Derelict fishing nets comprise a significant amount of the marine debris in the world's oceans and on its shorelines. These ‘ghost nets’ result in economic losses for the fishing industry, pose hazards to navigation at sea, and can entangle marine and terrestrial wildlife. Ghost nets are an acute problem along Australia's northern coastline, with most nets originating from Southeast Asian fishing vessels outside Australia's Exclusive Economic Zone (EEZ). To understand the causes of gear loss and identify tractable solutions to this transboundary problem, Australian and Indonesian fishers (N = 54) were asked why, when and in what circumstances and conditions they are likely to lose gear. Fishers identified snagging of nets (78%) and gear conflicts (19%) as the main causes of gear loss. These interviews informed the development of a fault tree, as a tool to identify the chain of events that result in gear loss or abandonment. The fault tree analysis provides recommendations for interventions and improvements in regional fisheries management to reduce fishing gear loss ultimately resulting from overcrowding, overcapacity and illegal, unreported and unregulated Fishing (IUU).
Derelict Fishing Gear and Ghost Fishing
In May 2016, the World Animal Protection appointed fisheries consultants Poseidon Aquatic Resource Management Ltd (Poseidon) of the UK to undertake a series of work packages. The objective was to support the GGGI’ s ‘Define best practices and inform policies’ working group in developing best practice guidance on the management of fishing gear.
The first output was a brief scoping study to provide:
I. a working quantification of the main fishing gears used on a global basis
II. a brief summary of the main characteristics of these gears regarding user type, geographical usage and contribution to ALDFG.
This first part of the work was submitted to World Animal Protection on 16 May 2016.
The second output was the identification of management options and mechanisms for responsible fishing gear use. It was also to include recommendations on how this could be developed into a best practice framework for managing fishing gear.
This second activity examined two main elements. First, it looked at the current management options for fishing gear. This included the use of tags and other identification of fishing gear, gear marking, gear storage to and from fishing grounds and gear retrieval in case of loss or temporary abandonment. It then examined how these are implemented – for example through legislation, codes of conduct or inclusion in third party and other certification schemes. This part of the study was the basis for the framework (see next) and has been issued as a standalone document, entitled ‘Part 1: Overview and Current Status’.
The purpose of this third and final output of the study was to develop a ‘best practice’ framework for the management of fishing gear. Its scope is defined in Part 1 of document, is global in nature, and covers a wide range of fishing gears and users.
As a framework, it focuses on the most commonly used gear types, both in industrial and artisanal fisheries. The framework is relevant to a broad spectrum of stakeholders. These include gear manufacturers, fishers, port authorities, fisheries management authorities, seafood companies and other interested parties.
This framework will be adopted by the GGGI, developed further and targeted at specific stakeholders.
Large whales are frequently entangled in fishing gear and sometimes swim while carrying gear for days to years. Entangled whales are subject to additional drag forces requiring increased thrust power and energy expenditure over time. To classify entanglement cases and aid potential disentanglement efforts, it is useful to know how long an entangled whale might survive, given the unique configurations of the gear they are towing. This study establishes an approach to predict drag forces on fishing gear that entangles whales, and applies this method to ten North Atlantic right whale cases to estimate the resulting increase in energy expenditure and the critical entanglement duration that could lead to death. Estimated gear drag ranged 11–275 N. Most entanglements were resolved before critical entanglement durations (mean ± SD 216 ± 260 days) were reached. These estimates can assist real-time development of disentanglement action plans and U.S. Federal Serious Injury assessments required for protected species.
Northeast coral gardens provide vital breeding and feeding habitats for fishes of conservation and commercial importance. Such habitats are increasingly at risk of destruction as a result of over fishing, ocean warming, acidification and marine litter.
A key cause for concern regarding the vulnerability of coral gardens to damage from any source is their slow growth rate, and thereby their ability to recover from damage. Hence protected areas are being put in place, which exclude the use of towed demersal fishing gear.
Citizen scientists observed that gorgonian coral (Pink Sea Fans) skeletons were stranding on beaches entangled in marine debris (sea fangles) across southwest England. Further, SCUBA divers reported that gorgonian corals were being caught up and damaged in lost fishing gear and other marine litter.
To determine the cause of the damage to coral gardens, sea fangles were collected and analysed.
The sea fangles were made up of a diverse range of litter from fishing and domestic sources, however, the majority comprised of fishing gear (P < 0.05).
Marine Protected Areas can protect coral gardens from direct fishing pressure, but risks still remain from ghost fishing pressure, demonstrating the need for sources of litter into the environment to be reduced and existing litter removed.
The EU Marine Strategy Framework Directive (MSFD) outlines targets for marine litter by 2020. This study highlights the importance of adhering to the MSFD and/or creating more ambitious regulation if the UK re-write existing legislation following BREXIT.
Fishing is the major human activity within the ‘semi-enclosed’ Arafura and Timor Seas (ATS). Since the early 2000’s, Australia’s sparsely populated, remote northern shores have reported very high levels of foreign, fishing-related marine debris. Limited information is available about the temporal and spatial variation of this fishing debris or its origin. We examine trends in derelict fishing nets (and marine debris) at multiple sites in the Northern Territory and Gulf of Carpentaria and, explore its potential origin and relationship with fishing activity in the region. Further, we investigate temporal trends in domestic and foreign fishing activity (legal and illegal) in the ATS and also foreign fishing vessel sightings in the northern waters of the Australian Exclusive Economic Zone (AEEZ). Our results confirm that foreign fishing debris (nets, rope and gear) is the major source of marine debris (63%) on Australia’s northern shores. Over the period 2003–2008, a total of 2305 derelict fishing nets were washed ashore; of these, 89% were identified of foreign origin (i.e. manufacture), compared to 11% attributed to Australian fishing vessels or fisheries. Industrial foreign and Indonesian-flagged fisheries – particularly, illegal, unreported and unregulated (IUU) trawling activity – and small-scale Indonesian IUU fisheries (primarily targeting shark) in the Arafura Sea are likely the major sources of these nets. Derelict nets comprised mostly trawl nets (71%) and gillnets/drift nets (12%); with 95% of all identified net sourced from the nations of Taiwan, Indonesia, Thailand and Korea. Our data also supports consistent under-reporting by these foreign trawl operators in the Indonesian Exclusive Economic Zone (IEEZ) of the ATS.
The arrival and increase in derelict nets in northern Australia post-2000 coincided with sharp increases in both industrial foreign fishing (illegal, legal) and Indonesian small-scale fisheries within the IEEZ waters of the ATS. Including, over the period 2000–2007, a 2-fold increase in ‘non-motorised’ vessels, and a 5-fold increase in the number of motorised vessels, particularly in vessels less than 5GT. Further, this major increase in fishing activity in the IEEZ corresponded to a 3-fold increase in foreign fishing vessels (FFVs) (legal, illegal) sightings in northern Australian waters. Within the AEEZ, derelict net loads and sightings of illegal FFVs, both peaked and reached a maximum in 2005 (188 kg km−1yr; 6956 vessels) and then sharply reduced (>80%) following major border control, surveillance and security operations in the northern Australia in 2005–2006. However, post-2007, illegal FFV sightings inside the AEEZ have increased again. Significantly, derelict nets and small-scale IUU fishing activity in the AEEZ is linked to a broader pattern of poverty, overfishing and displacement of small scale fishers in coastal fisheries in the Arafura Sea (and South East Asia), due primarily to the expansion of industrial (illegal, legal) trawl fisheries. Strengthening of regional fisheries management (particularly under the RPOA-IUU) is urgently required to tackle IUU fishing, the key source of fishing debris in the ATS. While fisheries capacity reduction is a critical priority, it needs to be supported by a regional multi-sectoral response framed within the context of food security and rural economic development.
Ghost gear – abandoned, lost, or otherwise discarded fishing gear – has been recognised as a global environmental challenge since the mid-1980s, and yet little social science attention has fallen on the phenomenon. This paper explores how the burden of global fisheries, materialised through its gear, is experienced and managed. How is ghost gear encountered? How is it understood? What influence does it have, and what responses does it provoke? To consider these questions, the paper begins with detailing of an encounter with ghost gear and Aboriginal rangers on the eastern coast of the Gulf of Carpentaria, northern Australia. Understanding encounters as tangles of interlaced threads, rather than isolated intimacies, the paper also follows ghost gear beyond the experience of beach clean-up. How ghost gear journeys to this beach, and the mobilities and meetings that occur during its travels is explored, as well as the policy responses to ghost gear that figure it primarily as marine debris to be managed through territorial control as isolated ‘waste’. These more-than-human stories offer insights into the distributed agencies, complex relations, and differential responsibilities involved in the phenomenon of ghost gear, and efforts to deal with it as part of land-sea assemblies.
Groupers are highly targeted and vulnerable reef fishes. The effects of fishing pressure on the density of three reef fishes were investigated in 21 islands outside (n=15) and inside (n=6) a Marine Protected Area (MPA) at the Paraty Bay, Brazilian southeastern coast. Two valued groupers (Epinephelus marginatus and Mycteroperca acutirostris) and a non-target grunt (Haemulon aurolineatum) were studied. The total biomass of fish caught in each island was considered as a measure of current fishing pressure, while the island distance from the villages was considered as a measure of past fishing pressure. Fish densities were recordedin number and biomass. The biomass of M. acutirostris was inversely related to current fishing pressure, which did not affect the other two fishes. The density of E. marginatus increased with the island distance from one of the fishing villages, which indicated that past fishing may have had decreased the abundance of E. marginatus. Densities of the three fishes and fishing pressure did not differ between islands inside and outside the MPA. Data on fishing pressure, densities of groupers and coral cover were combined here to assign conservation scores to islands. A redefinition of MPA boundaries to reconcile fish conservation, fishing activities and fishers’ food security was proposed.
Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US $21.3 million—a 27% increase above that which would have occurred without removals. Model results are extended to a global analysis where it is seen that US $831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use.
The impacts of human activities on cryptic marine species can be difficult to assess. The North Atlantic right whale is an endangered species numbering just over 500 individuals. Entanglement in fishing gear is one documented source of injury and mortality, but population-level effects have been difficult to quantify. We used documented entanglements, long-term population studies and mark-recapture statistical techniques to evaluate the effect of these events on North Atlantic right whale survival. Estimates were based on 50 individuals observed carrying entangling gear between 1995 and 2008, and compared to 459 others that were never observed with gear during the same period. Entangled adults had low initial apparent survival (0.749, 95% CI: 0.601–0.855), but those that survived the first year achieved a survival rate (0.952, 95% CI: 0.907–0.977) that was more comparable to unaffected adult females (0.961, 95% CI: 0.941–0.974) and males (0.986, 95% CI: 0.975–0.993). Juveniles had a post-entanglement survival rate that was comparable to the initial survival of entangled adults (0.733, 95% CI: 0.532–0.869) and lower than un-impacted juveniles (0.978, 95% CI: 0.969–0.985). Of three entanglement characteristics examined, health impacts were most predictive of subsequent survival, but the entanglement configuration and the resulting injuries also appeared to affect outcome. When the entanglement configuration was assessed as high risk, human intervention (disentanglement) improved the survival outcome. This is the first mark–recapture estimate of entanglement survival for any whale species. The results indicate the need for continued mitigation efforts for this species, as well as for a better understanding of entanglement impacts in other baleen whale populations.
Abandoned, lost and discarded fishing gear (ALDFG) can pose substantial ecological and socioeconomic problems. Over the past decade there has been increasing international recognition of the need for multilateral efforts to address transboundary problems resulting from ALDFG, including ghost fishing. To benchmark the status of international monitoring and mitigation of ALDFG and ghost fishing, an assessment was made of data collection protocols and management measures to prevent and remediate ALDFG and ghost fishing by 19 global and regional bodies and arrangements with the competence to establish binding controls for marine capture fisheries. Four organizations were explicitly mandated by their convention or agreement text to monitor and control ALDFG and ghost fishing. Modifying mandates of the other organizations might augment members' political will to monitor, prevent and remediate ALDFG and ghost fishing. Ten organizations collected logbook or observer data on ALDFG. Harmonizing data collection protocols where they are in place, and filling gaps where they are lacking, would improve regional monitoring of ALDFG. Twelve organizations have adopted binding measures that contribute to avoiding or remediating ALDFG. The organizations, however, make use of a small subset of available tools: Only half of 18 categories of methods identified as having the potential to prevent and remediate ALDFG and ghost fishing were used by the organizations. Organizations lacking relevant binding measures could begin to fill this gap and organizations can tap a broader suite of complimentary management methods.