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.