Marc Herlyn

Niedersächsischer Landesbetrieb für Wasserwirtschaft, Küsten- und Naturschutz / NLWKN Lower Saxony Water Management Agency · Flussgebietsmanagment Übergangs- und Küstengewässer / River Basin Management -Transitional and Coastal Waters

During biological effect monitoring studies of endocrine active compounds with the snail Assiminea grayana in 2007-2013, reproductive disorders including atresia, transformation of capsule/albumen glands into prostates in females and ovotestis, transformation of prostates to capsule/albumen glands, disruption of spermatogenesis, and calcification o...

On the basis of the summarized descriptions of their content, within this chapter the interrelationship between the individual publications of this thesis is described. In the first investigation, “Quantitative assessment of intertidal blue mussel (Mytilus edulis L.) stocks: combined methods of remote sensing, field investigation and sampling” (Ann...

Intertidal blue mussel beds are important for the functioning and community composition of coastal ecosystems. Modeling spatial dynamics of intertidal mussel beds is complicated because suitable habitat is spatially heterogeneously distributed and recruitment and loss are hard to predict. To get insight into the main determinants of dispersion, gro...

Since the 1960s Pacific oysters(Crassostrea gigas) were imported to the North Sea coasts for aquaculture. The species was introduced to replenish the stock of the indigenous European oysterOstrea edulis which was strongly diminished in the past by overexploitation, diseases and severe winters. The introduction of this non-native species was regarde...

Conclusions - Most of the seagrass in the Wadden Sea occurs in the northern part. Beds are mainly positioned on the leeside of islands or in the shelter of high sand bars. Few, and generally smaller, beds are found in the Central and Southern Wadden Sea. A larger stock is present in the Jadebusen, mainly consisting of Z. noltii. The large Z. marina...

Conclusions Long-term monitoring, during the last 30 years, has proven to be very important in the analysis of trends in biomass and species composition. Without such a long-term data set it would be impossible to distinguish real changes from incidental highs or lows. Continuation of the monitoring on these long-term sites remains also in the futu...

In 2005, Pacific oysters, Crassostrea gigas, were collected from May to September along the East Frisian coast and processed for histology. Because of mass mortalities in September, additional samples of moribund oysters and apparently healthy blue mussels, Mytilus edulis, were subjected to virological and ultrastructural investigation. The oysters...

Field surveys (dating back to 1950) and aerial photograph series (dating back to 1966) were evaluated to determine sites of intertidal blue mussel (Mytilus edulis) beds at the Wadden Sea coast of Lower Saxony. Maps were prepared indicating sites of blue mussel beds during the last decades. A table gives additional information on the presence (or ab...

The aim of this investigation was to develop appropriate methods for quantitative assessment of blue mussel beds. Combined methods of remote sensing, ground truth investigation and sampling in the field were applied to mature and young intertidal mussel beds. Three variables were measured to obtain reliable quantitative estimates of biomass and abu...

Since the middle of the 1980s, the intertidal blue mussel stock has decreased on the coast of Lower Saxony. In spring 1996, the remaining mussel beds covered an area of 1.7 km2 with a total fresh weight of about 1000 t. This is equivalent to a loss of nearly 95% of the mussel bed area and 98% of the biomass compared with 1989–91. In autumn 1995, a...

Surveys and aerial photograph series were evaluated to show the temporal development of the blue mussel (Mytilus edulis) stock in Lower Saxony. The data, which include the interpretations of aerial photographs (material back to 1966) and surveys (back to 1950/51) in irregular intervals, form the base for the construction of maps which represent the...

Predation by herring gullsLarus argentatus and oystercatchersHaematopus ostralegus was evaluated on a newly established musselMytilus edulis bed on tidal flats of the German Wadden Sea. The mussel bed covered an area of 2 ha and showed a decrease in biomass of 40% in the most densely covered parts from August to January. Synchronously, the extent o...

Die Bestandsentwicklung von Mytilus edulis im niedersächsischen Teil des Wattenmeeres ist seit Mitte der 1980er Jahre rückläufig. Als Ursache kommen mehrere potentiell bestandsreduzierende Faktoren - wie Fraßdruck durch Vögel, Stürme und Eisgang, Schadstoffbelastung, Blüten "unerwünschter" Algen und Muschelfischerei - in Betracht, deren Einfluss in...