Saturday, 27 April 2013

Work, work, work (and sea monsters)

It's been a hectic two weeks.

Busy busy busy.

After the weather finally decided to stop chasing us around, we got ourselves over to our study site at the Porcupine Abyssal Plain to start what has probably been the most diverse range of deep-sea work I've encountered on a cruise! We've deployed and recovered environmental moorings, autonomous gliders, and a time-lapse camera ("Bathysnap") that's been photographing the seabed for the last 12 months; we've sliced mud, trapped amphipods and sampled a LOT of water!

Trawling in the Abyss

But the work that I came out here for was the trawling, and despite a couple of minor issues with the net along the way, we managed to catch ourselves a decent selection of fish which will help massively with confirming the species identifications of the fish I'm seeing in my photographs from the region. It's also a bit more data to add to our long-term dataset from the PAP which has been being added to gradually over the last 20 years and is one of only two such datasets to exist in the world, so all of this is pretty valuable.

The benthic fishes include the grenadiers (top four images) and eels (bottom image).
My primary interest is in the benthic fish (the ones that live on or close to the seafloor), like the ones in the image above. However, from a purely photographic point of view it's the pelagic or mid-water species that have been holding my attention over the past few days, because they are brilliantly monstrous little things! Here's a selection (most backgrounds have been photoshopped out and replaced with black):

Female Anglerfish

Female angler fish (head detail).

Gulper Eel (head detail)


As usual though, we unfortunately also collected a lot of litter in our catches. It's not surprising - this far offshore there are few regulations regarding the disposal of waste at sea (it's legal to dump most things once you reach international waters), but it's still a shame to think that even out here in an environment that is so distant from us, we're still disturbing and impacting it.

The litter brought up in our first trawl.

A coke can in the net.  

Thursday, 18 April 2013

Stormy Weather!

Guess where our study site is? I'll give you a clue - it's under where the red bit's going

Well, it’s been five days at sea now, and so far we’ve spent most of that time steaming towards our survey site at the Porcupine Abyssal Plain (PAP) and then bravely running away again! In fairness, the forecast has had Force 11s right over where we want to be working and since those are neither comfortable nor safe conditions to be attempting to launch and recover hundreds of kilos of equipment in, we opted to pick up a monitoring buoy from a nearby site instead and then try and sneak back to our survey site around the back of the weather. The headwinds mean we can only do around 4 knots at the moment (about walking pace) so it’s looking like it’ll be Friday before we can start work at the PAP properly – keep your fingers crossed that we manage to get the fishing gear in the water before we have to come home again!

It's always good value when the sea is actively trying to get in your cabin!
The sun came out today so I took a break from working on PhD stuff in my cabin to try and take a few photos of the gales we’re trying to push through. I’ve got a few videos which show the size of the swell a lot better, but with the restricted internet you’re not going to get to see those until we get back to land! Still, at least we’re not out here in a sailing ship...

A square-rigger we passed yesterday evening. Anyone know what it might be?

Other than occasionally popping outside to admire the weather, I’ve been working on some of the photos from last year’s cruise to the PAP site when we had the AUV with us, and there are some pretty cool images of the fish:

Abyssal fish from last year's cruise - hopefully we'll get to see a few for real when we start fishing

With a bit of luck we’ll get to see a few of these in the flesh if we manage to get the fishing nets in the water this week!

Thursday, 11 April 2013

I'm on a boat...

After a rather hectic weekend of data processing and frantic presentation-writing in time for a meeting yesterday, it's now time to pack up my rigger boots again and head to Southampton for another two weeks at sea for what is likely to be my very last cruise as part of my PhD.

Mud and muddy animals! Yeah! 

This time, we're heading back out to the Porcupine Abyssal Plain to learn how to trawl for sample in deep-water! I've done a similar trip before, but the guys who knew all the details of how to work the gear and get it properly set up are starting to leave or retire now, so there's a bunch of us heading offshore to gather as much knowledge as we can (and hopefully catch some interesting things while we're out there too!).

An abyssal grenadier almost 5000m down

As well as a lot of mud-sampling (it just wouldn't be a trip to the abyss without it!), we'll be conducting at least two seabed trawls and hoping to collect another batch of samples to add to the long-term dataset which has been being collected at the PAP site since the early 1980s to track temporal changes in abyssal animals over the course of several decades to improve our understanding of the fragility of those systems. As always, I'll be on the lookout for fish specimens to bring back with me, and will of course keep you posted on our progress as we go. Keep your fingers crossed for us getting good weather!

Monday, 1 April 2013

Dive Guide: 5th Layby on the Left (Loch Creran)

Site Summary
I don’t know if this site has a real name, but this one is at least descriptive! From the one entrance point you have the choice of diving one of three shallow rocky reefs, all of which are at depths of around 3m - 25m. The off-reef areas are ideal for training on a sandy seafloor, but the real attractions here are the serpulid worms which form beautiful, fragile reefs with their calcareous tubes. For some reason (no-one knows why), this loch is the only site in the world where these worms form large reefs like this and they are well worth seeing.

Type: Shore dive (rocky reef / serpulid reefs)
Depth: 3m-25m 
Tides: None
Suitable for: All diver grades (but good buoyancy essential near serpulid reefs)

Getting there and getting in
From Google Maps. Click to enlarge.

5th Layby on the left site access.

To get to this site, drive north along the A828 towards Fort William, past the Sealife Centre, then turn left at the next roundabout and go under the bridge at the north of Loch Creran. From there (believe it or not!), it’s the 5th passing place on the left. There’s a large parking space there which can fit 4-5 cars. 

Site Access
From the parking bay,  you'll see a path and steps leading down to the shore. It can get a bit slippery underfoot when it's wet or icy so watch out, but basically you just walk straight down the beach and wade in!

You have a couple of options for your dives at this site. See below for details. 

Approximate map of the 5th Layby dive site. Click to enlarge.

Once under the water, you have a few choices to make. 

Option 1: If you head straight out from the shore, you'll swim over a sandy seabed to a depth of around 6m where you'll find a small rocky reef. It slopes down quite steeply to a depth of around 10m and at some point someone has tried to build an artificial reef out of old tyres, so you should find those pretty easily. It's a pretty small area though, so you should see most of it within about 20-30 minutes depending on how thoroughly you explore!

Option 2: Keep the line of rocks on your left and follow them out into the water. As you drop down, you'll see a stretch of bedrock on your left which is covered in mussels and horse mussels. Then just keep this rock face on your left and follow it round to about 12-15m. At that point, you'll come to a bend in the rock and you have two more choices: Either follow the rock round to the left a little then double-back over the top of the bedrock slope (option 2a), or head to the right and explore the boulders further out (option 2b).

Option 2a: Head back up and over the bedrock to a depth of about 6m and then search around and you should find a large serpulid reef (approximately 1m high) which is well worth a look, as well as some smaller colonies. They are extremely fragile though, so do not touch them and do NOT swim over them! From there, continue onwards and you'll get back to your entry point.

Option 2b: This is a route I've only ever taken once, so I don't know it as well as the others. But, if you head out towards the right away from the bedrock slope, you'll find yourself in a boulder field which has some nice life on it. Just retrace your steps to get back or follow Option 2a.

Whichever option you choose, you may find you run into a bit of current once you get past the end of the bedrock slope, but it never gets very strong here and you can swim against it quite easily.

Recommended Equipment

What to See
The serpulid worm reefs are really the main attraction here, but there is a LOT of life on these reefs and they are lovely dives even if you miss the worms. There is a lot of encrusting life over the rock surfaces including plumose anemones, cup corals, Sagartiogeton sp., crabs, fan worms, soft corals and sponges. There’s not usually a lot in the way of fish life, although I’ve seen thornback rays here and quite a few pipefish. In the shallows there are large stands of Ascophylllum seaweeds and horse mussel beds to investigate too which usually have loads of little animals living in amongst them.
Visibility is usually fairly good, but varies a great deal depending on prevailing weather conditions and tide. If you dive here after a period of heavy rain and on an ebb tide the visibility can drop to almost nothing.

On the surface it's pretty common to see seals and otters here too so keep an eye out for those!

Serpulid worm reef at Loch Creran

Greater Pipefish

Close-up of a serpulid worm. The trumpet-shaped operculum is a defining character of this family of worms.

Looking for more? Check out the Dive Guides page!