Bycatch—the unintentional capture of non-target species—is one of commercial fishing’s most persistent environmental problems. Globally, millions of seabirds, sea turtles, dolphins, and non-target fish die in fishing gear annually. Australia’s fisheries are generally better managed than global averages, but bycatch remains an issue. Several technologies are proving effective at reducing it without destroying fishery profitability.

Turtle Excluder Devices in Trawl Nets

Turtle Excluder Devices (TEDs) are mandatory in Australia’s prawn trawl fisheries. These are grid or trapdoor systems installed in trawl nets that let turtles and large fish escape while retaining prawns and target species.

TEDs work remarkably well. Studies in the Northern Prawn Fishery show TED use reduces turtle bycatch by over 95% without significantly affecting prawn catch. The technology is mature, proven, and widely accepted by industry.

The challenge isn’t proving TEDs work—it’s ensuring compliance. Illegal removal or modification of TEDs still occurs when enforcement is weak. Electronic monitoring (cameras on vessels) helps by creating verifiable records of TED use and bycatch rates.

Circle Hooks and Tori Lines for Seabird Protection

Longline fisheries catch seabirds when birds dive for baited hooks as lines are set. Seabirds get hooked and drown. Albatross and petrels—long-lived species with low reproductive rates—are particularly vulnerable.

Circle hooks (hooks with the point curved inward) reduce seabird bycatch compared to traditional J-hooks. Combined with tori lines (bird-scaring lines dragged behind the boat during setting), seabird bycatch drops dramatically.

Australia’s Southern and Eastern Scalefish and Shark Fishery has mandated these measures since the early 2000s. Seabird bycatch in that fishery has declined by over 85%. The Agreement on the Conservation of Albatrosses and Petrels credits Australia’s seabird bycatch mitigation as among the world’s most effective.

The technology is cheap—circle hooks cost similar to J-hooks, and tori lines are simple to construct. The main barrier is convincing fishers the measures don’t reduce catch rates of target species (they don’t, or reduce them only marginally).

Smart Drumlines for Shark Management

Traditional shark control programs in Australia used drumlines—baited hooks left overnight to catch sharks. These kill target sharks but also catch non-target species including dolphins, turtles, and rays.

SMART (Shark Management Alert in Real Time) drumlines address this. When a shark is hooked, the drumline sends an alert to operators who respond quickly, identify the animal, and either relocate target sharks or release non-target species alive.

New South Wales has replaced traditional drumlines with SMART drumlines at many beaches. Bycatch mortality has dropped significantly because animals aren’t left hooked for hours. Non-target species survival rates exceed 90% when released quickly.

The limitation is cost—SMART drumlines require active monitoring and rapid response teams. But for areas with high beach use and public opposition to shark culls, the reduced bycatch mortality justifies the expense.

LED Lights to Reduce Turtle Bycatch in Gillnets

Research has shown that attaching LED lights to gillnets reduces sea turtle bycatch by making nets more visible. Turtles can see the lights and avoid the nets. Initial trials showed 40-60% reduction in turtle bycatch without affecting target fish catch.

This technology is newer and not yet widely adopted in Australian fisheries, but trials are ongoing in Queensland gillnet fisheries. The challenge is battery life and light durability in marine environments. Current LED systems need battery replacement every few weeks, which is labour-intensive for gillnets that might be set for days at a time.

Researchers are working on solar-powered versions and lights activated by water contact (to conserve battery when nets are stored). If these technical challenges are solved, LED lights could become a standard bycatch reduction tool.

Acoustic Pingers for Dolphin and Porpoise Bycatch

Acoustic pingers emit high-frequency sounds that warn dolphins and porpoises away from gillnets. These work well for small cetaceans in many fisheries.

Australia’s gillnet fisheries in southern waters have used pingers for years. Studies show 50-70% reduction in dolphin bycatch when pingers are used correctly. The technology is proven.

The problems are practical. Pingers need regular battery replacement. Fishers sometimes don’t use them consistently (they’re an operational hassle). And some studies suggest dolphins habituate to pinger sounds over time, reducing effectiveness.

Compliance and maintenance are bigger issues than technological effectiveness. Combining pingers with electronic monitoring to verify use improves compliance significantly.

Bycatch Reduction Devices (BRDs) in Trawl Nets

Beyond TEDs for turtles, various Bycatch Reduction Devices reduce capture of non-target fish and invertebrates in trawl nets. These include square mesh panels (which allow small fish to escape), fisheyes (openings that let fish swim out), and excluder grids for specific species.

Australian prawn trawl fisheries use multiple BRDs to reduce bycatch of small fish, juvenile snapper, and rays. Combined use of TEDs and BRDs has reduced total bycatch (all species) by 30-50% in some fisheries while maintaining prawn catch.

The effectiveness varies by location, target species, and gear configuration. BRDs need to be tailored to specific fisheries. A device that works in northern prawn trawls might not work in southern scallop dredges. This requires ongoing research and adaptation.

Camera-Based Electronic Monitoring

Electronic monitoring (EM)—cameras on fishing vessels recording fishing operations—doesn’t directly reduce bycatch, but it enables accurate measurement and enforcement of bycatch rules. Knowing that all bycatch is recorded changes behaviour.

Australia is expanding EM across multiple fisheries. Fishers who know every interaction is recorded are more likely to use bycatch reduction devices properly and handle bycatch carefully to maximize survival of released animals.

EM also provides data for assessing bycatch reduction technology effectiveness. Without good data on bycatch rates, you can’t tell if new technologies actually work. Cameras provide that data far more completely than logbooks or observer programs.

The Economic Reality

All these technologies add costs—equipment, maintenance, labour, reduced efficiency. Fisheries adopt them when regulations require it or when market pressure (certifications like MSC) demands it.

The key to successful adoption is showing that bycatch reduction doesn’t kill profitability. TEDs proved this—after initial resistance, prawn fishers accepted them because catch rates didn’t decline significantly. Technologies that maintain catch while reducing bycatch get adopted. Technologies that reduce catch get resisted.

Government subsidies for equipment, research into low-impact gear design, and gradual phase-in periods help. Punitive regulation without support just creates illegal fishing and non-compliance.

What Comes Next

Artificial intelligence for real-time species identification in nets could allow selective release while still fishing. Machine learning models that predict bycatch hotspots could help fishers avoid high-risk areas. Improved gear materials and designs continue to evolve.

The technology exists to dramatically reduce bycatch in most Australian fisheries. The barriers are economic, compliance, and political will. When regulations mandate bycatch reduction and provide reasonable transition support, fisheries adapt. When regulations are absent or unenforced, bycatch continues.

Supporting well-managed fisheries that use proven bycatch reduction technology matters. Choose seafood with MSC certification or other credible sustainability labels. These certifications require demonstrated bycatch reduction. Market demand for sustainable seafood funds the ongoing development and adoption of better fishing technology.

Australian fisheries have made genuine progress on bycatch reduction. Turtle, seabird, and dolphin mortality in Australian waters is far below historical levels. But ongoing vigilance, research, and enforcement are needed to maintain that progress and address remaining bycatch challenges. Technology provides the tools—policy and market pressure provide the motivation to use them.