Using stable isotope analysis with telemetry or mark-recapture data to identify fish movement and foraging

Abstract

Information about animal movements has often been inferred from stable isotope analysis (SIA), but is dependent on animals assimilating site-specific isotopic signatures via diet. This potential weakness in ecological interpretation can be overcome by using other investigative tools that provide precise information about individual movement patterns. In this paper, we demonstrate the value of combining SIA with telemetry or mark-recapture data from trapping, electrofishing and remote detection of individuals to study the movement and feeding ecology of fishes in different habitats. In a fjord lake system in Newfoundland, Canada, juvenile Atlantic salmon delayed downstream migration (smolts) or actively moved into a large lake (parr) where they foraged for periods reflecting different life history strategies. In the Miramichi River (New Brunswick, Canada), SIA provided evidence of distinct foraging habitats (tributary versus large river). By tracking fish implanted with passive integrated transponder (PIT) tags, we distinguished between movements related to foraging versus seeking cool water refugia during high temperature events. Finally, site fidelity and limited mobility of slimy sculpin, a small benthic fish, was established where delta13C in muscle tissue showed a progressive enrichment downstream and where a median displacement of <10 m was estimated for sculpin tagged with PIT tags. Technological improvements have permitted non-destructive tissue sampling of wild fishes for SIA, and the tagging and remote detection of animals smaller than was previously possible. These advancements and the combination of investigative tools promise new insights into animal ecology.

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]). …”

Preliminary examination of food web structure of Nicola Lake (Taim Hydrological System, south Brazil) using dual C and N stable isotope analyses

“…Further food web studies in Taim's wetlands should include additional primary producers (e.g., phytoplankton, benthic microalgae) and consumers (e.g., benthic invertebrates, zooplankton and other fish species) to provide a more complete and detailed description of food web structure and dynamics. The isotopic ratio method could also be used to investigate ontogenetic changes in diet (Genner et al, 2003), temporal and spatial variation (Deegan & Garritt, 1997;Dalerum & Angerbjorn, 2005) and material transfers associated with animal movements (Cunjak et al, 2005;Herzka, 2005). Stable isotope analyses have been underutilized in investigations of food web structure within protected areas in Brazil.…”

Contributed Review: Source-localization algorithms and applications using time of arrival and time difference of arrival measurements

“…Telemetry systems are widely used to track fish to observe their behavior and obtain other information such as seasonal changes (e.g., preferences for water depths or temperatures), foraging behavior, habitat utilization, home range size, spawning behavior, site fidelity, and mortality (Priede et al, 1990;Metcalfe and Arnold, 1997;Roussel et al, 2000;Meyer et al, 2000;Cunjak et al, 2005;and Skalski et al, 2001). Because many fish of interest are small, methods for implantation of sources within their bodies or external attachment are an important topic of research.…”