Evaluation of Energy Expenditure in Adult Salmon Migrating Upstream in the Columbia and Snake Rivers

The Problem

Salmon ascending a fish ladder.

Many populations of anadromous salmonids are currently in decline in the Pacific Northwest. One factor possibly limiting salmonid production in the Columbia River is an excessive use of energy by adults migrating upstream through the network of dams. In the past, this study has estimated the relative amount of energy used by adult spring chinook salmon (SCHN) during their migration through dams using physiological telemetry. Data from laboratory experiments on the swimming performance, oxygen consumption, and electromyogram (EMG) output of these fish has allowed us to estimate the energy costs of passing Bonneville Dam. Currently, our focus is to determine whether fish have enough energy reserves to successfully reproduce after completing their migration through the hydroelectric system. This project is funded by the U.S. Army Corps of Engineers.

Objectives

Collect a temporal sequence of tissue samples (muscle, viscera, and gonad) to document the proximate composition (i.e., percent water, fat, ash, and protein), energy use during migration, and energy cost of reproduction in adult spring chinook salmon.

Scanning for a PIT tag.

Methodology

For this work, we used a technique called sequential proximate analysis to describe the energy use of adult chinook salmon during their migration. Basically, this technique estimates the energy content of fish tissues at different points during their migration. Since salmon do not feed during their spawning migration, we can use data on energy content of tissues to estimate the amount of energy used during migration and spawning.

For our analysis, we sampled SCHN at the start, middle, and end of their migration to the Yakima River (Washington). To provide an estimate of the energy content of these fish at the start of their migration,

Radio tracking salmon.

we sampled them at the Bonneville Dam adult fish facility. Fish swimming into this facility were collected by our colleagues from the University of Idaho and their origin as juveniles was determined by scanning them for small, electronic tags (PIT tags). Fish with a PIT tag indicating they originated from the Yakima River were weighed, measured, and sacrificed for tissue collection and analysis as described below. Similar samples of fish were collected at the mid-point of their journey, Roza Dam, and at the end of their journey soon after spawning in the Yakima River. To monitor fish movements and final location on the spawning grounds, we tracked fish with radio-tags using telemetry receivers.

To collect tissues, fish were euthanized and a large blood sample was taken from the caudal vasculature. We then dissected the fish and removed and weighed (1) the entire gonad, (2) the remaining viscera, and (3) a sample of muscle. The proximate composition was determined on all samples using standard methods. Using the proximate composition data from each tissue, we will determine the energy content for each tissue type and then derive total energy content of each fish. Using the sequential estimates of tissue and whole body energy content, we will then calculate the

Removing tissue samples from a fresh carcass on the spawning grounds.

energetic costs of different migration histories (e.g., fish that migrated slowly or migrated quickly) and assess the influence of energy reserves on reproductive success.

As an exploratory objective to this study, small portions of the tissue samples were dried, ground to a fine powder, and sent to Northern Arizona University for analysis of stable isotope ratios (ó¹³C and ó¹⁵N). In fasting animals, these stable isotopes become concentrated in tissues as lipids and proteins are used for energy. Consequently, changes in the isotope ratios have been correlated with changes in lipids and proteins during migration in different species of fish. Our intent is to explore this technique as a means to obtain energetic information on fish without sacrificing them.

Taking a muscle sample.

Highlights and Key Findings

The energy reserves of fish at Bonneville Dam can be summarized as follows. Lipid (fat) levels of male and female fish were about 20% in the muscle and 5% in the viscera. In the gonads, females had about 15% lipid and males had almost nothing. Protein levels were about 20% in the muscle and 17% in the viscera (both sexes), and about 25% in female gonads and 15% in male gonads. In the muscle only, we estimated a total energy content of about 11,000 joules/g. For fish sampled at Roza Dam, we noted that energy reserves decreased from about 1 to 5%, depending on tissue. There were no differences in energy reserves between fish that traveled slow and those that travel fast to Roza Dam. Results from our stable isotope analysis indicates that these isotopes were poor predictors of energy reserves, at least in the white muscle. We are currently analyzing data from fish sampled in the spawning grounds.

Where Are We Headed In 2003

We are currently in the final stages of analyzing the data from our spring chinook salmon proximate analysis project. We hope to use all of our data on the energetics of these fish in a bioenergetics model to predict energy use by migrating salmon under various environmental conditions. These model-derived estimates of energy use can then be compared to actual field-based estimates. We also are planning to PIT tag up to 10,000 juvenile coho salmon, a species that migrates in late summer and fall, for use in future studies of salmon energetics. We hope to determine the amount of energy coho salmon need to successfully reproduce and whether migration history has any influence on energy reserves.

Project Contact

Matthew G. Mesa
U.S. Geological Survey
Western Fisheries Research Center
Columbia River Research Laboratory
5501-A Cook-Underwood Rd.
Cook, WA 98605-9717

Email: matt_mesa@usgs.gov
Phone: 509-538-2299 x246
Fax: 509-538-2843

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