Klamath Basin Images
| Microcystin Toxin in Fish and Freshwater Mussels |
Background:In an effort to better inform the public and tribal communities regarding potentially toxic algae (cyanobacteria) blooms, and toxins affecting fish and freshwater mussels, the Klamath Basin Monitoring Program has developed an on-line interactive map for tracking blue-green algae and toxins throughout the Klamath Basin. This work is supported by the Public Health component of the Klamath Hydroelectric Settlement Agreement (KHSA) funded by PacifiCorp. The public health monitoring region encompasses the mainstem Klamath River from Link Dam in Oregon to the estuary, in California including several mainstem tributaries. The monitoring is part of a multi-agency effort by the Bureau of Reclamation, PacifiCorp, Karuk, and Yurok Tribes to provide data on cyanobacteria and related toxins to support public health decisions.
During the summer months in the Klamath Basin blooms of toxigenic algae (Microcystis aeruginosa) and other related species of algae (Aphanizomenon flos-aquae, Anabaena flos-aquae, and Oscillatoria sp.) are common in Copco and Iron Gate Reservoirs. M. aeruginosa produces a toxin, microcystin, a hepatotoxin which affects the liver. The toxigenic algae has been documented hundreds of miles downstream and in some years is found near the mouth of the Klamath River. Large blooms of M. aeruginosa create surface scums which may cover the entire surface of a waterbody (For a detailed map of monitoring locations and bloom conditions, please refer to the Blue-green Algae Tracker). Organisms such as fresh water mussels and yellow perch can ingest M. aeruginosa and there is the potential that the toxin can bioaccumulate in the tissue. Freshwater MusselsIn 2007 and 2009, the Karuk and Yurok Tribes conducted tissue analysis of fresh water mussels collected from the Klamath River mainstem. The results indicated a seasonal pattern of microcystin congeners beginning in July and persisting through December. In 2009 levels of microcystin congeners found in fresh water mussels frequently exceed the lifetime* total daily intake for a child weighing 22 pounds. In some cases, a single meal of fresh water mussels posed an acute* exceedance of toxin. The 2009, study also revealed that, while concentrations of microcystin in the water column were below levels of concern, substantial microcystin bioaccumulation occurred at all study locations. The results of this study, partially funded by the KHSA monitoring, suggest that consumption of freshwater mussels from the Klamath River mainstem should be exercised with extreme caution.
 For more information please refer to the following report:
*Acute Total Intake (250 ppb): single exposure event (e.g. week-end fishing trip). Seasonal Total Daily Intake (40 ppb): ongoing, “daily” exposure for several weeks during the cyanobacterial season. Lifetime Total Daily Intake (4 ppb): ongoing “daily” exposure for many months in settings where microcystin-producing cyanobacteria proliferate perennially. Fish Tissue
The presence of microcystin in fish tissue remains a health concern for the public and tribal communities. It has been proposed that the 2010 tissue sampling include salmon and steelhead liver and fillet samples from sampling locations on the mainstem Klamath, spanning the estuary to the hatchery. However, due to the unseasonably cool temperatures and late rains, the bloom is off to a slow start. Fish and Shellfish Tracker - BetaThe Fish and Shellfish Tracker current contains data from 2009. We plan to expand the Tracker and more data becomes available. How to use the Tracker Select a Matrix and Sampling Date and scroll down to select the desired location, click on the location name. The tracker will automatically navigate to the region of interest. Click on the balloon to see a graph of the cell counts and toxin level for that location
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In contrast to fresh water mussels, yellow perch sampled in Copco and Iron Gate Reservoirs in 2009 had no detectable levels of microcystin. However, the results from yellow perch sampled from Copco and Iron Gate Reservoirs have varied for microcystin over the past few years. Sampling conducted in the summer of 2007, found levels of microcystin in yellow perch fish tissue collected from Copco and Iron Gate reservoirs, exceeding the advisory level of 26 nanograms total microcystin/gram tissue. In 2008 PacifiCorp sampled yellow perch and crappie from Iron Gate and Copco Reservoirs, and rainbow trout from the Klamath River before, during, and after the bloom season; all tissue samples were non-detect for microcystin.