Issue 18, December 2011

Using 2-Dimensional Telemetry to Track Fish Response to Habitat Features

A large scale 180kHz and 69kHz VR2W Positioning System (VPS) study is currently underway in the Sacramento River, California to track fish response to habitat features for evaluating bank design alternatives. In 2010, researchers Brian Mulvey and Dave Smith of the U.S. Army Corps of Engineers Sacramento District used acoustic 2-dimensional positioning telemetry to investigate the movement behavior of salmon smolts and their predators as they migrate downstream through natural and modified sections of the river.

The primary question the researchers were trying to answer was whether or not salmon use these modified areas as refuge sites from predation and/or for feeding areas. In the initial phase of this study, over 200 smolts were implanted with VEMCO V6 transmitters and released upstream of the VPS system.

Approximately 60 VEMCO 180kHz receivers and associated synchronization tags were placed in triangular configurations along the river. As smolts swam through the river section, the VPS system calculated over 7,000 positions generating tracks similar to the three examples in the image below.

Due to the success of the 2010 experiment, according to Brian Mulvey, they plan on repeating this work in 2011/2012 expanding into other reaches of the Sacramento River.

The coloured dots represent the tracks of three tagged fish. The grey circles show positions of VEMCO receivers.