Corystes Blog

Corystes Blog – Danielle Crowley

Day 1, 1/10/18

We left Belfast harbour at 6am today while most of us were still in bed. By the time I was up at 7.30 for breakfast the nets were already down and there wasn’t long to wait for the first trawl.

The trawl routine was that once the catch was placed in the hopper we would go out with baskets to retrieve it. The sharks and rays would be separated by sex and dealt with separately while the rest of the catch was sorted. The process was repeated at each station we got to.

I was supposed to be tagging the sharks, rays and skates that we caught, in addition to taking my DNA samples, but due to unforeseen circumstances this was not possible. However they were still weighed and their length was taken before they were released. I soon found that measuring the length of dogfish could be tricky, as they were determined to make it difficult and often curled into a ball and had to be coaxed to stretch out! This is also a defence mechanism that they use against predators in the wild, in this case us.

Today I encountered four species of sharks, the lesser spotted dogfish, Critically Endangered spurdog, starry smoothhound and nursehound, or bulhuss. I managed to get DNA swabs from all of these except the last one, as the nursehound was quite large and aggressive, and so was released before I could get to it.

More importantly, I got my first set of samples from four species of ray and skate: the blonde ray, spotted ray, thornback ray (which is really a skate) and a cuckoo ray. To reduce the risk of contamination, the swabs were placed inside the spiracles rather than wiped across the skin. This was as they had been in contact with other fish in the net, there was a chance the sequencing process could focus in on the wrong species.

It was fantastic to get my project off to such a great start, and to get the chance to see other fascinating creatures, such as the Nephrops prawns which I have in the freezer ready to take home! (I only got one pinch for the trouble, which I feel is fair).

The day was rounded off by a spot of birdwatching, where we encountered hundreds of gannets, as well as some fulmars, gulls, auks and what may have been a sooty shearwater.

After dinner we kicked back and relaxed while watching The Goonies. You know, because we’re adults.

Day 2, 2/10/18

Today wasn’t terribly good for rays, as I only got to swab two individuals (a thornback and a spotted), but we did catch a wide variety of weird and wonderful creatures.

One of my favourites were the red band fish, which I didn’t know existed until today. They look like mini sea-serpents, complete with sharp teeth and pinkish-red and yellow colours. Some other worthy mentions include some large gurnards, monkfish, octopus and plenty of dogfish, as well as three large and grumpy nursehounds. While lesser spotted dogfish may not be what people typically think of as “proper sharks”, the nursehounds definitely act like it!

As well as taking my samples, I help process the rest of the catch. This involves sorting the animals by species and taking the weights and length frequencies of samples of the catch. This is quickly improving my ID skills, I can now tell a sprat and herring apart with fairly decent accuracy and I’m working on the difference between Norway pout and poor cod. I’m pleased to find that very happy distinguishing haddock and I’ve become better at sorting whiting even over the space of a day.

I also learned that dab have spines. This would have been nice to know before I picked up a handful to measure them.

I spotted the first great skua of the trip in between hauls and I am pleased to announce that I added silica beads to my swabs without spilling any. Yay!

Day 3, 3/10/18

Ray-wise, we started off slow but suddenly in the afternoon we were flooded with cuckoo, blonde, thornback and spotted rays. Some of these were large, at around 85cm in length, and there were so many of them that I’m now down to four swabs! As one of the other scientists has to kill some of the rays for his research on stomach contents I’ve decided to take fin clips from those unlucky rays to supplement my swabs and to save my remaining ones in case something really special turns up.

Two other interesting specimens that appeared in the nets were a river lamprey and a lesser weaver fish. The lamprey was very cool and latched on to whatever fish was nearest to it, in one case a small conger, which was not impressed. When I picked it up it even tried to grab my fingers!

The weaver fish was nice to see as I had always been careful of them when swimming and surfing but had never actually seen one. Their scales have an attractive golden sheen and their eyes are situated right on top of their heads so they can gaze upwards when they’re buried in the sand.

We did get quite a lot of spotted and blonde rays, as well as a few thornbacks. Most of these were released over the side, and we got to see some pretty big male blonde rays. What I didn’t expect to discover while handling the rays was just how slimy they can get, and when there are several of them together in a basket my gloves were very quickly covered in thick, viscous slime. I soon discovered that the bigger ones in particular have pretty numerous and sharp spines, and naturally I managed to draw blood from my finger when I put my hand on the tail of one of the bigger blonde ray males.

Oh well, another minor injury to add to the stabs I’ve gotten from dabs and gurnards, and the pinches from swimming crabs and Nephrops.

Day 5, 5/10/18

Although we started off with calm seas and it being relatively mild, the weather in the afternoon started to take a turn for the worse, with drizzle, wind, increasing swell and a drop in temperature. We are off the coast of Wales today and as we’re staying quite close to shore we get to admire the coastline.

This set of stations are known for being popular with weaver fish, so all of us were extra careful as we sorted the catch. Sure enough, we pulled out several large greater weavers, some over 30cm long, and quite a few lesser weavers. I’ve never been stung by one, and it’s an experience I wasn’t keen to experience for the first time out here!

I also had my first cetacean sighting on this trip today, when I looked up from measuring some fish and spotted a small pod of bottlenose dolphins keeping pace with us. Two of them played in our bow-wave very briefly, while the rest kept their distance. They didn’t stick around for very long.

There was also an increase in bird activity from the almost total lack of them yesterday. I may have spotted a Bonaparte’s gull, at least it seems to be the closest match to what I saw, which is quite exciting as they are a rarity in these parts. However, without a photo it’s hard to confirm this identification completely.

We met several of our old friends, the lesser-spotted dogfish, and some starry smoothhounds and some big tope. We pulled up a few spotted and thornback rays too, but as the sediment is changing to a sandier one as we continue on, I was told that we probably won’t see too many more. I did get some fin clips from these ones.

One of our hauls was full of mackerel, and we found two unusual looking individuals which we suspect may be Spanish mackerel, but it’s hard to tell for sure.