A recent preliminary report from NINA, the Norwegian Institute for Nature Research, on the effect of compensating net fishers for not catching salmon is positive (here is the abstract, the rest of the report is in Norwegian).
Fiske, P., Forseth, T., Hansen, L.P. & Hvidsten, N.A. 2006. Evaluation of the impact on salmon stocks of a compensation scheme to reduce bag-net fishery in the Trondheimsfjord – NINA Report 158. 15 pp.
This report evaluates how the compensation scheme implemented in 2005 to reduce bag-net fishery in the Trondheimsfjord have affected salmon fisheries in the main rivers draining to the fjord. We also analyse the impact on fisheries in the remaining bag-nets, and how this initiative has influenced the spawning population numbers of Atlantic salmon in the rivers in 2005. The compensation scheme to bag-net owners to refrain from operating their fisheries has only been effective for one year. Consequently, the results reported here are preliminary.
Our estimates indicate that the compensation scheme has resulted in a considerable increase in the catches of salmon in the rivers draining to the fjord. Based on the mean of five different methods we estimate that the river catches have increased by 3700 salmon (approximately 20 metric tons) compared to expected catches without the reduction in bag-net fisheries. Further, we estimated that the number of salmon entering the rivers increased by approximately 9300 fish (49 metric tons), compared to the expectations without a reduction in the bag-net fisheries. As a result, the spawning in the rivers may have lead to an increase of approximately one egg per square meter of river bed. One egg per square meter is a considerable increase in spawning deposition, considering that the mean egg deposition during spawning in the river Orkla (one of the largest rivers in the fjord) in the period 1979 – 2002 was estimated to 4.2 eggs per square meter (i.e., one additional egg extra constitutes a 24 % increase).