Linking genetic assignment tests with telemetry enhances understanding of spawning migration and homing in sea trout Salmo trutta L.

Abstract

Telemetric and molecular techniques are powerful tools for investigating patterns of species dispersal, habitat use, and reproductive behavior. Yet, these methods are rarely combined when studying spatial structures of migrating animals. This study combines migration data with genetic assignment tests of radio-tagged sea trout, Salmo trutta L., in two Swedish rivers. We investigate how the genetic information enhances the interpretation of the telemetry data. Individual gene frequencies of tagged fish are assigned to baseline samples of brown trout collected in tributaries and the main stems. The genetic assignment tests confirm that individuals returned from the sea to their natal stream, but also suggest that some individuals migrated to other than their native habitat. In total, 82% (R. Piteälven) and 37% (R. Vindelälven) of fish that were successfully assigned to a sample in a baseline migrated to an area in the vicinity of the sample location. The difference between rivers is likely due to low genetic differentiation among baseline samples and effects of stocking of fish in the R. Vindelälven. Combining the two techniques enhances understanding of migration behavior, important for conservation and management.

Tracking animals in freshwater with electronic tags: past, present and future

“…Such advances have increased the complexity of questions that can be addressed and provide more mechanistic explanations of animal behaviour through hypothesis testing (reviewed in [134]). This can be accomplished with integrative studies that combine techniques in parallel (for example, a study that has a laboratory and field component), by obtaining nonlethal biological samples from tagged animals (for example, stable isotope analysis [135], genetic tests [136], physiological status studies [27,137]), or by experimentally manipulating tagged animals (for example, hormone manipulations [138], controlling feeding [139], cortisol injections [59]) or their environment (for example, temporary holding studies followed by release [140]). …”

Assessing the consequences of habitat fragmentation for two migratory salmonid fishes

“…Connectivity can be assessed at different scales (Lowe and Allendorf, 2010). Here, both telemetry and population genetics are used, a powerful approach that is rarely used to its full extent (but see Ostergren et al, 2012). The methods operate on different timescales and explore different mechanisms (Wilson et al, 2004), and are thus very useful for understanding present-day patterns and also evolutionary processes.…”

Assessing spatial discreteness of Hudson Bay polar bear populations using telemetry and genetics

“…), and migration patterns considering genetic assignments (Östergren et al. ). From a population genetics perspective, telemetric data collected during the mating season may be of particular interest as it pertains to the potential for genetic differentiation if individuals have fidelity to different non‐overlapping mating areas.…”

“…Telemetry data provide tracking of individuals over a short period, compared to molecular markers that provide insights into population structure over longer time spans (Haig et al 1997). Despite the potential gain of integrating telemetric data with genetic marker information, their combination is uncommon, though some studies have investigated space use and genetic relatedness (Støen et al 2005, Shafer et al 2014, and migration patterns considering genetic assignments ( € Ostergren et al 2012). From a population genetics perspective, telemetric data collected during the mating season may be of particular interest as it pertains to the potential for genetic differentiation if individuals have fidelity to different non-overlapping mating areas.…”