English
norskBlar i forfatter "Vollstad, Jørgen"
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Alternative materialer til plast brukt i snurrevadtau og trålmatter
(Research report; Forskningsrapport, 2023-10-30)Dette prosjektet studerte ulike løsninger for å redusere effekten av slitasje fra fossilbasert, ikke-nedbrytbare plastmaterialer som brukes i snurrevad og trålmatter. Prosjektet testet ulike natur-, syntetiske og biologisk nedbrytbare materialer i laboratorium og i felt. Prosjektet kvantifiserte og sannsynliggjorde hvor mye reduksjon i utslipp ulike tiltak og løsninger kan bidra med. Det inkluderes ... -
Can biodegradable materials reduce plastic pollution without decreasing catch efficiency in longline fishery?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-23)Longlining is a widely used fishing method. During longline fishing, some of the snoods connecting the hooks to the mainline are often lost at sea. Since snoods are made of nylon or polyester, lost snoods contribute to marine plastic pollution. Replacing nylon or polyester with a new material made of biodegradable plastics can potentially reduce macro- and microplastic pollution that is caused by ... -
Comparison of fishing efficiency between biodegradable PBSAT gillnets and conventional nylon (PA) gillnets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-19)Gillnets made of a new biodegradable resin (polybutylene succinate co-adipate-co-terephthalate (PBSAT) were tested under commercial fishing conditions to compare their fishing performance with that of conventional nylon (PA) nets. The relative catch efficiency between the two gillnet 15 types was evaluated over the entire winter fishing season for cod (<i>Gadus morhua</i>) in northern Norway. The ... -
Comparison of the efficiency and modes of capture of biodegradable versus nylon gillnets in the Northeast Atlantic cod (Gadus morhua) fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-01)Modern gillnets are usually made of nylon with high breaking strength, suitable elasticity and durability making them an efficient fishing gear. Lost, abandoned, or discarded gillnets at sea cause plastic pollution and can continue capturing marine animals over long periods of time. Biodegradable materials are being developed to replace nylon in gillnets. However, biodegradable gillnets have shown ... -
Effect of gillnet twine thickness on capture pattern and efficiency in the Northeast-Arctic cod (Gadus morhua) fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-15)Gillnets are among the most common fishing gears worldwide. They are often made of thin twine, which is prone to wear and tear, limiting the lifespan of the gillnet. This increases gillnet turnover, and consequently increased risk of gear discarding, gear loss, ghost fishing and marine pollution. This might be mitigated by increasing twine thickness, and thereby breaking strength. However, the ... -
The effect of long-term use on the Catch efficiency of Biodegradable gillnets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-05)The effect of long-term use on the catch efficiency of biodegradable gillnets was investigated during commercial fishing trials and in controlled lab aging tests. The relative catch efficiency between biodegradable and nylon gillnets was evaluated over three consecutive fishing seasons for Atlantic cod (Gadus morhua) in Norway. The biodegradable gillnets progressively lost catch efficiency over time, ... -
Effect of mechanical properties of monofilament twines on the catch efficiency of biodegradable gillnets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-24)Gillnets made of the biodegradable resin polybutylene succinate co-adipate-co-terephthalate were tested under commercial fishing conditions to compare their fishing performance with that of conventional nylon polyamide (PA) gillnets. Both types of gillnets were made of 0.55 mm Ø monofilaments. However, since the biodegradable nets are weaker than nylon PA nets when using the same monofilament diameter, ... -
The effect of white and green LED-lights on the catch efficiency of the Barents Sea snow crab (Chionoecetes opilio) pot fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-05)In commercial snow crab (Chionoecetes opilio) fishery, the catch efficiency of the conical pots is important for increasing the profitability of the industry. This study evaluated the effect of adding green and white light emitting diodes (LED) on the catch efficiency of commercially used conical pots. The results from the field experiments showed that inserting artificial lights significantly ... -
Fishing efficiency of biodegradable PBSAT gillnets and conventional nylon gillnets used in Norwegian cod (Gadus morhua) and saithe (Pollachius virens) fisheries
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-10)Fishing trials were carried out to compare the relative fishing efficiency of gillnets made of a new biodegradable resin (polybutylene succinate co-adipate-co-terephthalate, PBSAT) with conventional (nylon) nets. The fishing trials covered two consecutive fishing seasons (2016 and 2017) for cod (<i>Gadus morhua</i>) and saithe (<i>Pollachius virens</i>) in northern Norway. Results generally showed ... -
Oceanic plastic pollution caused by Danish seine fishing in Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-06)Wear and tear on fishing gear is a sparsely investigated source of microplastic pollution in the sea. In Norway, Danish seine ropes and trawls are the fishing gears that contribute most to this pollution. The main reason for this pollution is that the seine ropes are dragged along the seabed over a considerable distance, creating a friction force that results in high ropes wear. This note reports ... -
Understanding and predicting the effect of entrance cone diameters on the catch efficiency of snow crabs (Chionoecetes opilio) in conical pots
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-11)Conical pots with a plastic entrance cone on the top are a type of fishing gear used to harvest snow crabs (Chionoecetes opilio) in Arctic regions. In this study, we assessed the effect of pot entrance diameter on the catch efficiency of snow crabs. We used catch data collected during sea trials of pots with different entrance cone diameters, and we conducted laboratory experiments where morphological ... -
Use of semi-pelagic trawling for reducing bycatch in shrimp trawls. Trials onboard R/V Johan Ruud 02-06 February 2015
(Research report; Forskningsrapport, 2015)The present study evaluates whether lifting the trawl doors and sweeps from the seabed can reduce bycatch in shrimp trawl fisheries. We carried out a catch comparison and catch ratio analysis between two gear setups, one with the trawl doors and sweeps at the seabed (the traditional way) and the other with the doors and sweeps lifted. The study was carried out on American plaice. The results ...
