Is Dolly Varden in Arctic Alaska Increasing in Length in a Warming Climate?

Abstract

The body condition, abundance, and size of several vertebrate taxa occupying the Alaskan and Canadian Arctic have increased in this rapidly changing environment. Presently, anecdotal stakeholder reports suggest that anadromous populations of Dolly Varden Salvelinus malma in Arctic Alaska are attaining greater maximum sizes than reported in the past. However, growth analyses have not been conducted for any substantial period of time. To qualitatively examine one facet of growth, we reviewed scientific journal articles, gray literature, and unpublished data for reported maximum lengths of Dolly Varden from the Chukchi and Beaufort seas collected over the past ∼50 y (1969–2015). Regression analyses of maximum length of Dolly Varden from 1969 to 2015 support the observations that the maximum size of this species is likely increasing in a changing Arctic. These results, coupled with the lack of comprehensive growth data, highlight the importance of long-term monitoring of organismal responses to a changing environment and provide valuable direction for future research on this important subsistence resource for Indigenous peoples who inhabit the Arctic.

Fisheries Volume 48 Number 7 July 2023

“…For anadromous species like Dolly Varden and Arctic Cisco, changes across different habitats (e.g., freshwater, estuarine, marine), such as increased availability of marine food resources or riverine overwintering habitat, may alter growth patterns, survival during various life stages, and the frequency of anadromy (Reist et al 2006 ). Observations of anadromous Dolly Varden maximum length from across the Arctic support the theory of increasing growth (Harwood et al 2013(Harwood et al , 2015Courtney et al 2019 ) as climate change warms marine habitats and alters food webs. Given the accelerated rate of change in Arctic ecosystems (Larsen et al 2014 ), conceptualizing the range of potential climate impacts to Arctic fi shes may help fi shery managers, land managers, and communities anticipate and adapt to shifts in the timing and abundance of these key subsistence resources.…”

Climate Change Risks to Freshwater Subsistence Fisheries in Arctic Alaska: Insights and Uncertainty from Broad WhitefishCoregonus nasus

“…For anadromous species like Dolly Varden and Arctic Cisco, changes across different habitats (e.g., freshwater, estuarine, marine), such as increased availability of marine food resources or riverine overwintering habitat, may alter growth patterns, survival during various life stages, and the frequency of anadromy (Reist et al 2006). Observations of anadromous Dolly Varden maximum length from across the Arctic support the theory of increasing growth (Harwood et al 2013(Harwood et al , 2015Courtney et al 2019) as climate change warms marine habitats and alters food webs. Given the accelerated rate of change in Arctic ecosystems (Larsen et al 2014), conceptualizing the range of potential climate impacts to Arctic fishes may help fishery managers, land managers, and communities anticipate and adapt to shifts in the timing and abundance of these key subsistence resources.…”