Indicator: CO-21 Non-target effects: Number and/or weight taken as bycatch, and change since introduction of exclusion devices

Data

The following is a summary of bycatch data reported in logbooks since the National Bycatch Policy was released in 1999. Some fisheries have patchy bycatch records back to 1997.

Northern Prawn Fishery: Turtle bycatch
Year 1999 2000 2001 2002 2003
Turtles caught 883 68 113 27 27
Southern and Western Tuna and Billfish Fishery: Bycatch
Southern Western All
1997 - 5466 5466
1998 339 8313 8652
1999 5705 19487 25192
2000 14854 23024 37878
22281 38643 60924
2002 N/a N/a 60116
2003 N/a N/a 51487
Southern and Western Longline Fishery: Wildlife Interactions
Birds Turtles Whales Seals Sharks Total
1997 - - - - - -
1998 1 - - - - 1
1999 10 25 - - 1 36
2000 12 26 1 1 1 38
15 38 - - - 53
Eastern Tuna and Bluefish Fishery: Wildlife Interactions and No-Take Species
Species Name and status Year
1998-99 1999-00 2000-01 2001-02 2002-03
Black Marlin
Alive 266 258 585 764 831
Dead 105 169 252 224 375
Unspecified 5 3
Blue Marlin
Alive 244 338 875 822 1017
Dead 92 117 336 405 431
Unspecified 1
Great White Shark
Alive
Dead 1
Grey Nurse Shark
Alive
Dead
Total all species 707 883 2053 2215 2658
Eastern Tuna and Bluefish Fishery Longline: Wildlife Interactions
Other fish Birds Whales Turtles Total
1997-1998 - 6 - 46 52
1998-1999 707 23 - 34 764
1999-2000 883 33 1 34 951
2000-2001 2059 29 7 34 2129
2001-2002 2216 217 2 55 2490
2002-2003 2658 59 2 38 2757
2003-2004 2166 62 3 53 2284
Bass Strait Central Zone Scallop Fishery
Non-target species 2003
Doughboy Scallop 56365
Oyster 31410
Arrow Squid 500
Shells 191
Flathead 42
Octopus 8
Crabs 5
Flounder 5
Bugs 3
Summary of all fisheries reported bycatch
Year 1999 2000 2001 2002 2003
Northern Prawn Fishery 1 883 68 113 27 27
Kimberley Prawn Fishery n/r n/r n/r n/r n/r
Southern 2 Squid Fishery n/r n/r n/r 0 30kg
Southern and Western Tuna and Billfish 3 25192 37878 60924 60116 51487
Southern and Western - Longline 4 36 38 53 n/a n/a
Southern and western Minor line and Domestic pole and purse seine n/r n/r n/r n/r n/r
Eastern Tuna and Bluefish Fishery 5 707 883 2053 2215 2658
Eastern Tuna and Bluefish Fishery: Longline 6 951 2129 2490 2757 2284
Eastern Tuna and Bluefish Fishery Minor Line 7 n/r 1 1 n/r n/a
Bass Strait Central Zone Scallop Fishery 8 n/r n/r n/r n/r 88,526
Great Australian Bight Trawl Fishery n/r n/r n/r n/r n/r

1. The only bycatch reported by this fishery is marine turtles
2. This fishery reports bycatch in kilograms rather than number of individuals
3. Only fish bycatch are reported by this fishery rather than all bycatch
4. This fishery reports only “wildlife interactions” (birds, turtles, whales, seals and sharks) rather than all bycatch
5. This fishery reports “wildlife interactions” and “no take species” only, not all bycatch. All species caught are also reported but non-target species are not disaggregated.
6. This fishery reports only “wildlife interaction” (other fish, birds, whales, turtles), not all bycatch
7. This fishery reported only 1 shark accidentally caught in 2000-2001 and 2001-2002. It is not clear whether this was the only bycatch recorded or the only bycatch considered worth reporting
8. Bycatch data available for 2003 only
n/r: Not reported
n/a: Not available for year as yet

Source: Derived from AFMA Australian Fisheries Logbook Summaries

Bycatch as a result of derelict fishing gear is dealt with under the issue of shipping pressure since it is included as marine debris lost or discarded from ships more generally. A summary of fishing debris recorded from coastal surveys in northern Australia gives some idea of the magnitude of this issue.

Summary of fishing debris recorded from coastal surveys in northern Australia
Location Total survey length/area Total amount of debris recorded
(items)
Total amount of debris recorded
(weight)
Total fishing debris
Recorded
(items)
Total fishing debris
Recorded
(weight)
Fishing items as a proportion of total Total derelict fishing nets recorded
Groote Eylandt NT 137km 1140 61 806 >812 55918 90% 812
Fog Bay NT 4km 596 n/k 107 18%
North-east Arnhem Land NT 100m >727 >100 14% 33
Cape Arnhem NT 8.25km 7561 3880 2027 1040 27% 502
Cape Arnhem NT 8.25km 21 714 1974
(excluding nets)
6255 1040 29% 590
Cape Arnhem NT 8.25km 7443 1546 n/a n/a n/a 482
Groote Eylandt NT (8 mile and Salt Lake Beaches) 4.95km 1603 n/k n/a n/a n/a 55
Groote Eylandt NT (South Point) 4.8km 2597 942 n/a n/a n/a 60
Elcho Island 3.25km 425 767 n/a n/a n/a 32

Source: Ilse Keissling 2003, Finding solutions:derelict fishing gear and other marine debris in Northern Australia, National Oceans Office.

What the data mean

With the notable exception for the Northern Prawn Fishery where turtle bycatch has been reduced dramatically since the introduction of turtle exclusion devices, most fisheries that have kept time series data on their bycatch (variously referred to as “Bycatch”, “Bi-product”, “No take species”, “Non-target catch” and “Wildlife Interactions”), show a steady increase in bycatch statistics since the late 1990s. This increase may well be due to improved recording and reporting of bycatch, rather than to an increase in actual bycatch.

Data Limitations

Until recently, bycatch data have not been collected consistently across all fisheries, and the data that have been available have not been regularly analysed by the Australian Fisheries Management Authority (AFMA).

AFMA has now made provision for collecting bycatch data in all its logbooks, but it will take time to collect sufficient data to support analysis and management decision making for bycatch.

AFMA has also introduced regulations to reduce the number of turtles killed or injured in the Northern Prawn Fishery through compulsory use of turtle excluder and bycatch reduction devices, and introduced codes of conduct and other measures to reduce seal deaths. These bycatch reduction measures and changes in fishing technology and practices should have reduced the levels of bycatch. The data do show a reduction in turtle bycatch since introduction of the excluder devices. However, in the absence of comparative data, the effectiveness of other bycatch reduction measures cannot be assessed or reported.

Not all fisheries report bycatch in their log books in a consistent manner. Additionally, a variety of different terms are used and different types of bycatch are recorded by different fisheries, some focusing on ‘wildlife’ (eg birds, cetaceans, turtles), some on protected marine fish species such as sharks, and some listing everything and anything they did not actually intend to catch.

At this stage time series data are more useful for showing improvements in recording than for showing changes in the extent of bycatch.

Issues for which this is an indicator and why

Biodiversity — Utilisation and value of biodiversity - Harvesting and trade in wildlife 

Harvesting of wild fish is the principal commercial harvesting of wild animals in Australia. The pressure of bycatch in the course of this harvesting on marine biodiversity is significant.

Other indicators for this issue:

Coasts and Oceans — Direct pressure of human activities on coasts and oceans - Pressure of fishing 

As well as affecting harvested species, commercial fishing affects a wide range of non-target animals. 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:

Biodiversity — Pressures on biodiversity - Pressures on marine biodiversity: pressures of fishing 

Non target effects of commercial fishing, such as bycatch, potentially impact on marine biodiversity. 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:

Australian Antarctic Territory — Environment - Human Pressures on the environment 

Impacts of commercial fishing in Australia’s Antarctic waters on Antarctic biodiversity include bycatch. 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:

Further Information

Source: Department of Agriculture, Fisheries and Forestry 2002, Monitoring the catch of turtles in the Northern Prawn Fishery.