The intense fishing mortality imposed on Atlantic cod in Icelandic waters during recent decades has resulted in marked changes in stock abundance, as well as in age and size composition. Using a molecular marker known to be under selection (Pan I) along with a suite of six neutral microsatellite loci, we analysed an archived data set and revealed evidence of distinct temporal changes in the frequencies of genotypes at the Pan I locus among spawning Icelandic cod, collected between 1948 and 2002, a period characterized by high fishing pressure. Concurrently, temporal stability in the composition of the microsatellite loci was established within the same data set. The frequency of the Pan I(BB) genotype decreased over a period of six decades, concomitant with considerable spatial and technical changes in fishing effort that resulted in the disappearance of older individuals from the fishable stock. Consequently, these changes have likely led to a change in the genotype frequencies at this locus in the spawning stock of Icelandic cod. The study highlights the value of molecular genetic approaches that combine functional and neutral markers examined in the same set of individuals for investigations of the selective effects of harvesting and reiterates the need for an evolutionary dimension to fisheries management.
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http://dx.doi.org/10.1111/j.1752-4571.2010.00176.x | DOI Listing |
Mar Environ Res
January 2025
National Institute of Aquatic Resources (DTU Aqua), Technical University of Denmark, Silkeborg, Denmark.
In the North Sea, offshore oil and gas (O&G) platforms must be totally removed through decommissioning at the end of their productive life. However, the role of O&G platforms in marine ecosystems, especially for fish assemblages, is not well enough defined yet. Here, we document the association between an O&G platform in the North Sea and the fish assemblages along a distance gradient of 1-600 m from the platform.
View Article and Find Full Text PDFJ Fish Biol
January 2025
Polar branch of the Russian Federal Research Institute of Fisheries and Oceanography ("PINRO" named after N.M. Knipovich), Murmansk, Russia.
More than 27,000 stomachs from 70 species of fish were collected from the Barents Sea in 2015. Quantitative stomach content expressed relative to the body weight of the predator fish (g g as %) varied by four to five orders of magnitude for six species with the largest sample size (Atlantic cod Gadus morhua, haddock Melanogrammus aeglefinus, Greenland halibut Reinhardtius hippoglossoides, long rough dab Hippoglossoides platessoides, polar cod Boreogadus saida, and Atlantic capelin Mallotus villosus). The quantitative stomach contents of individual fish followed a common and strict statistical relationship for predator species or groups of species (by families), and for prey categories across predator species.
View Article and Find Full Text PDFSci Total Environ
January 2025
Department of Arctic and Marine Biology, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
Increased industrial offshore activities in northern waters raise the question of impact of polycyclic aromatic hydrocarbons (PAHs) on key Arctic marine species. One of these is the ecologically important polar cod (Boreogadus saida), which is the primary food source for Arctic marine mammals and seabirds. In the present work, we have conducted the first comprehensive proteomics study with this species by exploring the effects of dietary PAH exposure on the hepatic proteome, using benzo[a]pyrene (BaP) as a PAH model-compound.
View Article and Find Full Text PDFR Soc Open Sci
January 2025
Institute of Marine Research (IMR), PO Box 1870, Bergen N-5817, Norway.
When haemoglobin genotyping was implemented in the early 1960s to investigate population genetic structure in Atlantic cod (), it became one of the first molecular genetic markers deployed in fisheries research worldwide. However, its suitability was questioned due to its potential for selection. While the issue of neutrality concerned the first population geneticists, markers under selection are now routinely used to study population genetic structure.
View Article and Find Full Text PDFJ Fish Dis
December 2024
Department of Fish Health and Biosecurity, Norwegian Veterinary Institute, Oslo, Norway.
Atlantic cod farming experiences renewed growth in Norway, and increased awareness is essential to address emerging diseases in this species. There are few reports on gill diseases in cod, and to date, no viral gill infections of cod have been documented. In this study, we collected samples from three sequential time points in summer 2023 from farmed cod suffering from cardiorespiratory disease.
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