|
British Columbia's Fraser River Sturgeon: Canaries in a coal mine Recently, worried professional fishing guides and deeply concerned anglers in British Columbia Canada contacted the Steelheader News sounding an environmental alarm with a rash of reports siting Fraser and Harrison River sturgeon stocks inflicted with mysterious black spots. A possible explanation to the mystery has been offered by Fisheries biologists and some local BC anglers who maintain that the black spots seen on Fraser and Harrison River sturgeon may be caused by a parasite called a fluke, which burrows into the skin of fish resulting in black pigment (about pinhead size) forming in surrounding tissue. However, with the size of black spots now found on fish ranging between .5 to 2 cms, there appears to be a growing body of evidence pointing directly toward possible prolonged exposure to transient ammonia spikes (or other toxins) coming from municipal sewage outfalls and farm waste present in the water causing burns to the sturgeon’s skin tissue. Recent findings of a four-year Lower Fraser Basin study (Fraser River, British Columbia Canada) have shown that some waterways in the Fraser Valley are overloaded with up to 15 times the level of fecal coliform bacteria considered safe by provincial recreational health guidelines; improper manure storage, dumping and spreading by Fraser Valley dairy, vegetable and poultry farmers were cited as being the main causes here. Laboratory experiments involving other fish species have clearly demonstrated ammonia levels as low as .5 parts per million (ppm) can create stress upon fish compromising their natural immune system. Moreover, ammonia levels of 2 ppm can cause the natural immune system of the fish to cease functioning. Ammonia can be extremely toxic to fish, although the extent of its toxicity relates directly to the pH and temperature of the water. In cold water of acid pH the ammonia occurs as NH4+ or ionized ammonia, which is not toxic to fish. Once the pH and/or temperature starts to rise the ammonia begins to convert to its toxic form - NH3- unionized or free ammonia. Very low levels of free ammonia are extremely toxic to fish. Scientists state that the effects of ammonia poisoning are disturbed osmoregulation (the maintenance of the fish's body salts), as ammonia makes the fish more permeable to water. Ammonia also reduces the oxygen-carrying capacity of the fish's blood and causes gill hyperplasia (excessive growth of new cells at the gills), which further hinders oxygen uptake. Other effects include destruction of mucous membranes, and degradation of the brain and central nervous system. The list of damage caused by ammonia on fish is seemingly endless. Additionally, say scientists, a fish does not have the strength to cope with both ammonia-related stress and disease prevention simultaneously. As the elevated ammonia level presents the more immediate possibility of death, all of the fish’s energy must be devoted to combating that threat. It should also be mentioned that a Nitrite is a toxic intermediary product created in the process of breaking down organic waste products such as manure. It occurs between ammonia and nitrate in the nitrification cycle. Nitrite interferes with a fish’s ability to use oxygen. Also present to some degree in our Fraser Valley water systems are remnants of chlorine and chloramine chemicals added by municipal water authorities to kill bacteria in our drinking water. Unfortunately, these substances are also extremely lethal to fish, causing irreversible gill damage. When the Steelheader News (British Columbia, Canada) reported on the Harrison River sturgeon deaths of June, 1999, Lee Nikl, a Federal Department of Fisheries and Ocean's biologist responsible for investigations said a naturally occurring bacteria may have been in part responsible for the yet unexplained mortalities. Nikl stated that a known fish pathogen, Aeromonas hydrophila bacteria was found to be present in the blood and gill tissue of sample sturgeon autopsied in Abbotsford, British Columbia at the time. "Apparently," said Nikl, "as with humans and the plague, not all fish are susceptible to this disease. Perhaps there is something we don't understand that makes certain sturgeon more likely to succumb to the bacteria that breaks down the blood cells in these fish." Steven McAdam, Senior Hydroelectric Impacts Biologist with the BC Provincial Ministry of Fisheries had this to say on the Harrison River sturgeon deaths: "I believe I would be looking for toxics or other multiple stressers before I pointed to the secondary fish pathogen, Aeromonas hydrophila as being the ‘main cause’ of sturgeon deaths." McAdam said that he has asked biologists with Federal Department of Fisheries and Oceans who are in charge of autopsies and toxicoligical tests to check the condition of ovaries in the dead sturgeon. McAdam explained that he has suspicions of unknown stress factors possibly related to illegal toxic chemical dumps, municipal sewage, or a yet undiscovered combination of naturally occurring chemical agents that affect sturgeon in ways we do not fully understand. McAdam, who was responsible for writing the final report on the Fraser River's 1993-94 sturgeon mortalities, also said the female sturgeon he examined had an odd ovary condition. He went on to say that of the 8 dead sturgeon found in Harrison Lake in July of 1988, and the notable die-off of white sturgeon in the Lower Fraser River during the summer/fall period of 1993 and 1994, the majority were large females. He also felt that multiple stressers may have been present previous to the female sturgeons’ spawning periods. These unknown stress factors might have forced the female sturgeon to resorb their eggs. Thus throwing the sturgeons’ biological clock completely out of tune with nature. McAdam went on to explain that known toxins collect in the fatty tissue of ovaries in female sturgeon. When the sturgeons’ biological clock is thrown out of time because of possible chemical contaminants or unknown multiple stressers, accumulated toxins may be released into their bodies after they forgo the natural process of propagation of their species. John Werring, a fisheries biologist with the Sierra Legal Defence Fund, had this to say: "I have no reason to suspect the known secondary fish pathogen, Aeromonas hydrophila as being ‘solely responsible’ for the death of sturgeon on the Harrison River. The Aeromonas hydrophila bacteria is ubiquitous (present everywhere simultaneously) and found in both fresh and brackish water throughout British Columbia. This bacteria is related to human sewage and primarily a bacteria found in human diarrhea. I feel the sturgeon would previously had to have been stressed by some unknown factor or agent before succumbing to the effects of the Aeromonas hydrophila bacteria," said Werring. "With respect to Aeromonas Hydrophila being a possible causative factor in the deaths of the Harrison River fish," Werring says McAdam stated, "Bacteriological tests identified a secondary fish pathogen, Aeromonas hydrophila." Werring went on to say, "The key word here is the bacteria is identified as a "secondary" fish pathogen, which is exactly where the literature takes us. Secondary pathogens typically exert their influence on stressed or otherwise compromised organisms. Clearly, McAdams concludes that even the presence of A. hydrophila in some of the dead fish was not sufficient to lead to the conclusion that disease killed the fish." "Aeromonas hydrophila in the Harrison river mortalities could easily have come from the sewage that is being discharged into the river from the town of Harrison. This bacteria is ubiquitous (found everywhere) in fresh or brackish water so its presence on a carcass would not be unexpected, especially if there is a nearby source like a sewage outfall," said Werring. "I am not an expert in fish diseases but I do know something about A. Hydrophila, and unless I saw clear evidence that this organism caused massive trauma to the body (i.e., gas bubbles in the musculature, liquifaction of muscle tissue and organs, gangrene, etc.), I would not be inclined to label it a causal factor in the death of these sturgeon," said Werring. According to scientists with the Cold Spring Harbor Laboratory, New York, who are currently studying several fish pathogens, Aeromonas hydrophila bacteria was said to cause gastroenteritis and sometimes more serious disease (soft-tissue infections, meningitis) in humans. It is also a known fish pathogen, causing hemmorhagic septicemia (blood-poisoning causing copious discharge of blood from the blood vessels) in a variety of fish species. Scientists have found that the infections in fish were usually opportunistic, occurring when the host is immunosuppressed, stressed, or infected with other pathogens. We leave the final decision on this matter up to you the reader: Is Aeromonas hydrophila bacteria or some form of pollution presently being introduced into our waterways possibly responsible for past sturgeon mortalities and the present spotted skin condition on an alarming number of sturgeon in the Fraser Valley,British Columbia, Canada. While many questions are left unanswered in the ongoing spotted sturgeon mystery here in BC, one has to sit back and wonder if sturgeon stocks residing on the bottom of the Harrison and Fraser Rivers (where pollutants just happen to be most heavily concentrated) might be acting like the veritable canary in the mine shaft forewarning mankind of gravely serious environmental problems yet to come? Ken Kristian
|
|
I hope (pray) your wrong Ken! For everyone, and everythings sake.
|
|
Great Ken! Good to see somebody sharing info with the rest of us instead of criticizing. Seemed informative and included different expert opinions. Took me all of 5 minutes to read, probably as long as it does to reach for the thesaurus and look up some big, large, and enormous words! Curious, are their any studies on the Columbia River sturgeon and are the finding's similar. Never heard about the Columbia, just the Fraser.
|
|
Thanks for the info Ken. Very interesting..and yes, even with my tiny brain I was able to read the whole thing and comprehend. Keep us posted as more info comes out. K
|
|
Just a thought Ken. I realise that the chemicals being poured into the Fraser over these past many years will one day be the demise of us all, but .. If stress seems to be the final nail in the coffin of these poor creatures would you not think that being caught and released over and over and over again might be a little stressful on these poor fish??
|
|
Thanks for all the great input -- even the stuff from the little kid in the peanut gallery that can't read! Hey, we were all little kids once upon a time. For anyone wishing to see a couple of recent spotted sturgeon photos and the original article I did regarding the 1993/94 Fraser River sturgeon deaths, you can check them out here: http://www.ufishbc.8m.com/index.html 1. Flyguide: Sadly, I hope and pray that I am right about what's now happening to Fraser/Harrison sturgeon. Can you imagine what might become of our precious sturgeon stocks if no one took the time to care and do something about it? I can assure each and every person that over the past 40-years fishing the Fraser River, I (and others) have never witnessed anything like this spotting on our sturgeon. On another note, In my experience in dealing with the men and women running the big show in our country, the one and only way to get things cleaned up with our environment, vital fish habitat and the fisheries themselves, is to put as much pressure on federal and provincial governments as possible. Please get involved. Join one of our fine fishing groups, or simply write a letter and voice your concerns. It all goes a long ways in speaking for our sport and the fish themselves. 2. William: A good point. Since I love fishing and am not about to give up my right (and yes, we do have a right to fish) to the resource, the only other alternative is a dead fish. I can't see much point in returning to the past, as it took one hell of alot of arguing to get the government swung to catch-and-release only on sturgeon. Believe it or not, I believe we sport-fishermen/women will "all" be seeing much more of catch-and-release in the very near future. Just in case you weren't aware, It's in Fisheries and Ocean's management toolbox and will be ushered in slowly over the next several years. 3. Kevin: Glad to see your posts keeping us all updated on the current shows. Fisherman's Heaven rocks! Don't forget our upper Pitt steelhead trip/show. Catch you soon. Ken Kristian
|
|
Thanks Ken, I am very concerned about the future of all the species affected by our actions regarding the Fraser in the past. I'm actually involved with several fishing and conservation groups, But if there any other ways you can suggest to help please mail me.
|
|
I hope the Fraser River Protection Society (not sure of the name) can get the attention of the news media. It seems like people hear the trouble the Fraser is facing; they get angry; a few weeks later it's all forgotten. We need to keep refreshing the public view of the greatest fishing river in the world. Ironically, I've seen more young sturgeon this last year than ever before. However, we need to clean-up the Fraser and it's polluters
|
|
Ken, thanks for your post. I did read the copy you sent me and responded to you in private.I would just like to put my 2 cents worth in on this discussion as none of the other anglers who have posted on this subject put the hours that I do on the river and angling effort for sturgeon. Last season i was alarmed at the number of spotted sturgeon we caught on the Harison system. You and i had a few discussions as did Dr Marvin Roseneau. To my knowledge there was never a lengthy investigation into the spots or the dead sturgeon that were found on the Harrison. I think the only real way to find out is to start a expensive but needed study. This season we have seen some spotted sturgeon but not at the alarming rate of the past two seasons. We have not had the die offs this year either which could suggest the die offs and spots are related.This is all speculation of course so please don't take this as anything more. The past two years I have been involved in a sturgeon study on the Fraser and Harrison River. Most of the angling is done on the Fraser so most of the 8000 fish we have tagged have been below Agassiz. I personally have tagged approx 1000 sturgeon so I think i have a pretty good idea on Stress and other factors related to recaptures. When sturgeon are stressed due to natural causes or otherwise we see two things. Lack of slime on the outer skin and a redish rash along the underside near the anal fin area. Usually the redish rash is the most noticeable. Out of the approx 1000 fish i have tagged there has been very few fish that had black spots. Most that did were larger Harrison Fish. We have caught several fish that i thought were stressed, for what reason i can't say but i know i have tagged redish marked fish then recaptured them 1 year later and they are fine. William brings up a good point and a question that is asked often. Does catch and release add stress or harm sturgeon? Your first thought would be yes of course, it must add some stress therefore add to the problem. Not that long ago I had pleasure of spending the day fishing with some very knowledgable biologists. These fellows have been studying sturgeon for many years. One study that i was very interested in was their stress study. These biologists wern't studying sturgeon for conservation reason but for a fish farm project that has been underway for several years on the sunshine coast. Without going into long details they had done extensive stress studies on both sturgeon and salmon. The big differance between the two was not a big surprise to me but confirmed what I have always believed. The big differance between sturgeon and salmon was that when a salmon got stressed the stress level would rise quickly, stay high even after release into a pen then slowly drop after a long period, sometimes never recovering. This confirms my belief that the penn stress factor used in studies related to gear types, bait and so on is probably much higher which would then make the study worthless, or atleast change the results dramaticly. Anyway, I guess that a discussion for another time. Back to Sturgeon. Their stress study results on sturgeon were much different. Sturgeon would slowly increase their stress levels and once stress was removed they would quickly go back to normal levels. I guess this is why sturgeon are so calm when we handle them, it's like the gentle giant. Ken, I know you know this but for those who have never caught a sturgeon it's quite incredible. They put up one hell of a battle,but once they give up it's like they become part of you. They are calm, relaxed and very easy to handle. If you handle them properly they usually just lay there and relax while you carefully release them. Once released they swim away like nothing ever happened. I have caught thousands of sturgeon, I care for them and handle them like i would my own children. They are the most spectacular fish that I have ever had the pleasure to learn about, fish for and study. I truly beleive that catch and release does not harm sturgeon, if handled properly these fish can be caught over and over without negitive effects. I have caught many recaptures ranging from 60 cm to 250cm. Out of 8000 fish tagged we have not yet had one fish die.I think that says alot.Last year I had my first fish that i ever caught 2 days in a row. First day on Eulichans, second day on ditch eels, the good news is it's still hasn't learned as it's been caught recently and grew 3 cm. I agree that the issues that ken has raised are important and need to be addressed. We need to understand what these black spots mean, we need to understand the impact of polution, sewer treatment out flow and other factors that effect water quality, sturgeon and salmon.Sturgeon truly are our canary in a coal mine. My biggest fear is that government will do nothing or even worse, over react. Ken,I would like to thank you for all you did during the past few months for anglers and for the salmon on the Fraser. If it wasn't for you there would have been a lot less salmon spawning this year. Letter writing does work.
|
|
Hi Vic, Great stuff! Should you ever have a chance to get your hands on the sturgeon stress study you mentioned above, I'd love to get a copy for my files. Out of twelve large sturgeon we caught two weekends ago off the mouth of the Vedder River (bedsprings, Vic) "all" were spotted to some degree. Regarding the redness you said you saw on the underside of sturgeon. I had mentioned to Marvin Rosenau seeing the same syptoms on fish just prior to the 1993/94 Fraser River sturgeon die-offs.The sturgeon we caught and examined were very reddened in the belly and also seemed extremely lethargic at the time. The following are excerpts from an article written by Dr. Hal Schramm that just might offer an explanation or two: According Dr. Hal Schramm, a fisheries research biologist with the U.S. BiologicalResources Division, Mississippi Cooperative Fish and Wildlife Research Unit and professor in the Department of Wildlife and Fisheries at Mississippi State University when sturgeon are stressed due to a lack of oxygen in the water the actually try and burrow into the lower substrate on the river and rub their skin tissue red and raw. Looking at a body of water from the surface, according to Dr. Schramm, it's hard to imagine the dynamic world below. Yet, in this mysterious, watery environment, fish are governed by many biological forces. Oxygen is among the most critical, as well as the least understood. First, a few facts about fish and oxygen. Oxygen in water is measured in parts per million (ppm). The amount of oxygen dissolved in water is usually in the range of 3 to 10 ppm. Commonly accepted lower limits for fish survival are 5 ppm for most warm-water fishes (bass, carp, crappie, catfish, etc.) and 7 ppm for cold-water species ( salmon, steelhead, trout and sturgeon). Oxygen concentration is inversely related to temperature---cooler water holds more oxygen than warmer water. But because fish metabolism, and therefore oxygen requirements, increase with temperature, fish need more oxygen in warmer water. In other words, just when fish need the most oxygen, it is least available. Besides temperature, other factors affect oxygen concentration. Dr. Schramm goes on to say that oxygen dissolves in water as it mixes at the surface and through underwater plant photosynthesis. In standing water, most oxygen comes from photosynthesis of plants, both rooted aquatic plants (macrophytes) and algae. Algae includes readily visible growths on substrates such as rocks and wood, as well as suspended microscopic phytoplankton. Flowing and turbulent water contains higher levels of oxygen because the water is constantly mixing with the oxygen in the atmosphere. Just as oxygen is added to water, it can also be removed. Respiration of fish and other aquatic animals depletes the oxygen in water. Decomposing organisms and aquatic plants, whether macrophytes (green plants) or phytoplankton, also deplete oxygen. During the day, photosynthesis exceeds respiration and oxygen levels increase; at night, or when light cannot penetrate the water, oxygen levels decline as respiration and decomposition continues. Two final notes, seemingly exceptions to the above information about flowing water, are worth remembering. First, water from underground springs has no oxygen. Where springs enter a lake or stream, no oxygen is present unless that spring water has been aerated by flowing above ground before entering the stream or lake. Second, inflowing water receiving animal wastes or industrial discharges, or water flowing through a shallow marsh, will likely contain little oxygen. Such waters, because they add oxygen-consuming organic matter, may further reduce the oxygen in the receiving lake, stream, or river. Let's not forget pollution from harmful material entering the environment is the primary concern. Municipal and industrial wastewater discharges from sewage and stormwater overflows may contain oils, solvents, paints, pulpmill effluents, gasoline, grease, detergents, road salts and chemical fertilizers used for lawns and agriculture (especially in the Fraser Valley). All may eventually make their way through drainage systems and into the sturgeon's life-sustaining ecosystem. Two key points keep continually popping up when it comes to either the Harrison or Fraser River sturgeon mortalities: animal wastes and wastewater discharges from sewage. Both of these effluents contain certain amounts of ammonia. And we all know where it goes from their. After all is said and done, and we know what type of real survivors the sturgeon are, I think there is an important link between pollution and sturgeon ending up dead. In closing my hopes are that mankind can come to realise that what we spew into our waterways now will eventually return to haunt us later. We live on Earth and it is a closed-containment system. Ken
|
|
Wow, that's wild stuff. I wonder why they burrow? Last spring when water was high, I was fishing just below Old Orchard on the flats. I called in a net to DFO. They arrived 1 hour (4 sturgeon)later to pull the net. They retrieved several early sockeye, and 1- 5 foot sturgeon. The fish looked pretty rough, he probably was tangled for several days. The underbelly was very red, looked like a bad rash. A week or so later I was fishing the same spot. I hooked what i believe is the same fish. It was very red,missing a few scutes and net marks all over it. I measured the length, Girth and Tagged it with a Pit Tag. Approx 8 months later I recaptured it Just above the Harrison, a distance of 12KM. At the time that I recaptured it I had no idea that it was the same fish. Once i got the data back i realized what happened. Tight Lines
|
|
If aerobic exercise is good for us and our pets, why not consider the thought that a battled sturgeon, with proper handling and release, will become stronger, thus healthier in the long run? I'm serious in my statement, so please be gentle with the criticism if there is any.
|
|
Steven, That's a very good possibility.Besides, there shouldn't be any criticism if people are open minded.That's why we have an open discussion site, so everyone can put their thoughts in.Hey who knows, you could be 100% right, and everyone will benefit from it.Keep writing. Brett Pott
|