Advisory: Limit eating Oregon freshwater bass due to mercury

Sharing is caring!

The Oregon Health Authority (OHA) is now advising anglers to avoid eating too many freshwater bass caught anywhere in the state, due to potentially toxic levels of exposure to mercury found in fish sampled from rivers and other water bodies across Oregon.

Interestingly, the April 19 advisory comes less than five months after the Oregon Department of Fish and Wildlife wiped away all catch limits on bass (and some other species) took effect on the Columbia, John Day and Umpqua rivers – three of the best smallmouth bass fisheries anywhere.

There’s a strong argument to be made that removing all limits by one state agency (ODFW) encourages more consumption of the very fish that another state agency (OHA) says could pose serious health problems if eaten in certain quantities – quantities easily achieved by fishing in those awesome waterways.

It’s worth noting that the danger posed by mercury is especially high for developing fetuses and young children but can cause a host of health problems (detailed in the news release included below).

“Removing regulation restrictions encourages consumption,” Herb Doumitt of the Oregon Bass & Panfish Club told us in an emailed statement on the issue. “So ODFW is saying increase consumption while it is theoretically and potentially unhealthy.”

Club members were among warmwater fishing advocates who unsuccessfully lobbied ODFW to put the brakes on removing limits of species like bass, walleye and catfish from the three water bodies.

They see size and numerical limits as protecting trophy fisheries many anglers enjoy, but human health also has been part of this discussion for years.

It is well-known that bass and other lifelong resident fish “bioaccumulate” higher levels of toxins such as mercury during their lifespans, and eating trophy-sized specimens may be more dangerous than eating smaller or shorter-lived fish, or fish like salmon and steelhead and stocked trout that spent the majority of their lives elsewhere.

OHA has long posted advisories, also published in ODFW’s annual Oregon Sport Fishing Regulations, related to specific bodies of water, but this is its first statewide advisory applied to an entire freshwater fish species.

It’s a complex issue in many ways, including the fact that eating fish in generally a very healthy choice. But limiting consumption of certain types of fish or those caught in certain areas can help safeguard health.

It should also be noted that this is not only an Oregon issue. Many states have similar warnings based on mercury and other contaminants including PCBs, dioxins and pesticides. Advisories often are applied to specific bodies of water that have been tested. (Not all have.)

A quick search found that largemouth bass meccas including Texas, Florida and California have advisories for those and other species. So do smallmouth bass strongholds like Minnesota and Michigan. Honestly, choose your state: It’s a much longer list.

To be sure, the Oregon Fish and Wildlife Commission has many (potentially conflicting) interests to consider in decisions related to setting or removing limits, and simplification of the rules that took effect in 2016 was a high priority.

For the Columbia, another goal was to match Washington’s management of warmwater game fish farther up in the system and plans to do the same where the states share the river.

One of the steps they took was to simply stop managing for non-native species in these three rivers, which also contain native salmon and steelhead, including some protected runs. Bass and other non-native predatory fish will eat young salmon and steelhead, to be sure.

Some defenders of our native species give little love to the “green fishes,” although their impact on native species threatened on multiple fronts is up for plenty of debate. And the fact of the matter is, the warmwater fish simply aren’t going anywhere.

Not that ODFW biologists honestly expect that removal of limits (and ensuing greater sport harvests) to improve life for troubled native fish. To wit, the following is from an ODFW staff report to the Commission last August, as the body was considering rule changes:

“While it is unlikely the removal of bag limits will have any real biological effect on salmon and steelhead, it sends a message that the recovery of ESA-listed species is the priority and that fish managers will take all the actions they can to reduce these threats.”

But, other arguments aside and focusing on the health issue, isn’t there a mixed message being sent here? Does the ODFW’s doubt about “real biological effect” to help salmon and steelhead trump the OHA’s clear concern for human safety?

Doumitt said he is very concerned about members of some of the ethnic groups living in Oregon, some of whom make our state’s abundant fish and shellfish a mainstay of their diets.

For one, some people eat not just the flesh but other parts of the fish known to have higher concentrations of mercury. Members of ethnic communities also might not be as aware of advisories due to language barriers, and Doumitt encouraged state officials to do more to get the word out.

For those who want to dive deeper into this issue, keep reading below to find the text of the following three documents:

1) OHA’s news release, which includes important consumption guidelines for bass caught anywhere in Oregon.

2) Excerpts from an August 2015 ODFW staff report describing reasons for recommending removal of catch limits on the three rivers.

3) Excerpts from Herb Doumitt’s email, with greater detail on the club’s concerns.

Also, if you want to catch bass or other warmwater fish in Oregon, follow the links to our many resources from Best Warmwater Fishing in Oregon.

1) OHA issues statewide advisory recommending limited bass consumption
Elevated mercury levels found in fish tissue from many state water bodies

The Oregon Health Authority (OHA) is issuing a statewide advisory for bass due to elevated levels of mercury found in fish tissue sampled from a number of water bodies across the state.

The fish consumption advisory affects bass in all water bodies statewide, including river systems.

“Fish are an important part of a healthy diet, especially migratory fish like salmon, steelhead and trout,” said Dave Farrer, Ph.D., toxicologist in the Environmental Public Health Section at the OHA Public Health Division.

“The elevated mercury levels we’re talking about in bass are of concern to us, but there are some simple steps people can take to reduce their exposure to mercury when consuming bass.”

Bass is the focus of the advisory because it is a resident species—it lives in one place its entire life—and is considered a top predator, eating other mercury-contaminated fish within an ecosystem.

The longer bass live, the more mercury they accumulate. In addition, bass are found across the state in many popular fishing waters, and the amount of data the state has for this species is adequate to warrant a statewide advisory.

OHA recommends the following monthly meal allowances for bass from all water bodies across the state, including river systems:

  • General population—Limit consumption to no more than six meals per month.
  • At-risk populations—Limit consumption to no more than two meals per month.

Mercury was found at levels above established screening values. This means it is high enough to be of concern to human health if fish contaminated with mercury are not eaten in moderation.

For reference, the screening values used by OHA when determining if the concentration of mercury found in fish tissue is a health risk are 0.2 mg/kg for at-risk populations (infants, children, and pregnant or breastfeeding women), and 0.6 mg/kg for the general public. Average total concentrations found in fish tissue from across the state ranged from 0.08 mg/kg to 0.86 mg/kg of mercury.

Tissue samples were taken from 62 bass from 11 water bodies across the state, including eight rivers, two reservoirs and one lake covering each region of the state, from 2008 through 2014.

The statewide advisory and recommended meal allowances cover those water bodies that do not currently have an individual advisory in place for resident fish, including bass. For a list of water bodies with an existing advisory, see the advisory table at

People should follow the recommended meal allowances for fish from these individual water bodies, rather than the statewide meal allowance of six and two.

A meal is about the size and thickness of your hand; for children, a meal is about the size and thickness of a child’s hand.

People who eat too much fish contaminated with mercury can suffer negative health effects over time, such as damage to organs, the nervous system and reproductive system. Fetuses, babies and small children are most vulnerable to the health effects of mercury and, if exposed to high levels, can suffer life-long learning and behavior problems.

For this reason, OHA recommends that pregnant and nursing women, and women of childbearing age (18 to 45), follow the consumption recommendations closely.

Anglers also should not give bass to others unless the recipients are aware of the mercury contamination issue and they understand the recommendations in the fish advisory.

Fish consumption advisories are issued when fish tissue data collected and analyzed verifies that a particular contaminant is over Oregon’s established screening value for that contaminant.

OHA has several advisories currently in place for mercury in resident fish including bass, although fish tissue in many water bodies has not been sampled and analyzed.

Because data for mercury in fish tissue is available for some, but not all, lakes across the state, and because environmental conditions are such that mercury is present in recreational waters and can accumulate in the fish that live there, OHA believes it is necessary to issue a statewide advisory to protect public health.

Issuing a statewide advisory helps prevent confusion and reduces the public’s exposure to mercury when consuming bass from non-monitored water bodies.

The advisory is expected to remain in place for the foreseeable future because mercury can come from both natural and human-made sources, and is transported globally through air pollution.

The monthly meal allowances represent the most consistent health protective recommendations possible based on available fish tissue data. Should more mercury data become available, OHA will evaluate those data and update this and other advisories as practical and necessary.

By issuing the advisory, health officials hope to increase the public’s awareness of fish species they should avoid or limit consumption of, and those they can keep eating. While it is important for people to know about contaminants in fish, it is equally important to keep fish on the table.

Health officials continue to encourage people, including pregnant women, to eat a variety of fish as part of a healthy diet. Migratory fish such as salmon and steelhead are an essential source of protein, omega-3 fatty acids and other nutrients, and are low in contaminants.

Visit to learn more about why fish is good for you, and for other fish-related topics.
Oregon Fish and Wildlife Commission agenda summary from August 2015, as commissioners considered removing limits for these fish.

2) ODFW state report from August 2015, before the 2016 regulations were adopted

(It’s a long summary, which you can read in full here.)

In one part of the report, it was stated generally: “The objective of this project was to simplify and streamline the angling regulations, making them easier to understand. Conservation needs, increased opportunity, consistency and enforceability were also prioritized.”

Elsewhere in the same report:

“For 2016, the department proposes removing the bag limits on warmwater fish (i.e., bass, walleye, and pinfish) in the Columbia, John Day, and Umpqua rivers. Warmwater fish are an abundant and well-established non-native species in the Columbia River and provide abundant and diverse fishing opportunities. ODFW has been approached by the Washington Department of Fish and Wildlife (WDFW), which proposes removing the limits on warmwater fish in the Columbia River. WDFW has already removed bag limits on warmwater fishes above the McNary Dam and is proposing the same regulation for the remainder of the Columbia River. Due to the impacts of predation from warmwater fish on ESA-listed salmon and steelhead, it is the policy of the WDFW to not manage for warmwater fish where they co-exist with listed salmonids, thus the removal of the bag limits. While it is unlikely the removal of bag limits will have any real biological effect on salmon and steelhead, it sends a message that the recovery of ESA-listed species is the priority and that fish managers will take all the actions they can to reduce these threats. In addition, as with any boundary waters, it is highly-desirable to maintain concurrent regulations for enforceability and consistency with the public. The proposed regulations streamline Columbia River rules, are consistent with WDFW’s proposal, will help with enforcement, while providing additional harvest opportunity for anglers.

“The John Day River also has a well-established population of smallmouth bass. Recent information has shown that smallmouth bass have expanded their range into the upper reaches of the North Fork and Middle Fork John Day River and now overlap with the rearing habitat for ESA-listed summer steelhead and sensitive spring Chinook salmon populations. In order to encourage the active removal of bass from the upper John Day River, ODFW proposes removing restrictive regulations in the John Day basin as an important conservation action for native fish. Similarly, ODFW proposes to remove bag limits for bass in the Umpqua River to further simplify the regulations, increase opportunity, and as a conservation measure for native fish. The current regulation allows for the retention of 15 smallmouth bass per day and the Umpqua is the only waterbody in the state where this regulation applies. This proposal would result in clear, understandable, consistent, and easily enforceable regulations.”

3) Pertinent selections from Oregon Bass & Panfish Club’s Herb Doumitt

“First some background, the Oregon Bass & Panfish Club has for decades advised Oregon’s fishermen to eat resident warmwater fish (bass, walleye, channel catfish) in moderation. OBPC has participated in several Portland and Oregon EPA fish sampling efforts building to this announcement. We frequently have guest speakers present programs on the health effects of consuming fish, resident and non-resident.

“That said, OBPC greets and applauds OHA on their mercury health advisory on eating resident fish. We believe it is better to error on the side of caution when it comes to notifying the public on this topic.

“But here’s the problem. Just recently the Department of Fish and Wildlife Commission passed a policy change that removed all bag and catch limits on bass, walleye and channel catfish on the Columbia, Umpqua and John Day Rivers. Removing regulation restrictions encourages consumption. So ODFW is saying increase consumption while it is theoretically and potentially unhealthy. By the way, ODFW has been aware of the upcoming OHA announcement for about a year now, but it still chose a faulty and hazardous direction.

“Now that this information has been formally released to the public, the State should reconcile what is OHA and ODFW are doing. We believe the Governor should be leading this effort. Both OHA and the OFW Commission report directly to her office.

“OBPC also is concerned with local, ethnic communities who consume the whole fish as staple in their diet. Mercury concentrations are higher when the whole fish is consumed versus just the filets. OHA’s advisory should be in multiple ethnic languages and distributed to our ethnic community leaders, churches, and state outreach organizations for announcement and discussion. ODFW is sponsoring a lot of family-focused, youth-focused fishing clinics throughout the state. What a perfect opportunity to educate the fishing public about this health hazard.”