Contrary to years of sustainability reports, our study indicates that excessive fishing pressure is contributing to decline of many Australian fish species.
In areas open to fishing, we found that exploited populations fell by an average of 33% between 2005 and 2015. This rate closely matches the 32% downward trend in total Australian fishery catches through the same period.
In contrast, in marine parks where fishing is prohibited, the same species increased by an average of 25%. Other species not targeted by fishers showed a small downward trend (11% decline in fished zones; 16% decline in no-take marine reserves), indicating that recent marine heatwaves off southeastern and southwestern Australia have probably adversely affected marine life over a wide area.
Our audit of 531 study sites was made possible by combining data from 50-metre long transects repeatedly surveyed by Australian Institute of Marine Science and University of Tasmania research divers, and by highly trained volunteers participating in the citizen science Reef Life Survey program.
After the collapse of some high-profile fisheries in the 1990s, such as gemfish, orange roughy and southern bluefin tuna, federal and state agencies took a more conservative approach to fish capture. Australian fisheries are now regarded as among the most sustainable worldwide.
Regardless, the prevalence of downward population trends in our investigation indicates that a reduction in fishing pressure and additional caution is needed. Otherwise, more Australian fisheries may not be economically viable if this trend continues.
Our analysis identified a variety of issues that affect fishery management practices, many of which are also evident overseas, including:
- little relevant data for decision-making related to ecological issues
- a lack of no-fishing reference areas to scientifically assess impacts of fishing
- poorly documented stock assessments with limited public accessibility
- management decisions made by committees dominated by industry-aligned members
- short-term catch maximisation prioritised over precaution
- fishery models that rarely consider species interactions or climate impacts
- wider effects of fishing on ecosystems and their resilience to multiple pressures are overlooked
No-fishing reserves work
Our study indicates that a highly effective but underused tool in the manager’s toolbox is expanded rollout of no-fishing “marine reserves”. Despite receiving wide public support, most Australian marine reserves are small and located in areas with few fishery resources. They consequently house few mature, egg-producing females and do little to assist in the rebuilding of overfished stocks. Nor are they likely to help much in the recovery of important ecosystem functions, as needed for fished-species populations to rebound after climate shocks and other pressures.
The July rollout of Australian Marine Parks, in particular, represents a lost opportunity that may prove a significant problem for fishers. Although covering 2.76 million square kilometres – the largest marine park in the world – it is of limited conservation value.
Through three rounds of public submissions, each largely aimed at minimising any remaining overlap with current fishing activities, the final zoning plans affect very few stakeholders. The outcome is neither an efficient nor effective solution to the actual problem of protecting the oceans.
For example, the Temperate East Zone covering waters from the Victorian border to southern Queensland includes no new “no-take” reserves shallower than 1,000m depth, although these waters are where virtually all fishing impacts occur in this region.
The widespread declaration of marine parks that allow current fishing to continue is perhaps useful when harmful fishing practices for ecosystems are excluded. However, our study indicates that this basic assumption does not apply to Australian Marine Parks.
The environmental and economic debt for future generations is both huge and unfair.
This article was co-authored by:
Graham Edgar - Senior Marine Ecologist, Institute for Marine and Antarctic Studies, University of Tasmania
Trevor J Ward - Adjunct professor, University of Technology Sydney
This piece originally appeared on The Conversation.
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About Graham Edgar
With leadership roles in both academia and business, Professor Edgar has influenced marine policy and management worldwide, while also forging new and innovative directions in ecology research. As a global leader in Marine Protected Area (MPA) research, his contributions to public policy have been documented in submissions to the US Congress, and a recent invitation to lead a session at the summit of Environment Ministers from OECD countries held every four years in Paris. He has also led recent efforts by an international team of experts to establish objective criteria for ‘key biodiversity areas’ in marine environments with a view to provide evidence-based recommendations to policy makers in government and industry regarding MPAs. At the University of Tasmania, Professor Edgar’s team comprises the largest marine ecological group in southern Australia with a focus on inshore habitats. Under his direction, the group plays an international leadership role in demonstrating how broad-scale data can inform marine protection policy. Professor Edgar also leads one of Australia’s most successful and longest-running citizen scientist projects, with the much lauded Reef Life Survey (RLS) now encompassing 260 volunteer SCUBA divers. The RLS has received multiple awards for its impact, and has redefined models for large-scale data collection on species populations.View Graham Edgar's full researcher profile