Long-term trends in relative abundance of larger predator fish species in Belgian sea fisheries

Master Thesis subject (30 ECTS)
1. Introduction and broader context of the thesis The project ‘A Century of sea fisheries’ is an on-going effort to collect historical data and information on sea fisheries from dispersed, fragmented sources In Belgium. Composition and value of landings by the Belgian fleet were digitized, standardized, quality controlled and integrated. The resulting database covers the period 1929 until present by species, by port of landing, and by fishing area of origin. Older data is also available on a fragmentary basis. Additional monthly distribution of landings for all species, and monthly landings by length class for the most important commercial species, were added covering 1929-1933 and 1947-1967. Economic information (value of landings) and fishing effort-related data is also collected and standardized. The database broadens the historical view on fisheries, underlines the decline in landings since reporting started, and serves as a basis for further (fisheries) research and policy-making in Belgium. The website promotes a better understanding of the history of Sea Fisheries in Belgium to the interested public. http://www.vliz.be/cijfers_beleid/zeevisserij/index.php/ 2. Thesis Subject The Belgian sea fisheries have focused mainly on demersal fishes since the 1950s. Demersal species are found near or at the bottom. The fishing gear used for this purpose is the beam trawl, which is dragged over and even through the bottom. The beam trawl fishery is specialized in flatfish like sole and plaice. The late 60s was a golden period for the demersal fisheries, with landings not equaled ever since. In 1968 a peak of 57,767tonnes demersal fishes was recorded, of which 4,380tonnes were landed in foreign ports. These ‘years of wealth’ in fisheries were mainly supported by the rich fishing grounds around Iceland. 1972 marked the end to this myth when access to the territorial waters of Iceland was further restricted for the foreign fleet. While the landings of demersal fish by fishermen in Belgian ports were in a clear decline, the Belgian supply in foreign ports saw a slight increase. Besides the ‘Coastal waters’, the ‘North Sea (south)’ and the ‘North Sea (central)’, other fishing grounds became relatively important for demersal fisheries of Belgium. Objectives: - Assess long-term trends in landings of 1 selected demersal species of commercial importance (sole, plaice, brill, cod, haddock, hake, …). The subject includes: - Acquaintance with basic data management procedures (digitization, standardization, quality control, integration) - Descriptive statistics: long-term trends by fishing area, by length class, in seasonal distribution of landings, by length class,… (describe observed changes in terms of statistic descriptors) - Explore and assess relationships between observed changes and environmental, economic and effort-related data and information. - Development and application of indicators of environmental and climate change (Marine trophic index MTI, Temperature index,..) and models . The outcomes of the thesis work will result in communication products (posted on the website) and policy-relevant products.
master education level, by preference in biology or ecology good knowledge of R and statistical analysis basics in data management
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Reference Number: RP-47941