0000000000653257
AUTHOR
Vadims Jermakovs
Baseline port surveys for invasive marine species in the Northeastern Baltic
Marine ecosystems around the world are being transformed and degraded by non-indigenous species, which affect the structure and function of the ecosystem, causing major ecological and economic implications. Ships have been recognized as a major vector for the introduction of non-indigenous harmful organisms, carrying them in ballast water tanks and sediments. Activities to prevent and mitigate the impact of invasive alien species have to be based on cooperation. Financed by Phare Cross Border Co-operation Programme in the Baltic Sea Region (2005–2006) Latvia together with Estonia will focus on baseline port surveys for non-indigenous species in the north-eastern part of the Baltic Sea.
Growth and production of three macrozoobenthic species in the Gulf of Riga, including comparisons with other areas
Three soft-bottom stations in the southern part of the Gulf of Riga were studied during the period December 1993 to January 1995. The amphipods, Monoporeia affinis and Pontoporeia femorata, and the poychaete Marenzelleria viridis, were analysed for production, using the cohort growth method. Animals were also analysed for carbon and nitrogen content in a CHN-analyser. Based on size measurements, the quantitative data were divided into age-classes and the growth of each cohort was calculated first as wet weight and then converted into carbon and nitrogen content. Total annual production of each species was calculated as well as turnover ratios. The turnover ratio for Monoporeia affinis was e…