Macrozoobenthic production and productivity on the northern Norwegian shelf
Important ecosystem services and goods such as marine biodiversity, long-term carbon storage and natural food resources for higher trophic level (e.g. for fish, birds, mammals and finally humans) are inextricably linked to the benthic system. Benthic production and productivity are thus of direct relevance for the management of commercial fish stocks and other ecosystem functions that benthos provide. The identification of essential feeding habitats, i.e. highly productive areas, in the benthos are therefore of commercial interest and consecutively also for a marine ecological management. The MAREANO project (Marine AREA database for NOrwegian coasts and sea areas) studies both the seabed environment and the benthic invertebrates, hitherto covering an area of 107 000 km² in the Barents and Norwegian Seas. The dataset may form a platform of benthic knowledge for an ecosystem-based sustainable management of these offshore waters. Hence, MAREANO links the environmental parameters to the benthic ecosystem in order to map the environment and fauna off the Norwegian coast. The area studied first by MAREANO was the Tromsøflaket bank in the Barents Sea (approx. 16 km2, 150 – 200 m depth) which served as a case-study area. Multibeam echosounder data which provide a basis for terrain analysis were combined with sampling with several biological sampling gears (video, beam trawl, grab and epibenthic sled) in order to analyse and map benthic habitat distribution. Based on the combined analysis, six different benthic biotopes were characterised for Tromsøflaket. The benthic production and productivity showed significant differences between biotopes and strong correlation with environmental parameters, i.e. terrain parameters from multibeam echosounder analysis, sediment type and trawl tracks. Production differences were also found between taxonomic groups and feeding guilds between biotopes. Consecutively, the results will enable to designate highly productive and/or sensitive areas important to understand ecosystem-related functional biotope aspects of Norwegian seas in the future.