Quantifying the behaviour of animals in the wild can provide important information on their ecology and welfare. External biologgers that ‘pop‐off’ to enable tag retrieval have been widely used in marine systems; however, they have only recently been applied to freshwater fishes. As a result, questions remain about the impact that external biologgers have on the behaviour of freshwater fishes. Here, two species of freshwater f...

Food web theory has illustrated that mobile top predators, such as lake trout ( Salvelinus namaycush ), can be potent stabilizers of food webs due to their ability to shift foraging behaviors in response to changing conditions. Consistent with this, research has demonstrated that mean lake trout food web attributes (i.e., trophic position and nearshore coupling) structurally change across environmental gradients; however, intr...

In the present study, pop‐off data storage tags (pDST) without any transmitting capabilities were attached to 118 adult salmonids in a 19 000 km 2 freshwater system (Lake Ontario). The 9·3 cm long cylindrical tags were externally attached to fishes using a backpack‐style harness, set to record pressure (dBar ≈ depth in m) and temperature every 70 s (and at some key times, every 5 s) and programmed to release from the harness a...

The Laurentian Great Lakes (LGL) constitute one of the largest freshwater systems in the world while providing social and economic value to two powerful nations. The spatial scale of these inland seas falls between two endpoints: small lakes and oceans. Lacustrine in many characteristics, the LGL often require a scientific approach with attributes similar to those of oceanography. There is a strong sense that within the LGL su...

This study used stable‐isotope analysis to define the nearshore regional residency and movements of the small‐bodied Australian sharpnose shark Rhizoprionodon taylori . Plasma and muscle δ 13 C and δ 15 N of R. taylori were collected from across five embayments and compared with values of seagrass and plankton from each bay. Linear distances between adjacent bays ranged from 30 to 150 km. There was a positive geographic correl...

Measures of trophic position ( TP ) are critical for understanding food web interactions and human‐mediated ecosystem disturbance. Nitrogen stable isotopes (δ 15 N) provide a powerful tool to estimate TP but are limited by a pragmatic assumption that isotope discrimination is constant (change in δ 15 N between predator and prey, Δ 15 N = 3.4‰), resulting in an additive framework that omits known Δ 15 N variation. Through meta‐...

Rapid climate changes are occurring in the A rctic, with substantial repercussions for arctic ecosystems. It is challenging to assess ecosystem changes in remote polar environments, but one successful approach has entailed monitoring the diets of upper trophic level consumers. Quantitative fatty acid signature analysis ( QFASA ) and fatty acid carbon isotope (δ 13 C‐ FA ) patterns were used to assess diets of E ast G reenland...