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GLOBEC INTERNATIONAL NEWSLETTER OCTOBER 2007 presence of noise in both measurement and environment. The workshop concluded with a number of specific recommendations for changes in: • productivity regimes that require adapting management procedures or procedures robust to regimes, • habitat influencing measurement and stock carrying capacity • growth and maturation influencing short and medium term advice, and • recruitment changes due to environmental influence in the short and medium term. Recommendations also include the use of multi-species models primarily for hypothesis testing and testing management procedures. Finally the group recognised the need for longer term prediction and thus for developing climate scenarios for sensitive areas such as the Baltic Sea. The report of the meeting is available through the ICES (http://www.ices.dk/reports/ACFM/2007/WKEFA/WKEFA_2007.pdf) and the EUR-OCEANS Knowledge Transfer websites (http://www.eur-oceans.eu/training_and_outreach/wp9/). ICES Working Group on Zooplankton Ecology meet in Riga, Latvia Roger Harris Plymouth Marine Laboratory, Plymouth, UK ([email protected]) Held from 26-29 March 2007, the meeting of the ICES Working Group on Zooplankton Ecology (WGZE) was the largest meeting so far of the group. The meeting, chaired by Astthor Gislason (Marine Research Institute, Reykjavik) was hosted in Riga, Latvia at the kind invitation of Solvita Strake from the Institute of Aquatic Ecology and was attended by 30 scientists representing 14 countries (Fig 1). This article provides a short summary of the discussions and outcomes. The full report of the WGZE meeting can be found at: http://www.ices.dk/iceswork/workinggroups.asp Some highlights of the WGZE discussions included: • • • In the North Atlantic, significant changes have occurred in the abundance, distribution, community structure and population dynamics of zooplankton and phytoplankton, mainly reflecting changes in regional climate, caused predominantly by the warming of air and sea surface. The changes in the zooplankton and phytoplankton communities which are at the bottom of the marine pelagic food web, affect higher trophic levels, as the synchrony between predator and prey (match-mismatch) plays an important role (bottom-up control of the marine pelagic environment) in the successful recruitment of top predators, such as fish and seabirds. Figure 1. Participants at the WGZE meeting in Riga. in hydrodynamics and sea temperature. Considering the OSPAR Climate Request the following evidence was provided of changes in the plankton in relation to hydroclimatic changes: • The NAO has been rising over the past 30 years, as have the surface water temperatures of the European continental shelf. This has caused changes in the planktonic compartment of the marine ecosystem affecting plankton production, biodiversity, species distribution which has had effects on fisheries production and other marine life (e.g. fish larvae and seabirds). • In North Sea, the population of the previously dominant zooplankton species (the cold water Calanus finmarchicus) has decreased in biomass by 70%, between the 1960s and the post 1990s. Warm-water species have moved northwards to replace this species although their biomass is not as abundant. • A shift in the distribution of many plankton and fish species by more than 10° latitude northward has been recorded in the OSPAR area over the past thirty years. • The seasonal timing of phyto- and zooplankton production also altered in response to recent climate changes. This has consequences for plankton predator species, including fish, The poor recruitment of several fish of commercial interest and the low seabird breeding productivity recorded in recent years in some regions are associated with changes in plankton biomass and in the seasonal timing of plankton. In reviewing the ICES Annual Plankton Status Report (http://www. ices.dk/pubs/crr/crr281/CRR281.pdf) various plankton trends and changes were noted and important additions and improvements to the report are planned. When considering phenological changes several examples were discussed (e.g. Acartia sp., Temora longicornis, Pleurobrachia pileus, echinoderm larvae in the North Sea). Phenology is already included in the ICES Annual Plankton Status Report and will be expanded. The WGZE had been asked to assess and report on changes in the distribution, population abundance and condition of zooplankton in the OSPAR maritime area in relation to changes 42 GLOBEC INTERNATIONAL NEWSLETTER OCTOBER 2007 Zooplankton studies in the Baltic During the Riga meeting a Baltic Sea Mini Session, which included the following presentations of the work of the regional research community. Short overview of Baltic Sea activities Piotr Margoński, Sea Fisheries Institute, Gdynia National research programme climate change impact on the water environment of Latvia Andris Andrushaitis, Institute of Aquatic Ecology, Riga Baseline port surveys for invasive marine species in the north-eastern Baltic Sea Solvita Strake, University of Latvia, Riga Figure 2. Cercopagis pengoi, an introduced species of cladoceran, which through its predatory activity has had a major impact on the plankton community structure in Baltic. Photographs courtesy of Arno Põllumäe and Julia Polunina (inset). Trying to find out more (about marine mesozooplankton). Anda Ikauniece, Latvian Institute of Aquatic Ecology, Riga whose life cycles are timed in order to make use of seasonal production of particular prey species. Monitoring of zooplankton in the SE Baltic Natalja Demereckiene, Latvian Fish Resource Agency • In the North Sea and around the British Isles, considerable increase in phytoplankton biomass has been recorded since the mid-1980s. Zooplankton in the south-east Baltic Julia Polunina, P.P. Shirshov Institute of Oceanology, Kaliningrad • In the North Sea functional changes in the phytoplankton community have been recorded in recent decades, with an increase of dinoflagellates and a decrease of diatom abundance in response to warmer sea waters. • In the North Sea, warmer conditions earlier in the year together with increased phytoplankton abundance since the late 1980s, have determined the significant increase of meroplankton, in particular echinoderm larvae of Echinocardium cordatum. This change in the food web structure, due to the competitive exclusion of the holozooplankton (i.e. permanent plankton species) by the meroplankton, may significantly diminish the transfer of energy towards top pelagic predators (e.g. fish) while increasing the same transfer towards the benthic component. Hydrological regimes instability and climate changes influence on zooplankton community of open parts of the Baltic Sea and the Gulf of Finland Larisa Litvinchuk, Zoological Institute of the Russian Academy of Sciences, St Petersburg • Future warming is likely to alter the geographical distribution of primary and secondary pelagic production, affecting oxygen production, carbon sequestration and biogeochemical cycling. These changes may place additional stress on already-depleted fish stocks as well as have consequences for mammal and seabird populations. Several examples of introduced species were noted from both sides of the North Atlantic, most notably Mnemiopsis leydii that has been observed in the Baltic Sea, the Kattegat and the North Sea, and has extended to waters off Bergen. The WGZE encouraged microzooplankton to be included in time series monitoring within the ICES area. Arrangements for the planning of the ‘Joint WGZE/CIESM Workshop to compare Zooplankton Ecology and Methodologies between the Mediterranean and the North Atlantic (WKZEM)’ (Co- 43 Recent newcomers in zooplankton of Estonian coastal areas Arno Põllumäe, Estonian Marine Institute, Tallin Zooplankton monitoring as it is carried out by FIMR Juha Flinkman, Finnish Institute of Marine Research, Helsinki Sea Fisheries Institute zooplankton activities Piotr Margoński, Sea Fisheries Institute, Gdynia Chairs: A. Gislason, Iceland, and G. Gorsky, France), adopted by ICES in 2006, are progressing well. It was decided that the workshop be held in Heraklion, Crete, Greece in the second half of October 2008. During the meeting a ‘Baltic Sea Mini Session ‘ was held during which scientists from the region presented their research activities (see text box). A particular focus of these talks was the importance of introduced species in affecting the community structure and dynamics of the Baltic. An example cited was the predatory cladoceran, Cercopagis pengoi (Fig. 2), which was first found in the Gulf of Riga in 1992. The species is thought to be of Ponto-Caspian origin having been introduced as a result of the discharge of ballast water.