Sweden: mark recapture

This has been a good long week of collecting pipefish. We had 2 weeks of gorgeous weather, and today our luck finally ran out. It’s nearly impossible to collect pipefish with our trawl when the wind is blowing too strongly. We’ve collected and marked hundreds of pipefish, and also collected a couple hundred to keep in the lab for experiments. It’s been a lot of work (one day we tagged 200 fish, which took about 6 hours), but it’s really rewarding and we’ve collected a lot of good data. Yesterday was another long day, because we also caught fish to process for a study to compare fat content in pregnant and non-pregnant males.

So, how do we collect the pipefish exactly? We go out in a little boat and to the field site, pull a trawl behind the boat, and after about 10 minutes of trawling we pull up the net, empty it into a bucket, and sort through the algae, grass, and fish until we find what we want. Those fish go into buckets, which we end up putting in coolers to transport back to the lab.

our sampling boat

our sampling boat

pulling up the trawl

pulling up the trawl

Collecting fish can be really fun, and it’s cool to see some of the things we find! We’ve found a few large flounder.

we found a big flatfish!

we found a big flatfish!

So we’re taking a bit of a break today because the wind prevents the trawl from staying on the bottom of the ocean, where the pipefish hang out, plus it can be dangerous (especially when the waves are really large, like they are today).

Field station on a windy day

Field station on a windy day

What the field station looks like when it's good weather

What the field station looks like when it’s good weather

Hopefully the good weather will return so that we can finish our mark recapture study (we’ll be done when most of the males are pregnant–we’re at ~45% now). But in the meantime I get to catch up on blogs and emails and other things like that!

First trips out in the boat

I have now been in Sweden for just over a week, and so far I’ve explored Visby, spent some time in the country, and of course spent some time at the field station and on the boat, collecting fish. We’ve had some really beautiful weather the past few days, and it really feels like spring!

Spring cowslips

Spring cowslips in Visby

We’ve gone out on the boat twice now, the first time to see if the fish were there and the second time to catch some fish to bring them back to the field station to practice marking them. The first time we went out, we caught 6 female and 8 male Syngnathus typhle, the broadnosed pipefish, which I’ll be doing some mark-recapture work with. We also got lots (maybe 100) Nerophis ophidion, the straightnose pipefish, which are really pretty with blue markings on their faces. I’ll be collecting those later to do some population genetics work.

Nerophis ophidion

A Nerophis ophidion (viewed from the top, so the blue isn’t visible, sorry!). In the background you can see the seagrass/fish ball from the trawl.

Bucket of Syngnathus typhle

A bucket of 16 Syngnathus typhle.

 

Yesterday we also practiced tagging the fish. To tag them, we mix up a colored plastic (elastomer) tag and inject it right below the skin of an anesthetized fish. We’ll be tagging every S. typhle that we catch before returning them to the population. After practicing a few times I got the feel for it, and I think it will work out really well. Now we’re monitoring the fish we caught because we want to make sure that they aren’t negatively impacted by the tags before tagging an entire population. 

tagging pipefish

Sander, a masters student helping with the project, is tagging a S. typhle

I made it to Gotland!

This is my first post from Sweden! I made it to Visby, the main city on the island of Gotland, after hours of travel without any trouble. Even my two checked bags made it! I traveled with a lot of luggage, especially since one of my bags was full of scientific supplies

Bag full of tubes!

Bag full of tubes!

My collaborator was waiting for me at the airport and we’re staying in the city for the next couple of days. This morning I got to tour the downtown area a bit. It’s a beautiful day, and I got to see the ocean!

Medieval church in Visby

Medieval church in Visby with the ocean in the background

This afternoon we’ll be talking science and planning our collecting trips, so soon I will have stories about collecting pipefish here in Sweden.