View article

Stable nitrogen isotopes have customarily been used to delineate trophic position with only infrequent regard to source variability. A compilation of literature data supports a previous tentative hypothesis that marine fish are enriched in¹⁵N relative to those inhabiting freshwaters. Estuarine and anadromous fish were also confirmed to have intermediate δ¹⁵N values depending on their respective time spent feeding in either fresh- or salt water. The use of fish δ¹⁵N as a measure of continental-marine coupling in complex coastal environments will therefore provide additional support for analyses based on the more traditionally utilized isotopes δ³⁴S or δ¹³C.