Tag Archives: nudibranchs

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

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!

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

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

Exposing the Indian Ocean staggering diversity: fieldtrip to Nuarro, northern Mozambique (October 2017)

Pursuing our goal to understand the diversity, origin and biogeography of the Indo-West Pacific biota, we went back to Mozambique to continue the exploration of the reef systems of the country. After a first fieldtrip to the subtropical southern coast of Mozambique in 2014, and a second during 2015 to the tropical Quirimbas islands (Vamizi I.) not far from the border with Tanzania, we visited this time for two weeks between the 15–28 October 2017 the coastal pristine reefs and mangroves of Memba District in Nuarro, Nangata Bay, together with Prof. João Macuio from the University Lurio, Pemba and Dr Yara Tibiriça based at Nuarro Lodge, that kindly organized the expedition.

The staggering diversity of the tropical Indo-Pacific is well known and the area between the Philippines, Indonesia, and New Guinea (the Coral Triangle) is famous for hosting the highest marine diversity in the planet. However, for various reasons (political, economic, etc.) the Indian Ocean has been comparatively less surveyed, and much fewer studies are available for this region. Some recent publications are though showing that for corals and molluscs, at least, the region is extremely diverse, nearly comparable with the coral triangle.

We want to understand why is this region so diverse and whether the Indian Ocean harbours similar or a different faunal composition compared to the West Pacific Ocean. The traditional view is that most tropical species are broadly distributed across the Indo-West Pacific, but recent evidence from DNA studies suggests otherwise, but this is not yet well understood. If significant differences are found, then, understanding what may have driven speciation across both realms becomes a major quest.

Jorunna rubescens

Phyllidia varicosa

Plakobranchus sp.

Reticulidia suzanneae

Nuarro is a remote place, four and half hours driving from Nampula international airport, half of them through earth roads. It is located in beautiful Nangata Bay lined by fine white sands and calm turquoise waters. The area is characterized by a large diversity of marine habitats like sand flats, coral bommies, seagrass meadows, coral reefs, and coralline drop-off walls plunging into the deep blue.

The expedition had its basecamp at Nuarro Lodge, an eco-lodge offering diving facilities and a research center. The lodge besides its hostel activities is engaged in social, educational, heath, and nature conservation programmes with the local communities helping to improve education standards for the younger generations, mitigate the impact of native diseases like malaria, and the sustainable use of nature resources. For this last goal a marine protected area was created in 2008.

João Macuio and Manuel Malaquias during a nudi photo session

Local fishermen in a wooden canoe

Measuring giant clams underwater

Yara Tibiriçá databasing the catch of the day

During two weeks we have surveyed the area for marine molluscs (sea slugs) and studied the impact of the marine protected area in the conservation of the highly sensitive and threatened giant clams (Tridacna spp.). The days at Nuarro began early, around 5.30–6am, with the sun already out and high in the blue sky. Waking up was not difficult, with the awesome strident ensemble of sounds from the many local different birds and the monkeys running and jumping on the thatched roofs of our housing! First sampling of the day around 8.30am, followed by a second one after lunchtime. The evenings were dedicated to study, photograph, identify, and database the catch of the day. We have collected approximately 68 species of sea slugs; 11 are new records to Mozambique and an additional 12 still undescribed. The conservation status of the populations of giant-clams was evaluated in areas under fishing pressure by the local communities and inside the marine reserve for comparison, and it was obvious the positive impact of the marine protect area.

Monkey jumping on the roof of our accommodation

A “family” of moray eels

Collecting in the mangroves

Crown-of-thorns starfish feeding on coral

Detail of a gorgonian coral

Garden eels

Nangata Bay, Nuarro

The flatworm Pseudoceros lindae

The days were busy and went far too fast, but there was time for a short social programme where we paid a visit to the local village and visited the primary school built by the lodge and met a group of local activists that work with the community to raise awareness for issues concerning hygiene, malaria, and other health matters, which regrettably still claim lives in the region far beyond acceptable numbers on the XXI century. Before the trip to Nuarro I was challenged to take a football ball with me for the local team. I have obviously eagerly done it, and it was a great delight to the see the joy of the players of the “Real Nangata” playing around with their new ball!

Primary school build by the lodge at Nangata village

Real Nangata football club

View of Nangata village with a baubau tree

The Nuarro expedition would not have been possible without the gratitude and support of the Nuarro Eco-Lodge to which I am deeply indebted.  I am also thankful to Prof. Isabel Silva from the University Lurio, Pemba and to the Fisheries Department of the Cabo Delgado Province from granting collecting and exporting permits.

Manuel António E. Malaquias, Associate Professor

Natural History Museum of Bergen, Norway

 

Door #21: A Norwegian oddity

In 1939 the Swedish malacologist Nils Odhner described the nudibranch Berghia norvegica based on two specimens collected at Frøya and Stjørna in the mouth of the Trondheimsfjord.

After its original description this species has been found very few times, the first of them by Hennig Lemche a Danish malacologist who in 1958 collected a single specimen, today housed at the Natural History Museum of Bergen (ZMBN 62033). The importance of this specimen, until recently the only one apparently available in museum collections, was demonstrated by its use in a systematics review of the genus Berghia recently completed by a team of Spanish and American researchers.

The original description of Berghia norvegica is fairly detailed, but was based on preserved specimens and therefore the colouration of this species remained elusive until very recently. For over half a century nothing was known about the colouration of this beautiful and unique animal and is only in 2011 and subsequent years that Berghia norvegica is finally rediscovered by divers and researchers participating in the NudiSafaris organized at Gulen in Sogn og Fjordane just north of Bergen.

These recent discoveries revealed the extreme beauty of this delicate animal and generated the first live images of this endemic and emblematic species of the Norwegian fauna, which we here illustrate with a photograph taken at Gulen on March, the 15th of 2014 at 38 m deep and kindly made available by Kåre Telnes author of the website “The Marine Fauna and Flora of Norway”.

The sea slug Berghia norvegica, an endemic species from Norway. Photo: Kåre Telnes.

The sea slug Berghia norvegica, an endemic species from Norway. Photo: Kåre Telnes.

Suggested reading:

Carmona, L., Pola, M., Gosliner, T. M. & Cervera, J. L. 2014. The Atlantic-Mediterranean genus Berghia Trinchese, 1877 (Nudibranchia: Aeolidiidae): taxonomic review and phylogenetic analysis. Journal of Molluscan Studies, 80: 482–498.

Evertsen, J. & Bakken, T. 2013. Diversity of Norwegian sea slugs (Nudibranchia): new species to Norwegian coastal waters and new data on distribution of rare species. Fauna Norvegica, 32: 45–52.

Odhner, N.H. 1939. Opisthobranchiate Mollusca from the western and northern coasts of Norway. Det Kongelige Norske Videnskabernes Selskabs Skrifter, 1: 1–93.

Door #18: A photosynthetic animal

You may already be confused with the title, but you did read it well! Animals can do photosynthesis and most incredibly some species are more efficient than plants or algae. Yet, this achievement is not for all; you must be special, you must be unique…, you must be a sapsucking slug!

Ercolania sp. feeding inside algae (Photo: M. Malaquias)

Ercolania sp. feeding inside algae (Photo: M. Malaquias)

This is a process named kleptoplasty (= chloroplast symbiosis; see Door #2 of this calendar series) where the slug while feeding from the plant tissue does not digest the chloroplasts but instead migrate these organelles to specific parts of the body where they remain active producing sugars that become available to the slug.

There are two species of sapsucking slugs with a remarkable life-history. The spectacular and rare tropical species Ercolania endophytophaga and E. kencolesi both only known from Australia do not retain chloroplasts as other species do, but they do feed on algae, however, only on a very special kind – the green grape-algae of the Order Siphonocladales. These are syncytial algae made of massive single cell grape-shaped structures which the animal pierce to move in and leave inside until “green-matter” is available.

detail of Ercolania sp. inside algae (Photo: M. Malaquias)

detail of Ercolania sp. inside algae (Photo: M. Malaquias)

I was very fortunate to find one of this slugs back in January 2014 in southern Mozambique. Usually one has to collect a large quantity of algae to carefully search through later on in the lab and hope for the best! However, in that afternoon while sampling in a beautiful shallow tidal tropical reef in Paindane sluggishly looking at a facies of a “grape-alga” growing over a boulder I suddenly notice a tiny animal moving gently inside the algae. I grabbed a few bunches of algae into my sampling jar to look at later on…, and voilà… I was rewarded with a few specimens of one of this spectacular and difficult slugs most probably an undescribed species, the first from the Indian Ocean.

Ercolania sp. after removal from algae (Photo: M. Malaquias)

Ercolania sp. after removal from algae (Photo: M. Malaquias)

-Manuel

Sampling for sea slugs in northern Mozambique (East Africa)

The "tree house", headquarters of the Conservation and Research project of Vamizi Island

The “tree house”, headquarters of the Conservation and Research project of Vamizi Island

An undescribed species of an aeolid. Vamizi Island.

An undescribed species of an aeolid. Vamizi Island.

 

 

 

 

 

 

The tropical waters of the Indian Ocean are part of the world’s richest biogeographical region – the Indo-West Pacific (IWP), where diversity picks its high in the “Coral Triangle” an area confined by the Philippines, Indonesia, and Papua New Guinea.

Within this vast realm, the east coast of Africa is probably the least studied area and Moçambique with one of the largest coastlines in the region and pristine mangrove, seagrass, and coral habitats hides a high and still largely unknown diversity of opisthobranch gastropods (sea slugs).

Phyllidia ocellata. Vamizi Island

Phyllidia ocellata. Vamizi Island

During January–February of 2014 I had the opportunity to sample in southern Moçambique together with local colleagues from the Zavora Marine Lab. The results have been so promising that we decided to organize a new fieldtrip but, this time to explore the fauna in the northern tropical latitudes of the country. In collaboration with the University Lúrio in Pemba and the Vamizi Conservation and Research Station managed by the International Union for Conservation of Nature (IUCN), we setup during May 2015 a two weeks fieldtrip to Vamizi Island, a remote pristine sanctuary located in the northern range of the Quirimbas archipelago. The goals were to continue the inventory of the sea slug fauna of Mozambique and Indian Ocean but also to collect specific material for several ongoing projects at the University Museum of Bergen (Natural History) related to the systematics, biogeography, and speciation of these molluscs.

Cerberilla ambonensis. Vamizi island

Cerberilla ambonensis. Vamizi island

The first challenge was to reach Vamizi! Four flights, a five hours 4-wheels drive, and at last a boat trip – all of it during four days! But, the sight over the turquoise, calm, and warm waters of Vamizi was breathtaking and well worth the effort! We were very well welcomed by the team of the Conservation and Research Project of Vamizi and the management of Vamizi Island, which have provided all the necessary conditions for a successful and pleasant work.

The white sandy beaches and turquoise waters of Vamizi Island

The white sandy beaches and turquoise waters of Vamizi Island

The pristine coastline of Palma in northern Mozambique.

The pristine coastline of Palma in northern Mozambique.

As the following days would unravel the pristine coral reefs, seagrass meadows and mangroves would not disappoint with their incredible diversity of sea slugs and all kinds of colourful marine live. Yet, and contrary to the experience of the previous year where we have collected in several southern sub-tropical areas of Moçambique (Vilankulo, Barra, Paindane, Zavora), this time was not so easy to find sea slugs and often each of us would not collect more than 4 to 10 specimens per dive; but steadily over the 2-weeks of fieldwork we reached the exciting number of about 85 species, with approximately 60 new records for Mozambique and around 14 new to Science. This seems to be a pattern on many pristine tropical areas; low abundances but high diversity of sea slugs.

Photographing the daily catch

Photographing the daily catch

The "crew". Left to right: Erwan Sola (University of KwaZulu-Natal), Isabel Silva (University Lúrio, Pemba / Vamizi Conservation and Research Project), Yara Tibiriçá (Zavora Marine Lab), Manuel Malaquias (University Museum of Bergen), and Joana Trindade (Vamizi Conservation and Research Project)

The “crew”. Left to right: Erwan Sola (University of KwaZulu-Natal), Isabel Silva (University Lúrio, Pemba / Vamizi Conservation and Research Project), Yara Tibiriçá (Zavora Marine Lab), Manuel Malaquias (University Museum of Bergen), and Joana Trindade (Vamizi Conservation and Research Project)

Transferring specimens to ethanol at Palma beach (Palma village not far from the border with Tanzania), under the puzzled eyes of a group of locals.

Transferring specimens to ethanol at Palma beach (Palma village not far from the border with Tanzania), under the puzzled eyes of a group of locals.

University Lurio. Newly graduated students with supervisors and opponents.

University Lurio. Newly graduated students with supervisors and opponents.

The farewell to Vamizi was not easy; the beauty, warm, and peaceful atmosphere of Vamizi together with its incredible underwater diversity and colours will last surely forever in our memories. Yet, the journey was not over! We headed to the town of Pemba for the last three nights where some formalities were still on the agenda.

Professor Isabel Silva from the University Lúrio in Pemba and member of the Vamizi Island Conservation and Research Project and a join-organizer of our expedition, have invited each member of the team to give a seminar at the university and to act as opponents on the defence of several theses of “licenciatura”. While my colleagues have talked about the sea slugs of Moçambique and the coral reefs of Vamizi Island, I decided to get a away from my field of research (but not of interest!) and discourse about “wired animals” such as loriciferans, xenoturbellids, kinorhynchs, and others… Biological diversity is definitely much more than turtles, sharks, whales, and manta-rays…, even goes beyond colourful sea slugs!

 

Melibe sp. Vamizi Island

Melibe sp. Vamizi Island.

Is this a slug? Yes it is! Marionia arborescens. Vamizi Island

Is this a slug? Yes it is! Marionia arborescens. Vamizi Island.

Chromodoris cf. quadricolor. Vamizi Island

Chromodoris cf. quadricolor. Vamizi Island.

Chromodoris boucheti. Vamizi Island

Chromodoris boucheti. Vamizi Island

Chelidonura punctata. Vamizi Island

Chelidonura punctata. Vamizi Island.

Chelidonura mandroroa. Vamizi Island

Chelidonura mandroroa. Vamizi Island.

Chelidonura electra. Vamizi Island

Chelidonura electra. Vamizi Island.

Phyllodesmium cf. magnum. Vamizi Island.

Phyllodesmium cf. magnum. Vamizi Island.

Cadlinella ornatissima. Vamizi island.

Cadlinella ornatissima. Vamizi island.

Baby green turtles recovered from a damaged nest, with a rare case of albinism in this group of reptiles.

Baby green turtles recovered from a damaged nest, with a rare case of albinism in this group of reptiles.

Conservation on the move; Release of green baby turtles on the beach at Vamizi Island.

Conservation “on the move”; Release of green baby turtles on the beach at Vamizi Island.

Philinopsis pilsbryi. Vamizi Island

Philinopsis pilsbryi. Vamizi Island.

Coconut crab. Extinct to nearly extinct in many islands of the Indo-Pacific. Vamizi Island.

Coconut crab. Extinct to nearly extinct in many islands of the Indo-Pacific. Vamizi Island.

Another resident of Vamizi Island locally named "jibóia".

A “slimy” resident of Vamizi Island locally named “jibóia”.

A kingfisher bird. Vamizi Island.

A kingfisher bird. Vamizi Island.

A surprising guest found in my bedroom.

An uninvited guest in my bedroom.

A weaver bird. Vamizi Island.

A weaver bird. Vamizi Island.

-Manuel