After a successful four days of sampling, we are heading back to Killybegs. We have calm seas and light winds for our steam back. The sun was shining this morning but now the fog has once again rolled in. As we were steaming this morning, a large sperm whale cruised by close to the ship. The size and grace of these animals never cease to amaze me.
A sperm whale cruises by in the distance.
On this final day of sampling, we found ourselves back up north…farther north than before. It seems that every day we steam north to start the sampling. The reason for this is to keep up with the migration of the salmon post-smolts. They are funneling along the shelf here off of the Voering Plateau moving with the northerly current.
With the anticipation of heading back to port, everyone was excited to have a great day here on the calm Norwegian Sea. With the net in the water, the sun came in and out most of the day and finally stuck around for the entire haul of the last tow. With the sun shining, the birds were soaring around the ship and the final haul came in yielding a fair number of post-smolts along with an escaped hatchery fish. This adult fish was in very good condition but had been eating seaweed because it looks like fish pellets. This is not a nutritious substitute for the small fish and plankton the fish should be eating.
An adult salmon from the trawl.
We are now steaming back to Killybegs from above the Arctic Circle. It should be a two and half day steam. Hopefully the seas will stay calm.
The evening brought a beautiful sunset as we passed below the Arctic Circle. The sun disappeared behind a bank of fog before we could see it skim across the horizon as it would up here, but it was a stellar evening nonetheless.
Trawls are commonly used to collect fish in fisheries research. They are also a very common way of fishing commercially for pelagic species (like the Russian trawlers we are seeing fishing for mackerel). The trawl being used to capture the post-smolts is not huge like those on a commercial vessel and is designed to stay on the surface. The post-smolts tend to be in the top 3 meters of the water column. Fishing right at the surface reduces our bycatch as well. The trawl is towed for anywhere from one to five hours in specific areas to target the post-smolts.
The net coiled coming off…
The net going out…the teal line is filled with floats to keep the net on the surface.
Floats are attached to the mouth of the net to keep it on the surface.
Large steel doors keep the net open as it is trawled.
The cod end of the net coming on board.
Emptying the cod end of the net…filled with post-smolts.
Just as we thought we had hit our northernmost position, we turned back north and this morning arose to find ourselves at 68°10’N. The first haul of the morning was quite successful so the turn back north seems to be the right decision for finding the post-smolts. We got 50 in our first haul and now the next one is out so it should be interesting to see what we come up with.
The seas are still smiling upon us, as it is calm. We saw our first glimmers of sun in a few days as well but we are in a blanket of fog. Hopefully by midday, it will burn off and we will have the perfect day at sea…this may be wishful thinking…I am quite satisfied with the calm seas and lack of wind.
We came about for the second trawl of the day and headed back north in an attempt to stay in the high concentration of smolts. The numbers were not as good so we are heading back south.
The floats of the trawl coming on deck.
The sun never came back out after noon so the RV Celtic Explorer was in a little bubble of fog for most of the day. There was not much to see so it was a perfect opportunity to catch up on some inside work and get ready for tomorrow, the final day of sampling. I got some great shots of the deck work, and look forward to wrapping up the sampling tomorrow. (Special thanks to all of the deck crew, especially Ken who helped me take the above shot from the gantry.)
Explorers Club Flag #81 at 68 degrees North
After ending the day with a smaller number of post-smolts, we are steaming farther north to sample tomorrow into the northerly current. We should be above 68°N in the morning to begin sampling so in fact our first proclamation of the northernmost point of the voyage will be incorrect.
The day was filled with quite a bit of wildlife though. We saw a few sperm whales cruising on the surface in addition to two minke whales and a fin whale. There are quite a few fulmars following the ship as well.
Sperm Whale Fluke
A fulmar soaring past the ship
I am quite excited to be heading so far north. Perhaps we will get some sunshine but the fog is rolling in so it is not looking promising.
One thing I find interesting on this cruise is that we only sample in so-called daytime hours. Despite the fact that we are above the Arctic Circle and have 24 hours of sunlight, the fish still sense the change in time of day. It is not the darkness that determines the fish behavior but the angle of the sun and light penetration into the water has an effect because of the albedo, the reflectivity of the light on the water. Even though we are in the land (or ocean) of the midnight sun, the fish still move to deeper waters at night. For this reason, we begin sampling in the early morning and end in the late evening noting that our highest concentration of fish are caught in the middle of the day.
We are also finding very small concentrations of plankton in the area. This is peculiar but apparently has been the case in this region of the Norwegian Sea for some time now. One theory is that the abundance of the small pelagic species, herring, mackerel, etc is leading to over-grazing driving the populations down. This will eliminate food for the young salmon on their way to grow and fatten up in the north before heading back to their natal rivers.
There is so much to learn about the Atlantic Salmon and the possible reasons why they are getting “Lost at Sea.” We are only just skimming the surface of our understanding and this cruise and the other SALSEA cruises are seeking to answer the question of what is happening to the post-smolt salmon that are leaving the rivers when they enter the ocean…
In the early morning (0330), We reached the anticipated northernmost point of the cruise, 67.5°N, the starting point for the sampling. The cruise plan was to head to this point and see what we find. If we found a large number of salmon, we would continue north. So with a CTD done and a plankton sample collected, the first trawl of the cruise was put out for one hour to test the waters. In this first haul, we found only one post-smolt so it was determined that we should turn southward to continue our sampling for the day in as Southerly direction. Our second haul was far more productive yielding 50+ salmon.
In addition to the post-smolt salmon, the net captured a few other species that were sampled as well: mackerel, herring and lumpsuckers. Lumpsuckers are one of my favorite fish. I don’t know much about them but they are absolutely beautiful with a crazy turquoise coloration and textured body. The mackerel are in large numbers as we see them on the surface. The population of mackerel and herring in this region is healthy and almost over-abundant due to the intense management of the stocks in the past years.
A small lumpsucker
A Large Mackerel
Herring (these made their way into the galley for breakfast)
We are in international waters. As we headed south, we encountered the Russian trawler fleet, targeting the large mackerel shoals we are seeing on the surface of the sea. These ships are massive, well over 100 meters. One possibility for the loss of the salmon at sea is that large numbers are being discarded as bycatch.
Our sampling trawls stay out for about 3 hours. In that time, there is ample time to spend on the bridge looking for passing wildlife. There were some sperm whales cruising by the boat and someone sighted some orca as well. I missed the orca but saw the sperm whales. Apparently because of the ridge here, we should see quite a few whales and the sperm whales seem to like this area very much. I hope at least one of the whales wants to check out this big green boat so that I can have a closer look at him.
With the day of sampling completed, we will turn and head back north to begin sampling in the morning at a spot close to where we began today. The smolts are moving at approximately 15 nautical miles per day so we must anticipate this movement when choosing where to sample. Essentially, we are looking for the highest concentration of post-smolts along our journey.
As many people know, I set strange goals for myself. One was to set foot on the seven continents before I was 25, I did this…Well going below the Antarctic Circle and above the Arctic Circle before I am 30 is another of these goals. With passing the Arctic Circle this evening at 10:43, I have accomplished this goal! Needless to say, I am very excited so I took a picture next to the map with the location.
We are now above the Arctic Circle just west of the Voering Plateau…Still steaming…
I woke up to a foggy morning with calm seas. We started the day around 63°N and continue to steam north. The water temperature is a balmy 8.5°C (47°F) and the air temperature is around 10°C (50°F). The winds are calm so the fog seems to be sticking with us but the wind is supposed to shift tomorrow so it could clear out some of the fog. I spent some time on the bridge today and saw some passing schools of mackerel on the surface. They quickly went below when they sensed the ship coming but it is always nice to see signs of life on the open ocean.
The rest of the day was spent preparing for the upcoming work which is going to be fast and furious. I have an early morning wakeup call at 3:30 am to get out on deck by 4:00 for the launching of the CTD (Conductivity Temperature Depth Recorder). We should be passing through the Arctic Circle shortly.