Klamath Basin Fishes and Aquatic Ecology
The Klamath Basin remains at the forefront of controversial water resource issues in the Western U.S. as evident by the 2006 closure and severe curtailment of the Chinook salmon (Oncorhynchus tshawytscha) (ocean fishery along 700 miles of coastline in Oregon and California due to projected poor returns of Klamath River stocks. The Basin’s finite water resources are shared by farmers, ranchers, municipal suppliers, recreationalists, fish, and wildlife. Considerable attention has been focused over the competing demands of water for agriculture and endangered species needs, particularly during dry years. Notable events include a National Research Council report critical of key components of two Biological Opinions, namely recommended lake levels and downstream flows, the death of 30,000 Chinook salmon in the lower Klamath River in September, 2002, and a narrowly averted week-long water cutoff in June, 2003 to meet a Biological Opinion mandated lake level to protect endangered fish. Recently, there has been a concerted effort by stakeholders to negotiate a basin-wide settlement to help resolve water availability and resource issues. The settlement process is proceeding as indicated by the release of a Proposed Klamath Basin Restoration Agreement in January 2008. This document recognizes that much work is needed to resolve resource issues in the Basin and that part of the solution will be the need for reliable biological and hydrological information.
As a non-regulatory science agency, the U.S. Geological Survey is an unbiased source of scientific information for natural resource managers in the Klamath Basin. Data from studies conducted by Klamath Falls Field Station scientists are being used to guide efforts to manage natural resources and endangered species in the Klamath Basin, recover Lost River sucker (Deltistes luxatus) and shortnose sucker (Chasmistes brevirostris) populations to healthy levels, and restore critical habitats. Examples of specific studies include:
- Investigating endangered adult Lost River and shortnose sucker population dynamics in Upper Klamath Lake, Oregon and Clear Lake, California to estimate annual mortality, recruitment into spawning populations, and finite rates of population change.
- Determining habitat use, movement, growth, health, and development of endangered juvenile Lost River and shortnose suckers throughout Upper Klamath Lake, Oregon as well as in and around the Williamson River Delta to help quantify benefits of this restoration project for young suckers.
- Describing the spawning distributions of endangered adult Lost River and shortnose suckers in the Sprague and lower Williamson rivers, identifying sucker spawning habitat in this watershed, and determining the relative abundance and timing of larval sucker emigration from these rivers.