Historie und aktueller Stand des Internationalen Heringslarvensurveys in der Nordsee

Since years the International Herring Larvae Survey Program (IHLS) is an important and internationally established survey program in the North Sea. The IHLS serves the calibration of stock abundance estimates based on information from the commercial fishery and the method of Integrated Catch Analysis (ICA) which is a specific derivate of the Virtual Population Analysis (VPA). Meanwhile the IHLS database has been transferred from Aberdeen to Kiel and it has been agreed that the Institut für Meereskunde Kiel should continue to maintain this database and provide the abundance indices to be utilized by the ICES Herring Assessment Working Group as one of the means for assessing the state of the herring stock in the North Sea. For establishing the calculation procedure at Kiel, it was necessary to optimize both, the survey design and the index calculation. This article gives an overview over the survey’s history, it’s geography, the sampling design, the information content of the IHLS data base and the various methods of calculating the different indices necessary for the calibration.

Recent research in the African Great Lakes: fisheries, biodiversity and cichlid evolution

The East African Great Lakes are now well known for (1) their fisheries, of vital importance for their rapidly rising riparian human populations, and (2) as biodiversity hotspots with spectacular endemic faunas, of which the flocks of cichlid fishes unique to each of the three largest lakes, Tanganyika, Malawi and Victoria, offer unique opportunities to investigate how new species evolve and coexist. Since the early 1990s research involving over a hundred scientists, financed by many international bodies, has produced numerous reports and publications in widely scattered journals. This article summarizes their main discoveries and examines the status of, and prospects for, the fisheries, as well as current ideas on how their rich endemic fish faunas have evolved. It first considers fisheries projects in each of the three lakes: the deep rift valley lakes Tanganyika and Malawi and the huge Victoria, all of which share their waters between several East African countries. Secondly it considers the biodiversity surveys of each lake, based on underwater (SCUBA) observations of fish ecology and behaviour which have revealed threats to their fish faunas, and considers what conservation measures are needed. Thirdly, using the lakes as laboratories, what have the international investigations (including DNA techniques and follow-up aquarium experiments) now revealed about the origins and relationships of their cichlid species flocks and mechanisms of evolution?