Seasonal cues of Arctic grayling movement in a small Arctic stream: the importance of surface water connectivity

Abstract

In Arctic ecosystems, freshwater fish migrate seasonally between productive shallow water habitats that freeze in winter and deep overwinter refuge in rivers and lakes. How these movements relate to seasonal hydrology is not well understood. We used passive integrated transponder tags and stream wide antennae to track 1035 Arctic grayling in Crea Creek, a seasonally flowing beaded stream on the Arctic Coastal Plain, Alaska. Migration of juvenile and adult fish into Crea Creek peaked in June immediately after ice break-up in the stream. Fish that entered the stream during periods of high flow and cold stream temperature traveled farther upstream than those entering during periods of lower flow and warmer temperature. We used generalized linear models to relate migration of adult and juvenile fish out of Crea Creek to hydrology. Most adults migrated in late June -early July, and there was best support (Akaike weight = 0.46; w i ) for a model indicating that the rate of migration increased with decreasing discharge. Juvenile migration occurred in two peaks; the early peak consisted of larger juveniles and coincided with adult migration, while the later peak occurred shortly before freeze-up in September and included smaller juveniles. A model that included discharge, minimum stream temperature, year, season, and mean size of potential migrants was most strongly supported (w i = 0.86). Juvenile migration rate increased sharply as daily minimum stream temperature decreased, suggesting fish respond to impending freeze-up. We found fish movements to be intimately tied to the strong seasonality of discharge and temperature, and demonstrate the importance of small stream connectivity for migratory Arctic grayling during the entire open-water period. The ongoing and anticipated effects of climate change and petroleum development on Arctic hydrology (e.g. reduced stream connectivity, earlier peak flows, increased evapotranspiration) have important implications for Arctic freshwater ecosystems.

Generalist feeding strategies in Arctic freshwater fish: A mechanism for dealing with extreme environments

“…oil wells, pipelines and roads) will affect hydrologic processes that are necessary for the movement and distribution of fishes (Heim, Wipfli, Whitman, Arp et al, 2016;Heim, Wipfli, Whitman & Seitz 2016;Laske et al, 2016). Changes in climate patterns (i.e.…”

The complementary role of lentic and lotic habitats for Arctic grayling in a complex stream‐lake network in Arctic Alaska

“…We used stream flow records from 2009 to 2015(Whitman et al, 2011 to calculate average mean daily flow for the months of June to September and compared these to the hydrograph in 2013, the year we collected fish movement data. by backpack electrofisher and angling (Heim, Wipfli, Whitman, Arp et al, 2016;McFarland et al, 2017). The Ublutuoch River is a primary overwintering habitat, and fish use the Crea Creek network during the summer (June-October) only, which is mostly frozen from November to May.…”

“…Mean F I G U R E 1 Crea Creek stream-lake network in Arctic Alaska, depicting lakes (L1-L4), beaded stream channels and locations of streamwide passive integrated transponder (PIT) antenna stations used to study Arctic grayling movement during the open-water period in 2013. Because this group had been at large for more than a year since the time of measurement, we applied an average annual year of growth to each individual using a Fabens' adaption of the von Bertalanffy growth model (Fabens, 1965;Heim, Wipfli, Whitman, Arp et al, 2016). Ephemeral and perennial stream channel designations refer to whether the channels flow all summer or only during spring run-off (June) in typical water years.…”

“…In Arctic Alaska and Canada, Arctic grayling (Thymallus arcticus) use small seasonally flowing tributaries to spawn and forage and migrate to deeper lakes and river habitats to overwinter (Craig & Poulin, 1975;Heim, Wipfli, Whitman, Arp et al, 2016;West, Smith, Barber, Reynolds, & Hop, 1992 (Northcote, 1995). Fry must vacate seasonally frozen natal streams before freeze-up in autumn (Craig & Poulin, 1975), but often show strong site fidelity returning to spawning and foraging areas (Buzby & Deegan, 2000).…”

“…Many of these networks include mosaics of habitats including multiple flow-through lakes and complex permafrost thaw pools within the stream channel (Arp, Whitman et al, 2015;Jones et al, 2017), which may serve as complementary habitat during the summer. Previously, we described how fish move between a large overwintering habitat and a small streamlake network named Crea Creek and found extensive movements that corresponded with seasonal hydrology and individual size and body condition (Heim, Wipfli, Whitman, & Seitz, 2016;Heim, Wipfli, Whitman, Arp et al, 2016). Not yet well understood is how individuals exploit the variety of habitats within this type of stream-lake network and whether there is high variation among individuals in behavioural strategies during this important period of growth.…”