Category Archives: Ireland

HAPPY HOLIDAYS!

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After an interesting fall spent mostly dry-docked, we are ending 2009 with a bang as we are heading down to Chile and Rapa Nui in a few hours…a fishing and scouting adventure. 2010 will be filled with exciting things, so stay tuned…in the meantime, we hope that your holidays are filled with oceans of cheer and that 2010 brings many adventures and great exploration!

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July 2: Back in Port

 

I arose to a cloudy foggy morning off the Northern Coast of Ireland.  Looking out of my porthole, I saw the coast shrouded in fog.  It was nice to awake to land outside my window.  The seas have remained calm so we should be in port early.  At this point in the cruise, the crew gets “the channels” which is the kind of itching to get home that makes you want to go faster, like the expression “like a horse to the barn.”  We are definitely all in what I would call “go mode,” with the knowledge of getting off the ship, it is about the only thing you can think about.  We will be getting in soon and in the meantime, enjoy the scenery and our last few hours at sea…

Around 11am, we were at the dock in Killybegs,  All packed up, it is time to do a few last interviews before I head to Dublin.  It is nice to be on land and reflecting back on a very successful expedition. 

 

Why are the salmon “Lost at Sea?”

 

As I have written about in an earlier post, the purpose of this research project, SALSEA-Merge, is to understand the life history of the Atlantic Salmon, and to the figure out why they are not returning to the river after their migration out of the rivers and into the sea.  This expedition is seeking to understand what is happening to these smolts along their journey through genetic testing, etc.  With the knowledge or lack there of about what is actually happening, some of the problems facing these salmon are known.  

Some of the problems facing these salmon include poor water quality in the rivers, over-harvest, discards of post-smolts as bycatch, sea lice, and lack of food when they reach the sea…to name a few.   The first two are clear, the fish need a good habitat to live in and with development, etc, water quality in the river goes down.  This needs to be improved so that the salmon don’t have to battle poor conditions in the beginning (and end) of their lives. 

Overharvest is also straight-forward.  If you take too many fish, there won’t be any spawners left to replenish the populations.  Overharvest is one of the largest problems facing the fisheries of the world and the salmon are right there in this losing battle. 

 

Two Russian trawlers in the distance

 

Bycatch is another issue that is key to the decline of many fisheries, but with the salmon, it was a new idea to me.  The post-smolts follow a similar migratory path to the shoals of mackerel that are targeted by the large Russian factory trawlers using massive surface trawls to harvest the mackerel in large numbers.  While the actual impact of these trawlers is unknown, it is hard to imagine that thousands of post-smolts are not captured in these trawls and processed with the mackerel.  The mackerel and post-smolt salmon occupy the same water and having seen the number of mackerel we captured in the sampling trawls, it is hard to imagine that with the size of the trawlers, they are not impacting the population of salmon. 

Mackerel bycatch from the sampling trawl…100 post-smolts were captured in this trawl…can you imagine how many are taken in the large factory trawls?  it must be thousands!

The other problems are distinct possibilities as well.  Many of the post-smolts we collected had sea lice on them.  I learned on the voyage that if a post-smolt has a certain number of sea lice on it, it will certainly die.  The sea lice attach themselves to the smolts on their way out of the river past fish farms.  Fish farms are the culprit in this game.  As the smolts pass, the nauplii (1st stages of development of the sea lice which are copepods, small crustaceans) attach themselves to the smolt and develop into adult sea lice which will remain on the salmon for the remainder of its life.  The level of infestation of the sea lice is tremendous and is one of the major problems arising from the use of fish farms to rear salmon. 

This salmon is infested with sea lice giving way to poor body condition.

Finally, the populations of the small pelagic fish, herring, mackerel, blue whiting, have boomed in the past years impacting the density of zooplankton in the Norwegian Sea.  With the increasing populations due to good management of the stocks for maximum abundance, the zooplankton has been grazed heavily leaving a sea nearly devoid of zooplankton.  Without zooplankton, our post-smolts have nothing to eat so their body condition is not good and they will not be able to survive without food.  This may be a cycle but it is largely unknown at this point…more research must be done.

With all of the potential problems outlined above, it may be something entirely different, but it is hard to imagine how one of our tiny post-smolts can survive its year-long journey in the sea to return to the river to spawn.  In fact, given all of the human obstacles we have put in front of them, it is remarkable that any return at all.  

 

July 1: Still Steaming

 

We continue to head south on our steam back to Killybegs.  The weather has changed slightly with a low-pressure system to our south sending us some swell and winds.  It is nice to feel the ship move a bit even though it is slight…it actually feels like we are at sea with the gentle roll of a swell. 

 

 

Packing up…The net is ready to be offloaded.

 

The movement gave way to glassy seas once again in the afternoon as we passed by the Hebrides.  The sun came out and glinted off the water and the distant islands making for a beautiful evening on the water.  There were puffins sighted diving for needle fish around the ship. 

 

 

 

With nightfall, the first since leaving Ireland ten days ago, the Irish rains arrived.  It is pouring outside so I don’t anticipate seeing the cliffs of Slieve League and the Irish Coast in the morning, but I will enjoy this final night at sea.  There is something very special and magical about darkness at sea…it is difficult to put into words, but I think that all on board are welcoming this first darkness.  We will be in Killybegs around midday tomorrow.  

 

June 30: Steaming Back to Port

 

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.

 

June 29: Final Day of Sampling

 

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.  

 

 

 

The Anatomy of a Trawl

 

 

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.

 

June 28: Day 3 of Sampling- Back North 68°10’N

 

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.)