Sea trout in Inner Oslofjorden : population biology, marine recreational fishing and spatial variation in fishing intensity

Abstract

Recreational fishing has been known since XV century. Nowadays, Arlinghaus and Cooke (2009) estimate, that around 10,6% of the population in studied countries participate in recreational fishing. However, marine recreational fishing in Inner Oslofjorden is not thoroughly controlled and studied, thus, it is impossible to make assumptions on the ecological effects it can cause. Sea trout is one of the species most studied nowadays due to its high popularity among recreational anglers and due to its economic value. However, as well as about recreational fishing, little is known about sea trout population in Inner Oslofjorden. It is impossible to evaluate population status or marine recreational fishing influence on it without adequate data, thus, serious damage could be done to the sea trout population in this area. My goal in this study was to collect more data both on sea trout and anglers, participating in marine recreational fishing in Inner Oslofjorden. I collected data on sea trout biological variables such as back-calculated first winter length, smolt size and age etc. From interviewing anglers was obtained data on catch rates, catch per unit effort, total number of anglers. Also I looked into the methods of obtaining such type of data and tried to estimate the most efficient way of conducting such studies in the future.