2006 Fish Kill
PHOTO CREDIT Harry Foster
January 10, 2007
Fish Kill Report Evaluation by Ottawa Riverkeeper
The Ontario Ministry of Natural Resources (MNR) and the Ministry of Environment (MOE) fish kill report provides important documentation of the fish kill event of August 2006. The report is a synopsis of the events as they unfolded and a summary of the investigation including information on pathology reports, water quality assessments, and some relevant climate data.
In general, the report concludes that the fish kill was a result of a columnaris infection in channel catfish. Columnaris is a fish disease caused by Flavobacterium columnare, a bacterium that is commonly present in the environment. I would concur that columnaris was likely the proximal mortality agent however; columnaris outbreaks tend to be mediated by a number of factors. In this case mortality was primarily restricted to juvenile channel catfish (although there is no data to support MNR’s observation that primarily juveniles were affected). Aspects of channel catfish life history likely contributed to the outbreak. Nonetheless, this fish kill is symptomatic of broader problems in the Ottawa River watershed and beyond, that likely represent the ultimate cause of the fish kill.
The warm water temperatures in the Ottawa River in summer 2006 coupled with other environmental conditions such as eutrophication (nutrient enrichment) and turbidity, could have predisposed channel catfish to columnaris infection. Unfortunately, the government report minimized the importance of point-source pollution or any other source of nutrient enrichment and sedimentation that may have increased stress on the fish. They boldly conclude that “the discharge of untreated sewage did not directly cause the fish kill” yet provide no evidence or data to back up the claim. Fish were not tested for pollutant contamination, only for presence of bacteria or viruses.
The term aquatic ecosystem health is used rather loosely in the report and after sampling a variety of indicator species the authors conclude that “the aquatic ecosystem of the river appeared healthy with no adverse affects observed on these species”. This statement is not backed up by a systematic survey with appropriate controls or longitudinal reference points – what samples were taken, how many and from what locations?
When reporting on public health precautions taken during the fish kill event, the report concludes that “no evidence of impact on human health was observed”. While Ottawa Riverkeeper has no direct evidence of human health impacts, I did speak to three people who claim they got sick after swimming in the river during the week of August 7th. I also had reports of numerous dogs living by the river that got sick at the same time. We will never know if these cases were linked to the water quality at the time of the fish kill.
The water quality data gathered for the analysis was extremely disappointing. The start of the event is identified as extreme temperatures on August 1st and a large storm event on August 2nd. By August 8th Ottawa Riverkeeper and the MNR were receiving many calls about the dead fish. It wasn’t until August 14th that MOE took any water quality samples from the river – a large river with high flows and high flushing rates. Of course these few water samples were of little use to help solve the mystery of the river conditions that may have contributed to the fish kill. It would have been helpful to compare the water temperatures and suspended solids from August of 2006 with other summers. The summer of 2006 was not a particularly hot one; 2005 was much warmer and river levels were much lower. Also, in summers past – particularly in the 1960’s – there must have been much higher nutrient loads in the river when raw sewage was continuously dumped into the river and pulp mills were unregulated and did not have secondary treatment as they do today.
Although findings of the report are somewhat inconclusive given that there are insufficient data, it is apparent that the MNR and MOE have taken the fish kill seriously. The investigation summary draws attention to the limited resources and water quality data that these government agencies have to work with. It is challenging to prove direct causes for the fish kill and the columnaris infection is probably the correct conclusion for eventual mortality, but should be stated as an indirect cause of mortality. It is unfortunate that the report does not provide a basis for the root cause and is therefore unable to predict what could cause recurrences.
Ottawa Riverkeeper would have liked to have seen recommendations for the future – what action needs to be taken to avoid more frequent and extensive fish kills? Climate change coupled with industrial water use can potentially increase river water temperatures. Chalk River nuclear laboratories and pulp mills discard used water into the river at elevated temperatures. Dam impoundments cause surface water temperatures to increase to temperatures higher than those found in a free flowing river. We need to start monitoring water temperatures more closely as fish and other aquatic species are influenced by temperature, particularly when combined with other stressors such as turbidity and nutrient enrichment.
We humans are impacting the river and efforts to reduce our impacts on the Ottawa River watershed are urgently needed to minimize the potential for future fish kills. There are other pathogens beyond Columnaris (e.g., largemouth bass virus) that could result in mortality of other species in the future if environmental conditions are not closely monitored and kept in balance.
December 21, 2007
The Ontario Ministry of Natural Resources and the Ministry of Environment have just released an information report about the Ottawa River fish kill that occured in August 2006.
To download the report, click here: [Fish Kill Report – pdf file: 1.66mb]
If you have any comments or concerns after reading the report, please contact the Riverkeeper.
August 22, 2006
Fishkill Mystery Not Solved Despite Blame Placed on Bacteria
PHOTO CREDIT Harry Foster
An article in the Ottawa Citizen today (August 22nd) reported that scientists have concluded that the bacteria columnaris killed thousands of fish along the Ottawa River. I would like to remind everyone that this bacteria is naturally present in the water and only attacks fish populations that are stressed. We have not yet determined what event or combination of events caused the fish to be stressed. Common stressors include dissolved oxygen levels, water temperature, ammonium and toxins.
Ottawa Riverkeeper is following up with the Ministry of Environment in Ontario to review their water quality data as well as their spills data. In a follow-up with the Pulp Mill at Portage-du-Fort, there were no reported spills during the month of August.
I encourage anyone with information related to the dead catfish to contact me.
Is it safe to swim?
I have been getting many questions about the quality of the river for swimming. The Renfrew County and District Health Unit has lifted their no swimming advisory. They have monitored the water quality at their beaches and the ecoli levels are considered safe for swimming. Click here to read the press release.
For City of Ottawa and Gatineau Beaches, please check the latest monitoring results to see if your local beach is open for swimming. I have heard from a few people who swam in the river and got sick, so be aware of the e.coli levels at the beach – when the beach is closed, it is not always clearly marked so be sure to ask.
Thurs. Aug. 17th – More Lab Results
Today, 2 more fish tested positive for the bacterial infection Columnaris. The MNR has taken live samples (catfish) from the river today to be analysed by the lab.
While it is looking like the fish have been hit with an infection, what we still don’t know is why the fish were stressed in the first place. Read below for the Riverkeeper’s thoughts on the situation…
Wed. Aug. 16th – Updated Information
The Ministry of Natural Resources in Pembroke have confirmed that the one dead catfish fish sent to the laboratory for testing has tested positive for a bacterial infection called Columnaris. The tested fish had high concentrations of Flexibacter columnaris. Bacteria such as columnaris are found in all natural waters and do not affect healthy fish. However, when fish become stressed, they are much more susceptible to diseases. Common stressors include unfavourable water quality conditions such as high levels of ammonia, unfavorable temperatures, or toxins. Columnaris can enter the fish through the gills, mouth, or via small wounds on the skin. The disease is highly contagious and may be spread through close populations.
PLEASE NOTE: These are very preliminary results based on one specimen only! The MNR will be doing some live sampling today.
PRECAUTIONS: For shoreline residents who are finding dead fish, please take caution when handling the dead fish. Ideally, handle the fish with gloves and bury them or put them in garbage bags for disposal.
RIVERKEEPER’S NOTES FROM THE RIVER: I was on the river yesterday with a biologist from the MNR, investigating the reach of the river from Arnprior to Chats Dam. The dead fish we found were primarily catfish, each one of them looking like they had been dead for many days. In the shallows I noticed quite a bit of algae growth, indicative of nutrients – particularly noticeable at the mouth of the Mississipi River.
It is really great to have the fisheries biologists from the MNR investigating this fish kill. These men and women know the river and its fish population better than most and they too work hard to protect the ecological health of the river.
RIVERKEEPER’S FOOD FOR THOUGHT: I believe this fish kill is a result of a combination of factors. Late July and early August were extremely hot days and water temperatures in the shallows soared. Rain events over the week kept soil conditions fairly saturated. On the evening of August 2nd there was a big storm up the valley and rainfall was extremely intense (large amounts fell in a short time period). As a result of the intense rain, there were several sewage spills into the river as well as stormwater runoff. Given that the ground was already fairly saturated (wet), most of this rainfall would have run right off fields, roads, etc. and into the river. The runoff into the river would give the river a blast of nutrients. Breaking down or decomposing these nutrients uses oxygen. Oxygen may have already been low given the high temperatures. Add a dam release of August 6th to this complicated puzzle, perhaps further affecting oxygen levels. MORAL of the STORY: Our actions have direct impacts on the aquatic life in the river. While some conditions are difficult to control (rain events), other factors we can control. The input of nutrients into the river is something we can control. Better wastewater treatment plants with the ability to handle volumes from intense storm events, vegetated buffer strips along the length of the river to reduce the nutrient runoff during rain events, reduce the use of fertilizers and pesticides that we know will end of in the river eventually, maintain your septic systems and pump them every two years. Every little bit helps.Large Fish Kill on the Ottawa River
Photo by Pat Tait
Dead Fish found in Lavergne Bay
Since August 8th, 2006 Ottawa Riverkeeper has been taking calls and emails from concerned citizens who are finding dead fish washed up on their shorelines. Reports are coming from Cheneaux down to Constance Bay, from both sides of the river. The dead fish are primarily catfish, but there have been reports of bass, pike, turtles and a few birds as well. Reports range from a dozen dead fish to over a hundred washing up over a few days. Shoreline residents who have lived on the river for 30 years and more are telling us that they have never seen anything like this before.
Currently the Ontario Ministries of Natural Resources (MNR) and the Environment (MOE) are conducting a joint investigation. Fish samples have been taken to a lab at the University of Guelph for analysis. Ideally the lab will be able to confirm the cause of death, whether from chemicals, bacterial, viral or natural causes. The MNR is on the river again today (August 13th) to take water quality samples and more fish samples. The Quebec Ministry believes the fish kill is a “natural” occurrence and is not undertaking any investigation of its own.
As soon as any causes are known, Ottawa Riverkeeper will post the news on this page.
Since the cause of the fish kill is still unknown, please excercise caution in the affected areas, do not drink water directly from the river and refrain from swimming until further notice. MVCA is recommending that people clean up their beaches and bury the dead fish or bag them for garbage pickup.
Thanks to everyone who has called or emailed with their reports, this information is very useful.
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