Undersøkelser av stortarehøsting i Nord-Trøndelag og Nordland i 2013

Abstract

The Institute of Marine Research surveyed the kelp vegetation, before and after kelp (Laminaria hyperborea) harvesting in the counties of Nord-Trøndelag and Nordland in 2013. Survey stations included both kelp harvested areas and nearby reference areas, and was performed by underwater video. In addition, kelp plants were collected from pristine areas for measurements of plant size, age and epiphytes. Age, size and epiphytes of kelp plants increased with wave exposure, and this correlation was strongest in Nordland. Total landings of kelp in 2013 were 28.922 tonnes from 7 fields in Nord-Trøndelag and 5.576 tonnes from 1 field in Nordland, respectively. Surveys of fields harvested in Nord-Trøndelag in the period 2010-2012 revealed that the recovery of kelp is going fine, although plant sizes and epiphytes are still below pre-harvesting levels. The density of sea urchins was generally low and grazing effects on recovering kelp plants appeared negligible. No negative effects of kelp harvesting on fish abundance were recorded.