The general Faroe Fisheries Act stipulates that the fisheries are to be conducted, both biologically and economically, in a sustainable manner. In order to substantiate these requirements annual assessments conducted in a scientific way are needed.
Stock assessments of individual fish stocks are for a number of reasons subject to great uncertainties. The natural conditions in the sea are ever changing, which makes predictions very difficult. For some stocks migration poses a problem, for all stocks the annual growth increment varies with the annual production in the area, predators and diseases may vary and the natural mortality accordingly etc.
The assessment of the demersal stocks cod, haddock and saithe in the Faroes rely on three independent fundaments.
- a) Samples from the landings of length, weight and otoliths for age determination of the various species. These data extend backwards to 1961.
- b) Bi annual bottom trawl surveys with the research vessel Magnus Heinason, from 1983 onwards.
- c) Logbook data from individual fishing vessels.
In addition environmental data are becoming increasingly important for assessing the state of the stocks and the prospects for the wellbeing of the stocks.
One of the most important datasets with fisheries logbook data is the Cuba series, which extends back to the early 1980s. Here identical trawlers have operated under the same ownership, conducting the same type of fisheries, in the same areas using the same type of gears. These data allow for analyses of the catches and the compositions from a number of different angles. Most important from an assessment point of view are the catch rates and age distribution of the different species. And the Faroese Fisheries Laboratory has used the Cuba logbook dataset for the annual assessments the last many years (ICES, 2005). However, several other aspects can be studied as well. Some of the examples are the effects of developments and improvements in fishing gear and other fishing technology; the importance of the skipper for the fishing success, the stability of the crew and the fishing success etc.
Bjarti Thomsen (2005) has investigated the success of the Cuba trawlers over time, in order to analyse the phenomenon “technological creeping”. This is of special interest in the Faroe Islands, where the fisheries regulation is based on allowed number of days fishing, in contrast to allowed volume of catch.
In conclusion it is fair to say that the Cuba trawler dataset is of very great value for investigations of Faroe fisheries.
Hjalti í Jákupsstovu, managing director, Faroese Fisheries Laboratory