Tahoe Non-Native Warmwater Fish Ecology and Management

Looking at Lake Tahoe from below the surface

Project Overview

In recent years, small satellite populations of non-native warm water fishes (e.g. largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus) have been found along the shoreline of Lake Tahoe. These populations are likely sourced from a larger, more established population in the Tahoe Keys. Non-native warm water fishes thrive in the warm, nutrient rich waters of the Keys. Their establishment has virtually eliminated native minnow population (e.g. Lahontan redside Richardsonius egregious and speckled dace Rhinichthys osculus) from the Keys’ lagoons. Lake-wide establishment of these non-native fishes can significantly impact the native biota of Lake Tahoe.

A series of research, ranging from distribution surveys, diet analysis, establishment projection models, to risk assessment based on water temperature projections have been conducted by researchers at AEAL and our partners (e.g. California Department of Fish and Wildlife, Nevada Department of Wildlife, Tahoe Resource Conservation District, TRPA, etc.) to examine the ecology of these nonnative warmwater fish species in Lake Tahoe. Information gathered is then used for the development and assessment of nonnative warmwater fish management strategies.

From 2011 to present, a pilot control study is underway to determine the feasibility and effectiveness of using mechanical removal methods for management of nonnative warmwater fishes, and in turn, examine how warm water fish removal may facilitate native fish restoration in Lake Tahoe. Mechanical removal of nonnative fishes in other lake systems has shown promising results in reducing nonnative fish reproductive success, limiting their recruitment, and helping restore native fish communities. This goal of this program is to examine the possibility of reducing the reproductive population of non-native warm water fish in Lake Tahoe to a controllable level through the use of non-chemical methods.

Project Photos

Christine Ngai Snorkeling in Lake Tahoe Brown Trout Electrofishing survey in Lake Tahoe Hydroacoustic receiver covered by aquatic weed Hydroacoustic transmitter tag surgery Juvenile Brown Trout found in Lake Tahoe Lahontan Redside Shiner eggs Christine Ngai Snorkeling in Lake Tahoe Largemouth Bass in Lake Tahoe

Publications and Field Reports

Tahoe nonnative fish research and identification guide