Abstract
The distributional response of marine fishes to climate warming would be expected to be very different than that of homeothermic birds and mammals, due both to more direct thermal effects on poikilothermic fish physiology and on reduced habitat fragmentation. In this study, we use a combination of linear models and graphical tools to quantify three-dimensional distribution shifts in 82 fish species caught in 5390 standardized groundfish survey tows over a 22-year time frame in the highly-productive sub-Arctic waters around Iceland. Over a 1 °C range, temperature significantly modified the distributional centroids of 72% of all fish species, but had relatively little effect on diversity. Most of the geographic shifts were to the northwest, and there was no overall tendency to move to deeper waters. A doubling of species abundance significantly influenced the distribution of 62% of species, but lacked the poleward orientation observed with temperature increases. Stenothermal species, those near their upper or lower thermal limits, and those with restricted spatial ranges were most likely to shift their distribution in response to climate warming, while deepwater species were not. A 2–3 °C warming of marine waters seems likely to produce large-scale changes in the location of many sub-Arctic fisheries.
Highlights
The distributional response of marine fishes to climate warming would be expected to be very different than that of homeothermic birds and mammals, due both to more direct thermal effects on poikilothermic fish physiology and on reduced habitat fragmentation
There is little debate surrounding the principle that climate warming should induce geographic re-distribution in marine fishes; what has been lacking to this point are quantitative predictions of the magnitude and direction of the re-distribution in a complex ecosystem
Our finding that climate warming will result in a net movement of 72% of the fish species to avoid warmer waters was to be expected, but not so the nonlinearity of the process, the very different sensitivities of the species, and the relatively small effects of depth shifts and fish abundance
Summary
The distributional response of marine fishes to climate warming would be expected to be very different than that of homeothermic birds and mammals, due both to more direct thermal effects on poikilothermic fish physiology and on reduced habitat fragmentation. The location of many spawning grounds and migration pathways is evolutionarily stable, constraining the range of re-distributions that are possible as the environment changes[18] It remains unclear if moderate and gradual temperature increases in the ocean will shift overall distribution independent of natural or fishing-related changes in population abundance. Abundance-weighted distributional data would seem to be the best representation of the entire population, but it is well documented that increased population abundance will expand the range that is occupied, even if the increased abundance is due to an increase in year-class strength or reduced fishing effort[20] Multispecies indicators such as community assemblages and diversity indices have been used in some studies of geographic change[11,21], but the results were not transferable to other regions. In both of these studies, the intent was to infer distributional shifts based on changes in the characteristics of the species or communities, rather than the actual species themselves
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
