 includes the Azores, ICES landings data, which lists the Azores landings separately was subtracted from Area 27 landings data to give figures for Northeast Portuguese waters (except the Azores). Annual landings here rose from 58 mt in 1986 to 283 mt in 1989, peaked at 406 and 373 mt in 1994 and 1995, respectively, and declined steadily to 165 mt in 1998 (FAO Fisheries Statistics, Capture Production 1998, ICES Marine Data Centre, 2001). The decline between 1994 and 1998 was 59%.
7) In Europe, only Portugal and Spain have reported significant (i.e., 50 metric tons per year) catches of wreckfish in recent decades. Annual landings for Spain in FAO Area 27 remained below 50 mt from 1984 to 1995, rising to 115 mt in 1996 and 265 and 250 mt in 1997 and 1998 respectively (FAO Fisheries Statistics, Capture Production 1998). No further information on this fishery could be located, including whether these levels of exploitation are sustainable.
8) Angola's annual landings of wreckfish stayed below 15 metric tons from 1984-1993. Landings rose sharply thereafter, from 66 mt in 1994 to 235 mt in 1995 and 1,002 and 1,326 mt in 1995 and 1997 respectively (FAO Fisheries Statistics, Capture Production 1998). No further information on this fishery could be located, including whether these levels of exploitation are sustainable. See note on systematics above regarding the taxonomic status of Polyprion americanus in southern Africa. Landings in South Africa include Polyprion oxegenios (some from South Atlantic seamounts and islands) and a species referred to as Polyprion americanus (P. Heemstra pers. comm. to G. Sedberry).
9) In New Zealand, catch data for Polyprion americanus and Polyprion oxygeneios (hapuku) are lumped together. Wreckfish have been caught in relatively small quantities by the early Maori, and then by European settlers from the mid 19th century. The first decades of the commercial fishery for both species of Polyprion are undocumented, but it was well developed with a combined catch of over 1,500 mt by the 1930s (Paul 2000). Management of both Polyprion species (together) is by Quota Management System, introduced in 1986, involving Total Allowable Catches (2,179-2,181 mt annually, 1996-2000). Landings of wreckfish alone for the 1990s are estimated to be in the region of 200-400 mt. (L. Paul, pers. comm., 2001). Only a few fishers specifically target the two species although many fishers have small quotas to cover wreckfish caught incidentally in many fisheries targeting other species (L. Paul, pers. comm., 2001). Stocks are probably overfished, but there has been very little fisheries research carried out to verify the nature of this (C. Roberts, pers. comm. 2000).
10) Both wreckfish (known in Australia as Bass grouper) and Hapuku (Polyprion oxygeneios) are taken in the blue eye (Hyperoglyphe antartica) fishery off south east Australia. Records of commercial catches since the mid-1980s indicate that catches of Hapuku and Bass grouper in this fishery, which are recorded together, are low, between 10 and 40 t a year, Hapuku being by far the major species. There is no indication as to whether numbers of wreckfish are stable or in decline although some research has recently been initiated which should provide some answers in the future (Pascale Baelde, pers. comm. April 2001).
In summary, fisheries specifically targeting wreckfish have only developed since the 1970s, apparently because of the technological advances in fishing needed to target a large animal living in deep waters. Where fisheries have suddenly targeted wreckfish specifically (Brazil, Bermuda, Portugal), the fishery has reached a peak and then gone into decline within a few years (
The wreckfish is only known to receive any protection, in the form of fishing restrictions, in the USA and New Zealand
In the USA, the South Atlantic Fishery Management Council put fishing regulations into place in 1990 and 1991. These cover the area between 3-200 miles off the coasts of North and South Carolina, and East Florida (the area bounded by 30 and 33º N latitude). Commercial fishers must have a wreckfish permit and Individual Transferable Quota (ITQ) shares to fish. There is no recreational fishery in the USA. The Total Allowable Catch (TAC) of wreckfish by ITQ holders is 2 million pounds (907 metric tonnes) per year. There is a spawning season closure from Jan 15 to April 15. In addition, longlines may not be used (Sedberry et al. 1999).
There is a TAC limit for the commercial fishery in New Zealand of 2,181 metric tons for Polyprion americanus and Polyprion oxygeneios (hapuku) together. There are also some complex bag limits for the much smaller recreational fishery.
|Citation:||Sadovy, Y. (Grouper & Wrasse Specialist Group). 2003. Polyprion americanus. The IUCN Red List of Threatened Species 2003: e.T43972A10845280.Downloaded on 21 October 2016.|
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