Acronym NA
Category
Fisheries
Title Migration and predation of Atlantic salmon smolts from Vosso Programme National Programme
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National Coordinator Bjorn Torgeir Barlaup Coordinator email bjorn.barlaup@uni.no
Coordinator institution
NA
Institutions involved
IMR - Institute of Marine Research (Norway) ,
Start year 2012 End year 2014 Funding (€) € 324,015 Website https://www.fhf.no/prosjekter/prosjektbasen/900778/ Summary In the Vossoproject predation has been suggested to be an element in the continued suppression of the famous Atlantic salmon population. The arguments behind this hypothesis are that experiments with acoustic transmitters in cultivated smolts have failed to register a large proportion of fish outside the Bolstadfjord, and that smolt has been found in the stomachs of trout captured in Bolstadfjorden. However, while these results indicate that sea trout predate on migrating smolts, they do not allow us to scale the results up to a population level.
For predation to have a role in the last two decades poor recruitment of the Vosso salmon, one out of two situations must have occurred. Either, (1) predation in the inner fjord system is strongly density dependent causing a higher prey mortality at low concentrations. Alternatively, (2) there has been an alteration in the ecosystem, increasing the predation rate due to an either reproductive numerical response or an aggregative response at small spatial and temporal scales. To study this it is imperative to apply a number of approaches. The different approaches cannot by themselves give a final answer to the role of predation, but will in combination be a large contribution to our understanding of the situation in Bolstadfjorden.
Goal: to document the migration of Atlantic salmon smolt through the inner fjord system “Bolstadfjorden” and the potential predation mortality during this early phase of migration.
Subgoals
• To document and identify predators in the estuarine system in Osterfjorden (WP1).
• To identify the habitat use of estuarine population of trout and sea-trout in the Bolstadfjord (WP2).
• To evaluate the timing and speed of migration of salmon through the Bolstadfjord (WP3).
• To design and carry out a stratified acoustic survey of the Evanger Lake, the Bolstadfjord, and at two positions north and south of Stamnes to monitor the smolt migration and predator abundance through the inner migration route of the Vosso smolt (WP4).
• To describe the development of the sprat stock in the Osterfjord system during the period 1980 to 2012 (WP5).
• To parameterize a multispecies model to estimate predation on and mortality estimates for smolt in Bolstadfjorden (WP6)
• To developed a bioenergetics model linking potential predation of smolts by trout and the growth of trout (WP6).
• To develop a hydrodynamic model to assess the fjord circulation in the Bolstadfjord (WP6).
Keywords
Fish;
Salmon;
Acoustic survey;
Fish stocks;
Fish biology;
Food web;
Marine Region
13
Northern North Sea (27.IVa)
1
Marine Region Map
