Antarctic toothfish

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Antarctic toothfish
Dmawsoni Head shot.jpg
Dissostichus mawsoni in McMurdo Sound
Not evaluated (IUCN 3.1)
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Actinopterygii
Order:
Perciformes
Family:
Nototheniidae
Genus:
Dissostichus
Species:
D. mawsoni
Binomial name
Dissostichus mawsoni
Norman, 1937

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Dissostichus mawsoni, the Antarctic toothfish, is a species of cod icefish native to the Southern Ocean. It is often mistakenly referred to as an Antarctic cod, consistent with the misnaming of other notothenioid Antarctic fish as rock cods. However, notothenioid fishes are unrelated to cods, which are in another taxonomic order, the Gadiformes. The generic name Dissostichus is from the Greek dissos (twofold) and stichus (line) and refers to the presence of two long lateral lines, which are very important to the species’ ecology. The common name "toothfish" refers to the presence of biserial dentition in the upper jaw, thought to give it a shark-like appearance. The habitat of the Antarctic toothfish is in subzero degree water below latitude 60°S.

Description

Fully grown, these fish (and their warmer-water relative, the Patagonian toothfish, D. eleginoides) can grow more than 1.7 m in length and 135 kg in weight, twice as large as the next largest Antarctic fish. Being large, and consistent with the unstructured food webs of the ocean (i.e., big fish eat little fish regardless of identity, even eating their own offspring), the Antarctic toothfish has been characterized as a voracious predator. Furthermore, by being by far the largest midwater fish in the Southern Ocean, it is thought to fill the ecological role that sharks play in other oceans.[1][2][3] Aiding in that role, the Antarctic toothfish is one of only five notothenioid species that, as adults, are neutrally buoyant. This buoyancy is attained at 100–120 cm in length[4][5][6] and enables them to spend time above the bottom without expending extra energy.[7][8] Both bottom-dwelling and mid-water prey are therefore available to them. Most other notothenioid fish and the majority of all Antarctic fish, including smaller toothfish, are confined to the bottom.[3] Coloring is black to olive brown, sometimes lighter on the undersides, with a mottled pattern on body and fins. Small fish blend in very well among the benthic sponges and corals.[9] They have a broad head, an elongated body, long dorsal and anal fins, large pectoral fins and a rudder-like caudal fin. They typically move slowly, but are capable of speed bursts that can elude predatory seals.[8]

Feeding ecology

Over the continental shelf, Antarctic toothfish feed on shrimp (Nauticaris spp.) and small fish, principally another neutrally buoyant nototheniid, the Antarctic silverfish (Pleuragramma antarcticum). This loosely schooling species is also a major prey of Adélie (Pygoscelis adeliae) and emperor penguins (Aptenodytes forsteri), Weddell seals (Leptonychotes weddellii) and Antarctic minke whales (Balaenoptera bonaerensis).[10][11] Therefore, competition for prey among toothfish and these other mesopredators (middle trophic level predators) could be very important. The large Antarctic toothfish are eaten by sperm whales (Physeter macrocephalus), killer whales (Orcinus orca), Weddell seals and possibly colossal squid (Mesonychoteuthis hamiltoni). Toothfish that are dwelling on the bottom, particularly those caught during the summer on the continental slope, eat mainly grenadiers (Macrouridae) but also feed on other smaller fish species and skates (Raja spp.).[12] Antarctic toothfish have been caught to depths of 2200m, though based on commercial fishing effort, few occur that deep.[13]

Aging and reproduction

Aging data indicate Antarctic toothfish are relatively fast-growing when young, but then growth slows later in life. They reach about one-third of maximum size after five years, and half maximum by 10 years, after which growth slows considerably.[14][15] To grow fast when small is an adaptation of most predatory fish, e.g., sharks, so as not to be small for very long. The maximum age recorded so far has been 48 years.[16] Antarctic toothfish take a long time to mature (13 years for males, 17 years for females) and once mature may not spawn every year, though the actual spawning interval is unknown.[17] Only a few Antarctic toothfish with mature eggs have ever been caught, meaning knowledge is sparse about fecundity.[7][18] They spawn sometime during winter.[18][19] Large, mature, older fish have been caught among the seamounts of the Pacific-Antarctic Ridge, a location thus thought to be important for spawning. Smaller, subadult Antarctic toothfish tend to concentrate in shallower waters on the continental shelf, while a large portion of the older fish are found on in the continental slope.[18][19][20] This sequestering by size and age could be another adaptation for small fish to avoid being eaten by large ones. The recruitment potential of Antarctic toothfish, a measure of both fecundity and survival to spawning age, is not known.

Anatomy and physiology

The Antarctic toothfish has a lightweight, partially cartilaginous skeleton, lacks a swim bladder, and has fatty deposits which act as a stored energy source, particularly during spawning. This fat also makes large toothfish neutrally buoyant. Many toothfish caught over the seamounts are very depleted of fat, and this is thought perhaps to be related to spawning and spawning migration, which are energy-demanding activities.[21] It is not known what happens to these fat-depleted fish, including whether they reach, or how long it takes them to reach, breeding condition again; this ostensibly occurs upon returning to continental slope waters. Antarctic toothfish have vision and lateral line systems well adapted to find prey in low light levels.[22] Since ice covers the surface of the ocean where Antarctic toothfish occur even in summer, these sensory specializations likely evolved to enable survival in the reduced light levels found under ice and in the Antarctic winter, as well as at deep depths. Antarctic toothfish also have a very well developed sense of smell,[22] which is why they are easily caught by baited hooks and also scavenge the remains of penguins killed by other predators.

Cold adaptation

The Antarctic toothfish is noteworthy, like most other Antarctic notothenioids, for producing antifreeze glycoproteins, a feature not seen in its closest relative, the Patagonian toothfish, which typically inhabits slightly warmer waters. The presence of antifreeze glycroproteins allows the Antarctic toothfish (and other notothenioids) to thrive in sub-zero waters of the Southern Ocean surrounding Antarctica. The Antarctic toothfish’s voracious appetite also is important in coping with cold water.[23] It is mainly caught in the Ross Sea in the austral summer, but has also been recorded from Antarctic coastal waters south of the Indian Ocean sector, in the vicinity of the Antarctic Peninsula, and near the South Sandwich Islands.

Fishery and associated ecosystem

A fishery for Antarctic toothfish, managed by the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), has existed since 1997. The existence of this fishery in the Ross Sea, the area where most Antarctic toothfish are caught, is very contentious - the main argument proposed for this being the lack of accurate population parameters, such as original stock size, fecundity, and recruitment. Moreover, the main fishing grounds is presumed by some researchers to cover the area through which the entire stock of Antarctic toothfish pass.[24] Typically the fishing season has finished in the area by the end of February and for the remainder of the year much of the area is covered by sea-ice providing a natural impediment to fishing.[25] This fishery is characterised by opponents as being a challenge to manage owing to the nature of benthic longline fishing. The bycatch of other fish can also be significant, with the ratio to tonnes of toothfish caught ranging from 4.5% to 17.9% and averaging 9.3% from the 1999/2000 fishing season to 2013/14 in CCAMLR Subarea 88.1 when the toothfish catch first exceeded 50 tonnes and from 2.3% to 24.5% averaging 12.4% in CCAMLR Subarea 88.2 up to the latest publicly available figure from 2013/14.[26] The bycatch of other fish species is also regulated to a maximum amount annually by CCAMLR. CCAMLR decision rules are based on determining the catch level that will ensure that the median estimated spawning stock biomass (not total biomass) is greater than or equal to 50% of the average pre-exploitation spawning biomass after a further 35 years of fishing (i.e. 35 years from each year of assessment), with the additional condition that there is less than a 10% probability that the spawning biomass will decline below 20% of the pre-exploitation level at any time during this period.[27] Current spawning stock biomass for Antarctic toothfish in the Ross Sea Region is estimated to be at 75% of the pre-exploitation level (95% Bayesian probability interval 71–78%), well above the 50% target reference point.

An independent study was reported to have detected the disappearance of large fish at the southern periphery of its range in the McMurdo Sound area and was postulated to be consistent with this apparent loss of large fish.[28] However more recent work has shown this was not to be the case in 2014.[29] Some studies have reported that the prevalence of fish-eating killer whales has been apparently decreasing in the southern Ross Sea, foraging efficiency of Weddell seals is decreasing, and numbers of Adélie penguins (competitors for silverfish) have been increasing.[28][30] More recent studies have confirmed visual sightings of Weddell seals and Type-C killer whales holding and consuming large toothfish in the McMurdo Sound area and raise questions over the previously assumed importance of assumed dominance of Antarctic silverfish (Pleuragramma antarcticum) in the diet of Weddell seal and Type-C Killer whales.[31][32] These reports highlight the importance of managing this fishery in the best interests of the ecosystem by continuing to collect information on both Antarctic toothfish life history and the interaction of that species with predators and prey. An important research programme in this regard is the annual 'Shelf' survey carried out annually since 2012 which is designed to monitor the abundance of subadult Antarctic toothfish in areas where subadult sized fish have been regularly found (e.g., in the southern Ross Sea) has been designed provide data to better estimate recruitment variability and provide an important early-warning signal of changes in toothfish recruitment. The project also is used for additional targeted data collection to better understand the life cycle and ecosystem role of Antarctic toothfish.[33]

Recent research provides evidence for long-distance migrations of Type-C killer whales between the Ross Sea and New Zealand waters indicating a much wider range that had been postulated by a number of scientists. One adult female Type-C Killer whale has been seen in both New Zealand waters and McMurdo Sound, Antarctica and a high large proportion of Type-C killer whales sighted in McMurdo Sound have scars caused by cookiecutter sharks that are currently assumed to be limited to north of 50°S.[34] At the same time as this study was occurring Italian whale experts at Terra Nova Bay, about 360 km north of Scott Base, deployed satellite transmitters on Type-C killer whales in to determine the whales' movements. Their results independently verified last month that type-C killer whales were commuting between Scott Base and the waters off Northland.[35]

The total catch of Antarctic toothfish in 2013/14 was 3820 tonnes. 3,320 tonnes of this was taken from the Ross Sea (FAO Statistical Divisions 88.1 and 88.2) with the remainder taken from other high seas areas within the CCAMLR convention area.[36]

Management

The ecosystem approach to fishing is encapsulated in Article II of the CAMLR Convention.[37] The ecosystem approach utilizes decision rules based on both population status targets and on limit reference points and incorporates uncertainty and ecosystem status in the calculation of these targets. Different reference points to account for the needs of dependent predators in the ecosystem are used depending on the location of the species in the food web. The ecosystem fisheries management approach by CCAMLR involves use of move-on rules to protect trophic interactions,[38] and limit direct effects of fishing on fish bycatch, seabirds and Vulnerable Marine Ecosystems (VMEs). There are annually reviewed mitigation measures such as line weighting and streamer lines to minimize seabird bycatch which have resulted in a substantial reduction in accidental seabird mortalities in the CAMLR Convention Area.[39] The 50% (target) and 20% (limit) reference points used by the CCAMLR decision rules exceed the requirements for target and limit reference points set by almost all national and international fisheries management organizations, even for species longer lived than toothfish. A wide study of many fisheries generally indicated that most reach maximum sustainable yield at 30–35% of their pre-exploitation abundances.[40] CCAMLR uses a more conservative reference level to allow exploitation at a level where toothfish recruitment and the ecosystem in general is not appreciably impacted. This is required by Article II of the CAMLR Convention. A common misunderstanding of the CCAMLR decision rules is an assumption that the decline in population size will follow a clear trajectory from the starting year to a point 35 years later when the stock size will reach 50% of pre-exploitation levels and an assumption that there is no feedback during each assessment. The catch limit however is re-calculated based on all updated and/or revised data at each annual or biennual assessment. This approach is used to ensure that the 50% level will be approached slowly and enables an ongoing readjustment of catch levels as knowledge improves.[27]

Environment and bycatch

CCAMLR imposes stringent environmental protection and bycatch mitigation measures to Antarctic toothfish fisheries, including:

  • Monitoring of daytime setting and movement of vessels from the fishery should any vessel catch more than three seabirds [41]
  • Use of streamer lines during setting to keep birds away from baited hooks [42]
  • Weighting of lines to ensure fast sink rates to prevent seabirds from accessing baited hooks [43]
  • The use of bird exclusion devices to prevent birds from accessing hooks whilst lines are being hauled [41]
  • Limitations on the release of fish offal overboard at the same time as setting and hauling of lines to avoid attracting seabirds. An additional requirement prohibits the dumping of all offal south of 60°S, the region where Antarctic toothfish are caught [44]
  • Prohibition on the dumping of oil, plastic, garbage, food waste, poultry, eggs or eggshells, sewage, and ash by fishing vessels [44]
  • Prohibition of the use of plastic packaging bands on fishing vessels [44]

Incidental mortality of seabirds as a result of fishing has fallen to near-zero levels in the CCAMLR convention area. No mortality of seabirds or marine mammals was recorded as a result of fishing for Antarctic toothfish in 2011/12 and only two seabirds (Southern Giant Petrels Macronectes giganteus) have been killed as a result of fishing in the Ross Sea since 1996/97.[45]

Compliance

Compliance measures adopted by CCAMLR apply to all Antarctic toothfish fisheries. These include:

  • At-sea inspections of fishing vessels [46]
  • Vessel licensing [47]
  • Port inspections of fishing vessels[48]
  • Continuous reporting of fishing vessel positions via satellite linked Vessel Monitoring Systems (VMS)[49]
  • Catch Documentation Scheme for Toothfish which tracks toothfish from the point of landing through to the final point of sale and requires verification and authorisation by government authorities at each step[50]
  • The requirement to carry two Scientific Observers on each licensed vessel - including one from a Member state other than the vessel flag.,[51][52]

Sustainability

In November 2010, the Marine Stewardship Council certified the Ross Sea Antarctic toothfish fishery as a sustainable and well-managed fishery.[53] The certification is contentious, with many conservation groups protesting the certification due to the paucity of information needed to reliably manage the fishery,[54] and the fact that only eight of the nineteen vessels in the fishery during the latest year for which data are publicly available were certified. During the 2013/14 season vessels operating under the Marine Stewardship Certification landed 51.3% of all Antarctic toothfish from the Ross Sea Region (CCAMLR Subarea 88.1) and 64.7% of Antarctic toothfish from the Amundsen Sea sctor (CCAMLR Subarea 88.2).[55]

The argument that only a portion of Antarctic toothfish is certified, the high price it commands and the remote areas where a large proportion of the fish are caught have been advanced as an encouragement to illegal, unreported and unregulated (IUU) fishing and mislabeling.[56][57] A recent genetic study of MSC-labeled Antarctic toothfish found in markets revealed a significant proportion were not from the MSC-certified stock, and many were not even toothfish at all.[58] However, the claims of this study were unable to be substantiated as the data were not made available for independent examination. The MSC had conducted an earlier study using more robust methodology which found no evidence of mislabelling.[59] The MSC conducts an annual audit of the fishery which includes sampling of certified product.

Due to the intense challenges that faced toothfish management in the 1990s and early 2000s (e.g., IUU fishing, mislabelling, inadequate data for management), consumer seafood guides such as Seafood Watch placed toothfish of both species (Chilean seabass) on their red, or “avoid”, list.,[60] however in light of up to date, internationally peer-reviewed scientific information, in April 2013, Seafood Watch upgraded the Ross Sea Antarctic toothfish fishery to a "good alternative".[61] Following a comprehensive review in 2012 the Monterey Bay Aquarium revised its rating of Antarctic toothfish to 'good alternative'.[62][63]

Greenpeace International added the Antarctic toothfish to its seafood red list in 2010. [64] This approach is at variance with the high score given the fishery when it was granted certification by the Marine Stewardship Council.[65]

References

  1. ↑ Andriashev, A.P. (1962). On the systematic position of the giant nototheniid fish (Pisces, Nototheniidae) from the McMurdo Sound, Antarctica. Zool. Zhur. 41:1048–1050 (in Russian; English translation available from National Institute of Oceanography, Wormley, Godalming, Surrey, UK, No. NIOT/1132, June 1970).
  2. ↑ DeVries, A.L.; and Eastman JT (1998) Brief review of the biology of Dissostichus mawsoni. CCAMLR Document WG-FSA-98/49, Hobart, Australia.
  3. ↑ 3.0 3.1 Eastman, J.T. (1993) Antarctic fish biology. Academic Press, San Diego.
  4. ↑ Eastman, J.T.; and DeVries, A.L. (1981). Buoyancy adaptations in a swim-bladderless Antarctic fish. Journal of Morphology 167:91–102.
  5. ↑ Eastman, J.T.; and DeVries, A.L. (1982). Buoyancy studies of notothenioid fishes in McMurdo Sound, Antarctica. Copeia 2:385–393.
  6. ↑ Near, T.J.; Russo, S.E.; Jones, C.D.; and DeVries, A.L. (2003) Ontogenetic shift in buoyancy and habitat in the Antarctic toothfish, Dissostichus mawsoni (Perciformes: Nototheniidae). Polar Biol. 26:124–128.
  7. ↑ 7.0 7.1 Yukhov, V.L. (1971). The range of Dissostichus mawsoni Norman and some features of its biology. Journal of Ichthyology 11: 8–18.
  8. ↑ 8.0 8.1 Fuiman, L.A.; Davis, R.W.; and Williams, T.M. (2002). Behaviour of midwater fishes under the Antarctic ice: observations by a predator. Marine Biology 140:815–822.
  9. ↑ Eastman, J.T.; and Barry, J.P. (2002) Underwater video observation of the Antarctic toothfish Dissostichus mawsoni (Perciformes: Nototheniidae) in the Ross Sea, Antarctica. Polar Biology 25: 391–395
  10. ↑ Eastman, J.T. (1985) Pleuragramma antarcticum (Pisces, Nototheniidae) as food for other fishes in McMurdo Sound, Antarctica. Polar Biology 4:155–160.
  11. ↑ La Mesa, M.; Eastman, J.T.; and Vacchi, M. (2004) The role of notothenioid fish in the food web of the Ross Sea shelf waters: a review. Polar Biology 27:321–338.
  12. ↑ Fenaughty, J.M.; Stevens, D.W., Hanchet, S.M. (2003). Diet of the Antarctic toothfish (Dissostichus mawsoni) from the Ross Sea, Antarctica (CCAMLR Statistical Subarea 88.1). CCAMLR Sci. 10:1–11.
  13. ↑ Hanchet, S.M.; Rickard, G.J.; Fenaughty, J.M.; Dunn, A.; and Williams, M.J.H. (2008). Hypothetical life cycle for Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea region. CCAMLR Sci. 15:35–53.
  14. ↑ Horn, P.L. (2002). Age and growth of Patagonian toothfish (Dissostichus eleginoides) and Antarctic toothfish (D. mawsoni) in waters from the New Zealand Subantarctic to the Ross Sea, Antarctica. Fish Research 56:275–287.
  15. ↑ Brooks, C.M.; Andrews, A.H.; Ashford, J.R.; Ramanna, N.; Jones, C.D.; Lundstrom, C.C.; and Cailliet, G.M. (2010). Age estimation and lead–radium dating of Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea. Polar Biology doi:10.1007/s00300-010-0883-z.
  16. ↑ Hanchet, S.M.; Stevenson, M.L.; Phillips, N.L.; and Dunn, A. (2005) A characterisation of the toothfish fishery in Subareas 88.1 and 88.2 from 1997/98 to 2004/05. CCAMLR WG-FSA-05/29. Hobart, Australia.
  17. ↑ Parker, S.J.; and Grimes, P.J. (2010). Length- and age-at-spawning of Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea. CCAMLR Sci. 17: 53–73.
  18. ↑ 18.0 18.1 18.2 Hanchet, S.M. (2010) Updated species profile for Antarctic toothfish (Dissostichus mawsoni). CCAMLR WG-FSA-10/24. Hobart, Australia.
  19. ↑ 19.0 19.1 Brooks, C.M.; Ashford, J.R. (2008) Spatial distribution and age structure of the Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea, Antarctica. CCAMLR WG-FSA-08-18. Hobart, Australia.
  20. ↑ Ashford, J.; Dinniman, M.; Brooks, C.; Andrews, A.H.; Hofmann, E.; Cailliet, G.; Jones, C.; and Ramanna, N. (2012). Does large-scale ocean circulation structure life history connectivity in Antarctic toothfish (Dissostichus mawsoni)? Canadian Journal of Fisheries and Aquatic Sciences 69: doi:10.1139/f2012-111.
  21. ↑ Fenaughty, J.M.; Eastman, J.T.; and Sidell, B.D. (2008). Biological implications of low condition factor “axe handle” specimens of the Antarctic toothfish, Dissostichus mawsoni, from the Ross Sea. Antarctic Science 20:537–551.
  22. ↑ 22.0 22.1 Eastman,JT; Lannoo, MJ. (2011). Divergence of brain and retinal anatomy and histology in pelagic Antarctic notothenioid fishes of the sister taxa Dissostichus and Pleuragramma. Journal of Morphology 272:419-441.
  23. ↑ Roberts, J.; Xavier, J.C.; and Agnew, D.L. (2011). The diet of toothfish species Dissostichus eleginoides and Dissostichus mawsoni with overlapping distributions. Journal of Fish Biology 79: 138–154.
  24. ↑ Ashford, J.; Dinniman, M.; Brooks, C.; Andrews, A.H.; Hofmann, E.; Cailliet, G.; Jones, C.; and Ramanna, N. (2012). Does large-scale ocean circulation structure life history connectivity in Antarctic toothfish (Dissostichus mawsoni)? Can. J. Fish. Aquat. Sci. 69: doi:10.1139/f2012-111
  25. ↑ Fenaughty and Parker (2014) Quantifying the impacts of ice on demersal longlining; a case study in CCAMLR Subarea 88.1 . WG-FSA 14/55 rev 2
  26. ↑ Fishery Report 2014: Exploratory fishery for Dissostichus spp. in Subareas 88.1 and 88.2. http://www.ccamlr.org/en/system/files/08%20TOT881%20882%202014_1.pdf
  27. ↑ 27.0 27.1 CONSTABLE, A.J., DE LA MARE, W.K., AGNEW, D.J., EVERSON, I. & MILLER, D. 2000. Managing fisheries to conserve the Antarctic marine ecosystem: practical implementation of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR). ICES Journal of Marine Science, 57, 778–791.
  28. ↑ 28.0 28.1 Ainley, D.G.; Nur, N.; Eastman, J.T.; Ballard, G.; Parkinson, C.L.; Evans, C.W.; and DeVries, A.L. (2012). Decadal trends in abundance, size and condition of Antarctic toothfish in McMurdo Sound, Antarctica, 1972-2011. Fish & Fisheries, DOI: 10.1111/j.1467-2979.2012.00474.x.
  29. ↑ Antarctic toothfish, lost - and found. http://www.comsdev.canterbury.ac.nz/rss/news/?feed=news&articleId=1531
  30. ↑ Ainley, D.G.; Ballard, G. (2012) Trophic interactions and the decrease in Killer Whale (Orcinus orca) prevalence with reduced availability of large fish in the southern Ross Sea. Aquatic Mammals 38:153-160.
  31. ↑ Eisert R., M.H. Pinkerton, S.D. Newsome, O.T. Oftedal. (2013) A Critical Re-examination of the Evidence for a Possible Dependence of Weddell Seals (Leptonychotes weddellii) on Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea, Antarctica. https://www.niwa.co.nz/sites/niwa.co.nz/files/emm-13-28.pdf
  32. ↑ Torres L., Matt H. Pinkerton, R. Pitman, J. Durban, Regina Eisert. (2013) To what extent do type C killer whales (Orcinus orca) feed on Antarctic toothfish (Dissostichus mawsoni) in the Ross Sea, Antarctica?
  33. ↑ Mormede S., S.J. Parker, S.M. Hanchet, A. Dunn, and S. Gregory (2014) Results of the third CCAMLR sponsored research survey to monitor abundance of subadult Antarctic toothfish in the southern Ross Sea, February 2014 and development of the time series WG-FSA 14/41. http://www.niwa.co.nz/sites/niwa.co.nz/files/fsa-14-51.pdf
  34. ↑ http://www.researchgate.net/publication/278672675_Seasonal_site_fidelity_and_movement_of_type-C_killer_whales_between_Antarctica_and_New_Zealand
  35. ↑ http://www.stuff.co.nz/science/69744937/killer-whales-swim-nearly-5000km-from-antarctica-to-nz.html
  36. ↑ Table 1, page 336 REPORT OF THE THIRTY-THIRD MEETING OF THE SCIENTIFIC COMMITTEE HOBART, AUSTRALIA 20–24 OCTOBER 2014. https://www.ccamlr.org/en/system/files/e-sc-xxxiii_1.pdf
  37. ↑ http://www.ccamlr.org/en/organisation/camlr-convention-text#II
  38. ↑ CONSERVATION MEASURE 41-09 (2014) Limits on the exploratory fishery for Dissostichus spp. in Statistical Subarea 88.1 in the 2014/15 season. http://www.ccamlr.org/en/measure-41-09-2014, CONSERVATION MEASURE 41-10 (2014) Limits on the exploratory fishery for Dissostichus spp. in Statistical Subarea 88.2 in the 2014/15 and 2015/16 seasons. http://www.ccamlr.org/en/measure-41-10-2014
  39. ↑ CONSERVATION MEASURE 24-02 (2014) Longline weighting for seabird conservation http://www.ccamlr.org/en/measure-24-02-2014
  40. ↑ HILBORN, R. 2010. Pretty good yield and exploited fishes. Marine Policy, 34, 193–196
  41. ↑ 41.0 41.1 CCAMLR CM 25-02, http://www.ccamlr.org/en/measure-25-02-2009
  42. ↑ CCAMLR CM 25-02,http://www.ccamlr.org/en/measure-25-02-2009
  43. ↑ CCAMLR CM 24-02, http://www.ccamlr.org/en/measure-24-02-2008, and CCAMLR CM 25-02, http://www.ccamlr.org/en/measure-25-02-2009
  44. ↑ 44.0 44.1 44.2 CCAMLR CM 26-01, http://www.ccamlr.org/en/measure-26-01-2001
  45. ↑ SC-CAMLR-XXXI, paragraphs 4.2-4.3, http://www.ccamlr.org/en/sc-camlr-xxxi
  46. ↑ CCAMLR System of Inspection, http://www.ccamlr.org/en/document/publications/inspectors-manual
  47. ↑ CCAMLR CM 10-02, http://www.ccamlr.org/en/measure-10-02-2011
  48. ↑ CCAMLR CM 10-03, http://www.ccamlr.org/en/measure-10-03-2009
  49. ↑ CCAMLR CM 10-04, http://www.ccamlr.org/en/measure-10-04-2010
  50. ↑ CCAMLR CM 10-05, http://www.ccamlr.org/en/measure-10-05-2009
  51. ↑ CONSERVATION MEASURE 41-09 (2014) Limits on the exploratory fishery for Dissostichus spp. in Statistical Subarea 88.1 in the 2014/15 season. https://www.ccamlr.org/en/measure-41-09-2014
  52. ↑ CONSERVATION MEASURE 41-10 (2014) Limits on the exploratory fishery for Dissostichus spp.in Statistical Subarea 88.2 in the 2014/15 and 2015/16 seasons. https://www.ccamlr.org/en/measure-41-10-2014
  53. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  54. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  55. ↑ https://www.msc.org/track-a-fishery/fisheries-in-the-program/certified/southern-ocean/ross-sea-toothfish-longline/assessment-downloads-1/20141216_SR4_TOO100.pdf
  56. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  57. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  58. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  59. ↑ http://www.msc.org/newsroom/news/update-lack-of-evidence-blocks-msc-investigation-into-toothfish-mislabelling-claims
  60. ↑ Seafood Watch (2012). http://www.montereybayaquarium.org/cr/cr_seafoodwatch/sfw_recommendations.aspx?c=ln
  61. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  62. ↑ http://www.seafoodwatch.org/seafood-recommendations/groups/toothfish?type=antarctic&q=Toothfish,%20Antarctic
  63. ↑ http://www.seafoodwatch.org/-/m/sfw/pdf/reports/mba_seafoodwatch_chileanseabassreport.pdf
  64. ↑ This assessment is contentious. Greenpeace International Seafood Red list
  65. ↑ http://www.msc.org/track-a-fishery/certified/southern-ocean/ross-sea-toothfish-longline

Further references

  • Lua error in package.lua at line 80: module 'strict' not found.
  • Froese, Rainer and Pauly, Daniel, eds. (2005). "Dissostichus mawsoni" in FishBase. 10 2005 version.
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