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Oceana proposal for a Marine Protected Area Marstrandsskärgården

Introduction Kattegat and Skagerrak are the transitional areas between the salty North Sea and the brackish Baltic Sea. Kattegat is relatively shallow with a mean depth of only 23 meters1, but its deeper areas can reach more than 150 meters2, as is the case in the Kattegat and Djupa Rännan trenches3. The latter is connected to the former (see also the fact sheet Kattegat trench), which runs 45 km south through mainly Danish waters4,5.

The surface salinity in the northern Kattegat is relatively salty (30 psu) compared to the southern part of Kattegat (15 psu)6. The bottom water in the entire Kattegat has an even higher salinity, as it comes from the north, namely the North Sea and Skagerrak. Skagerrak and Kattegat do not have any notable tidal activities, as such, the only changes of water between the North Sea and Baltic Sea happen using the wind power7.

Oceana conducted underwater studies in the area 2011 and 2012 (see Tables 1 and 2).

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Description of the area The deeper parts of Kattegat, including the aforementioned trenches, boast muddy soft bottoms, and communities of fauna that are specialized to live in those physical conditions, such as sea pens with burrowing megafauna. In shallow waters, the substrate is more diverse, and includes bottoms with various stone covers and sandy bottoms. Different benthic communities exist there, such as octocoral gardens, and in even shallower waters, in the photic zone, macroalgae and sea grass meadow can occur.

Coral gardens are aggregations of one or more anthozoan species, and can be found both on soft and hard seabeds. They are biodiverse, and starfish, brittle stars, crustaceans, as well as molluscs are associated with the community8. In the Kattegat, dead man’s fingers (Alcyonium digitatum) form such gardens. Common brittle stars (Ophiothrix fragilis), black brittle stars (Ophiocomina nigra) and the nudibranch, Tritonia hombergii, which prey on the dead man’s finger, are found in the octocoral community in Kattegat9. OSPAR has listed coral gardens as threatened and/or declining everywhere they occur10.

Two species of sea pens, the phosphorescent sea pen (Pennatula phosphorea) and the slender sea pen (Virgularia mirabilis), with burrowing megafauna form a soft bottom community that exists in Kattegat, where Norway lobster (Nephrops norvegicus) often represents the megafauna. The lobsters form complex tunnels in the mud, which allows oxygen into the sediment. This type of community is listed as threatened and/or declining in Kattegat11.

The shallow water of the Swedish west coast is mostly made up of soft bottoms, with zones bountiful in macroalgae (such as Fucus spp.) and macrophytes (Zostera marina)12. The latter is very productive and can form dense beds on sand or sandy mud13. They also provide shelter for fauna (such as bivavles, echinoderms, polychaet worms, amphipods etc.), and stabilize the seabed, making them important for the environment14. Eelgrass meadows are also important nursery grounds for commercial fish, like cod (Gadus morhua) and whiting (Merlangius merlangus)15,16. The high productivity of Zostera meadows leads to a large biomass, which make it an important player when looking for solutions to curb climate change17. Zostera marina has a broad distribution in European seas, has been declining throughout the last century, including along the Swedish west coast18,19. Due to their decline, seagrass is listed in the Rio Declaration20 as a habitat to protect21 and OSPAR list Zostera beds as threatened and/or declining wherever they occur22.

Proposal The proposal area, Marstrandsskärgården, is located in Swedish Kattagat waters and includes a small piece that extends into Skagerrak. It ranges from the coastal waters of the Gothenburg archipelago to the border of Danish EEZ covering both shallow and deeper waters.

In 2011, based on expedition findings, Oceana proposed the Djupa Rännan trench as a new offshore marine protected area23. This trench is also included in our current proposal. Using divers in shallower waters and an underwater robot (ROV) in deeper waters down to 95 meters depth, we documented and 61 species inside the proposal area (for entire list see Table 1). In 2012, Oceana extended the survey area to include dives in the shallow waters of the archipelago, five ROV immersions at depths ranging from 24 to 102 meters, as well as a bottom sample taken at 80 meters deep. The findings, which are described below, showed places with a relatively high biodiversity over a range of depths. On the muddy bottoms at 95 meters deep, a rich array of fauna was observed, including many buried brittle stars Amphiura chaijei, firework anemones (Pachycerianthus multiplicatus), which are large burrowing sea anemones that are not attached to hard sediment24, and the Suberites virgultosus sponge, which Oceana also recorded in Kattegat Trench in 201125. The area was also inhabited by hydroids (Abietinaria abietina, Tubelaria larynx), anthozoans (Alcynium digitatum, Pennatula phosphorea, Urticina felina, Virgularia mirabilis), and annelids (Filograna implexa, Sabella pavonina) etc. (see Table 2 for entire list).

Another ROV immersion at 85 meter deep showed the aforementioned community of sea pens with burrowing megafauna. A bottom sample from this area also revealed the crustacean Diastylis rathkei, the echinoderms Echinocardium cordatum and Ophiura affinis.

At 52 meters deep, in an area with scattered stones, on which many species were attached, a solitary Devonshire cup‑coral (Caryophyllia smithii) was documented, which is the only stone coral existing in this region26,27. A red sea fan (Swiftia rosea) was documented on the same stone. This type of sea fan has a limited distribution in the area because it requires stable cold water and moderate current to flourish28.

A coral garden, dominated by dead man’s finger, was documented at 32 meters depth, on a bottom covered with many stones interspersed withsmall sand patches. The current in the area was strong and visibility was relatively good. Several fish species were also found here, including both female and male colorful cuckoo wrasses (Labrus mixtus), ballan wrasses (Labrus bergylta), and a reddish coldsinny (Ctenolabrus rupestris).

2 At 16 meters deep, Oceana uncovered an area boasting several species of flora and fauna. Numerous types of sea squirts were found on rocks (Ascidiella aspersa, Ciona intestinalis, Corella parallelogramma, and Dendrodoa grossularia), as well as red (Delesseria sanguinea, Pelvetia canaliculata), and brown algae (Laminaria digitata, Laminaria saccharina, and Sargassum muticum).

The proposed area connects a number of smaller coastal N2000 sites29, and also includes the offshore and deeper waters in Kattegat and Skagerrak, which are currently unprotected. Most of the benthic communities documented during the expeditions, including sea pens with burrowing megafauna, are not getting any protection through the Natura 2000 Habitats Directive, even though some have been defined as threatened and/ or in decline by OSPAR. Little is known about many of the communities in the deeper areas, and the site should therefore be managed with precaution.

Possible threats and management proposals Fisheries in the area target mainly cod, lobster, and flatfish30. The cod stock in Kattegat has decreased dramatically since 197031 and inconsistencies between official landings data and total removals have increased in the most recent years, according to ICES32. Furthermore, cod is also frequently caught as bycatch in for instance, the Nephrops fishery. Sweden has handled this by introducing mandatory grids when trawling for Nephrops in their waters33.

Trawling and other disturbances to the seafloor, pose a serious threat to the benthic communities in the area, as well as to cod and flatfish34. In 2011, Oceana documented bottom trawling marks on a mud bottom inside the proposed site. This type of activity should be prohibited in the proposed area.

In Kattegat and the Baltic Sea, eutrophication is one of the major reasons for the decline of Zostera marina. Physical disturbances, such as dredging, upland development, and pollution also threaten eelgrass35,36.

A management plan should address all of these human caused threats. The communities which are threatened and/or in decline, should particularly be addressed in the management plan. The declining fish stocks should be managed through international EU regulations.

References 1 Matthew J. B. L., Buchholz F., Saborowski R., Tarling G. A., Dallot S. & Labat J. P. 1999, On the physical oceanography of the Kattegat and Clyde Sea area, 1996‑1998, as background to ecophysiological studies on the planktonic crustacean, Meganyctiphanes norvegica (Euphausiacea). Helgoland Marine Research 53: 70‑84. 2 Kirk Sørensen T. 2005. Beskyttelse af havnaturen I indre danske farvande ‑ status og anbefalinger. WWF Danmark. 84 pp. 3 Nordberg K., Lofstedt Filipsson H. & Malmgren B. 1999. Oceanographic conditions in the deepest parts of the Kattegat, Scandinavia, revealed through recent benthic foraminifera and hydrography. Estuarine, Coastal and Shelf Science, 49: 557‑576. 4 Nordberg K., Lofstedt Filipsson H. & Malmgren B. 1999. Oceanographic conditions in the deepest parts of the Kattegat, Scandinavia, revealed through recent benthic foraminifera and hydrography. Estuarine, Coastal and Shelf Science, 49: 557‑576. 5 Kirk Sørensen T. 2005. Beskyttelse af havnaturen I indre danske farvande ‑ status og anbefalinger. WWF Danmark. 84 pp. 6 Havsmiljoinstitutet. 2012. Havet 2012 ‑ om miljötillståndet i svenska havsområden. Havmiljöinstitutet. Available at http://www.havsmiljoinstitutet.se/digitalAssets/1391/1391098_havet_2012_121126.pdf [Viewed 1 February 2013]. 7 Nordberg K., Lofstedt Filipsson H. & Malmgren B. 1999. Oceanographic conditions in the deepest parts of the Kattegat, Scandinavia, revealed through recent benthic foraminifera and hydrography. Estuarine, Coastal and Shelf Science, 49: 557‑576. 8 OSPAR 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats. Biodiversity Series. 261 pp. 9 Paulomäki H., Abel C. & Aguilar R. 2011. Conservation proposals for ecologically important areas in the Baltic Sea. Oceana. 10 OSPAR 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats. Biodiversity Series. 261 pp. 11 OSPAR 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats. Biodiversity Series. 261 pp. 12 Troell M., Pihl L., Ronnback P., Wennhage H., Soderqvist T. & Kautsky N. 2005. Regime shifts and ecosystem services in Swedish coastal soft bottom habitats: when resilience is undesireable. Ecology and Society 10 (1): 30. Available at: http://www.ecologyandsociety.org/vol10/iss1/art30/ [Viewed: 1 February 2013]. 13 OSPAR 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats. Biodiversity Series. 261 pp. 14 OSPAR 2009. Background Document for Zostera beds, Seagrass beds. Biodiversity Series. 38 pp. 15 OSPAR 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats. Biodiversity Series. 261 pp. 16 Baden S., Gullstrom M, Lunden B., Pihl L. & Rosenberg. 2003. Vanishing seagrass (Zostera marina, L.) in Swedish coastal waters. Ambio, 32 (5): 374‑377.

17 Palacios S. L. & Zimmerman R. C. 2007. Response of eelgrass Zostera marina to CO2 enrichment: possible impacts of climate change and potential for remediation of coastal habitats. Marine Ecology Progress Series, 344: 1‑13. 18 Køie M. & Kristiansen A. 2000. Havets dyr og planter. Gads Forlag. 351 pp. 19 Baden S., Gullstrom M, Lunden B., Pihl L. & Rosenberg. 2003. Vanishing seagrass (Zostera marina, L.) in Swedish coastal waters. Ambio, 32 (5): 374‑377. 20 Rio‑declaration (1992/93:13). 21 Baden S., Gullstrom M, Lunden B., Pihl L. & Rosenberg. 2003. Vanishing seagrass (Zostera marina, L.) in Swedish coastal waters. Ambio, 32 (5): 374‑377. 22 OSPAR 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats. Biodiversity Series. 261 pp.

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23 Paulomäki H., Abel C. & Aguilar R. 2011. Conservation proposals for ecologically important areas in the Baltic Sea. Oceana. 24 Naylor P. 2005 Great British Marine Animals. 3rd edition. 25 Paulomäki H., Abel C. & Aguilar R. 2011. Conservation proposals for ecologically important areas in the Baltic Sea. Oceana. 26 Køie M. & Kristiansen A. 2000. Havets dyr og planter. Gads Forlag. 351 pp. 27 Naylor P. 2005 Great British Marine Animals. 3rd edition. 28 Moen F. E. & Svensen E. 2009. Djurlivet i havet. Nordeurpeisk marine fauna. Norstedts. 29 The Natura 2000 sites inside the proposal are Sälöfjorden, Nordre älvs estuarium and Älgön‑Brattön, which include the habitats reef and sandbank among others. 30 Thörnqvist S. 2006. Områden av riksintresse för yrkesfisket. Fiskeriverket. 31 ICES Advice 2008. Book 6, North Sea. 326 pp. 32 ICES Advice 2008. Book 6, North Sea. 326 pp. 33 Catchpole T. L. & Revill A. S. 2007. Gear technology in Nephrops trawl fisheries. Rev. Fish Biol. Fisheries. DOI 10.1007/ s11160‑007‑9061-y. 34 Moen F. E. & Svensen E. 2009. Djurlivet i havet. Nordeurpeisk marine fauna. Norstedts. 35 OSPAR 2008. Case Reports for the OSPAR List of Threatened and/or Declining Species and Habitats. Biodiversity Series. 261 pp. 36 Short, F. T. & Wyllie‑Echeveriia, S. 1996. Natural and human induced disturbance of seagrasses. Environ. Conserv. 23: 17‑27.

Species list for Marstrandsskärgården

Table 1: List of species recorded at Djupa Rännan Trench in 2011. Possible threat category indicated in brackets. Species PORIFERA Halichondria panicea Haliclona urceolus CNIDARIA Alcyonium digitatum Beroe cucumis Bougainvillia ramosa Cyanea lamarckii Eudendrium rameum Halecium halecinum Metridium senile Pennatula phosphorea Sagartiogeton laceratus Sagartia troglodytes Stomphia coccinea Tubularia sp. Urticina felina Virgularia mirabilis ANNELIDA Anobothrus sp. Polyphysia crassa Sipunculus sp. MOLLUSCA Balanus crenatus Balanus improvisus Coryphella verrucosa Cancer pagurus Caprella linearis Liocarcinus depurator Munida rugosa Pagurus bernhardus Pecten maximus BRYOZOA Crisia eburnea Electra pilosa

4 Table 1: List of species recorded at Djupa Rännan Trench in 2011. Possible threat category indicated in brackets. Species ECHINODERMATA Amphiura chiajei Asterias rubens Brissopsis lyrifera Ophiocomina nigra Spatangus purpureus Thyone fusus TUNICATA Ascidiella scabra Corella parallelogramma Dendrodoa grossularia FISH Callionymus lyra Hippoglossoides platessoides (probably declining, HELCOM) Lesuerigobius friesii Lumpenus lampretaeformis (CR, but not in Kattegat, HELCOM) Micromesistius poutassou (probably declining, HELCOM) Myxine glutinosa Microstomus kitt (probably declining, HELCOM) Platichthys flesus Pleuronectes platessa (probably declining, HELCOM) Pomatoschistus microps Reinhardtius hippoglossoides Trisopterus esmarkii ALGAE Corallina officinalis Delesseria sanguinea Dilsea carnosa Fucus vesiculosus Halidrys siliquosa Laminaria digitata Laminaria saccharina Lithothamnion glaciale Pelvetia canaliculata MAMMALIA Phoca vitulina

Table 2: List of species in Marstrandsskärgården in 2012 by depth and their threat category. Depth (m) Species 80‑102 PORIFERA Haliclona urceolus Suberites virgultosus CNIDARIA Abietinaria abietina Alcyonium digitatum Aurelia aurita Cancer pagurus Cerianthus lloydii Mnemiopsis leidyi Pachycerianthus multiplicatus

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Table 2: List of species in Marstrandsskärgården in 2012 by depth and their threat category. Depth (m) Species Pennatula phosphorea Tubularia larynx Urticina felina Virgularia mirabilis ANNELIDA Arenicola cf. marina Filograna implexa Sabella pavonina CRUSTACEA Anapagurus laevis Balanus balanus Diastylis rathkei Liocarcinus depurator Meganyctiphanes norvegica Nephrops norvegicus Pagurus bernhardus ECHINODERMATA Amphiura chiajei Asterias rubens Echinocardium cordatum Luidia sarsi Ophiura affinis Ophiura sp. TUNICATA Synoicum pulmonaria FISH Callionymus lyra Eutrigla gurnardus Gadus morhua (threatened and declining, HELCOM, OSPAR) Limanda limanda (probably declining, HELCOM) Lumpenus lampretaeformis (CR, but not in Kattegat, HELCOM) Lycodes vahli Melanogrammus aeglefinus Merlangius merlangus (probably declining, HELCOM) Molva molva (vulnerable, HELCOM) Myxine glutinosa Platichthys flesus Pleuronectes platessa (probably declining, HELCOM) Rhinonemus cimbrius Trisopterus esmarckii 26-60 CNIDARIA Abietinaria abietina Actinia equina Alcyonium digitatum Aurelia aurita Bolinopsis infundibulum Bougainvillia sp. Caryophyllia smithii Eutonina indicans Metridium senile Mnemiopsis leidyi Pennatula phosphorea

6 Table 2: List of species in Marstrandsskärgården in 2012 by depth and their threat category. Depth (m) Species Swiftia rosea Virgularia mirabilis MOLLUSCA Polycera faeroensis Solenidae sp. Turritella communis CRUSTACEA Balanus balanus Nephrops norvegicus Pagurus bernhardus BRYOZOA Flustra foliacea Securiflustra securifrons ECHINODERMATA Asterias rubens Marthasterias glacialis Ophiothrix fragilis Ophiura sp. Solaster endeca TUNICATA Ascidia virginea FISH Callionymus lyra Ctenolabrus rupestris Eutrigla gurnardus Gadus morhua Labrus bergylta Labrus mixtus Melanogrammus aeglefinus Trisopterus esmarkii RHODOPHYCEAE Hildenbrandia rubra 16 PORIFERA Halichondria panicea Haliclona cf. limbata CNIDARIA Alcyonium digitatum Aurelia aurita Bolinopsis infundibulum Hydractinia sp. Metridium senile Mnemiopsis leidyi Obelia geniculata Obelia cf. longissima Protanthea simplex Sagartiogeton undatus Urticina felina MOLLUSCA Coryphella verrucosa Cuthona cf. nana Mytilus sp.

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Table 2: List of species in Marstrandsskärgården in 2012 by depth and their threat category. Depth (m) Species CRUSTACEA Amphipoda sp. Balanus balanus Cancer pagurus Carcinus maenas Nucella lapillus Praunus flexuosus ECHINODERMATA Asterias rubens BRYOZOA Electra pilosa TUNICATA Ascidiella aspersa Ciona intestinalis Corella parallelogramma Dendrodoa grossularia FISH Ctenolabrus rupestris Entelurus aequoreus RHODOPHYCEAE Delesseria sanguinea Dilsea carnosa Hildenbrandia rubra Pelvetia canaliculata Phymatolithon laevigatum Phymatolithon sp. PHAEOPHYCEAE Chorda filum Halidrys siliquosa Halosiphon tomentosus Laminaria digitata Laminaria saccharina Sargassum muticum CHLOROPHYCEAE Cladophoraceae sp. MAMMALIA Phoca vitulina

Table 3: List of habitats and communities in the Marstrandsskärgården in 2011 and 2012, and their threat category. Habitats and communities Red list category Amphiura Coral garden Threatened and/or declining (OSPAR) Echinoderms Macrophyte meadow Threatened and/or declining (HELCOM) Sea pen with burrowing megafauna Threatened and/or declining (OSPAR and HELCOM) Tube worm Pelagic, offshore (deep) waters Listed as threatened by HELCOM

This report was made possible thanks to the generous support of the Arcadia Fund, Robertson Foundation, VELUX Foundations and Zennström Philanthropies. Nyhavn 16, 4 sal · 1051 Copenhagen (Denmark) · Phone: +45 33151160 · [email protected]

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