DCF (Data Collection Framework): Monitoring of cod, herring, sprat and flatfish stocks in the western Baltic Sea in the frame of internationally coordinated research cruises to estimate independent abundance indices.
Eine Seefahrt, die ist lustig… A research vessel cruise is mainly hard work onboard at sea, according to a fixed station grid and a tight schedule, under almost any weather condition. Expertise, routine and endurance are in demand.
In former times, each country conducted fisheries-independent surveys in its national waters using national standards. Fish stocks, however, do not stick to national sea boundaries. To ensure maximum comparability between national survey data, these research surveys are internationally standardized since 2000. Thus, every year large areas of the Baltic Sea are monitored simultaneously by fisheries biologist from different countries using standard procedures.
The survey results are analyzed nationally and uploaded into the data base DATRAS of the International Council for the Exploration of the Sea (ICES). The data are used for estimation of fisheries-independent stock indices, determination of year-class strength and fishing mortality. These data are used in models to estimate stock status, together with the data collected from the fisheries.
On fisheries-independent research cruises, the catch procedure, the workup of the catch and data analysis followed precisely defined standards, which differ according to the aim of the cruise. These standards are documented in so-called survey manuals. Each research cruise has a scientific cruise leader. Technicians and research assistants have a central role in the workup of the catches on board.
We conduct the following important fisheries-indepedent research sruveys: the „Baltic International Trawl Survey“ (BITS) in February and October/November targeting demersal species, as well as the „Baltic International Acoustic Survey“ (BIAS) in May/June, and the „Baltic Acoustic Sprat Survey“ (BASS) in October targeting the pelagic species herring and sprat. The „Rügen Herring Larvae Survey“ (RHLS) in the Greifswalder Bodden provides estimates on year class strength at the level of recently hatched larvae.
Based on the research surveys we regularly determine important indices to assess the year class strength of certain fish stocks and estimate the fishing mortality. These are essential input parameters in the population models we use to estimate stock size and derive a reliable catch advice.
Permanent task 1.2001 - 12.2020
Project status: ongoing