Indicator: AAT-20 Fishing by-catch numbers and/or weight taken as bycatch
Data
| Subarea/Division | Year | Estimated total potential seabird by-catch | ||
|---|---|---|---|---|
| Lower | Median | Upper | ||
| 48.3 | 2004 | 0 | 0 | 0 |
| 1996-2003 | 1811 | 3441 | 56031 | |
| 58.5.2 | 2004 | 596 | 727 | 1941 |
| 1996-2003 | 31857 | 38870 | 103787 | |
| 58.4.3 | 2004 | 522 | 636 | 1699 |
| Lower and upper confidence refer to 95% confidence limit | ||||
Source: Scientific Committee for the Conservation of Antarctic Marine Living Resources 2004, Commission for the Conservation of Antarctic Marine Living Resources, Hobart, Table 7.15
| Subarea/Division | 58.4.2 | 58.4.3b | 58.5.2 |
|---|---|---|---|
| Total rajid (a species of fish) | 0.04 | 0.11 | 61.71 |
| Total Macrourus (bird) species | 0.63 | 0.13 | 42.33 |
| Total rajid as a % of the species being targeted | 0.2 | 1.67 | 11.18 |
| Total Macrourus species as % of the species being targeted | 3.18 | 1.92 | 7.67 |
Source: Scientific Committee for the Conservation of Antarctic Marine Living Resources 2004, Commission for the Conservation of Antarctic Marine Living Resources, Hobart, Table 6.3
| Division 58.5.2 | |
|---|---|
| Total rajid (a species of fish) | 7.77 |
| Total Macrourus (bird) species | 2.88 |
| Total rajid as a % of the species being targeted | 0.44 |
| Total Macrourus species as % of the species being targeted | 0.16 |
Source: Scientific Committee for the Conservation of Antarctic Marine Living Resources 2004, Commission for the Conservation of Antarctic Marine Living Resources, Hobart, Table 6.4
What the data mean
By-catch commonly refers to the part of a fisher’s catch that is not the target species. The data estimates the by-catch associated with longline and trawl fishing in specified areas. The by-catch is estimated for a fish species and a bird species. The data shows that by-catch continues to be of concern especially when we consider the tonnage of by-catch compared to the tonnage of the fish species being targeted as part of the fishing operations. As high as 11% of longline catches (tonnes) is comprised of the by-catch fish species rajid but this varies between areas. Trawling seems to have less of an impact.
Data Limitations
It is difficult to accurately know the extent and level of by-catch.
Issues for which this is an indicator and why
Australian Antarctic Territory — Environment - Human Pressures on the environment
Each year thousands of seabirds and fish are accidentally killed on longline hooks and trawling lines (i.e. they are not the target species for the fishing operation). The level of by-catch that occurs in these fisheries is not sustainable for many populations of fish and especially for seabirds. Changes in the total numbers of other animals affected may be at least initially ambiguous: increases may reflect improved reporting, decreases a decline in wildlife species themselves, so that they are no longer available to accidentally catch or interact with. However, changes would be a reasonable indicator of reduced or increased pressure.
Other indicators for this issue:
- AAT-17 Types and concentrations of long range pollutants from outside Antarctica reaching Antarctica
- AAT-18 Annual tourist ship visits and tourist numbers
- AAT-19 Annual catch in tonnes of marine species harvested in Australian Antarctic and sub-Antarctic waters - legal and illegal
- AAT-21 Station and ship person days
- AAT-22 Wastewater - biological oxygen demand of wastewater discharged
- AAT-23 Annual fuel usage of generator sets and boilers
- AAT-24 Annual incinerator fuel usage
- AAT-25 Annual total of fuel used by vehicles
- AAT-26 Annual total potable water consumption
- AAT-27 Volume of runoffs and pollutants/emissions from stations
- CO-16 Status of Australian fisheries
- CO-17 Change in species and trophic structure of fish species caught
- CO-19 Estimated tonnage taken by illegal fishing; estimated number of illegal boats, estimated number of individuals of threatened species taken
- CO-21 Non-target effects: Number and/or weight taken as bycatch, and change since introduction of exclusion devices
Coasts and Oceans — Direct pressure of human activities on coasts and oceans - Pressure of fishing
Each year thousands of seabirds and fish, in Antarctic, as well as other fisheries, are accidentally killed on longline hooks and trawling lines (i.e. they are not the target species for the fishing operation), including in . The level of by-catch that occurs in these fisheries is not sustainable for many populations of fish and especially for seabirds. Changes in the total numbers of other animals affected may be at least initially ambiguous: increases may reflect improved reporting, decreases a decline in wildlife species themselves, so that they are no longer available to accidentally catch or interact with. However, changes would be a reasonable indicator of reduced or increased pressure.
Other indicators for this issue:
- CO-16 Status of Australian fisheries
- CO-17 Change in species and trophic structure of fish species caught
- CO-19 Estimated tonnage taken by illegal fishing; estimated number of illegal boats, estimated number of individuals of threatened species taken
- CO-20 Non-target effects: Area of seabeds trawled
- CO-21 Non-target effects: Number and/or weight taken as bycatch, and change since introduction of exclusion devices
- CO-22 Aquaculture: extent of habitat disturbed or removed
- CO-23 Aquaculture: volume of discharged sediments and nutrients
- CO-24 Aquaculture: origin species and tonnage of stockfeed used
- CO-25 Aquaculture: instances of disease and exotic species introduction from movement of live material
- CO-32 Number of injuries to marine animals from marine debris
- CO-53 Evidence or examples of noise or visual disturbance of marine species by human activities
- CO-62 Estimated number of marine animals harvested by recreational fishers
- CO-63 Estimated number of marine animals harvested by indigenous fishers
- CO-65 Correlation between various human activities and introduction of coastal and marine species
- AAT-19 Annual catch in tonnes of marine species harvested in Australian Antarctic and sub-Antarctic waters - legal and illegal
- LD-40 Current research into pressures and contributions of naturalised introduced species
- BD-09 The change in extent of selected nationally significant invasive species
Biodiversity — Utilisation and value of biodiversity - Harvesting and trade in wildlife
In terms of mass and number of individuals killed, harvesting of wild fish, including bycatch, is the principal commercial harvesting of wild animals in Australia and the AAT.
Other indicators for this issue:
- BD-23 Some selected nationally significant native terrestrial species subjected to harvesting and population trends
- LD-10 Number of compounds from terrestrial sources at some stage of commercial development
- CO-07 Australian fisheries production - national tonnage and value of retained catch
- CO-09 Number of compounds from coastal and marine sources at some stage of commercial development
- CO-16 Status of Australian fisheries
- CO-17 Change in species and trophic structure of fish species caught
- CO-19 Estimated tonnage taken by illegal fishing; estimated number of illegal boats, estimated number of individuals of threatened species taken
- CO-20 Non-target effects: Area of seabeds trawled
- CO-21 Non-target effects: Number and/or weight taken as bycatch, and change since introduction of exclusion devices
- CO-32 Number of injuries to marine animals from marine debris
- CO-62 Estimated number of marine animals harvested by recreational fishers
- CO-63 Estimated number of marine animals harvested by indigenous fishers
- CO-65 Correlation between various human activities and introduction of coastal and marine species
- AAT-19 Annual catch in tonnes of marine species harvested in Australian Antarctic and sub-Antarctic waters - legal and illegal
Biodiversity — Pressures on biodiversity - Pressures on marine biodiversity: pressures of fishing
Each year thousands of seabirds and fish, in Antarctic, as well as other fisheries, are accidentally killed on longline hooks and trawling lines (i.e. they are not the target species for the fishing operation), including in . The level of by-catch that occurs in these fisheries is not sustainable for many populations of fish and especially for seabirds. Changes in the total numbers of other animals affected may be at least initially ambiguous: increases may reflect improved reporting, decreases a decline in wildlife species themselves, so that they are no longer available to accidentally catch or interact with. However, changes would be a reasonable indicator of reduced or increased pressure.
Other indicators for this issue:
- CO-16 Status of Australian fisheries
- CO-17 Change in species and trophic structure of fish species caught
- CO-19 Estimated tonnage taken by illegal fishing; estimated number of illegal boats, estimated number of individuals of threatened species taken
- CO-20 Non-target effects: Area of seabeds trawled
- CO-21 Non-target effects: Number and/or weight taken as bycatch, and change since introduction of exclusion devices
- CO-22 Aquaculture: extent of habitat disturbed or removed
- CO-23 Aquaculture: volume of discharged sediments and nutrients
- CO-24 Aquaculture: origin species and tonnage of stockfeed used
- CO-25 Aquaculture: instances of disease and exotic species introduction from movement of live material
- CO-62 Estimated number of marine animals harvested by recreational fishers
- CO-63 Estimated number of marine animals harvested by indigenous fishers
- CO-65 Correlation between various human activities and introduction of coastal and marine species
- AAT-19 Annual catch in tonnes of marine species harvested in Australian Antarctic and sub-Antarctic waters - legal and illegal
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