Spatiotemporal and multispecies comparisons between a citizen science platform and recall surveys in recreational fisheries

Smartphone applications for anglers that function as citizen science platforms are an alternative to the traditional survey methods that are used to collect data from recreational fisheries. Comparisons between these two methods are needed to understand the impacts of the biases associated with data generated from smartphone applications. However, such comparisons are uncommon, especially for multiple fisheries over time and across space. In this study, we compared catch and effort data from an electronic citizen science platform for anglers with an offsite web-based recall survey for consecutive (i) 3-month periods in a spatially distinct (i.e., the Danish island of Funen) sea trout (Salmo trutta) fishery (2017–2020), (ii) 6-month periods in coastal sea trout and coastal/offshore cod (Gadus morhua) fisheries across eight ICES management areas (2016–2020), and (iii) 6-month periods in a freshwater pike (Esox lucius) fishery (2016–2020). Catch and effort data from the two surveys were, in most cases, consistently similar over time for the Funen sea trout and Danish freshwater pike fisheries. In contrast, we found that the recall survey estimates were consistently 100–200% larger than the citizen science platform for both sea trout and cod in ICES areas. Our findings suggest that the applicability of electronic citizen science platforms for anglers can be fishery-specific, and that systematic bias may occur

Integrating complementary survey methods to estimate catches in Norway’s complex marine recreational hook-and-line fishery

Marine recreational fishing is popular in Norway, but current estimates of the catches by resident and tourist anglers are lacking due to several challenges, in particular Norway’s long and intricate coastline with no defined access points and the large tourist fishery. To test methods for long-term monitoring of boat-based marine recreational anglers, estimate their catches, and characterize the fishery, we conducted a roving creel survey based on a novel spatial sampling frame and a survey of tourist fishing businesses in Troms and Hordaland County. These surveys showed that cod (Gadus morhua) and saithe (Pollachius virens) dominated the catches in Troms, while mackerel (Scomber scombrus) and saithe dominated the catches in Hordaland. The estimated total annual harvest of cod by all marine recreational anglers was 2 160 tonnes (relative standard error, or RSE 44%) in Troms and 73 tonnes (RSE 29%) in Hordaland, of which ∼40% (in weight) were landed in registered tourist fishing businesses, based on data from the tourist fishing survey. The results indicate that recreational anglers in Hordaland harvest more cod in coastal waters than commercial fishers. This study provides information for developing marine recreational fisheries monitoring in challenging survey situations to support science-based fisheries management.publishedVersio

Recreational sea fishing in Europe in a global contextParticipation rates, fishing effort, expenditure, and implications for monitoring and assessment

Marine recreational fishing (MRF) is a high-participation activity with large economic value and social benefits globally, and it impacts on some fish stocks. Although reporting MRF catches is a European Union legislative requirement, estimates are only available for some countries. Here, data on numbers of fishers, participation rates, days fished, expenditures, and catches of two widely targeted species were synthesized to provide European estimates of MRF and placed in the global context. Uncertainty assessment was not possible due to incomplete knowledge of error distributions; instead, a semi-quantitative bias assessment was made. There were an estimated 8.7 million European recreational sea fishers corresponding to a participation rate of 1.6%. An estimated 77.6 million days were fished, and expenditure was Euro5.9 billion annually. There were higher participation, numbers of fishers, days fished and expenditure in the Atlantic than the Mediterranean, but the Mediterranean estimates were generally less robust. Comparisons with other regions showed that European MRF participation rates and expenditure were in the mid-range, with higher participation in Oceania and the United States, higher expenditure in the United States, and lower participation and expenditure in South America and Africa. For both northern European sea bass (Dicentrarchus labrax, Moronidae) and western Baltic cod (Gadus morhua, Gadidae) stocks, MRF represented 27% of the total removals. This study highlights the importance of MRF and the need for bespoke, regular and statistically sound data collection to underpin European fisheries management. Solutions are proposed for future MRF data collection in Europe and other regions to support sustainable fisheries management.Institut Francais de Recherche pour l'Exploitation de la Mer; French Ministry of Fisheries Management; Greek National Data Collection Programme; European Commission, Data Collection Framework; Department for Environment, Food and Rural Affairs [MF1221, MF1230, MI001]; Norges Forskningsrad [267808]; State Department of Agriculture, Food Security and Fisheries Mecklenburg-Western Pomerania; Interreg IVa 2 Seas; Dutch Ministry of Economic Affairs; European Fishery Fund; Government of Galicia [ED481B2014/034-0

Evaluation of a citizen science platform for collecting fisheries data from coastal sea trout anglers

There are often limited data available to support the sustainable management of recreational fisheries. Electronic citizen science platforms (e.g., smartphone applications) offer a cost-effective alternative to traditional survey methods — but these data must be validated. We compared sea trout (Salmo trutta) data from a Danish citizen science platform with three independent traditional surveys: a roving creel survey, an aerial survey, and a recall survey. The comparisons include fisheries data (e.g., catch, release, effort, and fish size structure) and demographic descriptors (e.g., age) that were collected within the same spatial and temporal frame. We found general alignment between recreational sea trout catch and effort data that were provided by citizen scientists, or collected by more traditional survey methods. Our results demonstrate that citizen science data have the potential to supplement traditional surveys, or act as an alternative source of catch and effort data. However, results were from a highly specialized fishery within a limited spatial and temporal frame, so more research is needed to assess their relevance over time and to a broader set of fisheries

Field surveying of marine recreational fisheries in Norway using a novel spatial sampling frame reveals striking under-coverage of alternative sampling frames

publishedVersio

Field surveying of marine recreational fisheries in Norway using a novel spatial sampling frame reveals striking under-coverage of alternative sampling frames

Norway has the highest participation rate in marine recreational fisheries (MRF) in Europe, and is popular among marine tourist anglers. Fishing licences are not required for marine recreational anglers, and the complex and long coastline makes on-site surveys a challenge. A novel approach for spatial sampling was developed and tested in on-site surveys, as part of a National study of MRF using multiple sampling frames including a telephone screening survey based on the national telephone directory. Field surveys were conducted in Troms and Hordaland Counties, and in the Oslofjord. We created spatial sampling frames of modified Voronoi polygons with continuous sea-surface area, with clusters of polygons as primary sampling units (PSUs). Interviews of intercepted anglers were obtained quarterly from a stratified sample of PSUs searched by boat. Many anglers interviewed in Troms (63%) and Hordaland (53%) were non-residents, of which 92 and 66% stayed in registered tourist fishing camps, respectively. Most anglers in the Oslofjord were residents, and in the inner Oslofjord, 63% of the resident anglers interviewed on-site were born outside Norway, which was not reflected in the telephone survey. Thus, if only off-site methods were used to map Norwegian MRF, this could lead to biased results in some regions