Harmful Plankton Blooms

Plankton blooms are common in the worlds oceans. Plankton is found in the ocean throughout the year. Blooms are caused by large numbers of phytoplankton, microscopic plants that float in the sunlit layers of the ocean. In winter, the water is cool and the daylight is short. This keeps plankton populations low. In the spring and summer, water is warm and there is lots of daylight hours.Blooms begin with sunlight and nutrients being available to the phytoplankton. The plants will grow and reproduce quickly and get so dense that the water gets cloudy. A Heterosigma Bloom turns the water into tomato soup. There is no predicting how long a bloom will last once begun. Could be short lived or last weeks.

Phytoplankton Needs

Remember phytoplankton are plants and plants need sunlight as well as nutrients.Sunlight is needed for photosynthesis, this gives the cells the energy needed for cell growth and division.Phytoplankton need to take in nutrients from the water in order to grow. All species need phosphate and nitrogen and other elements like silicates, iron and sulphates. These nutrients are put into the surface waters from land run-off or by upwelling of high-nutrient deep water.

Plankton Growth

Factors that could influence plankton growth are water column stratification, species compitition and vertical migration as well as a trick called allelopathy. The water column is considered stratified when there is two or more distinct layers. The salinity of the ocean varies anywhere from 0 to 35 ppt (parts per thousand). Normally the salinity is 25-30 ppt. Fresh water when warmed by the sun will sit on top of heavier salt water. When water is stratified there is little or no mixing in the water and plankton can position themselves in the sunnier water for optimal growth. Some phytoplankton (like heterosigma) can swim through the water column using flagella to get the nutrients they need for growth. Many phytoplankton can only divide once per day, others like Heterosigma can divide up to five times per day. Allelopathy is when a species produces substances that kill or retard the growth of other plankton, taking over the water column once again like Heterosigma.

Harmful Concentrations of Plankton

Chaetoceros can be harmful to fish in concentrations of 25-30 cells/ml. Corethron Hystrix can be harmful at levels of 500cells/ml. There have been blooms of Corethron Hystrix with concentrations of 800 cells/ml that have had no mortalities. If more than 20 cells/ml of Heterosigma are seen there is soon to be cause fro concern. Concentrations have reached 100,000 cells/ml. Chattonella have killed fish with low concentrations of 50 cells/ml. Dictyocha have killed salmon in concentrations of 100 cells/ml. Alexandrium Catenella can be deadly to fish as well as humans. It causes PSP (paralytic shellfish poisoning). May be harmful to fish at higher concentrations like 500 cells/ml. 2000 cells/ml of Cochlodinium or or Gymnodinium will kill fish.

Fishfarmer Protocols

Fishfarmers are trained to sample, identify and count harmful plankton. Plankton tows are done instead of discrete samples to determine the initial presence of harmful species. Water samples are taken daily from three depths, 1 meter, 5 meter and 10 meter. Rafter slides are prepared and scanned for harmful plankton. The most dominate species is noted as well as any harmful plankton counts. Environmental conditions are also recorded daily.

In conclusion

Plankton blooms are a natural occurrence in all the oceans. Microscopic organisms survive in the water as well as on the land. Once a bloom occurs around a fishfarm, there is very little a farmer can do. Don't feed, turn on air compressors for bubble mats and in some situations tarping an entire farm are some things that can be done to minimize mortality. It is a sad thing when a Heterosigma bloom kills off half or more of the fish you worked so hard to grow.

Sea Lice and Slice

What is a sea louse?
Sea lice are small marine parasites commonly associated with salmon. There are 13 different species of sea lice found on the coast of British Columbia. Although large numbers of sea lice are usually associated with fish farming, sea lice originated from wild fish and, as early as 1940, long before the development of fish farming, there were reports of high numbers of lice causing severe damage/mortality in wild fish. Sea lice are common on adult salmon, and usually don’t cause major physical damage.

Two lice species typically found on farmed salmon are Lepeophtheirus Salmonis(or Leps for short) and Caligus Elongatus.
Caligus Elongatus
Considered not host specific. a parasite living on fish. It feeds on the mucus, skin and blood of the fish. There are approximately 200 known species. Caligus has been found on more than eighty different fish species in most of the world’s oceans. This louse doesn't seem to be as much a problem as Leps.
Lepeophtheirus Salmonis(Leps)
Grows to a length of 5 mm for the males, 10 mm for the females. Each generation takes about six weeks at a temperature between 10 and 12°C (50-54°F). Found on Pacific Salmon, farmed salmon and the three-spine sticklebacks. As sea lice develop from eggs to adults, they shed their exoskeletons in a series of moults. This creates a number of identifiable life stages.

Life-cycle of Sea Lice
Free-swimming larval stages - Nauplius I, nauplius II.
Immature attached stages - Copepodid, chalimus I, II, III and
Motile stages - (Lepeophtheirus) Pre-adult I, Pre-adult
- (Caligus,Lepeophtheirus) Mature adults

Sea lice in the first two stages are called nauplii. Nauplii can neither feed nor attach themselves to fish. In the next, copepodid, stage, the lice can attach themselves to fish (by a frontal filament). They then moult through four chalimus stages during which they are anchored to a host fish. As pre-adults (two stages) and adults (one, final stage), they can move about the host fish. It appears that they are most damaging to the host fish in these final, motile stages.

Yearly changes in population of Leps on high-seas Pacific salmon
http://www.springerlink.com/content/u833251k87778668/


Salmon Farmers do monthly lice counts, sampling 20 fish per pen in three pens. A BCSFA database is updated every month. Sampling intensity is increased to twice per month when lice levels reach 3 motile per fish.

The DFO is responsible for wild salmon. The province has jurisdiction over salmon farms. They are working together to monitor and manage sea lice levels. In the fall, levels of sea lice on fish farms tends to increase due to the return of wild stock to spawn. Veterinarians treat these fish to reduce lice levels. Typically, SLICE (EMAMECTIN BENZOATE) is used milled in feed.

SLICE (Emamectin Benzoate) Information Released by the Association of Aquaculture Veterinarians of British Columbia, December 14, 2004

SLICE (emamectin benzoate) is a therapeutant manufactured by Schering- Plough for the control of sea lice in farmed salmon. The product was submitted for approval in both the US and Canada in 1999. Both countries have very strict drug approval processes, and both Health Canada’s Veterinary Drug Directorate (VDD) and the US Food and Drug Administration’s Center for Veterinary Medicine are still reviewing the submission. In the interim the product is being used by veterinary prescription in both countries under strictly controlled situations.
In Canada the review of a new veterinary drug must undergo rigorous scrutiny and fully satisfy all scientific requirements under the Regulations to the Food and Drugs Act.i If a submission is accepted and the product is approved, the manufacturer receives a Notice of Compliance from Health Canada specifying the terms and conditions under which the drug can be sold and used. The drug must bear a Drug Identification Number (DIN) on its label. In Canada, Emergency Drug Releases (EDR’s) may be issued by Health Canada’s Veterinary Drugs Directorate to permit the manufacturer of a new drug to sell a limited quantity of the new drug to a veterinary
practitioner. Adequate evidence is required that the drug poses no known health risk to the animals to be treated or to consumers. The veterinarian must make a detailed submission, and after treatment report to the manufacturer and to the VDD on the results of the use of the new
drug, including efficacy and information respecting any adverse reactions encountered. The report must account for all quantities of the drug received.
For SLICE administered under an EDR, the Veterinary Drugs Directorate set an administrative Maximum Residue Limit (MRL) of 50 ppb (parts per billion) and a withdrawal time of 25 days, i.e., the number of days between harvest and the last day the drug was administered.

SLICE is registered in several countries. In Europe, the UK and Chile there is a 0 day withdrawal time and a tolerance of 100 ppb (allowable level of drug in harvested fish tissue). These numbers are derived from risk assessments based on amounts of fish consumed and knowledge of toxicology testing for emamectin benzoate. In Norway the withdrawal time is 175 degree-days (e.g., 17.5 days at a water temperature of 10 degrees Centigrade).
Emamectin is approved for use in Japan and in the US on vegetable crops. In the US, SLICE is also permitted to be used in food fish in Maine under an INAD (Investigational New Animal Drug) process. This requires a veterinary prescription and is monitored by the US Department of Agriculture (USDA). The drug has a 60-day administrative withdrawal period.
US regulations, based on US Environmental Protection Agency (EPA) assessments, allow for use of emamectin benzoate on leafy vegetables, turnip greens, cottonseed, fruiting vegetables and products such as tomato paste. Tolerance for combined residues of emamectin and its
metabolites range from .02 ppm (20 ppb) to .10 ppm (100 ppb). Regulations also establish tolerances for “indirect or inadvertent combined residues of emamectin” in food animals that may consume these vegetables. These range from .002 ppm (2 ppb) in meat of cattle, goats,
hogs and horses to .02 ppm (20 ppb) in liver tissues of cattle, goats, hogs, horses and sheep.
These tolerances are based on average consumption rates for each product and toxicological assessments of emamectin. “Based on these risk assessments, EPA concludes that there is a reasonable certainty that no harm will result to the general population…from aggregate exposure to emamectin residues. ” In the same regulations, emamectin is classified as a “not likely” human carcinogen.
Preliminary information from the British Columbia Ministry of Agriculture, Food and Fisheries indicates that the amount of product administered to farmed fish in British Columbia in 2003 was approximately 0.08 gm/ tonne of fish produced.vii Not all farm salmon sites were treated and, of those that were, only two sites were treated more than one time during the year.
In Canada, food safety testing is the responsibility of the Canadian Food Inspection Agency (CFIA). CFIA may target their testing or do generic testing for all products used in finfish. When EDR’s are approved, Health Canada notifies the CFIA regionally, and prescribing veterinarians are required to contact CFIA prior to the harvest of any populations treated with SLICE. Regulation in British Columbia also requires each lot of finfish sent to a processing plant to be
accompanied by detailed documentation for all therapeutants used. CFIA has tested approximately 100 samples per year Canada-wide for emamectin benzoate in the last two to three years. A large proportion of these samples were negative for emamectin benzoate, and of those that were positive, all were below Health Canada’s limits. As a result CFIA did not have to take any regulatory action during that timeix. In summary, the use of SLICE in Canada follows the strict regulatory controls established for the use of drugs in food producing animals. Withdrawal times in both Canada and the US are stricter than in countries where the drug has already been approved. In the last two to three years testing of harvested fish shows that there has been no finding of emamectin benzoate residues above limits set by Health Canada.

In Summary:
Lice outbreaks generally happen when wild salmon return to streams for spawning. That is what our year round lice sampling data tells us. Our vet then treats those fish with Slice. Our fish are not infected with lice until the next return of wild stock. For SLICE administered under an EDR, the Veterinary Drugs Directorate set an administrative Maximum Residue Limit (MRL) of 50 ppb (parts per billion) and a withdrawal time of 25 days.
It is registered in Chile, Norway, UK, Japan as well as Canada and the US
US regulations allow use of emamectin benzoate on leafy vegetables, turnip greens, cottonseed, fruiting vegetables and products such as tomato paste. Tolerance for combined residues of emamectin and its metabolites range from .02 ppm (20 ppb) to .10 ppm (100 ppb).
CFIA has tested approximately 100 samples per year Canada-wide for emamectin benzoate in the last two to three years. A large proportion of these samples were negative for emamectin benzoate, and of those that were positive, all were below Health Canada’s limits.
Use of SLICE in Canada follows the strict regulatory controls established for the use of drugs in food producing animals. Withdrawal times in both Canada and the US are stricter than in countries where the drug has already been approved. In the last two to three years testing of harvested fish shows that there has been no finding of emamectin benzoate residues above limits set by Health Canada.

Fish Farm Facts

Types of Salmon Grown in Canada.
Atlantic salmon (Salmo salar),Chinook (Oncorhynchus tshawytscha)and Coho (Oncorhynchus kisutch) are the main species of salmon farmed in Canada. Salmon farms can be found in British Columbia, Nova Scotia, Newfoundland and New Brunswick.

Farms get their smolts from Freshwater Hatcheries.
Hatcheries nuture baby salmon in temperature controlled environments until it reaches smolting stage. Smolting is a natural process of physiological changes which enable a salmon to live in salt water. This process takes about eighteen months and the smolts are about 10cm-15cm long and weigh anywhere from 60grams to 120grams.Once transferred to saltwater pens and over the next eighteen months the salmon will grow to the weigh of about 6 kilograms.

Steriods or Growth Hormones.
Some people will tell you that salmon farms feed their fish steriods or growth hormones, this is not true at all. Our fish get fed dry feed pellets which are full of nutrients and essential vitamins tailor made to dietary requirements for salmon and each stage of its life cycle. Two of the main ingredients are fish meal and fish oil. Both are made from forage fish too small and bony for human consumption.

Recommended by Canada Food Guide.
The Canada Food Guide recommends eating at least two portions of fatty fish like salmon per week. Farmed salmon is a rich natural source of protein, DHA omega-3 fatty acids, vitamin D, and other minerals and vitamins essential for health and nutrition.


: How To Fillet A Salmon

Plankton Identification

Plankton are tiny organisms that either move, drift or float about in the water. To classify plankton we can separate it into two groups: Zooplankton and Phytoplankton. Zooplankton eat other things, they are considered animal plankton. Phytoplankton on the other hand are photosynthetic and are considered plant plankton. We are going to focus on Phytoplankton as it is the most cause for concern to a fish farmer.
Phytoplankton can cause harm and create havoc on a fish farm in three major ways.
The first would be Mechanical Irritation.
As the fish breathe through their gills, any plankton in that water will also be filtered through these very sensitive organs. Certain species of phytoplankton like Chaetoceros Concavicorne and Chaetoceros Convolutus have spines that get stuck in the gill tissue and cause irritation. This causes the fish to create mucus which in turn causes the fish to suffocate.
Second major way is Production of Toxins.
Many species of phytoplankton can produce toxins that harm fish. Some of the species would be Heterosigma Akashiwo, Chattonella Marina, Dictyocha Speculum as well as Alexandrium Catenella which causes paralytic shellfish poisoning.
Third major way would be Low Dissolved Oxygen.
Fish start dying if the DO (dissolved oxygen) drops below 4 ppm. Low DO's can be associated with plankton blooms when a thick bloom starts to die off bacteria breakdown the cell material. Bacteria use the oxygen and produce Co2.
Here is a list of 10 different Phytoplankton that a farmer off the east coast of Vancouver Island should be familiar with and has to watch for every single day of the farm stocks life:
Chaetoceros Concavicorne , Chaetoceros Convolutus , Corethron Hystrix , Rhizosolenia Setigera , Heterosigma Akashiwo , Chattonella Marina , Dictyocha Speculum , Alexandrium Catenella , Cochlodinium Polykrikoides , Gymnodinium Mikimotoi.
We take water samples from the 1 meter depth, the 5 meter depth and the 10 meter depth. Each sample is then prepared on a rafter slide and scanned through a microscope. Usually done every morning before the day is started. Once any of the above Phytoplankton are seen its time to be diligent and maybe do your samples after lunch as well. We do environmental samples using a hach do meter. It gives us the DO and Temperature. We then use a secchi disk to tell us the visibility or also known as Turbidity. Then you can use your plankton samples to get the salinity using a refractometer. So to recap, before feeding starts you should know whats in the water at 1m,5m,10m. You should also know the Temperature, DO and Salinity at the three depths and know how far the visisbility is. If all is well, continue on knowing that your fish are safe.

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Random Pictures from a Salmon Farm

I have just joined flickr, so I have uploaded pictures there to check out.
Photo Gallery
Now I'm going to show you some of the fish we catch during our off time. We get to fish in pristine ocean waters, watch whales and dolphins go by, not too mention catch all types of fish.
Last year I was fishing off of the system a little and caught what I thought was a small rock cod, well all of a sudden my fishing rod bent straight down. It continued down until it reached bottom again. Now that little cod couldn't have done that, so I figured I had a masher ling cod. Brought it to the surface and saw a giant fish with a little rock cod in its mouth. Back down it went. I waited a little needing a break from the last surfacing. I started bringing it back up slowly, it pulled but up it was coming, this was by far the biggest ling cod I have seen caught, but they get way bigger apparently. Still like I said this was the biggest I had seen. Up it came and I land it. Wow, what a monster. waited for it to settle down, then weighed it. It was 28 pounds. The biggest one I had caught in the ten previous years was 19 pounds. I had to let this monster live. Hoping it breeds many more years to come. That is something that bothers me by the way, in B.C you have to catch a 65cm ling cod or bigger in order to keep it. That works out to be about 10 pounds or so. But the ling cod take a while to mature, I figure they mature at about the time they get to keeper size. Why take the brood stock who've proven to be survivors and are of age to reproduce. Why not have a max size rather than a minimum size? I don't know, maybe I am missing something. Anyways I always let the big fish go. Rather keep an average size fish. Stay tuned and I will be showing off a nice red snapper caught that same year.

Time Killing on the Farm

With harvesting done on the farm, its time to do a major clean up. Nets and predator nets have recently been removed. Twelve hundred pound weights and chain weights have been surfaced. Loads of scrap rope to clean up. Bubble mats are hanging insides the empty pens and ready to dry out. Everything needs to be pressure washed and cleaned. Then it will be time to setup for smolts after fouling for minimum of three months.

Lots of time to go fishing and crabbing and prawning now. Beautiful sunny day today, working in T-shirts. The ocean is flat calm, looks like a big sheet of glass. Soon it will be time to watch for plankton and low D.o's. Catching lots of prawns right off the system.

I always have luck with seafood just off the system. Catch ling cod and rock cod, snapper and prawns. See seals and sea lions and dolphins almost daily. Last year the guys at this site saw a grizzly on the beach. B.C mainland mountains surround our site, like most people say,"this is gods country." Most beautiful place in Canada by far. Can also be nasty when the storms hit.

Looking forward to showing more pictures and talk fish with you, come back soon, before you go leave a comment on things you'd like to know or see from the farm.

Harvesting Atlantic Salmon

Harvesting Atlantic Salmon in 100'x100' steel pens takes a large seine boat, 2 salmon farmers, gear and knowledge. The idea is to get a certain amount of fish, out of the pens and into a seine boat with minimal stress on the fish and the seine boat leaving on time to get to the plant with a full load.

Ideally, you would have all the gear in place and ready before the boat shows up. That means having a seine full of fish with a trough ready and corks on standby. The equipment you would need to accomplish this is 2 capstans, a seine net with built in gables, 3 seine lines, a set of corks, 2 cork lines and two cork retrieval lines, a trough line, 8 cannonballs and 4 blocks.

The first step is to setup the harvest gear.

The seine net has to be stretched out on the outside walkway with the lead line up on the stantions. The capstans get tied down on the side walkways one and a half stantions in from the outside walkway. The blocks get put on short posts and inserted into the system on the corners of the middle walkway. The other two blocks get tied down on the corners of the outside walkway. The corks are put into the pen and stretched across the middle walkway wall. Tie one cork-line on each end of corks and walk the opposite end to the outside walkway corner and go through the block and leave slack by capstan. Also tie a retrieval line on each end of the corks leaving slack at center walkway corner. Now add pull lines to the seine, one on each corner and one in the middle. Run corner lines through the post blocks and walk the rest of slack back to the capstans.

Now you are ready to pull a seine.

Pulling a seine isn't that difficult when you have the gear and two or three people to do it. Start by fleeting the web and throwing 10-20 feet in and allow the lead line to sink, keeping only the corners of the lead line up and pipped off half a stantion up the side walkways. Now just fleet the rest of the seine into the pen until you get to the other leadline. Before dropping the corners make sure the gable lines are tied to each end of the seine. Wait for the seine to settle and then start jigging the net across the botton of the pen. To jig the net you have to pull the seine line 5-10 feet and then let it go slack. Repeat until the line looks to be as close as possible to the center walkway. Then using the capstan pull the seine net corners up until leadline is pipped on center walkway stantions. Next pull the center rope and start pipping all the sides up. You should now have a full seine of Salmon.

Time to setup the trough.

Start your trough line at one capstan. Go through the half stantion, you may have to drop the main net a little. Feed the trough line between the main net and seine net along the outside walkway wall and then back through the half stantion and tie it off on the cleats of the capstan. The trough line ready, time to pull web for the trough. Pleat three distances of pip to water all along the outside wall. Pull the trough line up with the capstan that isn't tied to by the trough line. Drop 5 cannonballs into trough and drop the pleats. With a little tweaking, this should create a nice large pocket called a trough.

Now drop the trough line so the center of it is about 5 feet below the surface. To minimize stress on the fish in the back of the trough drop a cannonball in on each side and set to max depth. You are now ready for the boat.

When the boat shows up take cannonballs out of back three sides. Starting in the center of the center walkway wall, pull web out. Work out the slack from that wall and work towards the trough. Sometimes the fish will start poring into the trough, sometimes the fish will sound against the net. If the fish are poring in then wait until you think you have a full trough and then pull the trough line up until it is completely out of the water. Adjust cannonballs and net in trough, throw back three side cannonballs and slack back into the pen and wait until boat has pump in and ready to pump. If the fish are sounding we will have to pull the corks. Use capstans and pull the corks evenly until the fish flow into the trough. Again when full, pull up the trough line.

Once the boat has the uplift pump in place and is pumping start forcing the fish towards the bell by pulling web out of trough. Continue working web until trough is empty and repeat the filling process again until the boat is full.

Salmon Farming On The BC Coast

Alot of people on the coast of B.C are against farming Atlantic Salmon. I think that alot of people are not considering the main word, "farming" and also not considering that North America would not have chicken nor cattle if not for "farming". Most people dont go to their local market or restaurant and ask if that chicken or steak is farmed. So why does it happen with Salmon?

I have been working on the fish farms for the last 15 years, directly and indirectly. I started in the industry packing farm fish from the farms to processing plants. Contract work created for ex seineboats stripped of fishing gear and revamped with harvesting gear. I helped harvest Chinook, Atlantic and Coho Salmon. 70,000 pounds per harvest roughly 5 days per week, year round. Think of how well off the wild stock would be to supply that kind of demand.

I've been a proud fish farmer for the last 10 years and have seen how the industry has grown. Experience and technology have made farming salmon easier and better for the environment and people. We use cameras hanging at 20 feet in an 80 foot deep pen to watch the fish eat. We have a feed conversion rate of 1.2 (eg. an fcr of 1 equals 1 pound of flesh for 1 pound of food.) This fcr is by far superior to any other type of farming out there.

Lots of recreational fishermen and kayakers and people out on sailboats stop in to see the farms for themselves. Every single person that has come to tour a site that I have been at had some issues with farming that they learned about through the media. By the time they leave the site, they are informed and surprised at how much their own opinions had changed.

If you would like to hear more about salmon farming or have any questions feel free to post a comment and I will do my best to answer back as soon as possible. I have loads and loads of pictures and can tell you first hand how things are done out on a fish farm.