A Synthesis of Tagging Studies Examining the Behaviour and Survival of Anadromous Salmonids in Marine Environments

Abstract

This paper synthesizes tagging studies to highlight the current state of knowledge concerning the behaviour and survival of anadromous salmonids in the marine environment. Scientific literature was reviewed to quantify the number and type of studies that have investigated behaviour and survival of anadromous forms of Pacific salmon (Oncorhynchus spp.), Atlantic salmon (Salmo salar), brown trout (Salmo trutta), steelhead (Oncorhynchus mykiss), and cutthroat trout (Oncorhynchus clarkii). We examined three categories of tags including electronic (e.g. acoustic, radio, archival), passive (e.g. external marks, Carlin, coded wire, passive integrated transponder [PIT]), and biological (e.g. otolith, genetic, scale, parasites). Based on 207 papers, survival rates and behaviour in marine environments were found to be extremely variable spatially and temporally, with some of the most influential factors being temperature, population, physiological state, and fish size. Salmonids at all life stages were consistently found to swim at an average speed of approximately one body length per second, which likely corresponds with the speed at which transport costs are minimal. We found that there is relatively little research conducted on open-ocean migrating salmonids, and some species (e.g. masu [O. masou] and amago [O. rhodurus]) are underrepresented in the literature. The most common forms of tagging used across life stages were various forms of external tags, coded wire tags, and acoustic tags, however, the majority of studies did not measure tagging/handling effects on the fish, tag loss/failure, or tag detection probabilities when estimating survival. Through the interdisciplinary application of existing and novel technologies, future research examining the behaviour and survival of anadromous salmonids could incorporate important drivers such as oceanography, tagging/handling effects, predation, and physiology.

Genetic evaluation of the self-sustaining status of a population of the endangered Danube salmon, Hucho hucho

“…While not done in our study, it would also be possible to batch-tag stocked fish (e.g., with coded wire tags, visible implant tags, or fluorescent marking) to support differentiation from wild fish, although it would only be sensible if all stocked fish are marked, with the choice of tag, cost, and efficiency variable dependent on the size of the fish being stocked as well as the expected recovery methodology (Drenner et al, 2012). While not entirely new, recent developments in otolith marking show increased promise for such questions, as the natural differences in water chemistry between rivers and hatcheries should provide a natural mark in otoliths that allow distinction between hatchery and wild fish-albeit individuals must be sacrificed to retrieve the information (Barnett-Johnson et al, 2008).…”

The use of external electronic tags on fish: an evaluation of tag retention and tagging effects

“…Over 20 years ago, Baras [10] reviewed more than 1000 papers from studies using aquatic telemetry and found only 14 to evaluate the effects of external attachment of electronic tags on fish. In 2012, Drenner et al [11], reviewed tagging studies of salmonids in marine environments and commented on the lack of evaluations of tagging/handling effects. A generic problem in such evaluations is to disentangle the various effects of capture, handling, tagging, holding, and transporting wild fish.…”

Migration behavior of maturing sockeye (Oncorhynchus nerka) and Chinook salmon (O. tshawytscha) in Cook Inlet, Alaska, and implications for management

“…Previous telemetry studies in other areas generally indicated that Chinook swam deeper in the water column than Sockeye when studies contrasted depth of migration, and generally moved more slowly (the latter possibly due in at least some studies to tagged Chinook being sexually immature and not undertaking strongly directed homing migrations) [20][21][22][23][24][25]. Drenner et al [26] summarized much of the telemetry literature by noting that '…vertical position in the water column in coastal areas can vary among species and even within species between relatively short distances on continental shelves' and noting that Sockeye '… choose different depths when swimming in well mixed versus stratified coastal waters' , and that '… several species continue to exhibit diel vertical movement patterns during this (that is, the adult) portion of their life'. In Cook Inlet, earlier attempts to identify differences in migration depth by evaluating the depth of fish capture in setnets [27] were considered unsuccessful in providing useful information.…”