Despite several deep-sea investigations, only a minor part of this ecosystem is known. Until now approximately 4200 deep-sea fish species are identified, from which only 10% were examined for parasitological studies. Most people detest parasites because they are only known as germs of many diseases. But they are more than that.
By Esra Kellermanns and Markus W. Busch
We deal with parasites, especially from the deep-sea, because they are able to answer a lot of ecological questions. They are indicators for migrating behavior, food ecology and stock identification of fishes. Beside the ecological role, they are fascinating organisms. They had simple as well as complex lifecycles with high specific morphological adaptations to their hosts.
We, Esra Kellermanns and Markus W. Busch, are two young PhD- students working in the group of Dr. Sven Klimpel (MAR-ECO Group Leader, Parasitology). During our six week stay in Bergen, we worked in the Bergen Natural HIstory Museum were we examined 500 deep-sea fishes from the 2004 MAR-ECO cruise.
Esra Kellermanns and Markus W. Busch at Bergen Museum
Our aim was to observe fishes from the different layers of the deep-sea. For this we examined 11 fish species from the six families Bathylagidae, Dalatiidae, Myctophidae, Sternoptychidae, Stomiidae, Melamphaidae and Macrouridae. Myctophids are from special interest because they perform diurnal migrations from the mesopelagial (1000-2000m depth) in to the nutrient rich epipelagial (0-200m depth). The melamphaids and bathylagids are part of the bathypelagic layer (1000-4000m depth) were as the macrourids live near the sea floor.
The parasite studies include the examination of eyes, skin, fins, nostrils, gills and mouth cavity for ectoparasites and stomach intestine, pyloric caeca, liver and gonads for endoparasites. The isolated parasites were fixed in 4% borax-buffered formalin and preserved in 70% ethanol/ 5% glycerin. For genetically analyses some of the parasites were stored in 96% ethanol.
Beside the parasitological data we recorded the morphometrical data of each fish and took samples of otoliths, gonads, muscles (DNA, fatty acids and stabile isotopes) and stomach content. The identification of the stomach content is of special interest for us regarding the lifecycles of parasites. Food components like zooplankton play an important role as intermediate host for a wide range of marine parasites. The collected data will be compared with other data from previous studies, so we will be able to gain more inside the ecosystem deep-sea.
The study and our stay in Bergen were supported by the DAAD (German Academic Exchange Service, Klimpel D/05/51605).