fishing planet alaska chinooks where is the bend

The accelerated impacts of climate change at high latitudes are a major threat to Arctic freshwater ecosystems, altering streamflow, warming and drying aquatic habitats causing eutrophication and browning of lakes and allowing for northward range expansion of eurythermic species. Arctic freshwater ecosystems are no exception and recent assessments confirm that ongoing climate-driven changes threaten Arctic freshwater biodiversity. Consequently, environmental impacts on freshwater ecosystems can have a disproportionate effect on interspecific and intraspecific fish diversity. Freshwater ecosystems cover less than 1% of the global surface but support about half of the 30,000 described fish species. Global freshwater biodiversity is in decline and many fish species are at risk of extinction. This information on Broad Whitefish life histories and habitat use across time and space will help managers and conservation planners better understand the risks of anthropogenic impacts and help conserve this vital subsistence resource. Otolith 87Sr/ 86Sr data from juvenile and adult freshwater stages suggest that habitat use changed in association with age, seasons, and life history strategies. Nonanadromous life history types comprised the remainder (collectively, 13%). The semi-anadromous life history type comprised 28% of samples and entered marine habitat as larvae. Anadromous life history types comprised a large proportion of individuals sampled (collectively, 59%) and most of these (59%) migrated to sea between ages 0–2 and spent varying durations at sea. We found evidence of at least six life history types, including three anadromous types, one semi-anadromous type, and two nonanadromous types.

Using laser ablation Sr isotope otolith microchemistry, we analyzed Colville River Broad Whitefish 87Sr/ 86Sr chronologies (n = 61) to reconstruct movements and habitat use across the lives of individual fish. Broad Whitefish ( Coregonus nasus) is an important subsistence species for Alaska’s Arctic Indigenous communities, yet little is known about life history diversity, migration patterns, and freshwater habitat use. Conservation of Arctic fish species is challenging partly due to our limited ability to track fish through time and space, which constrains our understanding of life history diversity and lifelong habitat use.

Fishing planet alaska chinooks where is the bend