Arcata Fish and Wildlife Office
Pacific Southwest Region
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Juvenile Salmonid Monitoring
Arcata Fish & Wildlife Office Fisheries Program

Juvenile salmonid investigations have been conducted by the Arcata Fish and Wildlife Office since 1988. The monitoring efforts utilize frame nets, rotary screw traps, seine nets, electrofishing, and telemetry equipment. The purpose of these projects is to monitor the health, survival, abundance, timing, hatchery contribution, and biological parameters of emigrating anadromous salmonids in the mainstem Klamath and Trinity Rivers. It is intended that this information will provide basic biological information that can be used by freshwater habitat managers and potentially fishery harvest managers. The monitoring of emigrating juvenile salmonid populations in conjunction with habitat availability data and suitability studies may permit for the evaluation of restoration efforts because these studies focus on the juvenile phase of life which is most affected by instream conditions.

Survival and migration behavior of radio-tagged juvenile coho salmon relative to discharge at Iron Gate Dam

Since 2005, the U.S. Fish and Wildlife Service has worked cooperatively with the U.S. Geological Survey, California Department of Fish and Game, Bureau of Reclamation, and the Karuk and Yurok Tribes of California to determine the extent that spring Iron Gate Dam (IGD) flow regimes affect survivorship of coho smolts during their out migration.

biologist using radio telemetry equipment

Klamath River Fish Habitat Restoration Program

Declining fish numbers and controversy amongst competing interests for water in the Klamath River of Oregon and California, underscore the need for a scientifically credible and comprehensive flow study. Addressing gaps in existing information regarding fishery flow needs is a critical first step to resolving difficult and contentious issues in the Klamath Basin.

biologists seining in the Klamath River

Klamath River System Impact Assessment Model

Since 1996, AFWO has supported the development, calibration and validation of the USGS System Impact Assessment Model(SIAM). SIAM is an integrated set of models and data assembled to evaluate and compare the potential impacts of water management alternatives from an ecological perspective. SIAM's goal is to further the process of reaching a decisive consensus on management of water resources in order to stabilize and restore riverine ecosystems, and is meant to be used in the context of the Instream Flow Incremental Methodology. To achieve this goal, SIAM must help quantify consequences of water management alternatives in terms of the major physical, chemical, and biological indicators known or strongly believed to be intimately related to the success of anadromous fish restoration. SIAM is targeted for a portion of the mainstem Klamath River from Upper Klamath Lake, Oregon, to the Pacific Ocean. Important metrics for this evaluation include water quantity, water quality, fish habitat, fish production, and other measures of ecosystem health. USGS and AFWO recently completed an analysis that simulated Chinook salmon smolt production for the hydrologic and meteorological conditions experienced over the past 10 years. The results of this analysis demonstrate how flow regimes can greatly influence mortality rates and provides insight on the quantity and timing of flow necessary to maximize Chinook production.


Juvenile Fish Health

In recent years, Ceratomyxa shasta, an endemic disease to the Klamath River Basin has been documented as a leading cause of mortality of juvenile salmonids emigrating to the Pacific Ocean during the spring. The severity of this disease has lead to its considerable study, including the use of quantitative polymerase chain reaction (QPCR) assays to identify the infectious spores of this disease in filtered water samples.The AFWO, in cooperation with the Hoopa Valley Tribe, and Oregon State University conducted a study in the spring of 2005 to examine the variability in densities of infectious spores across the Klamath River. The study was designed to provide baseline information to guide future monitoring programs on where and how many samples to collect. Study findings are undergoing statistical review and will be submitted to a journal for publication in the spring of 2007.


Last updated: April 16, 2015