Search results for "VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920"
showing 10 items of 24 documents
Assessing the added value of the recent declaration on unregulated fishing for sustainable governance of the central Arctic Ocean
2016
Accepted manuscript version. Published version available at https://doi.org/10.1016/j.marpol.2016.01.013. Accepted manuscript version, licensed CC BY-NC-ND 4.0. The ‘Declaration concerning the prevention of unregulated high seas fishing in the central Arctic Ocean’ signed by the Arctic 5 nations, limits unregulated high seas fishing in the central part of the Arctic Ocean, and holds potential social, economic and political impacts for numerous stakeholders. In this paper, the four Interim Measures in the Declaration are discussed and what value these measures bring beyond the existing international agreements is explored. It is found that even though the Declaration fills a gap in the manag…
Interbreeding between local and translocated populations of a cleaner fish in an experimental mesocosm predicts risk of disrupted local adaptation
2019
Source at https://doi.org/10.1002/ece3.5246. Translocation of organisms within or outside its native range carries the risk of modifying the community of the recipient ecosystems and induces gene flow between locally adapted populations or closely related species. In this study, we evaluated the genetic consequences of large‐scale translocation of cleaner wrasses that has become a common practice within the salmon aquaculture industry in northern Europe to combat sea lice infestation. A major concern with this practice is the potential for hybridization of escaped organisms with the local, recipient wrasse population, and thus potentially introduce exogenous alleles and breaking down coadap…
Lobster and cod benefit from small-scale northern marine protected areas: inference from an empirical before - after control-impact study
2013
Published version of an article from the journal: Proceedings of the Royal Society B-Biological Sciences. Alsop available from the Royal Society: http://dx.doi.org/10.1098/rspb.2012.2679 Open Access Marine protected areas (MPAs) are increasingly implemented as tools to conserve and manage fisheries and target species. Because there are opportunity costs to conservation, there is a need for science-based assessment of MPAs. Here, we present one of the northernmost documentations of MPA effects to date, demonstrated by a replicated before-after control-impact (BACI) approach. In 2006, MPAs were implemented along the Norwegian Skagerrak coast offering complete protection to shellfish and parti…
Ocean-scale connectivity and life cycle reconstruction in a deep-sea fish
2014
Author's version of an article in the journal: Canadian Journal of Fisheries and Aquatic Sciences. Also available from the publisher at: http://dx.doi.org/10.1139/cjfas-2013-0343 As human exploration and harvesting moves to the high seas, ecological understanding of the deep sea has become a priority, especially in those commercially exploited species whose life cycle, habitat use, and demographic structure remain poorly understood. Here we combine otolith trace element and stable isotope analyses with microsatellite data to investigate population structure and connectivity in the migratory deep-sea black scabbardfish (Aphanopus carbo), sampled along a latitudinal gradient spanning much of …
Socializing makes thick-skinned individuals: on the density of epidermal alarm substance cells in cyprinid fish, the crucian carp (Carassius carassiu…
2010
Published version of an article in the journal: Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology. Also available on SpringerLink: http://dx.doi.org/10.1007/s00359-010-0550-4 In cyprinid fish, density of epidermal club cells (i.e. alarm substance cells) has been found to vary between lakes with different predator fauna. Because predators can be labelled with chemical cues from prey, we questioned if club cell density could be controlled indirectly by predators releasing prey cues. In particular, we suspected a possible feedback mechanism between chemical alarm signals and their cellular source. We raised crucian carp singly and in groups of four.…
Challenging fear: chemical alarm signals are not causing morphology changes in crucian carp (Carassius carassius)
2010
Published version of an article in the journal: Environmental Biology of Fishes. Also available at SpringerLink: http://dx.doi.org/10.1007/s10641-010-9707-9 Crucian carp develops a deep body in the presence of chemical cues from predators, which makes the fish less vulnerable to gape-limited predators. The active components originate in conspecifics eaten by predators, and are found in the filtrate of homogenised conspecific skin. Chemical alarm signals, causing fright reactions, have been the suspected inducers of such morphological changes. We improved the extraction procedure of alarm signals by collecting the supernatant after centrifugation of skin homogenates. This removes the minute …
Spatially structured interactions between lobsters and lobster fishers in a coastal habitat: fine-scale behaviour and survival estimated from acousti…
2013
Fishing can have profound impacts on the ecology and evolution of marine populations. Understanding population-level changes ultimately depends on knowledge about individual survival and how it varies in time and space. We used acoustic tags and a network of receivers to monitor individual behaviour and fate of European lobster (Homarus gammarus) exposed to commercial and recreational trap fisheries on the Norwegian Skagerrak coast. In August 2011, 50 male lobsters above minimum legal size were tagged and monitored before and during the lobster fishing season. We also quantified the spatial and temporal variation in fishing activity. There was no significant effect of home-range size on th…
Catch-and-release of Atlantic cod (Gadus morhua): post-release behaviour of acoustically pretagged fish in a natural marine environment
2014
Studying the sublethal effects of catch-and-release (C&R) is challenging, as there are several potential sources of bias. For example, if behavioural alterations immediately after the release event are to be studied, separation of tagging effects from actual C&R effects is required, which is a challenge in the wild, particularly in marine environments. To investigate the effects of C&R on Atlantic cod (Gadus morhua) in their natural environment, 80 cod were caught in fyke nets, fitted with acoustic transmitters, and released. After recovery from tagging and handling for at least 14 days, nine individuals were recaptured and released at least once during experimental angling, fo…
Climate change and genetic structure of leading edge and rear end populations in a northwards shifting marine fish species, the corkwing wrasse (Symp…
2013
Published version of an article in the journal:PLoS ONE. Also available from the Public Library of Science: http://dx.doi.org/10.1371/journal.pone.0067492 Open Access One mechanism by which marine organisms may respond to climate shifts is range shifts. The corkwing wrasse (Symphodus melops) is a temperate fish species, inhabiting the coasts of Europe, that show strong indications of current as well as historical (ice-age) range shifts towards the north. Nine neutral microsatellite DNA markers were screened to study genetic signatures and spatial population structure over the entire geographic and thermal gradient of the species from Portugal to Norway. A major genetic break (FST = 0.159 a…
Seasonal dynamics of atlantic herring (Clupea harengus L.) populations spawning in the vicinity of marginal habitats
2014
Published version of an article from the journal PLoS One. Also available from the publisher: http://dx.doi.org/10.1371/journal.pone.0111985 Gillnet sampling and analyses of otolith shape, vertebral count and growth indicated the presence of three putative Atlantic herring (Clupea harengus L.) populations mixing together over the spawning season February–June inside and outside an inland brackish water lake (Landvikvannet) in southern Norway. Peak spawning of oceanic Norwegian spring spawners and coastal Skagerrak spring spawners occurred in March–April with small proportions of spawners entering the lake. In comparison, spawning of Landvik herring peaked in May–June with high proportions f…