In this stock, both the length and age at first maturity decreased significantly in the second part of the 20th century. It is, however, unknown whether this is caused by a change in environmental conditions (better food conditions, higher growth rates) or by a genetic selection. The idea behind the latter is that over-fishing of the plaice stock results in high evolutionary pressures that lead to a genetically based decrease in age and size at reproduction. At high fishing mortality rates, as plaice is currently facing, reproduction at an earlier age and size may be more beneficial for the population.
After his masters' study in fish culture and fisheries management, Rob Grift received his PhD at Wageningen University. In his PhD study, he investigated how fish utilize floodplains along the River Rhine during their life cycles and how their populations can benefit from floodplain restoration. Their utilization was inferred from the description of patterns of presence of fish in time and space in 25 floodplain water bodies during three consecutive years. At present, he is a fisheries biologist at RIVO Netherlands Institute for Fisheries Research in IJmuiden, the Netherlands. At RIVO, Rob Grift investigates fish communities and fisheries in the North Sea and Dutch coastal zone and studies the impact of infrastructural works (such as an airport and a wind mill park in the sea) on fish populations.
Last edited: 22 July 2013
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