| 1. |
- Waldo, Åsa, et al.
(author)
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Local attitudes towards management measures for the co-existence of seals and coastal fishery - A Swedish case study
- 2020
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In: Marine Policy. - : Elsevier BV. - 0308-597X. ; 118
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Journal article (peer-reviewed)abstract
- Marine mammals and coastal fisheries are two features commonly associated with thriving marine environments, but it is also a case of wildlife impact on human interests. This paper analyses the seal-fisheries encounter in a Swedish Baltic Sea fishery. The problem concerns seals eating fish from the fishing gear which causes considerable economic losses to small-scale fishermen. This mixed-method study addresses local attitudes towards management measures that might be introduced. A questionnaire was sent to all households in three traditional fishing villages and interviews were conducted with local stakeholders. The results show a consensus that something needs to be done or the local fishery cannot continue. Economic compensation for lost catches is viewed as a short-term strategy, while investment subsidies for seal-proof gear are considered positive but problematic due to low efficiency of the new gear. The management measure viewed as most positive in the local context is hunting. In general, a more active management is perceived as urgent for the survival of the small-scale coastal fishery in the studied area.
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| 2. |
- Waldo, Staffan, et al.
(author)
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Swedish coastal herring fisheries in the wake of an ITQ system
- 2013
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In: Marine Policy. - : Elsevier. - 0308-597X .- 1872-9460. ; 38, s. 321-324
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Journal article (peer-reviewed)abstract
- The European common fisheries policy (CFP) advocates measures to sustain small-scale fisheries; hence, in the European Commission's proposal for a reformed CFP, these are exempted from a mandatory system with tradable fishing concessions. This opens up for management actions designed for small-scale fisheries, but also implies new management issues. This article provides insights into the topic based on a Swedish small-scale herring fishery in the western Baltic Sea that was exempted from an ITQ-system. The fishery has been profitable since the system was introduced, and the increasing effort of both incumbent fishermen and new entrants implies a situation where fishermen compete for a limited quota. The migratory pattern of the herring implies high densities in the southern parts of the fishing areas during spring and in the northern parts during autumn. This forms the basis for two different fisheries in the area, as well as for the current management proposal to divide the quota into a spring and an autumn part. This and other management proposals are discussed in the paper. The main conclusion from the case study is that, when exempting a fishery from tradable fishing concessions, it is important to build other institutions dealing with the fundamental problem of access to the quota. Failure to do so might result in an over-capacity issue and threaten the long-run development of an otherwise successful small-scale fishery.
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| 3. |
- Ericsson, Philip, et al.
(author)
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Personality-dependent inter- and intraspecific foraging competition in the invasive round goby, Neogobius melanostomus
- 2021
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In: Journal of Fish Biology. - : Wiley-Blackwell. - 0022-1112 .- 1095-8649. ; 98:5, s. 1234-1241
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Journal article (peer-reviewed)abstract
- This study examines the impact of boldness on foraging competition of the highly invasive round goby Neogobius melanostomus Pallas 1815. Individual risk tolerance, or boldness, was measured as the time to resume movement after a simulated predation strike. Fish that resumed movement faster were categorized as "bold," fish that took more time to resume movement were categorized as "shy" and those that fell in between these two categories were determined to have "intermediate" boldness. Competitive impacts of boldness in N. melanostomus were determined in a laboratory foraging experiment in which interspecific (juvenile Atlantic cod Gadus morhua Linnaeus 1758) and intraspecific (intermediate N. melanostomus) individuals were exposed to either bold or shy N. melanostomus competitors. G. morhua consumed fewer prey when competing with bold N. melanostomus than when competing with shy N. melanostomus, whereas intermediately bold N. melanostomus foraging was not affected by competitor boldness. Bold and shy N. melanostomus consumed similar amounts of prey, and the number of interactions between paired fish did not vary depending on the personality of N. melanostomus individuals. Therefore, intraspecific foraging competition was not found to be personality dependent. This study provides evidence that individual differences in boldness can mediate competitive interactions in N. melanostomus; nonetheless, results also show that competition is also governed by other mechanisms that require further study.
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| 4. |
- Sande, Hege Anett, et al.
(author)
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Temperature and age effects on latitudinal growth dynamics of the commercially valuable gadoid Northeast Arctic saithe (Pollachius virens)
- 2019
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In: Fisheries Research. - : Elsevier BV. - 0165-7836. ; 213, s. 94-104
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Journal article (peer-reviewed)abstract
- It is well known that marine fish dynamics relate with climate variability, and predicting future population developments have become increasingly urgent with on-going climate change. One approach in widespread populations is to study how individuals from different parts of the distribution area respond to climate, thereby testing for potential resilience in terms of local adaptions against environmental change. In this study, we collated extensive survey data on size-at-age for Northeast Arctic saithe (Pollachius virens) (1992–2013; 62–70 °N; ages 0–3 years) and detailed hydrographic information from three fixed, coastal stations along the Norwegian coast (at ≈63, 68 and 71 °N). Dedicated ad libitum feeding experiments were additionally performed to further strengthen the insight in saithe growth dynamics, also including adults (≥4 years). Likely temperature-mediated effects on whole body weight (W), total length, Fulton's K, and specific growth rate (SGR) of wild saithe were explored using generalized linear models with age and region as fixed factors. A positive relationship with temperature was found, as evidenced by the before-mentioned body metrics of saithe age 2–3 years all becoming higher at positive local annual temperature anomalies, i.e. the deviation from the long-term mean temperature. The direct use of corresponding, absolute temperature instead of temperature anomalies gave comparable results. Hence, acclimatization to local temperatures per se was likely minor. Furthermore, examination of GLM interaction terms indicated that dissimilar feeding conditions in part of the study area, using K as a proxy, were not a confounding factor. Taken together, the present material provided an excellent opportunity to scrutinize temperature-mediated effects on growth dynamics across age classes, regions, and years. However, data sets pooled over years turned out to be more informative: SGR from age 0 to 1 year was clearly highest in the warmer, southern region but individuals in the colder, northern region gradually caught up and thereby showed higher W at age 3 years. This pattern mechanistically speaks for a gradual displacement of response curves for growth towards lower temperatures as saithe become larger or older. Although the present feeding experiments evidenced steady declines in SGR with W for younger individuals while this size effect faded away in the adults, the results also implied that saithe in the field show far from optimal growth performance, according to standard physiological principles. Thus, the term “optimal growth” should be treated with caution. Nevertheless, further studies are merited in this research area, potentially aiding body growth predictions and thereby management routines of this productive stock.
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