You are here:
Patterns of d18O in fish tissues in two Oregon Coast range streams
Citation:
CHURCH, M., J. L. EBERSOLE, B. Miller, AND C. WIGINGTON. Patterns of d18O in fish tissues in two Oregon Coast range streams. Presented at 6th International Conference on Applications of Stable Isotope Techniques to Ecological Studies, Honolulu, HI, August 25 - 29, 2008.
Impact/Purpose:
We are using stable isotopes of C, N, O and S (H planned) to study the ecology of coho salmon in streams of the Oregon Coast Range.
Description:
We are using stable isotopes of C, N, O and S (H planned) to study the ecology of coho salmon in streams of the Oregon Coast Range. As part of this work we have examined changes in d18O in coho salmon juveniles (from eggs to smolting) and sculpin (from 0.5 to 20 gm.). For fish of the West Fork Smith River we found a monotonic decline in d18O from coho spawner muscle tissue (+16‰) to eggs (+14.5‰), to recently emerged fry (+12.5‰) to a rapid attainment by juveniles of a near-constant range of d18O (+10.5 to 11.5‰). Sculpin from West Fork Smith River rapidly attained the same range of values as coho in that stream, as did sculpin from another Coast Range stream, Winchester Creek. Attainment of a constant muscle d18O for coho occurred more rapidly (within one month post emergence and at a size range of 1-2 gm) than that of d15N (approximately six months at a weight of 5-6 gm) for the same individual fish, indicating the operation of controls more rapid than growth and tissue turnover alone. Sculpin muscle for fish from Winchester Creek also reached a constant range (from values initially below this range) at a size of 1-2 gm. We hypothesize that direct exchange reactions between tissues and absorbed ambient stream waters (d18O ~ –8‰) largely govern these rapid changes. Oxygen stable isotope values in fish muscle might prove useful (especially in combination with other isotopes and other tissues) as an indicator of timing of fish movement between waters (e.g., large mainstem vs. small tributaries) possessing different values of H2d18O.