Per Johannessen

Regulating the local environmental impact of intensive marine fish farming I. The concept of the MOM system (Modelling-Ongrowing fish farms-Monitoring)

Abstract The paper describes the concept of a management system called MOM (Modelling-Ongrowing fish farms-Monitoring) which may be used to adjust the local environmental impact of marine fish farms to the holding capacity of the sites. The concept is based on integrating the elements of environmental impact assessment, monitoring of impact and environmental quality standards (EQS) into one system. The amount of monitoring is dependent on the level of the environmental impact. Two terms are introduced: (1) the degree of exploitation, which is an expression of how much the site is being utilised, and (2) the level of monitoring, which determines the amount of monitoring depending on the environmental impact. For Norwegian conditions, a monitoring programme, including EQS, has been developed concerning the impact on the sediment under fish farms. It consists of three types of investigations of increasing elaboration and accuracy. A model, which simulates the environmental impact on a site given information about the farms size and production and the hydrodynamic conditions and topography of the site, has been developed but not yet tested. The model and the monitoring programme with EQS are only briefly described, but will be published later. The MOM system should help to maintain satisfactory environmental conditions in and around fish farms and may be a valuable tool in site selection and coastal zone management.

Regulating the local environmental impact of intensive, marine fish farming: II. The monitoring programme of the MOM system (Modelling–Ongrowing fish farms–Monitoring)

A programme for monitoring the impact of organic waste from marine fish farms is presented. . It consists of three types of investigation of increasing complexity and accuracy A, B and C , which are applied more frequently with increasing environmental impact. The A-investigation is a simple measurement of sedimentation rate beneath the net cages; the B-investigation is a sediment investigation providing a trend monitoring of the sediment condition, and the C-investigation is a comprehensive investigation of the benthic macrofaunal community structure. The A- and B-investigations were designed specifically for fish farming and the latter utilises several parameters in order to make the investigation more robust. The C-investigation employs well- established methods and procedures, which have been used previously in monitoring programmes. . Environmental quality standards EQS have been set for the B- and C-investigation. The monitoring programme is part of a larger management system in Norway called Modelling- . Ongrowing fish farms-Monitoring MOM . q 2001 Elsevier Science B.V. All rights reserved.

Ecological Criteria Used to Help Site Fish Farms in Fjords

We reviewed the biological and oceanographic data used to help decide on the siting of salmon farms in Canada (British Columbia and New Brunswick), Norway, Scotland, Ireland, Iceland, United State (Washington and Maine). The LENKA program in Norway and a ranking technique based on biophysical features in British Columbia are examples of semi-quantitative approaches. A zoning system partially based on detailed data on fjord oceanography has been initiated in Scotland. Guidelines to protect critical fish habitat, especially for wild salmon, have been developed in each of the jurisdictions. Models to help predict sedimentation, hypernutrification, and dissolved oxygen levels have been used in Norway and Washington. Siting criteria need to be supplemented with these models, which consider cumulative effects and predict the carrying capacity of key fjord areas where farms are likely to cluster. Coordinated and comprehensive research programs are needed which consider salmon production in the context of the oceanographic regimes within fjords. For site-specific evaluations and as communication methods, referral systems and guidelines are relied on extensively in site evaluations in the various jurisdictions.

Xylodiscula planata sp. nov., a “lower” heterobranch gastropod from Norwegian waters

Abstract A small gastropod, closely related to a couple of species known from moderately deep water in the Mediterranean, is described as a new species based on nine specimens. The snails were found in four grab samples, one on a sandy-rocky bottom in outer Sognefjorden, two on silty-sandy bottom in outer Hardangertjorden, both from 34m, and finally one from 54 m depth outside Sotra, W of Bergen. This is the tirst record of a member of the heterobranch family Xylodisculidae from Norwegian waters. The specimens were all found in the immediate vicinity of salmon farms, and a preference by the species for the reducing environment of decaying, surplus fish feed is suggested.

Devonia perrieri (Malard) (Bivalvia, Galeommatacea) found in Scandinavian waters

Abstract Devonia perrieri is recorded from four localities in southern Scandinavia. The Scandinavian populations probably maintain themselves but may receive recruits from British waters. D. perrieri is known to be associated with Leptosynapta spp., possibly also with Labidoplax buskii, though this seems unikely.

Controlled ecosystem experiment in Lindåspollene, western Norway, June 1979: Comparisons between the natural and two enclosed water columns

The vertical structure and development of phyto- and zooplankton were studied in the natural water column and in two naturally stratified water columns enclosed in plastic bags, 1 m in diameter and 13 m deep. More than half of the primary production occurred in the uppermost 4.5 m. In contrast, the dominant copepods (Oncaea spp., Temora longicornis, and Oithona spp.) were distributed mainly below this upper layer. There were no marked differences between the day and night distributions for any of the zooplankton groups. It is argued that the high production in the upper layer must reflect a high mineralization activity, presumably by smaller organisms such as bacteria and protozoans. The phytoplankton biomass and primary production were somewhat lower inside than outside the bags. The zooplankton distributions were initially similar, but during the two weeks of observation the development within the bags diverged somewhat from that outside. Copepod nauplii, Oncaea spp., and Temora longicornis tended to be...

Formation of cavities in calcareous rocks in the littoral zone in northern Norway

Abstract Numerous small cavities containing algae and specimens of Littorina are described from littoral calcareous rocks in Nordland county, northern Norway, Such holes have not been previously described so far north but are often found in the tropics. It is suggested that the cavities result from the scraping loose of algae from the rocks by Littorina, Some of the cavities were found above the littoral zone and must have been formed during a period when the sea level was higher.

Ecological studies on the deep-water pelagic community of Korsfjorden, western Norway

Abstract The studies are based on six double oblique hauls. There is no consistent difference in catch efficiency between the descending and ascending section of the haul. Hang-up on the net is the most serious sampling bias in this particular LHPR device; most affected are those small forms, e.g. young Euchaeta copepodids, which are only hindered from passing through the meshes of the net by their strong setae.

Hydrography and hydro chemistry from March to July 1976 in Fauskangerpollen, western Norway

Abstract Hydrography and nutrients (phosphate/total P, nitrate/nitrite, and silicate) were studied at a station in Fauskangerpollen near Bergen on three days in 1976, one in March, one in May, and one in July. The surface layers were highly stable, while there were only small density gradients in deeper layers. While oxygen conditions were good in the upper layers, the bottom layers were stagnant with H2 S being produced. An inflow took place in the middle layers between March and May. Nutrient concentrations were high throughout the water column in March, but decreased in the top layers during spring due to consumption in primary production. The stagnant bottom layers acted as a ‘nutrient trap’ and had extremely high nutrient concentrations. Variations coinciding with the tidal cycle were observed, a result of change in surface level due to tidal movement, such that samples were taken relatively nearer the bottom at low tide than at high tide. This means that when samples were taken at a level with large...

Notes on Norwegian marine Amphipoda 6. Menigratopsis svennilssoni (Lysianassidae), an amphipod new to the Norwegian fauna

Abstract The lysianassid amphipod, Menigratopsis svennilssoni Dahl, 1945, is recorded for the first time from Norway, where one specimen was collected at 47 m depth near Stavanger. The sediment composition and the amphipod fauna at the locality are treated.