|The macrobenthic fauna of rocks and boulders in the Luebeck Bay (Western Baltic Sea) investigated from the underwater laboratory 'Helgoland'|
Gulliksen, B. (1975). The macrobenthic fauna of rocks and boulders in the Luebeck Bay (Western Baltic Sea) investigated from the underwater laboratory 'Helgoland'. Helgol. Meeresunters. 27(4): 439-449
In: Helgoländer Meeresuntersuchungen. Biologische Anstalt Helgoland: Hamburg. ISSN 0174-3597, more
Benthos; Biological collections; Community composition; Population density; Rocks; Salinity effects; Temperature effects; Vertical distribution; Dendrodoa grossularia (Van Beneden, 1846) [WoRMS]; Diastylis rathkei (Krøyer, 1841) [WoRMS]; Facelina drummondi; Idotea balthica (Pallas, 1772) [WoRMS]; Invertebrata; Nereimyra punctata (Müller, 1788) [WoRMS]; Polydora ciliata (Johnston, 1838) [WoRMS]; Marine
1) A diver-operated suction sampler was used to collect the macrobenthic fauna on a rocky bottom in Lubeck Bay (Western Baltic Sea) from the Underwater Laboratory (UWL) 'Helgoland' in Oct 1974. A comparison of the faunal composition with the angle of inclination of the substrates was the prime goal of the investigation. (2) The ascidian Dendrodoa grossularia and the polychaete Polydora ciliata constituted 95.6% of the total number of specimens sampled. The lowest densities of both species occurred on overhanging substrates. Both spp appeared to have a heavy settlement during the late summer or autumn. (3) In general, the angle of inclination of the substrate bore little relation to the qualitative composition of the fauna on a rocky bottom in Niendorf Bay, but some of the species (Dendrodoa grossularia, Polydora cilliata, Astrias rubens, Diastylis rathkei) were more sparsely distributed on overhanging substrates.(4). The calculated values for Fisher's coefficient of dispersion' indicates that all the 3 most abundant spp (Dendrodoa grossularia, Polydora ciliata, N. punctata) show some degree of aggregated distribution. (5) Four motile invertebrates, Nereimyra punctata, Idotea balthica, Diastylis rathkei and Facelina drummondi were observed swarming in the water. N. punctata and I. balthica were most abundant in samples taken during the daytime, D. rathkei was most abundant in samples obtained during the early part of the survey when water temps were higher, while no relation could be found between the occurrence of F. drummondi and the time of day of sampling. For the ultimate picture of the composition of the fauna on rocky bottom substrates, the time of day at which the samples are taken is of importance, due to the varying degree of activity of the motile benthic invertebrates.