Vegetation is beneficial for fish recruitment

Fish in the hand of humans – a Baltic Seminar. At the Baltic seminar last week two interesting presentations were given, one about the linkage between benthic vegetation cover and fish recruitment and production and the other one the strong impact by large fishing companies.First, Johan Eklöf, Department of Ecology, Environment and Plant Sciences, Stockholm University, presented the impact of cascading effects and the close interaction between rooted aquatic plants and seaweeds and fish recruitment of for instance pike and perch in shallow Baltic Sea bays. Shown both in more and more scientific studies and experiments.

1Large fish -plant benefits

In the first figure the positive effect of large fish is shown on the filamentous algae and how rooted aquatic plants benefit the recruitment of fish .e.g perch in shallow parts of the archipelago.

2PLants juvenlie pike

Fig. 2 shows that there seems to be a threshold of 20 % cover that is optimal for recruitment.This was followed by a presentation by Henrik Österblom, from Stockholm resilience centre about the large impact of big companies managing the fish stocks, both, on a global scale and in the Baltic Sea.

3fishmarket

The seminar ended with a panel discussion addressing the question if the fish stocks are in the hand of humans and if we will be able to find ways of sustainable use of and management of fish stocks.

4panel Balticseminar

Can the knowledge of the strong link between vegetation and fish recruitment be transferred to better management of shallow bays and coastal areas? Sofia Wikström and Gustaf Almqvist at the Baltic Sea centre, Stockholm University added to the discussion about the need of further improving our understanding of these complex ecosystems for a long-term sustainable management of fish species like pike and perch.

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Fucus radicans takes to the Royal Dramatic Theatre stage

To celebrate the 70th birthday of His Majesty King Carl XVI Gustaf, a unique show “An evening about the Baltic Sea- Hopes and threats” was given in his honour at the Royal Dramatic Theatre on the 25th of April. On stage was more than 10 scientists together with leading dignitaries from several authorities and politicians who gave lively narratives of what is happening in the Baltic Sea. Everything from the slow geological changes over the years to the formation of new species all the way to the political situation today.
1Dramaten

A truly dramatic moment was when Ett mycket dramatiskt ögonblick var när professor emeritus Ragnar Elmgren from Stockholm University spoke of what species can be found in the Baltic Sea today. Suddenly, a large Ascophyllum nodosum falls down from above, landing just behind him!

Professor Elmgren cooly states that this species has not managed to migrate into the Baltic Sea due to the low salinity. The common seaweed species that most people reckognise, the bladderwrack, is an important foundation species for life in the Baltic Sea. Many species find shelter or food in the bladderwrack.
This is the moment when Fucus radicans enters the stage, from the pocket of Ragnar. Fucus radicans has formed an own species from Fucus vesiculosus in less than a couple of thousand years. It is the only known endemic species in the Baltic Sea, which means it is not found anywhere else i the world seas.

Seaweed smells of the sea and is also edible. Someone who has tried Fucus radicans canapées (se tidigare inlägg) is the Swedish king, on a visit to the Askö Laboratory.

It is relatively easy to separate Fucus radicans and Fucus vesiculosus when they grow together in sympatry. Fucus radicans appropriate common name is narrow wrack. The thallus is much narrower that that of Fucus vesiculosus and Fucus radicans lacks the bladders that have given Fucus vesiculosus its name.
4Smal o blåstång

Between the presentation on stage, we the audience were entertained with beautiful music from the orchestra and songs. Amonst them an interpretation of ”Rönnerdal han dansar över Sjösala äng” (Rönnerdal is dancing over Sjösala meadow)by Evert Taubes, where the background was a lovely seagrass meadow.

5sjögräsäng

The show ended with all participants on stage and His Majesty the King expressed his thanks for a rewarding evening, emphasizing his own keen interest in environmental questions in general and those of the Baltic Sea in particular.

6Kungen tackar

Artificial algalbelt created by ferry traffic

h3>In the non-tidal Baltic Sea, the daily wash from the regular ferry traffic along the archipelago shores creates an algal zonation similar to a tidal shore. The regular wash of the rocky shores bordering the ferry route results in marked green algal zone. In the springtime it is composed of e.g. Spirogyra species and in the summer by Cladophora glomerata and Enteromorpha/Ulva species. Just below the green algal belt a zone of Fucus vesiculosus is found. The swell created by the ferry traffic is enough to keep the thalli wet and not drying out. The daily wash from the ferry traffic also affects the communities in rock pools. If you want to know more about these changes have a look at the article by Östman and Rönnberg Effects of ships’ waves on rock-pools in the Åland …

algzonering ovan ytanSvallvågor

3Spirogyra i luppen

A stone with Spirogyra spp. collected from the Askö laboratory a week before.

This algal belt could be observed from the ferry last week when I was travelling from Mariehamn, Åland to Stockholm,Sweden. The other less positive effects from the traffic is the strong erosion of sandy coastal parts where threes are falling down and the shores are disappearing, leaving larger stones and boulders along the shore.

erosionsstrand

 

 

Nordic OIKOS poster sessions

The number of posters was very large and one poster presented by a PhD student won the award as the best poster, selected by the board of Oikos during the conference. This was number 100 with the title: “Ant larvae as a secret weapon against social parasites” by Unni Pulliainen. During the poster session lots of engaged presentations occurred.

1Winning poster Ants

Winner of “Best Poster Award”

1 a Ben presents his poster

Ben presents his poster

There were also a number of marine and aquatic posters, for some the author had the possibility to pitch their poster in 3 minutes.

Tiina Salo, now being on a post-doc, showed in her poster that Lymnea stagnalis responds more strongly to a heat wave after exposure to a mixture of micropollutants. But they recovered fast after the heat wave had passed. To feed the snails she used ecological salad. In the future experiments they will be fed leaves from different aquatic plant species.

2Tiina presents her poster

Tiina (left) pitches her poster

Several posters presented different aspects on the hot topic “ top- down – bottom-up” regulation of different ecosystems and impact of cascading effects and interactions between species. One species that creates lots of emotions is the cormorant, when establishing large populations on small islands along the Baltic coast.

4 aPelagic food-web  poster

Top-down fish poster

5Cormorant poster

Bottom-up cormorant poster

From the Department of Ecology, Environment and Evolution two posters were presented, one on the long-term effect of Pilayella on the settlement of Fucus vesiculosus by Susanne Qvarfordt and the other one presented results from a master project on the Swedish west coast about two closely related Littorina snail species behaviour when placing their egg sacs on different fucoid species.

6Pylaiella påverkan på etablering av blåstång

Susanne Qvarfordt show how the effects of Pylaiella can be seen for a long time in the macroalgal community

7Littorina poster

Our poster!

The last poster that I want to present was of high interest dealing with the new crab species, the mud crab, Rhithropanopeus harrisii and its impact on the local fauna. It is just a question when this crab will arrive on the Swedish coast. Keep your eye out for it.
8Mud crab introduced

The conference ended after three intense days.

9Thanks for the conference

 

Final day at the EMBS

Well, it has been a very interesting and inspiring symposium, as the EMBS always is. We have been well fed, both with science, cake and drink by all the lovely organizers, who have worked very hard during the week.

Today, there were som interesting talks, such as that by Laura Kauppi from Tvärminne fieldstation in Finland. She presented how the effect of the invasive polychaete Marenzelleria spp. differs between shallow and deep bottoms in the Gulf of Finland. This is a species that we also have in Sweden, and it is important to know how it affects the ecosystem.

The very entertaining Trine Bekkby from NIVA in Norway held a very pedagogical talk on how to use models and when to top due to data deficiency. This was really nice, as many of us agreed on afterwards, since one often just hears the results, not much on hpw it is done “backstage”. Another nice thing is that Trine works on kelps, so the examples were interesting and there were some nice pictures of kelp.

Todays plenary talk was by professor Bernd Blasius, entitled The risk of marine invasion by global shipping. It is very interesting to see the maps of how different species have been unintentionally transported around the globe and how they have managed to either blend in or totally take over in different habitats. The most difficult part of this research is apparently to get the data over ship movement, and a lot of time is spent pleading with authorities, shippers and harbour authorities. There is huge amounts of work put into the maps and graphs presented. He rightly point out that if you show a diagram, perhaps some expert in a conference might be interested. If you make a picture, then the press will come. And, apparently, the U.S Navy. A very thought-provoking presentation. I wonder if the early seafarers ever envisioned the intensity of shipping that the oceans see today.

The conference closed with a very amusing summary of professor Hempel, who was a participant of the very first EMBS here on Helgoland 50 years ago. He reflected over the changes of the EMBS, saying it was now a younger, female dominated symposium, which was positive. He also mentioned the very nice presentation by Angela Wulff, and how micro organisms were now more popular, bridging the gap between organism biologists and molecular biologists.

Herman Hummel presented the poster and presentation prizes to PhD students, handed out by the MARS network and MBA. Mark Frost of the Marine Biology Association first presented the different memberships, urging all and sundry with an interest in marine biology to sign up as members. First prize of 250 EUR went to Norwegian collegue Ann Evankow and the two 100 EUR prizes to Merle Bollen and Christopher Gross.

And so, finally, this years Yellow Submarine was won by Russia, who made a huge gorgonian seastar, also honouring the biggest calstle (Team Asia) and most creative castle by Team Finland (although cleverly disguised as Norway during the award ceremony).

Day 3 and 4 of the EMBS at Helgoland

Wednesday at week-long conferences is usually the day with excursions. Today, we started out with some talks in the morning, among them Alexey Sukhotin showing different studies done at the Russian field station Kartesh in the White Sea over the last 50 years. This was very interesting to us, as Lena went there in 1995 and we would like to return and do some experiments on their Fucus vesiculosus populations.
Also, Hartvig Christie held another talk on the Norwegian kelp forests and seagrass beds, this time on how they can survive being both food and habitat. This study clearly shows how fish help maintaining the kelp and seagrass by feeding on the any grazing gastropods and crustaceans that would otherwise prove too much grazing pressure for these ecosystems.

Since the sun was out and the wind was low, we went for a discovery trip up on the oberland, admiring the view of the North Sea horizon and the interesting geology of the island.

The red sandstone of Helgoland

The red sandstone of Helgoland

We took our packed luch by the nesting colony of Northern gannet, Morus bassanus.

Nestng colony of Northern gannet

Nestng colony of Northern gannet

The birds seem not to mind the passing humans

The birds seem not to mind the passing humans

It was rather sad to see how they have used plastic or nylon netting for nesting material. Several young birds have gotten entangled in the nets and died, so the colonies were draped with more or less mummified birds hanging from the rock.

Plastic as nesting material comes with a prize

Plastic as nesting material comes with a prize

Lange Anna, a monument to erosin by wind and waves.

Lange Anna, a monument to erosin by wind and waves.

After some mandatory selfies at Long Anna at the tip of the island, we walked back towards unterland, passing the local allotment area. Gardening here is very affected by the wind, but lots of dense hedges seems to do the trick.

The allotment gardeners have plenty of sun, rain and seaweed as fertilizer. Using hedges to screen out the wind makes for bumper crops.

The allotment gardeners have plenty of sun, rain and seaweed as fertilizer. Using hedges to screen out the wind makes for bumper crops.

In the afternoon, we took the boat over to Düne to look at the seals and browse the shores there for interesting finds. There are so many beautiful speciments of Laminaria hyperborea kelp here, and I would like to bring all of them home. Best not, I think. A kelp forest in a small appartment might not be such a good idea.

The beuty of kelp, even when washed on to the beach.

The beuty of kelp, even when washed on to the beach.

Typical dune landscape, with few but tough species

Typical dune landscape, with few but tough species

After enjoying the dune-landscape with its typical flora and falcons, we strolled to the southern beach, where the conference dinner and Yellow Submarine competition would be held. The Yellow Submarine has been running since 1968 and although its all in good fun, it is still a prestigeous prize to win.

The Swedish team compeating for the Yellow Submarine. Nils, Lena, Ellen and Angela.

The Swedish team compeating for the Yellow Submarine.
Nils, Lena, Ellen and Angela.

This year, we entered a strong team for Sweden, with no less than 3 professors and one fresh-from-the-oven doctor. Lena and Nils kautsky, Angela Wulff and yours truly worked hard, spinning around bottles, answering questions while building sand castles and collecting water (huge effort by aquatic gazelle Angela).

All the teams did very well and the winner will be announced later in the week. The evening ended pleasantly late after drinks and high spirits amongs all.

Day 2 of the EMBS on Helgoland

After a crab-pizza for dinner and a good nights sleep, it is yet another day of interesting talks on the EMBS conference.

Another day of interesting talks!

Another day of interesting talks!

Agnese Marchini from Italy presented her research on foreign visitors in Venice lagoon. There are 71 non-native species in this one lagoon, most came from Japan, but also Indo-Pacific and other origin. Most of these have been introduced by boats, as Venice is the main port for cruiseships in the Mediterranean. There are also oyster and clam farms, who import the ”seeds” from other countries, enabling hitchikers to sneak along. The pacific oyster Crassostera gigas was first introduced in 1966 and expanded enormously in the mid 70’s, still showing a high rate of expansion. The brown macroalgae Undaria pinnatifida and Sargasum muticum are also present, forming large floating mats in favourable condditions. Many species have been shown to be poly-vector spread, meaning that they might arrive on an oyster but then hitch a ride with another species to spread further into the Mediterranean. If you want to look for new species in a harbour, the wooden structures of for example the diktalbs is a very good substrate for first settlement. It is not possible to eradicate the new species in Venice lagoon, but it might be possible to prevent new introductions and contain those who are there, with good management measures.

Her collegue Jasmine Ferrario followed, in the same track, presenting her work as a PhD on investigating if harbours and nerby marinas share the same non-native species or not. Sampling one harbour and one marina each in three different regions by scraping gave 16 non-native species out of 260 total number of species collected. Some species are recent arrivals, such as a cute ghost-shrimp, and they also found 2 new species not previously found in the Mediterranean Sea. One of them was also first record outside the Pacific Ocean! Jasmines research show how recreational boating is a vector which helps spreading new species in the Mediterranean. Harbours do not seem to differ in species composition, being fairly similar, but marinas do. The results that the marinas had the same or even higher number of non-native species was contraty to what was expected, and an important finding for management of the non-native species in the Mediterranean Sea.

Anya Zalota from Russia then spoke of crustaceans, deapods in particular, found in Russian waters, pointing out that the far East is lacking information since it has not been studied. Many non-native species have been found, but not established, in Russian waters. The highest record of non-native species is of course the Black Sea, and the polar seas seem to have only native species. Taking previous speaker into account, this is only to be expected, since ther eis not much boating in the polar seas. Anya and her team are working in the Sea of Azov, just east of the Crimean, but also look at the distribution of the giant Kamchatka crab. They actually found one of these crabs in the White Sea, near the small marine station Kartesh in Chupa Bay, where we would like to go and looka at seaweed. There is also an ongoing expedition trying to determine the extent of the snow crab, which can be seen on the ”Deadliest Catch” TV-show. The invasions of snow crab seem to coincide with ice conditions the winter before a spread-phase. Although this crab can be caugth and used for human consumtion, there are worries that it is spreading too rapidly and might knock out the native Russian species. The best way of hindering an invasion is to fish it heavily, but one where other species are not damaged, the snow crab might be kept off the Russian shores.

Nadezhda Berezina from Russia, who I have met on several conferences, then showed data from the Neva estuary and the Curonian lagoon in the Baltic Sea and how these estuarine environments are affected by nutrient loads, looking at biomass of annual macroalgae such as Cladophora, Pilayella and Ulva, and also how these ecosystems are dominated by crustaceans. At the ice breaker event when we arrived here this Sunday, Nadezhda told me that she has observed how Fucus is now establishing on the southern coast of Gulf of Finland on the Russian side. This is very interesting news, and it might be worth the hsasle of getting a visa and permission to go there to make some observations and sample, so that the speed of establishment might be assessed.

Before coffee (and very nice cakes), Sabine Horn from AWI have investigated the rôle of birds in the Wadden Sea food web, asking which areas are most important for birds, how do they impact fodd webs and can they be used as indicators. The Wadden Sea is really shallow, with vast expamnses of mudflat containing different types of mussels and clams, seagrass meadows and lots of burrowing worms, all food for different birds. This is a very special area and I would like to go there, just to experience the flatness. The highest bird concentrations are found on the sand flats and the seagrass meadows, and Sabine show how the Wadden Sea food web has both top-down and bottom-up effects.

After coffee Markus Brand showed the composition of the shallow fish community in Kongsfjorden at Spitsbergen on Svalbard. A very interesting arctic gradient was present in the fjord, with warmer water coming in and being cooled by meltwater from the glacier. They do some diving there, which I also would like to, as they only sample during summer when they can access the fjord.

Stefanie Dekeyzer from WoRMS presented their new database World Register of Introduced Marine Species (WRIMS), wich is compiled by numerous experts and makes this data very accessible.

Shasha Wang is working with Martin Wahl at Geomar in Kiel, trying to determine if the invasive forms of the red algae Gracillaria vermiculophylla have stronger defense against fouling by the red alga Ceramium spp. She has compared Gracillaria from Germany and France, where it has been introduced, to specimens from the species’ natural range in China and Japan.

We were then very interested to hear from Torjan Bodvin, a Norwegian collegue, about the speed and rate with wich the pacific oyster Crassostrea gigas, is currently travelling up along the Norwegian coastline. Their rapid colonization might well be a problem, and I for one am ready to assist our dear neighbours by coming over to Norway and eat as many oysters as I can.

Main beach on Helgoland

Main beach on Helgoland

We took our packed lunches and ate them on the pier by the beach, admiring the seaweed diversity on the breakwater structures. We then took yet another foraging walk on the beach, looking at what new species had been washed up since last tide. Today we found more red algae. I had expected several species of molluscs washed ashore, but so far there is only Gibbula sp, some Littorina obtusata and the odd fragment of Littorina littorea. Tomorrow we will walk on the other side of the island, perhaps there will be more shells there.

Studying seaweed from above...

Studying seaweed from above…

and from (during high tide) below

and from (during high tide) below

Tuesday plenary talk was by Hans Otto Pörtner, who has an immense publication list and is very inspiring. He was adressing the impacts of climate change on ocean biology. The feeling was a bit bleak, as the numbers for human impact on the oceans is not very happy reading. However, one must not give up hope on the effects of good management, hightened awareness and alternative methods in fisheries etc.

This pretty much summarizes it

This pretty much summarizes it