2021
Rossi, Gabriel J.; Power, Mary E.; Pneh, Shelley; Neuswanger, Jason R.; Caldwell, Timothy J.
Foraging modes and movements of Oncorhynchus mykiss as flow and invertebrate drift recede in a California stream Journal Article
In: Canadian Journal of Fisheries and Aquatic Sciences, 2021.
Abstract | Links | BibTeX | Tags: bioenergetics, ERCZO, foraging behavior, Mediterranean streams, Oncorhynchus mykiss, salmonids, stream hydraulics, video, videogrammetry
@article{Rossi2021,
title = {Foraging modes and movements of Oncorhynchus mykiss as flow and invertebrate drift recede in a California stream},
author = {Gabriel J. Rossi and Mary E. Power and Shelley Pneh and Jason R. Neuswanger and Timothy J. Caldwell},
doi = {10.1139/cjfas-2020-0398},
year = {2021},
date = {2021-02-12},
journal = {Canadian Journal of Fisheries and Aquatic Sciences},
abstract = {Salmonids frequently adapt their feeding and movement strategies to cope with seasonally fluctuating stream environments. Oncorhynchus mykiss tend to drift-forage in higher velocity habitat than other salmonids, yet their presence in streams with seasonally low velocity and drift suggests behavioral flexibility. We combined 3-D videogrammetry with measurements of invertebrate drift and stream hydraulics to investigate the drivers of O. mykiss foraging mode and movement during the seasonal recession in a California stream. From May to July (2016), foraging movement rate increased as prey concentration and velocity declined; however, movement decreased in August as pools became low and still. In May, 80% of O. mykiss were drift-foraging, while by July, over 70% used search or benthic-foraging modes. Velocity and riffle crest depth were significant predictors of foraging mode, while drift concentration was a poor univariate predictor. However top ranked additive models included both hydraulic variables and drift concentration. A drift-foraging bioenergetic model was a poor predictor of foraging mode. We suggest that infall and benthic prey, as well as risk aversion, may influence late-summer foraging decisions.},
keywords = {bioenergetics, ERCZO, foraging behavior, Mediterranean streams, Oncorhynchus mykiss, salmonids, stream hydraulics, video, videogrammetry},
pubstate = {published},
tppubtype = {article}
}
Salmonids frequently adapt their feeding and movement strategies to cope with seasonally fluctuating stream environments. Oncorhynchus mykiss tend to drift-forage in higher velocity habitat than other salmonids, yet their presence in streams with seasonally low velocity and drift suggests behavioral flexibility. We combined 3-D videogrammetry with measurements of invertebrate drift and stream hydraulics to investigate the drivers of O. mykiss foraging mode and movement during the seasonal recession in a California stream. From May to July (2016), foraging movement rate increased as prey concentration and velocity declined; however, movement decreased in August as pools became low and still. In May, 80% of O. mykiss were drift-foraging, while by July, over 70% used search or benthic-foraging modes. Velocity and riffle crest depth were significant predictors of foraging mode, while drift concentration was a poor univariate predictor. However top ranked additive models included both hydraulic variables and drift concentration. A drift-foraging bioenergetic model was a poor predictor of foraging mode. We suggest that infall and benthic prey, as well as risk aversion, may influence late-summer foraging decisions.