Behavioural economics in fisheries: A systematic review protocol.

BACKGROUND: The field of behavioural economics holds several opportunities for integrated fisheries management and conservation and can help researchers and managers alike understand fisher behaviour and decision-making. As the study of the cognitive biases that influence decision-making processes, behavioural economics differentiates itself from the classical field of economics in that it does not assume strictly rational behaviour of its agents, but rather looks for all mechanisms that influence behaviour. This field offers potential applications for fisheries management, for example in relation to behavioural change, but such applications require evidence of these mechanisms applied in a fisheries context. Thus, we have developed a systematic literature review protocol focusing on the primary question: "Which behavioural economics mechanisms influence fisher behaviour?" The aim is to provide a comprehensive overview of these different mechanisms and how they have been applied in the study of fisher behaviour. METHODS AND EXPECTED OUTPUTS: The review protocol was developed in close collaboration with the International Council for the Exploration of the Sea (ICES) Working Group on Maritime Systems (WGMARS). WGMARS members were therefore considered the key stakeholders for this study, and were consulted to develop a suitable systematic review question and methodology. Three academic databases will be searched using a customized Boolean keyword search string. Research articles deemed eligible for inclusion in the systematic review are those that studied the influence of behavioural-economics mechanisms on the behaviour of marine fishers in any location, and at any scale. Insights from this literature will be collated in order to provide an overview of the relevant behavioural-economics mechanisms and actions, how effective these mechanisms are and at what scale, geographic region and in which fisheries sector they have been applied. Any fisheries management implications identified by the studies under review will also be outlined. Finally, it will be recorded whether or not ethical considerations were made in the reviewed literature, so that in the discussion it will be possible to reflect on the ethics of conducting behavioural-economics research and policy actions in a fisheries context.

Importance of suspended particulate organic matter in the diet of Nephrops norvegicus (Linnaeus, 1758).

The extent to which commercially important Nephrops norvegicus lobsters feed on particulates in the wild is unknown, even though this could be an important way for burrow-dwelling females to avoid starvation during the long breeding season. This was investigated using δ13C and δ15N isotopic signatures in tissues with long and short turnover rates to provide diet discrimination and compare this between males and females. Secondary objectives examined size-related differences and calculated the trophic position based on the new results. Almost half the diet (47%) was made up of suspended particulate organic matter (POMsusp) alone. Fish was another important item in the diet, with plankton and invertebrate sources coming much lower down in dietary importance. Significantly more suspension feeding was observed in small or medium sized individuals than large ones in both sexes. However, there were no sex-related patterns, despite females being restricted to burrows for part of the analysis period. Female diet was almost identical to males and POMsusp comprised a large component of the diet in both sexes. The trophic position was estimated at 2.94 ± 0.16 (mean ± SD), which was at the lower end of the range reported in previous studies (2.60 to 4.32).

Microplastic Ingestion by Gelatinous Zooplankton May Lower Efficiency of the Biological Pump.

The impacts of microplastics on some individual organisms have been well studied but what is less clear is what impacts microplastics have on wider ecosystem processes. Using salps as model organisms, we studied the effect of microplastic ingestion on the downward flux of high-density particulate organic matter in the form of salp faecal pellets. While to date most microplastic studies used virgin microplastics at unrealistic environmental concentrations here we exposed Salpa fusiformis to fractured and UV exposed polyethylene and polystyrene microplastics possessing a biofilm. It was found that when exposed to environmentally relevant concentrations, reported for the Mediterranean and the South Pacific Gyre, only few faecal pellets had microplastics incorporated within them. Under potential future scenarios, however, up to 46% of faecal pellets contained microplastics. Incorporated microplastics significantly altered the size, density and sinking rates of salp faecal pellets ( p-value < 0.05 in each instance). Sinking rates decreased by 1.35-fold (95% CI = 1.18, 1.56) for faecal pellets with polyethylene microplastics and 1.47-fold (95% CI = 1.34, 1.61) for polystyrene. These results suggest that today, microplastic ingestion by salps has minimal impact on the biological pump. However, under future microplastic concentrations (or in areas such as convergent zones), microplastics may have the potential to lower the efficiency of the biological pump.

Field-recorded data on habitat, density, growth and movement of Nephrops norvegicus.

The availability of growth data in N. norvegicus is important for management purposes due to a lack of aging criteria and the commercial importance of fisheries in this species. Growth varies as a function of stock density, hence comparisons of growth rates between stocks at known density is particularly valuable. Growth is also related to starting size in males, making raw data on size-specific growth rates more valuable. Internally injected passive tags allowed us to track the growth of male and female individuals over one or two years. The spatial position of tagged recaptures was recorded to measure site fidelity of tagged releases. A total of 3300 pots were fished and their spatial positions were recorded to enable Catch Per Unit Effort calculations. Similarly, spatially geo-referenced v-notching and notched recovery enables spatially gridded densities to be calculated. Finally, acoustic mapping was carried out both on and off the fishing ground and was ground-truthed with sedimentology from grabs at 22 stations. These data are useful for fisheries and macroecological studies.

Stable-isotope analysis reveals the importance of soft-bodied prey in the diet of lesser spotted dogfish Scyliorhinus canicula.

This study examines the diet of lesser spotted dogfish Scyliorhinus canicula, one of the most ubiquitous predators of European coastal waters. This species is of increasing ecological significance as other large predatory fish decline as it has known interactions with fisheries. Scyliorhinus canicula diet was investigated in Irish coastal waters during June and July 2014 using both stomach-content analysis and δ13 C and δ15 N stable-isotope ratios. Prey contribution to the diet from dual stable-isotope data was estimated using Bayesian mixing models. It was found that only stable-isotope analysis provided a time-integrated picture of the diet of S. canicula and allowed for a new estimation of their trophic position. Trophic positions from stomach-content analysis within the present study and previous studies were found to be higher than revealed by isotopes. Stomach-content analysis could not reveal the importance of soft-bodied animals in the diet of these fish, however this approach remains a valuable tool to understand the potential prey spectrum in advance of isotope analysis and allows for a better resolution down to species level. The results highlight a greater variety in the diet of this important predator and the benefit of taking a multidisciplinary approach in dietary studies.