Data for: Higher abundance of adult pike in Baltic Sea coastal areas adjacent to restored wetlands compared to reference bays

The abundance of pike, a keystone top-predator, has declined dramatically
in the Baltic Sea since the 1990s likely owing to recruitment failure. It
has been proposed that wetland restoration can aid the recovery of the
pike stock by increasing the number of recruits produced by anadromous
populations. Yet, no previous studies have addressed whether wetland
restorations are associated with higher abundances of adult pike in the
coastal habitat. To address this, we performed standardised rod-and-reel
survey fishing in paired bays with and without wetlands across three
coastal areas and three years. To estimate dispersal and the contribution
of wetland pike to the coastal stock, we tagged captured pike with passive
integrated responders (PIT) and employed PIT-reader stations in wetland
inlets. The results showed that pike abundances were on average 90% higher
in bays with an adjacent wetland although the effect varied among areas.
Moreover, PIT-data uncovered that wetland pike constituted a high
proportion of the pike found in adjacent coastal habitats and that some
wetland fish dispersed up to 10 km. These results support that wetland
restoration is a valuable tool to aid the coastal pike stock and
ultimately restore the function and services of the coastal ecosystem.