Open-ocean orientation and return migration routes of chum salmon based on temperature data from data storage tags

Abstract

Temperature data storage tags were applied to maturing chum salmon Oncorhynchus keta in the Bering Sea during summer 1998, 5 of which were recovered in the coastal waters around Japan. These tags recorded water temperatures experienced by the fish for periods of 62 to 118 d at resolutions of 15 to 30 min. We considered fine-scale aspects of the data by analyzing diel temperature patterns in regard to the migration behavior and orientation of the fish. During the night, temperatures experienced by the fish changed little, and were among the highest temperatures experienced whereas daytime temperatures often showed dramatic changes as the fish changed depth. We analyzed a time series of temperature differences between sunrise and sunset as an indication of progress made by the fish against horizontal thermal gradients, which was assumed to represent changes in latitudinal position. Daytime differences were positive when the fish were migrating to warmer waters, whereas night-time differences were zero or slightly negative. This suggests that the fish made more progress migrating during the day than at night. We also considered large-scale aspects by examining oceanographic data in relation to the temperatures recorded by the tags. Analysis of possible migration routes based on large-scale patterns of sea surface temperature distributions suggests that zonal (east-west) routes are preferred. These data support the hypothesis that chum salmon utilize orientation cues associated with the sun during open ocean migration. However, whether salmon also utilize additional orientation or navigation mechanisms remains to be determined. KEY WORDS: Chum salmon · Data storage tag · Orientation · MigrationResale or republication not permitted without written consent of the publisher

Exceptional aerobic scope and cardiovascular performance of pink salmon (Oncorhynchus gorbuscha) may underlie resilience in a warming climate

“…T opt for many fish species corresponds with the most frequently encountered environmental temperature (Asbury and Angilletta, 2010) and is often close to (or slightly higher than) the temperature that permits optimal growth rates (Brett, 1971;Elliott, 1976;Elliott, 1981;Jobling, 1997). This is clearly not the case for pink salmon, which migrate to the ocean shortly after hatching and thus spend the majority of their lifecycle and growth phase in the marine environment at temperatures below ~10°C (Walker et al, 2000;Friedland et al, 2001;Azumaya and Ishida, 2005;Walker et al, 2006;Morita et al, 2010). Indeed, if the temperaturedependent pattern in aerobic scope is similar in saltwater to that in freshwater, it can be estimated that pink salmon spend the marine phase of their adult life restricted to <68% of maximal aerobic scope, where the absolute aerobic scope would be <12.4mgmin -1 kg -1 .…”

“…While Pacific salmonids generally experience water temperatures below 10°C during the marine phase of their lifecycle (Walker et al, 2000;Friedland et al, 2001;Azumaya and Ishida, 2005;Walker et al, 2006;Morita et al, 2010), summer-migrating species can be abruptly exposed to significantly warmer temperatures (>8°C increment in 1h) as they enter the Fraser River during their oncein-a-lifetime migration to freshwater spawning grounds following cessation of feeding in the ocean [see, for example, fig. 5 of Cooke et al ].…”

Persistent habitat use by Chinook salmon Oncorhynchus tshawytscha in the coastal ocean

“…Such tags have been used widely on Pacific salmonids to characterize migratory patterns in the open ocean (e.g. Ogura & Ishida 1995, Friedland et al 2001) and short-term patterns of habitat use in the coastal ocean (Hinke et al 2005). An ongoing effort to tag Chinook salmon Oncorhynchus tshawytscha off the Oregon and California coasts has yielded numerous tag returns across 5 yr, each with time series of the temperatures and depths used during the time that each fish was at liberty.…”

Ocean habitat use in autumn by Chinook salmon in coastal waters of Oregon and California

“…The descriptions of habitat use that were derived from these studies have helped to infer migratory behaviors (e.g. Candy & Quinn 1999, Friedland et al 2001) and served as a basis for comparing habitat use among salmonid species (e.g. Walker et al 2000).…”