Reflex impairment as a measure of vitality and survival potential of Atlantic cod (Gadus morhua)

A ssur ing the v itality and survival potential of live-caught Atlantic cod (Gadus morhua) is important for improving the sorting of fish before net penning operations designed to hold fish for growth and later market. When Atlantic cod are captured by Danish seine, the most commonly used fishing gear for live-caught fish, they undergo stressors such as forced swimming, net abrasion, and air exposure. Laboratory experiments (at an air temperature of 9°C and water temperature of 8°C) were conducted with the aim of constructing a RAMP (reflex action mortality predictor) curve for prediction of vitality and survival potential in Atlantic cod captured in Danish seines, by varying the levels of these stressors. Atlantic cod exposed to increased duration in air (5–20 min) showed increased reflex impairment and mortality, with 75% mortality at 10 minutes of air exposure. Forced swimming in combination with net abrasion and air exposure did not increase reflex impairment or mortality above that associated with air exposure alone. The Atlantic cod RAMP curves indicated that fish with reflex impairment less than 50% would not show mortality and would likely recover from capture stress

Optimal føringskapasitet og velferd for levende, villfanget torsk. Teknisk tilrettelegging ombord på MS Trino

Fangstbasert akvakultur har lange tradisjoner i Norge. Næringen har et betydelig potensial for økt verdiskaping, særlig for mellomlagring og oppforing av villfanget torsk. Med en sikker tilgang av villfanget torsk i et oppforingssystem, vil en kunne oppnå en forutsigbar leveranse av fersk torsk i et internasjonalt marked. I tillegg vil industrien ha sikker tilgang til råstoff for en jevn produksjon av ferske fiskeprodukter. For å videreutvikle fangstbasert akvakultur som en lønnsom næring, må nye løsningerfor føring av vill fisk utvikles og utprøves

Surface selection of haddock and cod in the Norwegian demersal seine fisheries

Size selection in active fishing gears is a continuous process and undersized fish may escape during the whole fishing operation. Fish that escape during the surface hauling operation are likely to experience higher mortality due to barotrauma-related stress than fish escaping at the fishing depth during the towing process. A well-functioning selectivity device should therefore select mostly at depth for enhancing survival probabilities of escaping fish. The current gear regulation in the Norwegian demersal seine fishery is likely to cause large proportion of undersized fish to escape at the surface. In this study, we estimated surface selection of haddock and cod in demersal seine by using an automatic release system and a small meshed codend that collected fish escaping during surface hauling. The collecting bag contained 19% undersized haddock compared to 10% in the conventional square-mesh codend indicating that about 50% of undersized haddock brought to the surface were released. The proportions of undersized cod were 8% for the collecting bag and 1% for the conventional square-mesh codend. These results demonstrate that surface selection is significant for both haddock and cod. Based on this finding, we discuss methods to improve size selectivity at the fishing depth.publishedVersio

Kollektivtransport : en lønnsomhetsanalyse av nattbuss i Stavanger

Utredningen omhandler en lønnsomhetsanalyse av nattbussen i Stavanger. Det blir gjennomført en analyse av de ulike faktorer på inntektssiden og kostnadssiden av nattbusstilbudet. Det blir tatt utgangspunkt i faktiske inntektstall fra 2006 og 2008, og kostnadsestimater fra konsulentselskapet Asplan Viak. Usikkerheten i oppgaven er i stor grad knyttet til kostnadsestimatene. Konsekvensene av denne usikkerheten blir drøftet i utredningen. Resultatene viser at nattbussen i Stavanger samlet sett er lønnsom, selv med en kraftig overestimering av kostnadene. For de enkelte ruter fremkommer det at ikke alle rutene er lønnsomme fra et bedriftsøkonomisk ståsted

Selective flatfish seine: A knee-high demersal seine barely catches cod

Norwegian coastal cod (Gadus morhua) protection restricts the use of active fishing gears. Demersal seines, acknowledged as being efficient for targeting flatfish, are therefore largely excluded from the fjords. To exploit plaice (Pleuronectes platessa), a species-selective gear that avoids catching cod is needed. We therefore designed a low-rise demersal seine with a 0.6 m vertical opening and tested it on fishing grounds in Lofoten (Northern Norway), comparing it with a conventional seine that had a vertical opening of ∼3.5 m, and fished both during the day and at night. Six to nine hauls were taken with each of the four gear/time-of-day categories (32 hauls in total). The low-rise seine caught no fewer plaice during day-time fishing, but less at night. Cod and haddock (Melanogrammus aeglefinus) catches were reduced by 94% and 98%, respectively, while catches of sole (Solea solea) increased with the low-rise seine. No catch differences were found for halibut (Hippoglossus hippoglossus), common dab (Limanda limanda), or monkfish (Lophius piscatorius). The low-rise seine therefore enables targeting flatfish while avoiding gadoid catches, although loss of plaice during night-time fishing is to be expected.publishedVersio

Rapid characterization of emulsions by pulsed field gradient nuclear magnetic resonance

A method for rapid characterization of emulsions is presented. From the proposed setup we are able to measure the droplet size distribution of brine or water droplets confined by an oil phase, even though there is complete overlap in relaxation times and/or molecular mobility between the water and the oil phases. A PFG-NMR sequence is presented that applies the spoiler recovery method for significant reduction in acquisition time, and the method is used for rapid characterization of emulsions

Development and evaluation of dynamic catch control devices in the demersal seine fisheries for cod (Gadus morhua)

publishedVersio