Rearing of halibut larvae (Hippoglossus hippoglossis L.) to metamorphosis and beyond.

A female halibut caught by gill-net was stripped and the eggs were imediately fertilized and incubated in the laboratory. About 50% of the eggs hatched when incubated in a refrigerator in stagnant water treated with antibiotics and with increased salinity. Of the about 1700 larvae kept in the refrigerator, about 35% were alive after 30 days, the temperature being about 5°C. The salinity of the water was about 37°/oo and was treated with antibiotics as before. A functional mouth started to develop 25 days after hatching. The last larvae in the refrigerator died on 5 May at an age of 60 days. At an age of 40 days larvae were transferred to a large basin in two black plastic bags with 50 larvae in each enclosure. In one of the plastic bags two of the halibut larvae survived and reached metamorphosis at the end of May at an age of 80-90 days and at a length of about 30 cm

Growth and survival studies on 0-group plaice (Pleuronectes platessa L.) in a small basin with a closed ecosystem

A growth and survival experiment on 0-group plaice was carried out in a small basin during the summer of 1976. The volume of the basin was about 25 m³, and the seawater was left stagnant during the summer. Of the initial 200 metamorphosed fry released, 154 survived, and a mean daily length increment of 0.28 mm was observed for a period of 105 days. The temperature was about 20°C for half of the experimental period. The main energy flow is supposed to have followed this simplified route: phytoplankton -> Mytilus edulis produced faeces -> detritus-eating crustaceae -> plaice fry. Calculations of food intake and gross growth efficiency have been carried out, applying the metabolic values earlier reported (EDWARDS, FINLAYSON and STEELE 1969), and the present data have been compared with their results. The basin appeared to be an ecosystem with a high production, giving better survival and growth than previous tank experiments. In spite of the extreme temperature during midsummer, the growth was comparable to that observed under natural conditions (Loch Ewe), but the survival was far better due to lack of predators in the basin

Fjordranching with conditioned cod

In June 1986, 1600 pond-reared one-year old cod were released into a fjord after being conditioned with a pulsed 160 Hz sound signal to search for food at a feeding location. Echosounders, UW-video and ultrasonic transmitter tags were used to monitor the fish behaviour. The fish were fed four times a day (0900, 1200, 1500 and 1900) in the current lobe from a propeller. A majority of the trained fish returned to the stimulus location, and also some "wild" cod and other species adapted the same behaviour. The ultrasonic tagged fish were distributed within 400 m from the stimulus location between the feeding periods. The experiment was terminated after three months. In this period the mean daily length increment was 0.6 mm/day

Survival and growth of turbot (Scophthalmus maximus L.) in a land-situation mesocosm. In: Flødevigen rapportserie no 2, 1990

A mesocosm study of turbot larvae was undertaken in a 2000 m^3 outdoor basin into which 15000 yolk sac larvae were released. Scarce food supply during first feeding gave high initial mortality and only 10% survived the first 10 days. The diet was dominated by nauplii through first feeding followed by a swift change to larger food items, mainly calanoid copepods. These were replaced from day 20 onwards by juvenile amphipods. The surviving turbot were distributed in the surface layer from day 15 until the onset of settlement on day 25. Standard length increased from 3 mm at release to 20 mm on day 30, and during the same period the dry weight increased from 0.030 mg to 32 mg. At termination on day 74, standard length was 38 mm and mean dry weight was 340 mg (wet weight being 1.9 g) with 600 juvenile turbot surviving to this stage (4%). All juveniles were normally pigmented and without any deformations

Norwegian roadside survey of alcohol and drug use by drivers (2008-2009)

Objective: To examine alcohol and drug use among random drivers in different regions of Norway by analyzing oral fluid, compare drivers in urban and rural areas, compare with results from the roadside survey in southeastern Norway in 2005–2006, and roughly estimate the prevalence of driving with blood drug concentrations above the new Norwegian legislative limits among random drivers. This roadside survey was part of the European DRUID (Driving Under the Influence of Drugs, Alcohol and Medicines) Project. Methods: Drivers were selected for a voluntary and anonymous study using a stratified multistage cluster sampling procedure in collaboration with the Mobile Police Service. Samples of oral fluid were taken using the Statsure Saliva Sample (Statsure Diagnostic Systems, Framingham, MA), and the drivers’ gender, age, and nationality were recorded. Samples of oral fluid were analyzed for alcohol or drugs, for a total 28 psychoactive substances. Results: One hundred eighty-four roadside survey sessions were conducted and 10,004 drivers were asked to participate. The refusal rate was 5.8 percent. Psychoactive substances were found in 4.8 percent of the 9410 oral fluid samples analyzed. Alcohol was detected in 0.3 percent, medicinal drugs in 3.2 percent, and illegal drugs in 1.5 percent of the samples. Illegal drugs were significantly more frequently detected in samples from southeastern Norway including the capital Oslo, whereas medicinal drugs were more frequently detected in samples from southeastern Norway excluding Oslo. Illegal drugs were significantly more frequently detected in samples from drivers in urban areas than in rural areas, though there were no significant differences for alcohol and medicinal drugs. Medicinal drugs were most commonly found in samples collected during the daytime on weekdays (3.8%), and illegal drugs were most commonly found in samples collected during late night on weekdays or weekends (2.8%–3.2%). The most commonly found substances were the sleeping agent zopiclone (1.4%), the main active substance in cannabis tetrahydrocannabinol (1.1%), and the sedative drug diazepam (0.7%). The prevalence of driving with drug concentrations above the Norwegian legislative limits for blood was estimated to be about 0.2 percent for alcohol, 0.6 percent for illegal drugs, and about 1.3 percent for medicinal drugs. Conclusions: The incidence of drink driving was very low, though driving after using psychoactive illegal or medicinal drugs was more frequent. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.publishedVersio

Production of juvenile flatfish species in different sized mesocosms

Mesocosm studies with larvae of halibut (Hippoglossus hippoglossus), sole (Solea solea) and turbot (Scophthalmus maximus) was carried out at Austevoll Aquaculture Station and at Flødevigen Biological Station in 1985. Very low survival was observed for halibut beyond first feeding in plastic bags. Sole larvae had very high survival in plastic bags, but fairly low in basin studies. Turbot had survival below 10% in plastic bag studies, no survival in one of the basin studies and about 10% in another basin study. Altogether 5-10 000 sole and turbot survived beyond metamorphosis