| 1. |
- Bergendahl, I. Ahlbeck, et al.
(författare)
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Feeding range of age 1+year Eurasian perch Perca fluviatilis in the Baltic Sea
- 2017
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 90:5, s. 2060-2072
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Tidskriftsartikel (refereegranskat)abstract
- Using the widespread Eurasian perch Perca fluviatilis as a model organism, feeding ranges were investigated using stable-isotope ratios (N-15 and C-13) and body condition. Differences were found between closely located sampling sites in a littoral area without obvious migration barriers, indicating that individual fish had small feeding ranges. Body condition differences between sampled stations were consistent over 4 years. Such sedentary behaviour is important to consider in, e.g. fisheries management and environmental monitoring, as local catch regulations may be meaningful or geographic stability in sampling locations may reduce noise in data.
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| 2. |
- Cooke, Steven J., et al.
(författare)
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Searching for responsible and sustainable recreational fisheries in the Anthropocene
- 2019
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Ingår i: Journal of Fish Biology. - : John Wiley & Sons. - 0022-1112 .- 1095-8649. ; 94:6, s. 845-856
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Tidskriftsartikel (refereegranskat)abstract
- Recreational fisheries that use rod and reel (i.e., angling) operate around the globe in diverse freshwater and marine habitats, targeting many different gamefish species and engaging at least 220 million participants. The motivations for fishing vary extensively; whether anglers engage in catch-and-release or are harvest-oriented, there is strong potential for recreational fisheries to be conducted in a manner that is both responsible and sustainable. There are many examples of recreational fisheries that are well-managed where anglers, the angling industry and managers engage in responsible behaviours that both contribute to long-term sustainability of fish populations and the sector. Yet, recreational fisheries do not operate in a vacuum; fish populations face threats and stressors including harvest from other sectors as well as environmental change, a defining characteristic of the Anthropocene. We argue that the future of recreational fisheries and indeed many wild fish populations and aquatic ecosystems depends on having responsible and sustainable (R&S) recreational fisheries whilst, where possible, addressing, or at least lobbying for increased awareness about the threats to recreational fisheries emanating from outside the sector (e.g., climate change). Here, we first consider how the concepts of R&S intersect in the recreational fishing sector in an increasingly complex socio-cultural context. Next, we explore the role of the angler, angling industry and decision-makers in achieving R&S fisheries. We extend this idea further by considering the consequences of a future without recreational fisheries (either because of failures related to R&S) and explore a pertinent case study situated in Uttarakahand, India. Unlike other fisheries sectors where the number of participants is relatively small, recreational angling participants are numerous and widespread, such that if their actions are responsible, they have the potential to be a key voice for conservation and serve as a major force for good in the Anthropocene. What remains to be seen is whether this will be achieved, or if failure will occur to the point that recreational fisheries face increasing pressure to cease, as a result of external environmental threats, the environmental effects of recreational fishing and emerging ethical concerns about the welfare of angled fish.
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| 3. |
- Faulks, L. K., et al.
(författare)
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Adaptive major histocompatibility complex (MHC) and neutral genetic variation in two native Baltic Sea fishes (perch Perca fluviatilis and zander Sander lucioperca) with comparisons to an introduced and disease susceptible population in Australia (P-fluviatilis) : assessing the risk of disease epidemics
- 2016
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 88:4, s. 1564-1583
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Tidskriftsartikel (refereegranskat)abstract
- This study assessed the major histocompatibility complex (MHC) and neutral genetic variation and structure in two percid species, perch Perca fluviatilis and zander Sander lucioperca, in a unique brackish ecosystem, the Baltic Sea. In addition, to assess the importance of MHC diversity to disease susceptibility in these populations, comparisons were made to an introduced, disease susceptible, P. fluviatilis population in Australia. Eighty-three MHC class II B exon 2 variants were amplified: 71 variants from 92 P. fluviatilis samples, and 12 variants from 82 S. lucioperca samples. Microsatellite and MHC data revealed strong spatial genetic structure in S. lucioperca, but not P. fluviatilis, across the Baltic Sea. Both microsatellite and MHC data showed higher levels of genetic diversity in P. fluviatilis from the Baltic Sea compared to Australia, which may have facilitated the spread of an endemic virus, EHNV in the Australian population. The relatively high levels of genetic variation in the Baltic Sea populations, together with spatial genetic structure, however, suggest that there currently seems to be little risk of disease epidemics in this system. To ensure this remains the case in the face of ongoing environmental changes, fisheries and habitat disturbance, the conservation of local-scale genetic variation is recommended.
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| 4. |
- Forsman, Anders, et al.
(författare)
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Pike Esox lucius as an emerging model organism for studies in ecology and evolutionary biology: a review.
- 2015
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 87:2, s. 472-479
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Forskningsöversikt (refereegranskat)abstract
- The pikeEsox luciusis a large, long-lived, iteroparous, top- predator fish species with a circumpolardistribution that occupies a broad range of aquatic environments. This study reports on a literaturesearch and demonstrates that the publication rate ofE. luciusresearch increases both in absolute termsand relative to total scientific output, and that the focus of investigation has changed over time frombeing dominated by studies on physiology and disease to being gradually replaced by studies on ecol-ogy and evolution.Esox luciuscan be exploited as a model in future research for identifying causes andconsequences of phenotypic and genetic variation at the levels of individuals, populations and speciesas well as for investigating community processes.
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| 5. |
- Franco-Belussi, Lilian, et al.
(författare)
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Regulation of eye and jaw colouration in three-spined stickleback Gasterosteus aculeatus
- 2018
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112. ; 92:6, s. 1788-1804
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Tidskriftsartikel (refereegranskat)abstract
- Fish can change their skin and eye colour for background matching and signalling. Males of Gasterosteus aculeatus develop ornamental blue eyes and a red jaw during the reproductive season, colours that are further enhanced during courtship. Here, the effects of different hormones on physiological colour changes in the eyes and jaws of male and female G. aculeatus were investigated in vitro. In an in vivo experiment, G. aculeatus were injected with a receptor blocker of a pivotal hormone (noradrenaline) that controls colour change. In males, noradrenaline had aggregating effects on melanophore and erythrophore pigments resulting in blue eyes and a pale jaw, whereas melanocyte-concentrating hormone (MCH) and melatonin resulted in a pale jaw only. When noradrenalin was combined with melanocyte stimulating hormone (MSH) or prolactin, the jaw became red, while the eyes remained blue. In vivo injection of yohimbine, an alpha-2 adrenoreceptor blocker, resulted in dispersion of melanophore pigment in the eyes and inhibited the blue colouration. Altogether, the data suggest that noradrenalin has a pivotal role in the short-term enhancement of the ornamental colouration of male G. aculeatus, potentially together with MSH or prolactin. This study also found a sex difference in the response to MCH, prolactin and melatonin, which may result from different appearance strategies in males, versus the more cryptic females.
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| 6. |
- Gordon, T. A. C., et al.
(författare)
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Fishes in a changing world : learning from the past to promote sustainability of fish populations
- 2018
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Ingår i: Journal of Fish Biology. - : John Wiley & Sons. - 0022-1112 .- 1095-8649. ; 92:3, s. 804-827
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Tidskriftsartikel (refereegranskat)abstract
- Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important challenges raised by these issues have been recognized and have led to considerable advances over past decades in managing and mitigating threats to fishes worldwide. In this review, we identify the major threats faced by fish populations alongside recent advances that are helping to address these issues. There are very significant efforts worldwide directed towards ensuring a sustainable future for the world's fishes and fisheries and those who rely on them. Although considerable challenges remain, by drawing attention to successful mitigation of threats to fish and fisheries we hope to provide the encouragement and direction that will allow these challenges to be overcome in the future.
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| 7. |
- Hedberg, Per, et al.
(författare)
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Fish larvae distribution among different habitats in coastal East Africa
- 2019
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 94:1, s. 29-39
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Tidskriftsartikel (refereegranskat)abstract
- Fish larvae abundances, diversity and trophic position across shallow seagrass, coral reef and open water habitats were examined to characterize their distribution in coastal East Africa. Larvae were identified to family and analysed for abundance differences between sites and habitats, trophic level using stable-isotope analysis and parental spawning mode. Abundances differed greatly between sites with the highest numbers of larvae occurring in the open-water and seagrass habitats. Larval fish diversity was high across habitats with 51 families identified with small differences between sites and among habitats. Notably, larvae of abundant large herbivorous fishes present in reef and seagrass habitats were almost completely absent at all sampling locations. In the seagrass, demersal spawned larvae were more abundant compared with the reef and open-water habitats. Stable-isotope analysis revealed that fish larvae have a varied diet, occupying trophic level two to three and utilizing planktonic prey. This study offers new insights into distributional aspects of fish larvae along the East African coast where such information is sparse.
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| 8. |
- Hilvarsson, Annelie, et al.
(författare)
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Effects of freezing on length and mass measurements of Atlantic cod Gadus morhua in the Baltic Sea
- 2019
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 95, s. 1486-1495
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Tidskriftsartikel (refereegranskat)abstract
- An aggregated sample of 925 Atlantic cod Gadus morhua collected by four countries in different regions of the Baltic Sea during different seasons were measured (total length, L-T = 161-890mm and weighed (mass, M = 45-6900g) both before freezing and after defrosting. The cod were found to decrease significantly in both L-T and M following death and frozen storage. There was an average (+/- SD) change in L-T of -2.91% (+/- 0.05%) following freezing, independent of starting L-T. Total M changed by -2.65% (+/- 0.14%), independent of starting mass. Shrinkage of L-T and M did not differ significantly between 1 and 4 months frozen storage, though L-T shrinkage was significantly greater after 1 or 4 months in the freezer compared with after 5days. There was significant variation in L-T and M shrinkage between regions of capture. A significant negative relationship between condition of cod and L-T or M change was also observed. Equations to back-calculate fresh L-T and M from thawed L-T, M and standard length (L-S), gutted L-T, gutted L-S and gutted M are provided.
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| 9. |
- Jeuthe, Henrik, et al.
(författare)
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Thermal stress in Arctic charr Salvelinus alpinus broodstock: a 28 year case study
- 2015
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 86, s. 1139-1152
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Tidskriftsartikel (refereegranskat)abstract
- Temperature and egg viability data from an Arctic charr Salvelinus alpinus hatchery covering a period of 28 years were analysed. During the study period, there was a significant increase in the mean water temperature in May, July, August and September of c. 2 degrees C. Independent of year, the egg viability showed a negative correlation with the mean monthly temperatures in July, August and September as well as with the temperature difference between October and November. The negative effect of high summer temperatures was further supported by a comparison of egg viability from replicate brood-stock reared at two sites differing mainly in summer water temperature. The eggs from the colder site were, on average, significantly larger (4.4 mm compared with 4.0 mm) and had higher hatching rates (57% compared with 37%). These results suggest that unfavourable temperature conditions during the summer and autumn can explain much of the excessive egg mortality experienced at the main facility used for the Swedish S. alpinus breeding programme. The main effect was supra-optimal temperatures during the period July to September, but there also appears to have been an effect from the temperature regime before and during spawning (October to November) that was unrelated to the summer temperatures. These findings emphasize the importance of site selection and sustainable management of aquaculture hatcheries in the light of the ongoing climate change. (C) 2015 The Fisheries Society of the British Isles
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| 10. |
- Jokela-Määttä, Mirka, et al.
(författare)
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Photoreceptors and eyes of pikeperch Sander lucioperca, pike Esox lucius, perch Perca fluviatilis and roach Rutilus rutilus from a clear and a brown lake
- 2019
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Ingår i: Journal of Fish Biology. - : Wiley. - 0022-1112. ; 95:1, s. 200-213
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Tidskriftsartikel (refereegranskat)abstract
- The photoreceptors and eyes of four fish species commonly cohabiting Fennoscandian lakes with different light transmission properties were compared: pikeperch Sander lucioperca, pike Esox lucius, perch Perca fluviatilis and roach Rutilus rutilus. Each species was represented by individuals from a clear (greenish) and a humic (dark brown) lake in southern Finland: Lake Vesijärvi (LV; peak transmission around 570 nm) and Lake Tuusulanjärvi (LT; peak transmission around 630 nm). In the autumn, all species had almost purely A2-based visual pigments. Rod absorption spectra peaked at c.526 nm (S. lucioperca), c. 533 nm (E. lucius) and c. 540 nm (P. fluviatilis and R. rutilus), with no differences between the lakes. Esox lucius rods had remarkably long outer segments, 1.5–2.8-fold longer than those of the other species. All species possessed middle-wavelength-sensitive (MWS) and long-wavelength-sensitive (LWS) cone pigments in single, twin or double cones. Rutilus rutilus also had two types of short-wavelength sensitive (SWS) cones: UV-sensitive [SWS1] and blue-sensitive (SWS2) cones, although in the samples from LT no UV cones were found. No other within-species differences in photoreceptor cell complements, absorption spectra or morphologies were found between the lakes. However, E. lucius eyes had a significantly lower focal ratio in LT compared with LV, enhancing sensitivity at the expense of acuity in the dark-brown lake. Comparing species, S. lucioperca was estimated to have the highest visual sensitivity, at least two times higher than similar-sized E. lucius, thanks to the large relative size of the eye (pupil) and the presence of a reflecting tapetum behind the retina. High absolute sensitivity will give a competitive edge also in terms of short reaction times and long visual range.
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