MARELITT

PILOT PROJECT: REMOVAL OF MARINE LITTER FROM EUROPE'S FOUR REGIONAL SEAS

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Toolkit: Derelict Fishing Gear Retrieval, Implementing your project, Selection of locations

See also: Timing of retrieval operations | Technical parameters for the vessels | Involving fishermen in retrieval | Involving divers in retrieval | Reception of DFG at the port | Recycling and disposal | Monitoring DFG | Development of prevention and mitigation measures | Raising awareness of the causes and impact of DFG | Project communication

As only small areas of fishing grounds can be covered in retrieval projects, the identification and subsequent selection of the most appropriate areas to retrieve lost and discarded nets is vital to making your retrieval activities efficient and effective. Prioritisation of areas is also crucial to enhance the environmental impact of the retrieval operations.

Identification:A three-step approach can be followed to identify areas where lost and discarded nets have accumulated:

  1. As a first step, desk research can provide basic information on DFG in the open seas. Relevant information relates to the location of areas with high potential loss rate (the vicinity of busy shipping lanes, potential gear conflicts between different fisheries, the existence of bad weather conditions, risky seabed topography etc.). Information relating to fishing effort is also relevant to identify locations and to tailor the retrieval equipment, more in particular information on types of fishing gear used (i.e. some types are easier lost than others); areas where certain types of fishing gear are used; which types of gear are used in which loss sensitive areas. To assess both historical and present spatial distribution of the fishing effort regarding various fleet segments (e.g. bottom rigged gillnets, demersal trawlers) standard logbook data can be used. By analysing the distribution data, a map with geographical sites that are potentially DFG accumulation sites can be identified. Desk research can also provide basic information on wrecks (e.g. existing inventories of shipwrecks).
  2. As a second step, the basic information can subsequently be combined with detailed information from consultation with fishermen (and possibly divers) which are active in the identified areas of interest. Discussions with the fisherman can provide valuable information on what they have come across during their fishing trips and can lead to the identifications of hot spots or locations with incidental net loss. In certain areas – such as shallow areas relatively close to the coast - it can also be useful to involve recreational fisherman. It can also be agreed with fisherman that they shall report to your organisation when they see lost or abandoned gear at sea or lose fishing gear themselves and cannot retrieve it.
  3. A last possible, but costly, step could be to verify and complement the information gathered, using underwater inspection equipment (such as ROV robots and side-scan sonars).

WWF Poland created an open web-based interactive database of obstacles present on the sea bottom in three languages, where all sea users can report information on the location of underwater obstacles that may cause gear losses. A similar web based tool could be developed for your country.

Prioritisation: Once DFG has been located, the locations from which DFG will be retrieved should be prioritised. It is best to document this selection process, including the criteria that you use. Selection criteria could include:

  • Environmental impact: The impact of the DFG retrieval operation on the environment must be considered and weighed against the environmental impact of DFG if not removed. Grappling can damage marine habitats, can impact soft bottom habitats and damage or kill bottom dwelling organisms. If damage to the environment from the retrieval operation would exceed the damage caused by the gear, it is more appropriate to leave the gear in place or to disable the gear, instead of retrieving it. Disabling the gear would reduce the catching efficiency of the gear and as such reduce one of the environmental impacts of the gear, i.e. ghost fishing. The environmental impact of DFG, and therefore the benefits of retrieval, depends on issues as gear type, the condition of the gear, the nature of the local environment (currents, depth and location), the presence of sensitive habitats and the timing of the retrieval operation. A marine biologist could be consulted on the presence of habitats of special concern in the retrieval area and in respect to the optimal timing of activities. Retrieval in areas with sensitive habitats or during spawning periods should in principle be avoided. One aspect to consider is that the catching efficiency of DFG decreases rapidly at first, and continues to decrease at a slower rate over time. If the removal of a high priority DFG is deemed necessary and some negative habitat impacts are anticipated, a habitat restoration plan may have to be included in the DFG retrieval plan.
  • Health and safety risks: Risk, such as entanglement for swimmers, will be reduced if DFG is retrieved. 
  • Cost-efficiency: While the benefits of DFG retrieval are difficult to quantify, when considering the cost-efficiency of retrieval operations, the costs of retrieving DFG from a given location should be compared to the estimated benefits. Where the benefits cannot be quantified at all, prioritisation will therefore have to be done based on a qualitative understanding of the benefits, which may also differ between locations. 
  • Effectiveness: The level of concentration of DFG at a single location will determine what amounts can be retrieved with a single retrieval operation. The higher the amounts, the more effective the retrieval operation will be. An element to consider here is that retrieval projects may be less necessary in areas of high trawl activity, where nets are picked up over time, provided that these nets are landed.