The impact of commercial fisheries on the marine environment varies, with different fishing gear and fishing methods having different impacts on species that might be caught as bycatch and the habitats where fishing takes place. Methods are highly varied, and include the use of small-scale nets, pelagic longlines and large-scale trawl nets (Flood et al. 2014). Trophic structure and ecosystem productivity can be affected if target or nontarget species are removed at too high a level in the long term (Smith et al. 2011), or if habitats are degraded through commercial fishing (e.g. see Box MAR2). The variability in impacts associated with commercial fishing, the management arrangements in place and changes in these arrangements since 2011 mean that commercial fisheries, on a national basis, are assessed as having a low impact and an improving trend.
The status of the main species caught by commercial fisheries is regularly reported by the Australian Government, the states and the Northern Territory (e.g. QDAFF 2013, Grubert et al. 2013, André et al. 2015, Fletcher & Santoro 2015, NSW DPI 2015a, Patterson et al. 2015a, PIRSA 2015). In addition, the Australian Bureau of Agricultural and Resource Economics and Sciences, in conjunction with the Fisheries Research and Development Corporation, produces annual reports on commercial fisheries and aquaculture statistics, and biennial reports on the status of key Australian fish stocks across state, territory and Australian Government jurisdictions (Flood et al. 2014, Savage & Hobsbawn 2015).
Of a total of 238 identified stocks from 68 species, (Flood et al. 2014) assessed 170 stocks across state, territory and Australian Government jurisdictions, focusing predominantly on commercially fished species, but also including recreational catches, where appropriate. Of these stocks, they classified:
- 129 as sustainable
- 7 as recovering from past overfishing
- 19 as being in a state where fishing is too high (but not yet in a state of being overfished)
- 4 as being in a state where environmental processes have reduced the stock to a low point
- 11 as overfished.
Those stocks classified as overfished occurred in both Australian Government, and state and territory jurisdictions (Flood et al. 2014). The remaining 68 stocks were unable to be assigned a stock status classification, because insufficient information exists to determine stock status or information is conflicting.
In addition to target species, nearly all commercial fisheries catch species that are not the target of the fishery. These are mostly other fish or invertebrate species, but can also include species protected under the EPBC Act in threatened, migratory or marine categories, such as sea snakes, marine turtles, seabirds, sharks and marine mammals.
The EPBC Act allows interaction with listed species if they are undertaken in accordance with an accredited management plan or regime. All Australian Government–managed fisheries have been assessed and accredited under the EPBC Act, on the basis that management plans or regimes include all reasonable steps to ensure that listed species are not adversely affected by fishing operations. Sharks listed under the Act as migratory species (porbeagle, shortfin mako and longfin mako) can be kept and traded if brought up dead, if the operator is fishing in accordance with an accredited fisheries management plan. Live sharks that are listed as migratory species must be returned to the sea unharmed. All interactions (whether animals are dead or alive) must be reported. A memorandum of understanding between the Australian Fisheries Management Authority (AFMA) and the Australian Government Department of the Environment and Energy allows AFMA to report interactions with protected species in AFMA-managed commercial fisheries on behalf of fishers (Table MAR1).
Although interactions with protected species are required to be reported under state or territory legislation and the EPBC Act, information on species caught across state and territory jurisdictions is not as readily available as that for the Australian Government jurisdiction. Further, reporting is often at the species group level rather than the individual species level, and few details of individuals caught are collected. This limits the use of reporting frameworks for assessing the impacts of commercial fishing on individual species and populations (see also below). Reporting is largely based on logbook information provided by commercial fishery operators, with observations of interactions by fishery observers, in general, restricted to less than 10 per cent of all commercial fisheries (although, where interactions have been recorded, observer coverage in some commercial fisheries can be as high as 100 per cent).
Table MAR1 Number of reported interactions of AFMA-managed fisheries with species listed under the EPBC Act, 2012–15
Fishery
|
Year
|
Turtle
|
Sea snake
|
Dolphin
|
Whale
|
Fur seal/sea lion
|
Seabird
|
Sawfish
|
Shark
|
Seahorse/pipefish
|
Eastern Tuna and Billfish Fishery
|
2012
|
10
|
0
|
0
|
0
|
0
|
0
|
0
|
1683
|
0
|
2013
|
15
|
0
|
1
|
0
|
1
|
0
|
0
|
2015
|
0
|
2014
|
7
|
0
|
0
|
0
|
0
|
0
|
0
|
1125
|
0
|
2015
|
30
|
0
|
7
|
3
|
0
|
14
|
0
|
2093
|
0
|
Northern Prawn Fishery
|
2012
|
72
|
8977
|
2
|
0
|
0
|
0
|
476
|
0
|
74
|
2013
|
72
|
8150
|
2
|
0
|
0
|
0
|
507
|
0
|
140
|
2014
|
36
|
4787
|
1
|
0
|
0
|
0
|
343
|
0
|
140
|
2015
|
63
|
7527
|
0
|
0
|
0
|
7
|
307
|
0
|
140
|
Small Pelagic Fishery
|
2012
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
2013
|
0
|
0
|
0
|
0
|
0
|
1
|
0
|
0
|
0
|
2014
|
0
|
0
|
0
|
0
|
0
|
1
|
0
|
0
|
0
|
2015
|
0
|
0
|
9
|
0
|
15
|
2
|
0
|
23
|
0
|
Southern and Eastern Scalefish and Shark Fishery
|
2012
|
1
|
0
|
19
|
0
|
217
|
196
|
0
|
288
|
405
|
2013
|
0
|
0
|
9
|
0
|
259
|
94
|
0
|
157
|
0
|
2014
|
0
|
0
|
14
|
0
|
133
|
18
|
0
|
157
|
0
|
2015
|
0
|
0
|
29
|
0
|
128
|
66
|
0
|
166
|
0
|
Torres Strait Prawn Fishery
|
2012
|
0
|
242
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
2013
|
4
|
771
|
0
|
0
|
0
|
0
|
1
|
0
|
0
|
2014
|
4
|
1091
|
0
|
0
|
0
|
0
|
1
|
0
|
0
|
2015
|
3
|
669
|
0
|
0
|
0
|
0
|
1
|
0
|
0
|
Western Tuna and Billfish Fishery
|
2012
|
6
|
0
|
0
|
0
|
0
|
0
|
0
|
764
|
0
|
2013
|
2
|
0
|
0
|
0
|
0
|
0
|
0
|
325
|
0
|
2014
|
2
|
0
|
0
|
0
|
0
|
0
|
0
|
263
|
0
|
2015
|
3
|
0
|
0
|
0
|
0
|
0
|
0
|
87
|
0
|
AFMA = Australian Fisheries Management Authority; EPBC Act = Environment Protection and Biodiversity Conservation Act 1999
Note: Interactions include those with animals that are reported as alive, injured, dead or unknown. Values presented are the total of all categories across all commercial fisheries managed by the Australian Government. All interactions are reported as per reporting requirements under the EPBC Act. Interactions listed are derived from commercial fisheries logbooks and may not include all interactions listed in fishery observer logbooks. Logbook data are not routinely verified, and therefore AFMA cannot attest to the accuracy of these data or authenticate that records are complete. Values are numbers reported and do not account for variability in effort across fisheries.
Source: Protected species interaction reports, Australian Fisheries Management Authority
Total bycatch has been estimated for some commercial fisheries and jurisdictions (e.g. Kangas et al. 2007, Tuck et al. 2013), but there has been no national assessment to date, largely because reporting frameworks are not consistent across jurisdictions.
A framework for assessing the ecological impacts of fishing has been developed and applied to several Australian commercial fisheries to assess the risks to the many nontarget species taken in fisheries managed by the Australian Government (Hobday et al. 2011). However, such assessments and the estimated impacts of fisheries on bycatch species are limited by a general lack of information on bycatch species, resulting in high uncertainty in assessments. Similarly, habitat assessments have been completed for only a small number of fisheries, and these have been mostly semiquantitative. The cumulative impacts of fishing on marine habitats have not been analysed on a national scale (see Box MAR2).