Abstract
Equinor commissioned the Marine Directorate of the Scottish Government to undertake a trial of the use of static commercial fishing gear within the Hywind floating offshore wind farm. This is the first known trial of its kind worldwide, and the Hywind Scotland floating wind farm was the world’s first floating wind farm, becoming operational in 2017. The aim of the ‘SeaShare’ project was to investigate the safety and viability of using static commercial fishing gear within a floating offshore wind farm. Three types of static fishing gear were trialled: fish traps, crab and prawn creels and electronic jiggers. The trial included four trips to sea on board Guard Vessel Seagull BF 74 a 30 m ex-commercial fishing vessel with considerable prior experience of working in offshore renewable sites from July to November 2022.
There has been no previous work at the Hywind site or other floating offshore wind farms to understand the risk of gear snagging in a floating offshore wind farm, so testing these areas were a main focus of the trial. Equinor identified three ‘fishing trial areas’ within the wind farm, based on a minimum distance of 200 m to the wind turbines and the dynamic sections of the export/inter-array cables, and 50 m minimum distance to the remaining subsea infrastructure. A control area was designated outside the wind farm area. These four areas were fished in rotation using all gear types in each rotation within each area.
All gear was successfully operated within the designated ‘fishing trial areas’ in the Hywind floating offshore wind farm and there were no safety issues, gear snagging or fishing gear lost. The fishing trial areas allowed adequate space to operate the vessel and static fishing gear and were deemed to be safe distances away from the turbines for the vessel and fishing gear in this trial. The commercial viability of these fishing methods was not within the scope of the project. Static fishing was not a prominent fishery in the area prior to the wind farm construction and therefore the catch rates are not representative of a static fishery.
In addition to testing the safety of deploying and hauling static fishing gear in a floating offshore wind farm, catch composition and rates and species biodiversity at the wind farm were also recorded. The most prominent species caught in the trial were Haddock (Melanogrammus aeglefinus), Brown crab (Cancer pagurus) and Mackerel (Scomber scombrus). No Prawns (Nephrops norvegicus) were caught using the prawn creels due to apparent lack of suitable Prawn habitat in the Hywind site. Fish and shellfish species caught were largely limited to the targeted commercial fish and shellfish species due to the selectivity of the gear and bait used, and by-catch of other species was minimal. A smaller mesh fish trap was also used to target any other species of interest. There was an increase in Brown crab numbers caught between August and October which was expected based on the species’ seasonal behaviour patterns.
This trial has demonstrated that under the right sea and weather conditions, it is possible to fish safely within the Hywind floating offshore wind farm with the static fishing gear tested, within the safety distances to the infrastructure that were used for 3 these trials, and adherence to standard maritime safety and navigation rules of the sea.
It is hoped that this trial can be replicated in other operational floating offshore wind farms across the world and that the knowledge and experience gained from this trial can help to inform future studies.
This fishing trial will play a major role in helping to understand what types of commercial fishing may be compatible with floating offshore wind and help to facilitate coexistence between the two sectors. The knowledge gained from the trials will also be available to help inform wind farm design, configuration and turbine spacing, and in marine spatial planning for future floating offshore wind farm development.