Results of the flyshoot fishery sampling programme 2021-2023

Wageningen Marine Research report C071/23 | 5 of 66 Summary The rationale for the project ‘VISwijzer en flyshootvis’ (FISHguide and flyshoot fish) stems from the increasing demand for transparency regarding the production and origin of food. Despite the general impression that fish stocks in the North Sea are doing well, certain fish species in the North Sea and the English Channel currently do not qualify for favourable ratings on the ‘VISwijzer’ and/or MSC certification. This pertains, among others, to commercially less attractive fish species in the Netherlands, such as gurnard, cuttlefish, and red mullet. There is insufficient data on fish stocks and fishing pressure for these data-deficient species, making it currently impossible to assert the sustainability of fisheries on these species. The project was set up as an initiative from the fisheries industry (Jaczon-Vrolijk), to partner with the Good Fish Foundation and Wageningen Marine Research. The primary objective of the partnership project was to pave the way for improved data collection in flyshoot fishing. The second objective was to adapt the VISwijzer method to make it more suitable for assessing mixed fisheries. The third objective is the dissemination of project results and the knowledge gained about flyshoot fishing. This report focuses mainly on the results of the first objective. A total of fifteen observer trips were conducted. During these trips, which took place on board three different vessels from Jaczon-Vrolijk, discard samples were collected and sorted, the total catch was estimated, the presence of ETP (Endangered, Threatened, or Protected) species was recorded, and the length distribution of selected species in the marketable catch was determined. This data was used to study the catch composition and efficiency of the Dutch flyshoot fishery, calculate the mean length-at- catch and identify the risk of catching ETP species. The majority of the sampled hauls were in the eastern Channel. Additionally, sampling was conducted in the southern North Sea, as well as a small number of hauls in the central North Sea. In the winter months effort was concentrated in the Eastern Channel. In quarters 2 and 3, effort shifted to the southern North Sea. Landings clearly display a seasonal pattern, with squid being the dominant catch in winter months, and mackerel in summer. Discards were almost entirely composed of fish, with few benthos, invertebrates and debris being caught. The most dominant species in the discards included whiting, herring, dab, bib, horse mackerel, mackerel, as well as sharks. Both landings and discards vary throughout the seasons. Several species had a ratio between length-at-catch and maximum length that was above the 2/3 limit set by the GoodFish Foundation, namely red gurnard (69%), mackerel (77%), and herring (90%). For tub gurnard (57%), red mullet (65%), whiting (60%), and horse mackerel (52%) mean length-at-catch/L inf was below the 2/3 limit. In total, three ETP species were reported as incidental bycatch: twait shad, seahorse and small-spotted catshark. Discard ratios were found to be highly variable between hauls, trips, quarters and areas. Overall discard percentages were found to be between 45.49 and 50.04%. The protocol developed in this project was evaluated positively, though certain lessons learned during the sampling period should be taken into account when sampling in the Dutch flyshoot fishery. Total catch was estimated using the volume in the hopper, and even though this method proved workable, it did pose several problems. Firstly, this method sometimes resulted in negative discards weights. Also, in case of small catches, the hopper could be split into smaller compartments to more accurately read the height of the catch, however, this was often impractical. Alternatives to the hopper-volume method are considered. Another issue in the protocol was encountered in the length measurements of the landings. In the protocol the length of the most common species in each haul was sampled. However, this posed problems for the data analysis. The lack in spatial coverage in the presented project is probably mainly caused by the fact that very few trips were sampled in summer. To improve the coverage of future sampling programmes, (observer) trips should also be carried out in other areas, such as the central and northern North Sea. It should also be noted that sampling took place on board three vessels of the same shipping company, and to fully understand the fishing practices, sampling should be extended to other vessels in the Dutch fleet. 6 of 66 | Wageningen Marine Research report C071/23 The results of this project can be used to inform science and policy, especially on data deficient target species of the flyshoot fishery. The data has already been used in a sustainability assessment by the GoodFish Foundation, and the project is a good example of how cooperation between the scientific community, industry, and NGOs can increase data availability and transparency in a fishery.