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  • 1.
    Blicharska, Malgorzata
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Rönnbäck, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Recreational fishing for sea trout – Resource for whom and to what value?2018In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 204, p. 380-389Article in journal (Refereed)
    Abstract [en]

    Recreational fishing is an important activity that delivers substantial social and economic values. Proper management of recreational fisheries relies on information about resource use and associated values by different fishers, but such information is rare, particularly for open access fisheries. In this study a survey of 471 fishers on the Swedish island of Gotland in the Baltic Sea, assessed catches, proportion of catch-and-release (C&R), and economic value (expenditures and willingness to pay, WTP) of sea trout fishing in 2015-2016. Data was analysed in relation to gear used (fly and spin angling, nets and mixed fishery) and fisher connection to fishing site (permanent and temporary residents, Swedish and international tourists). There were marginal differences in daily catch rates, but significant differences in effort and annual catches between different fishers, with resident fishers having the highest catches. Anglers had 86% C&R rates, and fly fishers (> 95%) differed significantly from other anglers. Anglers, particularly fly fishers and fishing tourists, had much higher expenditures per year, fish caught and fish kept compared to net fishers. WTP before refraining from fishing, for doubling of fish supply and for potential fishing license was also highest among anglers. Our findings are discussed in terms of distinguishing characteristics for different types of recreational fishers. Fishing efforts, economic values and the need for further studies are also outlined in the context of fisheries and tourism management.

  • 2.
    Blyth, Samuel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Rönnbäck, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    To eat or not to eat, coastal sea trout anglers' motivations and perceptions of best practices for catch and release2022In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 254, article id 106412Article in journal (Refereed)
    Abstract [en]

    The wide variety of perspectives and actions of individual anglers contribute greatly to success or failure when adopting and implementing fisheries management tools. Catch-and-release (C&R) is one such tool where success is influenced by both variation in human factors, but also species and fishery specific characteristics. In this study, an intercept survey of 94 sea trout anglers in a C&R dominated fishery on the Swedish island of Gotland investigated motivations to release or retain catches, self-assessment of anglers' own ability to release fish, and their rating of the importance of various factors influencing the successful outcomes of C&R. Retention of catches was most strongly motivated by situations where anglers deemed the fish unlikely to survive, however more than half of anglers acknowledged being unaware of delayed mortality in released fish. The spawning status of an individual fish was the primary motivation for release, particularly among anglers that prefer to keep at least some of their catches. The roles of water temperature, using single, and barbless hooks were scored as significantly less important than other components contributing to the success of a release. Anglers that gave a favourable rating to their ability to release sea trout also gave greater importance to various factors influencing the success of release, reported higher catch per unit effort, and released a greater proportion of their catches. These findings are discussed in the context of bridging knowledge and behavioural gaps around best practices for C&R in this fishery.

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  • 3.
    Corell, Hanna
    et al.
    DHI Sverige AB.
    Nissling, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Modelling of larval dispersal of Baltic flounder (Platichthys solemdali) revealed drifting depth as a major factor determining opportunities for local retention vs large-scale connectivity2019In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 218, p. 127-137Article in journal (Refereed)
    Abstract [en]

    For flatfishes, transportation of larvae to nursery areas is regarded a key mechanism for recruitment, with adaptations in larval behaviour to reach a suitable habitat. Here we model different possibilities of larval drifting of coastal spawning Baltic flounder Platichthys solemdali (recently identified as a species from European flounder P. flesus) to reveal opportunities for local retention vs large-scale dispersal to ensure settling in coastal nursery areas. Drifting depth, duration of drifting and effects of year and time during season were modelled using 1) a high-resolution local dispersal model, and 2) a large-scale connectivity database. The outcome revealed drifting depth as a major factor affecting larval dispersal. Drift at 10-22 m depth involved retention along the coast with the majority of larvae (>= 94% or 69-93% according to 1 and 2, respectively) with end points <= 20 km from the coast enabling further successful migration to nursery habitats. Contrary, larval drift close to the surface resulted in advection with end points in the open sea (72-76%), i.e. loss of larvae, but with a small fraction (5-12%) displaying cross-basin connectivity. The results suggest, in agreement with depth distribution of spawning, a larval behaviour promoting drift in the lower part of the water mass, favouring retention close to coastal nursery areas. Obtained dispersal patterns may sustain both local recruitment but also connectivity with other areas, potentially explaining the low genetic diversity between areas for P. solemdali. Low inter-annual variability in dispersal patterns when drifting at 10-22 m depth suggests that larval drift is not a major bottleneck explaining recruitment variability in P. solemdali in the area. The study highlights the differences in life-history strategies of the species pair of flounder in the Baltic Sea; P. flesus spawning in the deep basins with extensive larval dispersal, and coastal spawning P. solemdali with, according to the model outcome, mainly local larval dispersal for sustaining a viable population, i.e. request for different management strategies.

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  • 4.
    Nissling, Anders
    et al.
    Gotland University, Department of Biology.
    Johansson, Ulrika
    Jacobsson, Marie
    Effects of salinity and temperature conditions on the reproductive success of turbot (Scophthalmus maximus) in the Baltic Sea2006In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 80, no 2-3, p. 230-238Article in journal (Refereed)
    Abstract [en]

    In the Baltic Sea, a large brackish water area, turbot (Scophthalmus maximus) occurs at the border of its distribution with respect to salinity. Using turbot caught in ICES subdivision (SD) 28 (mid-Baltic), salinity requirements for successful egg development were evaluated by assessment of spermatozoa mobility, fertilisation and egg survival at different salinities. Further, to evaluate potential effects of temperatures, egg survival at different temperatures was assessed. Spermatozoa activity and fertilisation rate decreased with decreasing salinity with a significant drop at <7 psu. The viable hatch was significantly lower at <7 psu compared to at 7–15 psu. Hence, due to decreasing salinity this implies lower egg survival in SD 29 and 30 compared to in SD 24–28, and that salinity conditions in SD 31 are insufficient for egg development. Further, following a long period without major inflows of saline water into the Baltic Sea, salinity has decreased. From 1995 onwards salinities <7 psu prevail in SD 27–28 suggesting decreased reproductive success and potentially weaker year-classes in this area. Egg survival was high at 12–18 °C and considerably lower at 9 and 21 °C. Comparing the results with environmental data suggested that spawning time of turbot is adapted to optimum temperatures for egg development, but that occasions with temperatures involving increased egg mortality may occur, e.g. during upwelling situations.

  • 5.
    Nissling, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Nyberg, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics.
    Petereit, Christoph
    GEOMAR Helmholtz Ctr Ocean Res Kiel, D-24105 Kiel, Germany..
    Egg buoyancy of flounder, Platichthys flesus, in the Baltic Sea-adaptation to salinity and implications for egg survival2017In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 191, p. 179-189Article in journal (Refereed)
    Abstract [en]

    Vertical distribution of eggs as determined by the egg buoyancy, i.e. the difference in specific gravity between the egg and the ambient water, have profound implications for the reproductive success and hence recruitment in fish. Here variability in egg specific gravity of flounder, Platichthys flesus, was studied along a salinity gradient and by comparing two reproductive strategies, spawning pelagic or demersal eggs. Egg characteristics of 209 egg batches (covering ICES subdivisions (SD) 22-29 in the brackish water Baltic Sea) was used to reveal the significance of egg diameter and egg dry weight for egg specific gravity (ESG), subpopulations, and egg survival probabilities of pelagic eggs following a major saline water inflow event. As an adaptation to salinity, ESG (at 7 degrees C) differed (p <0.001) between areas; three subpopulations of flounder with pelagic eggs: 1.0152 +/- 0.0021 (mean +/- sd)g cm(-3) in SD 22, 1.0116 +/- 0.0013 g cm(-3) in SD 24 and 25, and 1.0096 +/- 0.0007 g cm(-3) in SD 26 and 28, contrasting to flounder with demersal eggs, 1.0161 +/- 0.0008 g cm(-3). Egg diameter differed (p <0.001) between subpopulations; from 1.08 +/- 0.06 mm (SD 22) to 1.26 +/- 0.06 mm (SD 26 and 28) for pelagic eggs and 1.02 +/- 0.04 mm for demersal eggs, whereas egg dry weight was similar; 37.9 +/- 5.0 mu g (SD 22) and 37.2 +/- 3.9 mu g (SD 28) for pelagic, and 36.5 +/- 6.5 mu g for demersal eggs. Both egg diameter and egg dry weight were identified as explanatory variables, explaining 87% of the variation in ESG. ESG changed during ontogeny; a slight decrease initially but an increase prior to hatching. Egg survival probabilities judged by combining ESG and hydrographic data suggested higher egg survival in SD 25 (26 vs 100%) and SD 26 (32 vs 99%) but not in SD 28 (0 and 3%) after the inflow event, i.e. highly fluctuating habitat suitability. The results confirm the significance of ESG for egg survival and show that variability in ESG as and adaptation to salinity is determined mainly by water content manifested as differences in egg diameter; increase in diameter with decreasing salinity for pelagic eggs, and decreased diameter resulting in demersal eggs.

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  • 6.
    Raby, Graham D.
    et al.
    Carleton Univ, Dept Biol, Fish Ecol & Conservat Physiol Lab, 1125 Colonel Dr, Ottawa, ON K1S 5B6, Canada;Univ Windsor, Great Lakes Inst Environm Res, 2601 Union St, Windsor, ON N9B 3P4, Canada.
    Messmer, Vanessa
    James Cook Univ, ARC Ctr Excellence Coral Reef Studies, Townsville, Qld 4811, Australia.
    Tobin, Andrew J.
    James Cook Univ, Coll Marine & Environm Studies, Ctr Sustainable Trop Fisheries & Aquaculture, Townsville, Qld 4811, Australia.
    Hoey, Andrew S.
    James Cook Univ, ARC Ctr Excellence Coral Reef Studies, Townsville, Qld 4811, Australia.
    Jutfelt, Fredrik
    Norwegian Univ Sci & Technol, Dept Biol, Hogskoleringen 1, NO-7491 Trondheim, Norway.
    Sundin, Josefin
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Physiology.
    Cooke, Steven J.
    Carleton Univ, Dept Biol, Fish Ecol & Conservat Physiol Lab, 1125 Colonel Dr, Ottawa, ON K1S 5B6, Canada.
    Clark, Timothy D.
    Deakin Univ, Sch Life & Environm Sci, Geelong, Vic, Australia.
    Swim for it: Effects of simulated fisheries capture on the post-release behaviour of four Great Barrier Reef fishes2018In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 206, p. 129-137Article in journal (Refereed)
    Abstract [en]

    After being caught and released by a fishery, some animals may be sufficiently impaired so as to be vulnerable to predators. The duration and severity of post-release impairments have rarely been studied under natural conditions; the vitality of animals is usually assessed aboard a vessel, prior to release, while examinations of post-release behaviour are usually restricted to what is within view of a vessel. In this study, we quantified the post-release behavior of the common coral trout (Plectropomus leopardess), two species of emperor (Lethrinus spp.), and the Spanish flag snapper (Lutjanus carponotatus), each of which is actively fished throughout the Great Barrier Reef. SCUBA divers followed fish in the field and recorded their behavior with underwater video cameras after a simulated catch-and-release event. Relative to a low stress treatment (held in an aerated tank prior to release), fish exposed to forced exercise and 5 min of air exposure spent more time in vulnerable positions after release, including 5.8 x more time immobile under the boat upon release, 1.6 x more time to reach the reef floor, and 2.4 x longer to reach the protection of the reef. The effects of the catch-and-release simulation on tailbeat frequency, ventilation rate, and the proportion of overall time spent immobile were not significant except in L. carponotatus, which spent significantly more time immobile when exposed to the high stress treatment. Indeed, there were some notable differences among species, with the magnitude of the behavioural impairments being lower and less variable in coral trout than in Lethrinus spp. or L. carponotatus. These findings provide support for the notion that minimizing air exposure time in hook-and-line fisheries should reduce post-release behavioural impairments and thus vulnerability to predators.

  • 7.
    Vallin, Lars
    et al.
    Gotland University, Department of Biology.
    Nissling, Anders
    Gotland University, Department of Biology.
    Maternal effects on egg size and egg buoyancy of Baltic cod, Gadus morhua: Implications for stock structure effects on recruitment2000In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 49, no 1, p. 21-37Article in journal (Refereed)
    Abstract [en]

    Successful spawning of cod in the Baltic is restricted to the deep basins: the Bornholm basin, the Gdansk Deep and the Gotland basin, at salinities varying between 11 and 20 psu. Due to oxygen-depletion commonly prevailing in these areas, neutral egg buoyancy above oxygen-critical levels is of substantial importance for egg and larval survival in the Baltic. In the present study, large females were found to produce larger eggs with neutral egg buoyancy at a lower salinity, implying egg development in more favourable oxygen conditions. An age- and batch-specific model of egg production, egg size and egg buoyancy showed a substantial increase in the probability of egg survival with female age. The relationship between egg production by old females and subsequent recruitment was tested in two separated periods with different conditions: 1967-1980 and 1981-1994. The number of recruited cod (age 2), in the Baltic Sea, was positively related to the fraction of eggs produced by old females ( greater than or equal to 5 years). That recruitment was positively related to the proportion of eggs spawned by old fish reveals that stock age structure should be seriously considered in stock-recruitment relationships and in the management of the cod stock in the Baltic.

  • 8.
    van den Heuvel, Lotte
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development. Radboud Univ Nijmegen, Fac Sci, Inst Sci Soc, Heyendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands.
    Blicharska, Malgorzata
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Blyth, Samuel
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Rönnbäck, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Catch reporting in recreational fishing: Swedish anglers’ attitudes andpreferences, and the effect of social factors2020In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 223, article id 105444Article in journal (Refereed)
    Abstract [en]

    Recreational fishing activities have the potential to negatively affect fish populations worldwide, but data about fishing pressure is lacking in many countries. The Swedish government anticipates tackling this problem by implementing a national catch reporting program. Through an online survey among members of the Swedish Anglers Association (±60.000 members), this study gathers the attitudes and preferences of Swedish anglers (n=910) through a variety of statements relating to the potential introduction of a catch reporting program and investigates the effects of different social factors (consumptive orientation, motivations to fish, centrality to life and environmental attitude) on these attitudes and preferences. The results reveal that support for a potential catch reporting program was high for most anglers. Significant positive relationships were found between support for a catch reporting program and the sense of responsibility towards conservation issues, the desire to catch big fish and experiencing the environment as a motivation to fish. On the other hand, the desire to keep fish and catch large numbers of fish had a significant negative relationship with catch reporting support. Support for a mandatory catch reporting program increased with age, education level, income and years of fishing experience. Despite the generally positive attitude towards a potential catch reporting program, consumptive orientation, motivations to fish, environmental attitude and demographic characteristics were proven to play an important role in the anglers’ preferences towards catch reporting, and should not be overlooked when designing such a program. Our study shows that investigation of the social composition of an angler population is vital to obtain a better understanding of the diversity of attitudes and preferences towards recreational fisheries management, which can in turn facilitate implementation of management measures, such as catch reporting programs. Since this study focused only on members of the national angling association, who are likely more avid than non-members, additional research is needed to obtain results that are more representative of the total Swedish angler population.

  • 9.
    van den Heuvel, Lotte
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Blicharska, Malgorzata
    Rönnbäck, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Blyth, Samuel
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Catch reporting in recreational fishing: Swedish anglers’ attitudes and preferences and the effect of social factors2020In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 223, article id 105444Article in journal (Refereed)
  • 10.
    van den Heuvel, Lotte
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    Rönnbäck, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Natural Resources and Sustainable Development.
    What you see isn't always what you get: On how anglers' fish stock perceptions are influenced by motivations, satisfaction and engagement2023In: Fisheries Research, ISSN 0165-7836, E-ISSN 1872-6763, Vol. 258, article id 106519Article in journal (Refereed)
    Abstract [en]

    Recreational anglers collectively spend a great amount of time on fishing activities. While being out fishing, these anglers perceive various components of aquatic ecosystems, allowing them to accumulate knowledge of the ecological status of the system and the fish they are targeting in it. Such fishers' ecological knowledge (FEK) is increasingly being recognized as a valuable source of information in fisheries research and management, but it has also been criticized for a lack of accuracy. People's perceptions of their environment are shaped by a variety of psychological and environmental factors, and the same is expected for anglers' perceptions of fish stocks and the resulting FEK. This study assessed anglers' perceived change in salmon and sea trout stocks at the Mo center dot rrum river in Sweden, comparing the year that they first fished there to the present (2019). In addition, effects on these perceptions of the anglers' motivations to fish, satisfaction with catches, and their engagement with this fishery were examined. The majority of the respondents perceived a negative trend for both species, even when the reported total catches during the year they first fished at Mo center dot rrum were lower than the present catches. Binomial regression models indicated significant influences of engagement at Mo center dot rrum on the anglers' stock trend perceptions. The results of this study emphasize the importance of understanding different individual angler characteristics when collecting and interpreting FEK. Moreover, the fact that anglers with a longer history at Mo center dot rrum had a more negative perception overall, regardless of actual stock status in their first year in this fishery, suggests the occurrence of the shifting baseline syndrome in recreational fisheries. Therefore, the prevailing narrative on stock trends and its effect on angler perceptions should be considered when using FEK.

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