Category Archives: Sea slugs of Southern Norway (SSoSN)

Sea slugs from Vestfold

Larvik & Sandefjord 22.10.2019 – 27.10.2019

From October 22 to October 27, Sea slugs of Southern Norway crossed the Hardangervidda mountain pass to pay a visit to Larvik Dykkeklubb (LDK) and Sandefjord Dykkeklubb (SDK). Vestfold, in particularly the Larvik area, was a thorn in the side for the sea slug project. With fieldwork and collection trips covering most of the Hordaland area (Bergen, Espegrend), Rogaland (Egersund), Mandal (Vest-Augder), Drøbak (Oslofjord area) a lot was left to be discovered still for Aust-Agder and Vestfold. Therefore, a visit to Vestfold was very high on our bucket list.

With Winter just around the corner, we decided to squeeze in a short fieldwork trip to Larvik just before the end of 2019. Me and Anders Schouw drived from Bergen to Larvik with our rented caddy to meet up with Tine Kinn Kvamme and members of the LDK. On Tuesday morning, after packing our mobile laboratory in the car, we drove off to Larvik. In the early evening we arrived at the LDK, there we were welcomed by Lene Borgersen from LDK, who facilitated access to the clubhouse for sorting sea slugs during our stay. That evening was also a club members evening, and I took that opportunity to give a presentation about sea slugs and the Sea slugs of Southern Norway project

It was a great evening talking about sea slugs with interested club members while eating pizza! The next day Tine, Anders and I met up with LDK member Mikkel Melsom, who joined to help on our hunting for sea slugs

Picture 2. Some sea slugs from Larvik; from left to right; Limacia clavigera, Edmundsella pedata, Diaphorodoris luteocincta, Tritonia hombergii, Tritonia lineata and Cadlina laevis. Photo credits Anders Schouw

Later that day we met up at the SDK clubhouse with Stein Johan Fongen, where I had the opportunity to once again talk about sea slugs this time to the SDK members. This was a very special evening because among the audience, besides SDK members, we also had students from Sandefjord videregående skole (Sandefjord High School)

Sea slug presentation for students of the Sandefjord videregående skole and Sandefjord Dykkeklubb members. Photo credits Tine Kinn Kvamme

In the following days several members of the SDK also joint us collecting sea slugs. Despite the fact that October is known for being not an ideal season to find sea slugs (most species are observed during Winter and (early) Spring) we still somehow ended up with hours of sorting work at the Larvik clubhouse

Cessa Rauch & Anders Schouw sorting sea slugs in the Larvik clubhouse. Photo credits Tine Kinn Kvamme

Overall, we collected 21 different species, all newly registered specimens for the project with regard to this part of the country. It would be great to see what the species abundance would be during a sea slug season like February or March!

Overview of the species collected at Larvik and the Sandefjord area

Besides sea slugs and enthusiastic club members, another highlight of the week was a visiting seal at SDK! On our last day of fieldwork, a young seal was very bold and decided to rest close to the clubhouse in the harbor. It let people come up really close, which was great for making cute seal pictures. Cherry on the cake, in my opinion!

Young seal in the harbor close to the Sandejord Dykkeklubb. Photo credits Anders Schouw

On Sunday the tree of us had to say goodbye, Tine would go back to her hometown Oslo and Anders and I would cross the snowy mountains again back to Bergen. It was a short but sweet visit and great opportunity to meet members of Larvik and Sandefjord dykkerklubbs. I therefore want to thank LDK and SDK for their interest, enthusiasm and help for the few days Anders, Tine and I were around. I surely hope we will meet again next year, and find many more sea slugs. And of course, thanks to Anders and Tine for helping again, hope we can share many more sea slug adventures together

Left to right; Tine Kinn Kvamme, Cessa Rauch and Anders Schouw in front of the Larvik Dykkeklubb were most of the ‘lab’ work was done. Photo credits Lene Borgersen

More sea slugs: 

Do you want to see more beautiful pictures of sea slugs of Norway? Check out the Sea slugs of Southern Norway Instagram account; and don’t forget to follow us. Become a member of the Sea Slugs of Southern Norway Facebook group, stay updated and join the discussion! Hunger for more sea slug adventures, check our latest blog posts.

Explore the world, read the invertebrate blogs!

– Cessa

World Congress of Malacology 2019: 10 – 17 August 2019

On August 10, four delegates from the University Museum of Bergen made their way to Monterey Bay California, USA.

Attending the World congress of Malacology 2019, from left to right; Jenny Neuhaus, Justine Siegwald, Manuel Malaquias & Cessa Rauch

This year the World Congress of Malacology took place at the Asilomar conference grounds in Pacific Grove, Monterey. Monterey Bay is well known among many marine biologists due to its world-famous aquarium and aquarium research institute (MBARE), many marine protected areas (7; including the Asilomar State Marine reserve, close to where the conference was held), Hopkins Marine Station of Stanford University, Steinbeck Center (although located in Salinas, close enough to make it count). The latter was named after the famous marine biologists John Steinbeck and Ed Ricketts from the Monterey County; Among other works they contributed to marine biology with their famous books ‘The sea of Cortez’ and ‘Between Pacific Tides’. All in all, Monterey Bay seems like an exciting place to be for us marine biologists.

The World Congress of Malacology was organized and chaired by the famous Terry Gosliner (Terry described more than 1000 species of sea slugs!) a senior curator of the California Academy of Sciences. About 300 participants contributed to a very lively and busy scheduled week

Some of the participants of the World Congress of Malacology 2019

Registration for the conference started on Sunday the 11th of August, but Monday was the real kick off of the program with fabulous keynote speakers such as Geerat Vermeij, David Lindberg, Susan Kidwell, etc.. During the poster session Jenny Neuhaus and Cecilie Sørensen, two of our master students working in close collaboration with the Museum project Sea Slugs of Southern Norway have presented their preliminary results. Unfortunately, Cecilie could not join us due to time constraints, and the poster was presented by Cessa

Justine presenting her work on Scaphander

On Tuesday we had a crammed agenda with multiple speakers talking at the same time, divided over the different halls in a variety of sessions. It was a busy day of running around trying to catch those talks one were most interested in. Justine had her talk in the Systematics session about her PhD research on Scaphander titled; First global phylogeny of the deep-sea gastropod genus Scaphander reveals higher diversity, a possible need for generic revision and polyphyly across oceans. It received a lot of attention and numerous questions afterwards, it was great to see how her research was perceived with so much curiosity and enthusiasm.

Wednesday we had a day off filled with several excursions. Jenny went to the whale watching trip, Justine went to spot marine mammals and Cessa to a trip along the coast to meet and greet the Californian red giants. The trips were all well organized and a very nice break off the week as the many presentations and sessions made the days long and intense. The whale watching trip took place in Monterey Bay and Jenny was lucky enough to observe the mighty blue whale, Balaenoptera musculus, plenty of humpback whales (Megaptera novaeangliae), and several sunfish (Mola mola) swimming at the surface. It was an incredible experience for her to be able to watch the animals thrive in the great Pacific Ocean.

Whale-watching with Jenny Neuhaus in Monetery Bay

Cessa walking in between the Californian red giants

 

The trip to South Monterey was along the California’s rugged coastline and provided one of the most spectacular maritime vistas in the world. It has peaks dotted with the coast redwoods that go all the way to the water’s edge. The trip took you to Pfeiffer Big Sur State Park where we got the opportunity to walk through the redwood forest. Along the way we stopped at numerous scenic vistas, it was definitely a memorable day .

 

On Thursday, all well rested, we had another hectic day full of presentations, this time it was Cessa’s turn, she would talk about the ‘Sea slugs of Southern Norway project as an example of citizen science’ (Picture 8. Cessa presenting the sea slugs of Southern Norway project). It was placed in the citizen science session and many that attended had questions about citizen science which constituted a great opportunity to share our experience acquired during the last year of our project.

Cessa presenting the sea slugs of Southern Norway project

Friday, on the last day of the conference, Manuel had his talk about the phylogeny and diversity of the Indo-West Pacific gastropods Haloa sensu lato (Cephalaspidea: Haminoeidae): Tethyan vicariance, generic diversity, and ecological specialization. This was part of the recent collaborative work his previous PhD student Trond Oskars

Manuel Malaquias presenting his and Trond’s work on the phylogeny of Haminoeidae

Jenny Neuhaus won the best poster award for her research on Jorunna tomentosa

 

The day was closed off with a big dinner and the award ceremony. Prizes were handed out to the best student’s oral and poster presentations. Jenny was awarded by the Malacological Society of London the prize for the best student poster. This was a very exciting way to end a successful conference trip!

 

 

 

-Cessa & Jenny

Success in the South; fieldwork in Mandal

From May 20th to 27th the sea slugs of Southern Norway team headed South to Mandal to pay a visit to the Mandal dykkerklubb and try to find more enthusiastic citizen scientist to join the sea slug project. We had a few special guests invited for the week and the team consisted of Cessa Rauch, Manuel Malaquias, Anders Schouw, Erling Svensen, Nils Aukan, Tine Kvamme and Heine Jensen. In Mandal the head of the club Erling Tønnessen would be there to help us around and organize club activities for collecting the sea slugs.

The first day basically consisted of traveling to Mandal and setting up our “hyttes” for a week of sea slug hunting. As usual we underestimated the amount of space needed to bring our ‘mobile’ lab to the camping site in Mandal. Even though a station wagon theoretically fit a family of five plus luggage, it was barely enough space for a family of sea slug hunters with their equipment.

Picture 1. We accomplished to fit everything in this rental car, picture Cessa Rauch

We ended up with a challenging Tetris game and me being squeezed between microscopes and jars in the back seat, still, no complaints! At least I was spared for driving the long hours from Bergen all the way to Mandal, that every local would be able to fix in less than 7 hours, we managed to take 12. I guess the car was heavy loaded! Manuel did a fantastic job while Anders and me where dozing off. Eventually we managed to arrive safely in Mandal and there we were greeted by our team of citizen scientists that helped us out through the week. They as well had to travel from all corners of the country; Kristiansund, Egersund, Oslo and Sarpsborg. It was quite special to arrive all together in Mandal with only one thing in our minds; finding sea slugs!

The next days in collaboration with the local Mandal dykkerklub and their fantastic club boat equipped with a lift to get people in and out of the water, we operated most of the sampling activities. After a day out collecting we would all go back to our cabins and start photographing and registering the samples.

Even though late spring is supposedly not the best season for collecting sea slugs, due to low abundance of the different species, together we were still able to collect 47 different species!

Picture 4. Overview of the species collected during fieldwork in Mandal

On our last day of the expedition, the Mandal dykkerklubb organized an evening social gathering for their members in which we had the chance to give a presentation about sea slugs and the project, and to give away a few sea slug sampling kits to all those interested.

Picture 5. Cessa and Manuel presenting the sea slugs of Southern Norway project, picture Erling Svensen

Picture 6. Interested dive members of the Mandal dykkerklubb showing up to learn more about sea slugs and having a good time, picture Erling Svensen

With every fieldwork trip we get more experienced in the organization and execution of the event and this is definitely paying off in the diversity of species we manage to collect. We were not able to register so many species before as with this fieldwork trip to Mandal. This was by far the most successful expedition and together with the joined efforts off all the excellent citizen scientist we formed a real professional sea slug team!

Picture 7. Group picture of the expedition members on board of the Mandal dykkerklubb boat, left to right; Heine Jensen, Erling Svensen, Anders Schouw, Cessa Rauch, Tine kinn kvamme, Nils Aukan and the expedition leader Manuel Malaquias in front, picture Erling Svensen

At the moment we are waiting for the first DNA barcode results in order to confirm the species diversity we found that week. An update will follow; but Manuel and I would like to take this opportunity to gratefully acknowledge all the efforts and interest of our team members of that week and the good times we had together! Hope to meet you all again soon during yet another sea slug hunt! Tusen takk!

-Cessa

Some hydroids, four naturalists, and a small island in the North Sea

NorHydro partner (and hydrozoan expert) Joan J. Soto Àngel from the Sars International Centre for Marine Molecular Biology went in a sampling trip to Kinn to collect benthic hydroids. Here is an account of his experience in this trip:

Kinn is a small grassy island on the western Norwegian coast. Today it is a quiet, peaceful place with only a few inhabitants, but in the past it was an important fishing town and the center of the cultural and religious life of the area, as evidenced by its imposing medieval stone church (Kinnakyrkja). The island is also a place of historical relevance for biologists, since it is intimately tied to the life and discoveries of one of the most prominent naturalists of the XIX century, Michael Sars, who worked as a priest in Kinnakyrkja for many years.

Here I am, ready to sample! The island behind is Kinn, easy to recognize thanks to its characteristic cleft silhouette. Picture: Cessa Rauch

The islands in the area face the ocean and are rather exposed, so the vegetation is not particularly tall, but the waters are teeming with life. Picture: Joan J. Soto

The XIX century Norwegian naturalist Michael Sars. Picture from Wikicommons (public domain)

Sars described many species inhabiting the waters around Kinn and also made key observations about their distribution and life cycle. Indeed, he was the first to discover that jellyfish and polyps are in fact different stages of the same animals!

This finding led him to be recognized as an outstanding zoologist of his time. Even now, ca 200 years after, his extensive work is regularly consulted by researchers of many fields. Like me and the other participants of the Artsdatabanken project NorHydro, Sars was fascinated by the group we call Hydrozoa, which is why it was very interesting for our project to join a sampling trip of the University Museum of Bergen in the same waters where he sampled and described many hydroids, hydromedusae and siphonophores.

Because Sars was also interested in other critters of the sea besides hydrozoans, it was only natural to make this sampling trip a joint, collaborative effort. In our case, three marine scientists were involved, each representing a different project: I was in charge of the hydrozoans for NorHydro, while Anne Helene Solberg Tandberg focused on amphipods (NorAmph2) and Cessa Rauch concentrated on sea slugs (Sea Slugs of Southern Norway). But we did not limit ourselves to our favorite animal groups; we also sampled some poychaetes, bryozoans, ascidians and echinoderms for two other projects based at UMB, Hardbunnsfauna and AnDeepNor. In addition, while we sampled extensively the waters around Kinn, we also stopped in the way to the island and back and collected some animals in two other localities in the coast of Sogn og Fjordane. Our efforts paid off and, despite some windy weather, we came home with many specimens to analyze and samples to sort.

Three more contemporary naturalists working for different projects: Joan (left, NorHydro), Cessa (middle, Sea Slugs of Southern Norway), and Anne Helene (right, NorAmph2). Picture: Joan J. Soto

For the hydrozoans, the majority of samples consisted in colonies of hydroids belonging to the families Sertulariidae, Haleciidae and Campanulariidae. This was not surprising as Sertulariidae (sensu lato) is the largest and most diverse family in all Hydrozoa, and their conspicuous colonies are relatively easy to recognize and collect. The haleciids are represented in Norway mainly by species of Halecium, whose colonies are among the largest benthic hydrozoans of the country. As for the campanulariids, particularly those belonging to genera Obelia, Laomedea and Clytia, they are common inhabitants of rocky and mixed bottoms all around the world, and are especially conspicuous when growing on macroalgae such as kelp. To correctly identify some of these specimens, we will look closely at their morphological characteristics and will also employ molecular techniques of DNA analysis. Hopefully this approach will help us understand the diversity of benthic hydroids living around Kinn, and will allow us to determine whether the species that we encountered are the same that Sars studied.

Dynamena pumila was one of the most conspicuous species of hydroid that we collected in this trip. It belongs to the speciose family Sertulariidae.

We were very lucky to have the help of the crew of RV Hans Brattström. This is how the command center of the boat looks like!

You’ll find the results of these and other NorHydro’s analyses here in the blog as we progress, and more updates on the project can be found on the Hydrozoan Science facebook page and in Twitter with the hashtag #NorHydro.

– Joan


References and related literature about Michael Sars

Tandberg AHS, L Martell (2018) En uimodstaaelig lyst til naturens studium. Yearbook of the University Museum of Bergen: 17 – 26.

Sars M (1835) Beskrivelser og Iagttagelser over nogle mærkelige eller nye i Havet ved den Bergenske Kyst levende Dyr af polypernes, acalephernes, radiaternes, annelidernes, og molluskernes classer. Thorstein Hallagers forlag, Bergen.

Windsor MP (1976) Starfish, jellyfish and the order of life. Issues in Nineteenth-Century Science. Yale University Press, New Haven. 228 pp

Workshop week at Espegrend field station

The final week of March was teeming with activity, as no less than three Norwegian Taxonomy Projects (Artsprosjekt) from the Invertebrate Collections arranged a workshop and fieldwork in the University of Bergen’s Marine biological field station in Espegrend.

The projects – Sea Slugs of Southern Norway(SSoSN), Norwegian Hydrozoa (NorHydro) and Invertebrate fauna of marine rocky shallow-water habitats: species mapping and DNA barcoding (Hardbunnfauna) fortunately overlap quite a bit in where and how we find our animals (as in, Cessa’s seaslugs are eating the organisms the rest of us are studying..!), and so it made sense that we collaborated closely during this event.

That meant more hands available to do the work, more knowledge to be shared – and definitely more fun! All projects had invited guests, mostly specialists in certain groups, but also citizen scientists, and our students participating. We stayed at the field station, which has excellent facilities for both lodging and lab work.

Participants on our Artsprojects workshop in March. Left from back: Peter Schuchert, Manuel Malaquias, Bjørn Gulliksen, Jon Kongsrud, Tom Alvestad, Gonzalo Giribet. Middle row from left: Heine Jensen, Luis Martell, Endre Willassen, Eivind Oug, Front row from left: Katrine Kongshavn, Cessa Rauch and Jenny Neuhaus (Photo: Heine Jensen)

The fieldwork was carried out in the Bergen region, and was done in various ways. We had the R/V “Hans Brattstrøm” available for two days, where we were able to use triangular dredges, plankton net, and grab to sample.

Other days we used a small boat from the station to go to the islands close to Espegrend to examine the tide pools and tidal belt. We also went to local marinas and scraped off what was living on the piers, and a brave soul donned her wet suit and went snorkeling, which enabled us to sample very specific points of interest (“take that green thing over there!”).

We are fortunate here in Bergen in that we have a very active local student dive club, SUB-BSI, whose divers kindly kept an eye out for – and even collected – some of our target animals, as well as sharing their photos of the animals in their natural habitat, all of which is amazing for our projects!
We gave short presentations of each of the projects at SUB in the beginning of the week, and invited the divers out to the lab to on the following Thursday to show some of the things we are working on. It was a very nice evening, with a lot of interested people coming out to look at our critters in the lab. We also decimated no less than 14 homemade pizzas during that evening – learning new stuff is hard work!

Guests in the lab (photos K. Kongshavn)

All together, this made it possible for us to get material from an impressive number of sites; 20 stations were sampled, and we are now working on processing the samples.

The locations where we samples during the week (map: K. Kongshavn)

We are  very grateful to all our participants and helpers for making this a productive and fun week, and we’ll make more blog posts detailing what each project found – keep an eye out for those!

You can also keep up with us on the following media:

 NorHydro: Hydrozoan Science on Facebook, and Twitter #NorHydro

@Hardbunnsfauna on Instagram and Twitter

SeaSlugs: on Instagram and in the Facebookgroup

 Cessa, Luis & Katrine

Sea slug hunt in Egersund!

I’m always scared to look at the current date, time flies! It was already two months ago that we went on a blitz fieldwork trip to Egersund with a very special group of people. But nevertheless, good times become good memories (and especially good museum specimens) and it definitely does not get too old for a small blog about it.

From January 17 to January 21 a small group of sea slug enthusiasts consisting of a student, citizen scientists, a collaborator and museum members rented a van and drove 7 hours down to our Southern neighbor town Egersund.

Egersund was not randomly picked as it is the home town to one of Norway’s most productive and dedicated ‘citizen scientist’; Erling Svensen. Author of a number of books and the most well-known and worldwide used ‘Dyreliv I havet – nordeuropeisk marin fauna’ (English Marine fish and invertebrates of Northern Europe), which amateurs and professionals alike use as an extensive research source.

Erling Svensen’s famous book Dyreliv I Havet

With his almost 5000 dives and counting, Erling knows the critters of the North Sea, big and small, on the back of his hand. Already since the beginning of the sea slug project, Erling was helping providing valuable sea slug species, so it was about time to pay him a visit and bring our team over to make Egersund “biologically unsafe” – enough so to end up in the local news!

We made Egersund unsafe enough to have a small news item about it in the ‘Dalane Tidende’, a local newspaper

The group consisted of Manuel, Cessa, citizen scientist Anders Schouw, collaborator from Havard University Juan Moles and master student Jenny Neuhaus

From left to right Erling Svensen, Anders Schouw, Jenny Neuhaus, Cessa Rauch, Juan Moles and Manuel Malaquias. Photo by Erling Svensen

Jenny just started her Masters in Marine Biology at the University of Bergen in the fall of 2018, she will be writing her thesis on the diversity of sea slugs from the Hordaland county and on the systematics of the genus Jorunna (Nudibranchia) in Europe. The results of this work will definitely become a blog entry of its own.

Jorunna tomentosa, Jennies new pet! Photo by Nils Aukan.

Two of the five days of our fieldwork were basically spendt driving up and down from Bergen to Egersund, it left us only with a good 3 days to get an overview of Erling’s backyard sea slug species. Little time as you can imagine. But time was used efficiently, as Anders and Erling are both extremely good sea slug spotters and with help of sea slug specialist Juan and the eager helping hand of Jenny, Manuel and I were able to identify and add 36 species to our museum sea slug database.

Overview of collected specimens in Egersund

In comparison, we registered 41 one species in Drøbak last year by spending almost a week at the field station! No one thought this would be the outcome (not even Erling himself, as he mentioned that he didn’t find that many sea slug species this time of year on earlier surveys). But we were all very happily surprised, and maybe it was not just luck but also the combination of people we had attending this short field trip. With so many good specialists, either professional or amateur, senior or junior, we were able to work extremely efficient and with a clear communal goal. There was little time spend in reinventing the wheel and explaining the work flow, it was a good valuable exercise that will definitely help us with future brief fieldwork trips and how to make the most from short and tight time schedules. Besides it was a very valuable experience for our student Jenny, as she got first-hand experience with what it’s like to see her study specimens alive, how to handle these fragile individuals, how to sort them from other species and how to document them, which is a good thing to know for her thesis and future career

Jenny learning a lot from the master himself. Photo by Erling Svensen

So yes, all in all our Egersund fieldtrip was short but very sweet!

Furthermore
You want to see more beautiful pictures of sea slugs of Norway! Check out the Sea slugs of Southern Norway Instagram account; and don’t forget to follow us. Become a member of the sea slugs of southern Norway Facebook group, stay updated and join the discussion.

Explore the world, read the invertebrate blogs!

-Cessa & Jenny

New year, new field work!

2019 will bring a lot of field work for us at the invertebrate collections – not only do we have our usual activity, but we will also have *FIVE* Norwegian Taxonomy Initiative projects (Artsprosjekt) running!

On a rather windy Tuesday in January, four of us – representing four of these projects – set out with R/V “Hans Brattstrøm”.

Four projects on the hunt for samples! Photo: A.H.S. Tandberg

Our main target for the day was actually not connected to any of the NTI-projects – we were hunting for the helmet jellyfish, Periphylla periphylla. We need fresh specimens that can be preserved in a nice way, so that they can be included in the upcoming new exhibits we are making for our freshly renovated museum. We were also collecting other “charismatic megafauna” that would be suitable for the new exhibits.

We have been getting Periphylla in most of our plankton samples since last summer, so when we decided this was a species we would like to show in our exhibits about the Norwegian Seas, we did not think it would be a big problem to get more.

This is a species that eats other plankton, so normally when we get it, we try to get rid of it as fast as possible; we want to keep the rest of the sample! But we should have known. Don’t ever say out loud you want a specific species – even something very common. Last November, we planned to look specifically for Periphylla, and we brought several extra people along just because of that. But not a single specimen came up in the samples – even when we tried where we “always” get them…

Lurefjorden is famous for being a hotspot for Periphylla – so the odds were in our favor! Map: K. Kongshavn

Wise from Novembers overconfident cruise, this time we planned to call to the lab IF we got anything to preserve. The Plankton-sample did not look too good for Periphylla: we only got a juvenile and some very small babies. So we cast the bottom-trawl out (the smallest and cutest trawl any of us have ever used!), and this sample brought us the jackpot! Several adult Periphylla, and a set of medium-sized ones as well! Back in out preparation-lab an entire size-range of the jelly is getting ready for our museum – be sure to look for it when you come visit us!

We of course wanted to maximize the output of our boat time– so in addition to Periphylla-hunting, we sampled for plankton (also to be used for the upcoming ForBio-course in zooplankton), tested the traps that NorAmph2 will be using to collect amphipods from the superfamily Lysianassoidea, checked the trawl catch carefully for nudibranchs (Sea Slugs of Southern Norway, SSSN) and benthic Hydrozoa (NorHydro), and used a triangular dredge to collect samples from shallow hard-bottom substrate that can be part of either SSSN or the upcoming projects NorHydro (“Norwegian marine benthic Hydrozoa”) or “Invertebrate fauna of marine rocky shallow-water habitats; species mapping and DNA barcoding” (Hardbunnsfauna).

The Hardbunnsfauna project was especially looking for Tunicates that we didn’t already have preserved in ethanol, as we want to start barcoding these once the project begins in earnest (last week of March). We also collected bryozoans, some small calcareous sponges, and (surprise, surprise!) polychaetes.

When it comes to hydrozoans, we were lucky to find several colonies of thecate hydroids from families Campanulariidae and Bougainvilliidae that represent some of the first records for NorHydro. Hydroid colonies growing on red and brown algae were particularly common and will provide a nice baseline against which diversity in other localities will be contrasted.

Different hydroid colonies growing on algae and rocks at the bottom of Lurefjorden. Photo: L. Martell

There were not a lot of sea slugs to be found on this day, but we did get a nice little Cuthona and a Onchidoris.

But what about the Amphipod-traps? Scavengers like Lysianassoidea need some time to realize that there is food around, and then they need to get to it. Our traps have one small opening in one end, but the nice smell of decomposing fish also comes out in the other end of the trap. We therefore normally leave traps out at least 24 hours (or even 48), and at this trip we only had the time to leave them for 7 hours. The collected result was therefore minimal – we even got most of the bait back up. However, knowing that we have a design we can deploy and retrieve from the vessel is very good, and we got to test how the technical details work. It was quite dark when we came to retrieve the traps, so we were very happy to see them! All in all not so bad!

We had a good day at sea, and it will be exciting to see some of our animals displayed in the new exhibits!


If you want to know more about our projects, we are all planning on blogging here as we progress. Additionally you can find more on the

-Anne Helene, Cessa, Luis & Katrine 

Door #17: Sea bunnies of Norway?

Some years ago, in 2015, the internet was taken a storm by the sudden rise of the so-called sea bunnies. It all started with a video taken the year before by a SCUBA diver in Japan who filmed the little creatures crawling around the seabed:

The species seen in the video is called Jorunna parva, and are since then worldwide unofficially known by the adorable pet name ‘sea bunny’ as it has a ‘fur’ like exterior with tiny upright ‘ears’ and a fluffy tail like bunnies do. The ‘fur’ is actually created by bunches of tiny rods, called the caryophyllidia. The caryophyllidia are arranged around little knots that are often dark coloured, which create the illusion of black dots on the animals. The seemingly ears are the animals rhinophores, that function as chemical receptors that make the animal able to detect its environment in search of food and other sea bunnies. Its tail on the back are actually its gills to extract oxygen molecules from the surrounding water, the ‘fluffier’ it is, the bigger the surface area, the easier it is to diffuse oxygen from the water. This sea bunny is small, often less than 2.5 cm, and can be found throughout the Indo-Pacific; from South Africa to Central Pacific. They have, like many sea slugs do, a high degree of colour polymorphism in the species, with colours varying from white with black dots, to yellow and even bright orange:

Different colours of Jorunna parva, aka the sea bunny (photo credits on image)

Unfortunately, our sea bunny J. parva is only short-lived and just lives from a few months up to a year, but at least during its short life it doesn’t need to worry about predators. They are very toxic, because of the food they eat, which are sponges. All dorid nudibranchs (the group of slugs J. parva belongs to) are toxic because of their diet, and these toxins are often used in cancer treatments for people. Who would have thought that sea bunnies would be lifesavers, besides  being cute? But is the word sea bunny only referring to this particular species called J. parva? A quick search on the internet definitely tells us otherwise, it seems people refer to sea bunnies when they talk about any other dorid nudibranch with a fluffy and round appearance.

So, the question remains, do we have any sea bunnies in Norway? And the answer is yes, we do!

Sea bunnies of Norway (click to enlarge!)

And they are absolutely great and adorable to encounter underwater. Let us make a list of the sea bunnies of Norway, so we know what species we are talking about. Sea bunnies of Norway are; Doris pseudoargusGeitodoris planataJorunna tomentosaRostanga rubraCadlina laevis, Aldisa zetlandicaAdalaria loveniAdalaria proximaOnchidoris muricataOnchidoris bilamata,
Onchidoris pussilaOnchidoris depressaAcanthodoris pilosaDiaphorodoris luteocincta and I personally would draw the line at Goniodoris nodosa, as the other Goniodoridae don’t resemble that much the typical sea bunny characteristics. What do you think? Which species do you think are missing in this list, or which species should be left out?

I think it is time to take over the internet with our sea bunnies of Norway!

 

Furthermore
You want to see more beautiful pictures of sea slugs of Norway!

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-Cessa

Door #16: Basic anatomy of the sea slug

Haminoea sp, photo by M. Malaquias

“Sea slugs” include both the by far most famous nudibranchs, and groups such as the Sacoglossa (sap-sucking slugs, more about these later in the calendar!) and Cephalaspidea (the bubble snails), amongst others. These latter ones often do have shells – but reduced ones, too small for the animals to completely retreat into, like this Haminoea:

Nudibranchs, however, are the “naked” snails: Their name “nudibranch” comes from the Latin nudus, naked, and the Greek βρανχια, brankhia, gills. They don’t have a shell, but this wasn’t always the case. In their early larval life stage, they actually have a shell, but when settling down and transforming from zooplankton into adults, they lose the shell. The loss of the shell in adults might be responsible for the amazing diversity we see in body forms present in sea slugs.

So, in this basic anatomy of sea slugs we will focus mostly on the body forms of nudibranchs, but all other sea slug orders are not far off from this anatomy, if you know the basics of nudibranchs, you can extrapolate to the other orders as well. So here we go!

Nudibranchs are roughly divided in two type of body forms; the dorid nudibranchs and the aeolid nudibranchs.

Two basic body types found within the Nudibranchia; the dorids and the aeolids. (Illustration: C. Rauch)

The dorid nudibranchs have a thick mantle that extends over their foot. In some species the surface of the mantle is covered with tubercles than can vary in different sizes, numbers and shapes. This gives them often a rigid body that offers some protection.  In most of the dorids it is the mantle that contains toxins to defend themselves, the toxins are extracted from their food sources.

Aeolid nudibranchs have mantles that are covered with finger-like extensions called cerata. The cerata are very special as they contain branches of the digestive tract, and in some species, this is also visible! The tips of the cerata contain special organs called the cnidosacs. Cnidosacs store stinging cells (called nematocysts). These are obtained from their food source which are often cnidarians like hydroids, sea-anemones and soft corals. The cnidosacs are activated when the nudibranchs feel threatened and the stinging cells will be discharged!

All sea slugs have rhinophores. On the head of all sea slugs you can find a pair of sensory tentacles called the rhinophores. They detect smell and taste and in most of the dorid nudibranchs the rhinophores can be retracted into a basal sheath. Sea slugs know all kind of shapes of rhinophores which are a very important tool for identification of the species.

Diversity of sea slug rhinophore shapes

Besides a pair of rhinophores many nudibranchs also have a pair of oral tentacles, one on each side of the mouth. They are most likely involved in identifying food by taste and touch.

Sea slugs also need to breathe oxygen. They do this via the surface of their entire bodies, but their main reparatory organ are their gills. Dorid nudibranchs have often a feather like structure encircling their anus on the back of their body (the branchial plume). Some dorid species can also retract their gills into a pocket. Within the aeolid nudibranchs the cerata act like gills by diffusing oxygen from the surrounding water. The cerata are sometimes branched in order to increase the surface area, also here, like the rhinophores, different species can have different forms of cerata.

Diversity of aeolid cerata shapes

-Cessa

Door #15: The eye of the beholder

It’s funny to see the different reactions to fresh material that comes in to the museum;  the exhibition team had  received some kelp that will be pressed and dried for the new exhibitions (opening fall 2019), and I ducked in to secure some of the fauna sitting on the kelp before it was scraped off and discarded. For the botanists, the animals were merely a distraction that needed to be removed so that they could deal with the kelp, whilst I was trying to avoid too much algae in the sample as it messes up the fixation of the animals.

I chose the right shirt for the day- it’s full of nudibranchs! (photo: L. Martell)

 

I then spirited my loot into the lab, and set up camp.

Count me in amongst the people who stare at lumps of seaweed.

 

Who’s there? The whole lump is ~12 cm.

How many animals do you see here? Which ones appeal to you?

I have made a quick annotation of some of the biota here:

Note that these are just some of the critters present…! (photo: K. Kongshavn)

Let’s go closer on a small piece of algae:

Now, what do you see? (photo: K. Kongshavn)

For Luis, the first thing to catch the eye was (of course) the Hydrozoa

Hydrozoans (the christmas light looking strings), encrusting bryozoans (the flat, encrusting growth on on the algae – you might also know them as moss animals), and some white, spiralling polychaete tubes  (photo: K. Kongshavn)

Did you spot the sea hare (Aplysia punctata?) Look a bit above the middle of the photo of the tiny aquarium with the black background. Do you see a red-pink blob?

Hello, Aplysia punctata! (photo: K. Kongshavn)

There were also several other sea slugs that I have handed over to Cessa for inclusion in the sea slugs of Southern Norway project, here are a few:

Then there were the shelled gastropods:

The brittle star from the earlier image – this is a Ophiopholis aculeata, the crevice sea star (photo: K. Kongshavn)

In fact, they both are Ophiopholis aculeata (in Norwegian we call them “chameleon brittle stars” – they live up to the name!), one of the very common species around here. (photo: K. Kongshavn)

One of the colonial ascidian tunicates (and some of the ever present bryozoa just below it) (photo: K. Kongshavn)

Most of these animals will be barcoded, and will help build our reference library for species that occur in Norway. I also hope that they may have helped open your eyes to some of the more inconspicuous creatures that live just beneath the surface?

2019 will see the start of a new species taxonomy project where we will explore the invertebrate fauna of shallow-water rocky shores, so there will be many more posts like this to come!

-Katrine