A new method for estimating illegal fishing effort is put forward. The results from this new method are similar to the Agnew and Kirkwood method and this suggests that the current method is adequate under circumstances of low evasion and for when good knowledge exists that zero observations reflects zero illegal fishing. The new method performs better in the case of zero detections and can potentially better handle the evasion of detection by illegal activity.
Both the new and the current method suffer from the type of observations method used, which directly affects the system. This is the prevention/detection problem, in which the greater the number of detections for a given level of illegal fishing the more often the illegal fishers will curtail their fishing trips. This leads to a negative correlation between the amount of fishing and the estimated amount of fishing, for a given number of illegal vessels.
As the number of illegal vessels increase, both the estimate and the average amount of illegal fishing increases. This gives us some confidence that the method can produce results that have a degree of legitimacy. However, the range of actual fishing (in the simulation data sets) for a given estimated level of fishing is very large. This range of uncertainty increases as the evasion rate increases.
This research suggests that it would be possible to calculate a precautionary assessment of illegal fishing such that the actual number of illegal fishing days is less than or equal to the precautionary estimate with some given level of confidence (for example 80%).
Abstract:
A multi-disciplinary research cruise in the Atlantic sector of the Southern Ocean was conducted during the 2004 austral winter as part of the International Collaborative Expedition to collect and study Fish Indigenous to Sub-antarctic Habitats (ICEFISH). Sampling during the ICEFISH cruise included demersal finfish, benthic invertebrates, and information of seafloor composition. The objectives of the cruise included Antarctic fish and invertebrate biochemical, molecular and physiological, ecological and population genetics research. Trawling was conducted within the CCAMLR Convention area at Shag Rocks, South Georgia, the South Sandwich Islands, and Bouvetoya Island from 5 June to 30 June, 2004. A description of demersal finfish and benthic invertebrate collections, distribution, and composition from each island group is presented, including some preliminary information on the seabed composition of shelf areas. The total number of finfish specimens recorded within the Antarctic convergence during the ICEFISH cruise trawl deployments was 9105 specimens of 29 species.
A wide contrast in finfish and invertebrate species composition between island groups was observed, with the greatest differences between the South Sandwich Islands and Bouvetoya, where the isolation of the latter island likely played a role in the different community structure. Due to mixed gear selectivity and possible avoidance, it was not feasible to make quantitative estimates of finfish abundance. However, using data from the Blake trawl, estimates of benthic invertebrate densities by station were computed and maps generated that provide information on benthic communities.
Abstract:
This paper summarised progress made in the BioRoss marine biodiversity research programme administered by the New Zealand Ministry of Fisheries since 2000. The objective of the BioRoss programme is to develop a more complete understanding of the biodiversity present in selected marine communities in the Ross Sea, allowing better management, and to facilitate better state of the environment reporting. This objective is being achieved by commissioning directed research on the diversity of selected marine communities within the Southern Ocean and Ross Sea.
Abstract:
The marine habitat exploited by black-browed Diomedea melanophyrs and grey-headed albatrosses D. chrysostoma breeding at Campbell Island, New Zealand, was studied using satellite telemetry. Data were analysed in relation to the bathymetry and sea-surface temperature of the foraging zones. Black-browed albatrosses spent 55% of their time on the Campbell Plateau but also carried out long foraging trips to the Polar Front and Antarctic Zone at a distance of over 2000 km. They relied heavily on juvenile Micromesistius australis, a schooling fish, during foraging trips to the shelf but over oceanic waters the squid Martialia hyadesi was the main prey item. Grey-headed albatrosses spend 71% of their time foraging over the deep waters of the Polar Frontal Zone where M. hyadesi comprised over 90% of the mass of prey taken. No satellite-tracked birds fed over the shelf, but data from the duration of foraging trips and dietary analysis suggests that shelf-feeding is important for this species. Significant inter-species differences in the time spent in neritic and oceanic zones show that black-browed albatrosses were reliant primarily on shelf resources while grey-headed albatrosses are primarily oceanic feeders. In addition, the 2 species overlapped little in the zones used over oceanic waters, with black-browed albatrosses feeding in more southerly waters than grey-headed albatrosses. However, both species fed on M. hyadesi when foraging in association with the Polar Front.
Abstract:
The numbers of Black-browed Albatrosses Diomedea melanophrys and Grey-headed Albatrosses D. chrysostoma at Campbell Island, New Zealand, have declined dramatically since the 1940s. Black-browed Albatross numbers went into a steep decline in the 1970s and, since at least 1984, have been increasing slightly at average rates of 1.1% and 2.1% per annum at two colonies. The long-term downward trend in numbers of the Grey-headed Albatross has continued into the 1990s, averaging annually between 3.0% and 4.8% per annum at different colonies. A demographic study carried out between 1984 and 1996 indicates that Black-browed and Grey-headed Albatrosses have similar high annual adult survival rates (0.945 and 0.953, respectively). Black-browed Albatrosses breed for the first time at a younger average age than do Grey-headed Albatrosses (10 years and 13.5 years, respectively), have a higher average breeding success (0.663 compared with 0.397 for the latter species) and are annual breeders where as Grey-headed Albatrosses show a typical biennial pattern of breeding. Both show low survival from fledging to first breeding; averaging 0.186 and 0.162 for Black-browed and Grey-headed Albatrosses respectively. Both species are accidentally killed in the Japanese long-line fishery for tuna Thunnus sp. In the Australasian region. The steep decline of Black-browed Albatross numbers in the 1970s was concomitant with the development of this fishery in the foraging region of the Campbell Island birds. Currently, the slight increase in numbers is due to high adult survival rates and breeding success, and is coincident with a great reduction in long-line fishing. With stable and high adult survival rates, it is expected that future population trends will be mainly influenced by the recruitment rates. The continuous decline of Grey-headed Albatrosses since the 1940s, before long-line fishing developed in this region, indicates that natural environmental processes contributed to the downward trend in breeding numbers. Modelling indicates that Grey-Headed Albatrosses numbers will continue to decrease with the present demographic parameters. A comparison between the species breeding at different sites shows that differing environmental conditions influence demographic characteristics.
Abstract:
Ministry of Fisheries observers reported 595 seabird captures from observed fishing operations in 2002–03: 265 from observed trawl fishing operations (67% landed dead); 113 from tuna (Thunnus spp.) longlining operations (83% landed dead); and 217 from ling (Genypterus blacodes) longline operations (95% dead). The trawl-caught seabirds were from at least eight target fisheries, four of which had less than 50 observed tows. Observed squid (Nototodarus spp.) and hoki (Macruronus novaezelandiae) trawl fisheries accounted for 87% of observed trawl-caught seabirds.
Incident rates (expressed as the percent of observed fishing operations with seabird captures) for longline fisheries in 2002–03 were highest in chartered albacore tuna (T. alalunga) sets in northern waters (17%), compared with 10% for the observed chartered southern bluefin tuna (T. maccoyii) longlines off the southwest coast of the South Island and 9% of observed ling sets. About 2% of observed hoki tows in the main fishery areas had incidental captures, compared with 9% of observed squid trawls.
Mean seabird catch rates were estimated for the main fisheries with observed seabird captures: 0.048 seabirds per 1000 hooks (s.e = 0.010) for the chartered southern bluefin tuna fishery; 0.096 seabirds per 1000 hooks (s.e. = 0.017) for the chartered albacore effort; for ling longlines, mean catch rates ranged from 0.013 seabirds per 1000 hooks (s.e. = 0.002) in LIN 4 to 0.079 (s.e. = 0.032) in LIN 3; for hoki fisheries, 0.007 seabirds per tow (s.e. = 0.008) at Cook Strait to 0.185 (s.e. = 0.103) at the Puysegur fishery; and for squid fisheries, 0.035 seabirds per tow (s.e. = 0.011) at Puysegur and 0.198 (s.e. = 0.032) off the Stewart-Snares shelf.
Total estimates are provided for the main fisheries: 42 seabirds (c.v. = 6%) were estimated caught on chartered southern bluefin tuna longlines; 94 seabirds (c.v. = 8%) were estimated from chartered albacore effort; 543 seabirds (c.v = 10%) for ling autoline fisheries in areas LIN 4, LIN 5, and LIN 6 compared with 412 seabirds (c.v. = 8%) for the six observed vessels by area and season; 269 seabirds (c.v. = 23%) for hoki fisheries at Puysegur, Sub-Antarctic, and west coast South Island; and 841 seabirds (c.v. = 12%) for squid trawl fisheries at Puysegur, Stewart-Snares shelf and SQU 6T. Numbers are given for seabirds in total, rather than individual taxa, because of problems extrapolating by seabird species over a fishery.
In fisheries for which the observer coverage was
Of the reported captures, 438 were returned for identification and represented nine albatross and ten petrel taxa, one of which was previously unrecorded as caught during observed fishing operations: white-headed petrel (Pterodroma lessoni). About 75% of the seabirds returned for identification comprised four taxa: 28% were white-chinned petrels (Procellaria aequinoctialis), 18% were sooty shearwaters (Puffinus griseus), 16% were white-capped albatrosses (Thalassarche steadi), and 13% were white-chinned petrels (Procellaria aequinoctialis).
Abstract:
Ministry of Fisheries observers reported 851 seabird captures from observed fishing operations in 2001–02: 324 from observed trawl fishing operations (87% landed dead); 167 from tuna (Thunnus spp.) longlining operations (87% landed dead); and 330 from ling (Genypterus blacodes) longline operations (93% dead). Observers recorded another 104 seabirds from unobserved parts of ling longline hauls. Observed squid (Nototodarus spp.) and hoki (Macruronus novaezelandiae) trawl fisheries accounted for 87% of observed trawl-caught seabirds.
Demersal and surface longline fisheries had the highest incident rates (numbers of seabirds per observed fishing operation) in 2001–02, with seabirds reported caught from 26% of observed domestic tuna sets in northern waters, 22% of observed chartered Japanese longlines off the southern west coast of the South Island, and 10% of observed ling sets. About 1% of observed hoki tows in the main fishery areas had incidental captures, compared with 9% of observed squid trawls. Observed incident rates in at least seven other trawl fisheries ranged from
Mean seabird catch rates were estimated for the main fisheries with observed seabird captures: for ling longlines mean catch rates ranged from 0.098 seabirds per 1000 hooks (s.e. = 0.020) in LIN 4 to 0.057 (s.e. = 0.012) in LIN 5; for hoki fisheries, 0.010 seabirds per tow (s.e. = 0.004) at the Chatham Rise to 0.023 (s.e. = 0.017) at the west coast South Island fishery; and for squid fisheries, 0.118 seabirds per tow (s.e. = 0.027) at SQU 6T and 0.163 (s.e. = 0.024) off the Stewart-Snares shelf.
Total estimates are provided for the main fisheries: 81 seabirds (c.v. = 4%) were estimated caught on chartered tuna longlines in southern waters; 20 seabirds (c.v. = 53%) were estimated from domestic tuna effort in southern waters; 1450 seabirds (c.v = 16%) were caught in ling autoline fisheries by area compared with 685 seabirds (c.v. = 13%) for the four observed vessels by area and season; 334 seabirds (c.v. = 33%) for hoki fisheries; and 710 seabirds (c.v. = 11%) for squid trawl fisheries at Stewart-Snares shelf and SQU 6T. Numbers are given for seabirds in total, rather than individual taxa, because of problems extrapolating by seabird species over a fishery.
In fisheries for which the observer coverage was
Of the reported captures, 690 were returned for identification and represented nine albatross and eleven petrel taxa, one of which was previously unrecorded as caught during observed fishing operations: broad-billed prion (Pachyptila vittata). About 86% of the seabirds returned for identification comprised three taxa: 52% were white-chinned petrels (Procellaria aequinoctialis), 20% were white-capped albatrosses (Thalassarche steadi), and 15% were sooty shearwaters (Puffinus griseus).
Abstract:
Ministry of Fisheries observers reported 1236 seabird captures from fishing operations in 2000–01: 701 from observed trawl fishing operations (87% landed dead); 53 from tuna (Thunnus spp.) longlining operations (87% landed dead); 452 from ling (Genypterus blacodes) longline operations (99% dead); 26 seabirds from snapper (Pagrus auratus) longlines (100% dead); and 4 from bluenose (Hyperoglyphe antarctica) longline operations (75% landed dead). Observed squid (Nototodarus spp.) and hoki (Macruronus novaezelandiae) trawl fisheries accounted for 94% of the 701 seabird captures in observed trawl fisheries.
Observed incident rates in longline fisheries were highest in the ling longline fishery: 24% of observed ling autoline sets caught seabirds, compared with 6% of observed chartered tuna longline sets caught seabirds, 15% of domestic tuna longlines, and 16% of snapper longlines. Lower incident rates were observed in the trawl fisheries: 8% of observed tows in the squid fishery, 4% in hoki, barracouta (Thyrsites atun), and scampi (Metanephrops challengeri) fisheries, and
Mean seabird catch rates were estimated for the main fisheries with observed seabird captures: for ling longline fisheries, mean catch rates varied from 0.218 seabirds per 1000 hooks (s.e. = 0.033) in LIN 6 to 0.004 (s.e. = 0.004) in LIN 2; for chartered tuna fishery off the southern west coast of the South Island, 0.026 seabirds per 1000 hooks (s.e. = 0.008); for hoki fisheries, between 0.014 seabirds per tow (s.e. = 0.004) in the west coast South Island fishery and 0.037 (s.e. = 0.030) in the Puysegur fishery; and for squid trawl fisheries, 0.095 seabirds per tow (s.e. = 0.009) at the Stewart-Snares shelf fishery and 0.073 seabirds per tow in SQU 6T.
Total estimates are provided for the main fisheries: 16 seabirds (c.v. = 6%) were caught during chartered tuna longline sets, primarily off the southern west coast of the South Island; 757 seabirds (c.v. = 11%) were estimated caught by four autoline vessels when stratified by area and season compared with an estimated 2 367 seabirds (c.v. = 12%) for the six autoline vessels by area; 1065 seabirds (c.v. = 9%) were estimated caught during hoki targeted trawls; and 586 seabirds (c.v. = 11%) were estimated caught during squid trawls. Numbers are given for seabirds in total, rather than individual taxa, because of problems in extrapolating by seabird species over a fishery.
In fisheries for which the observer coverage was
Apart from one black-backed gull (Larus dominicanus), the remaining 1045 seabirds observed caught and returned for identification represented nine albatross and thirteen petrel taxa. These taxa included three previously unrecorded as caught during observed fishing operations: Buller’s shearwater (Puffinus bulleri), fluttering shearwater (Puffinus gavia), and short-tailed shearwater (Puffinus tenuirostris). White-chinned petrels (Procellaria aequinoctialis), sooty shearwaters (Puffinus griseus), grey petrels (Procellaria cinerea), white-capped albatrosses (Thalassarche steadi), and Salvin's albatrosses (T. salvini) accounted for 92% of the seabirds landed dead and returned for autopsy.
Abstract:
Industrial longline fisheries are considered worldwide as the main threat to albatross and petrel populations, particularly at open oceans. However, inside countries’ EEZ artisanal fleets account for a significant fishing effort and eventually, could represent a major threat to albatrosses and petrels than industrial fishing. Here we described the fishing technique and provide the first assessment of incidental mortality for the artisanal fleets for Austral hake and Patagonian toothfish in southern Chile, which accounts for 0.9 and 20 millions hooks/year, respectively. Both fleet use vertical longlines that sink fast: 0.33 and 0.69-0.22 m?sec-1 in the hake and toothfish longlines, respectively. Accordingly, seabird by-catch was 0.030 birds/1000 hooks in the Austral hake fishery, mainly accounted by birds caught during the slow process of hauling. The overall by-catch rate in the Patagonian toothfish was 0.047 birds/1000 hooks. Considering the big fishing effort deployed by the artisanal toothfish fleet, some recommendations are giving in order to improve fishing compliance with today high conservation standards.
Abstract:
Research undertaken in New Zealand on seabird interactions with fisheries, and research into the population status and distribution at sea of New Zealand seabirds is documented.