English
norskBlar i forfatter "Grimaldo, Eduardo"
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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 ... -
Alternative Rope Materials in Towed Fishing Gear to Reduce Plastic Waste, A Comparative Study of Mechanical Properties and Tolerance Against Wear and Tear
(Chapter; Bokkapittel, 2023-06)This paper presents a comparative study assessing the wear tolerance of rope materials in demersal fisheries, specifically seine ropes and dolly ropes. Fourteen different rope materials were assessed in this study, including conventional and alternative commercially available synthetic polymers, and biodegradable materials including natural fibre ropes and custom-made polyester monofilaments. The ... -
Bycatch reduction in the deep-water shrimp (Pandalus borealis) trawl fishery with a large mesh top panel
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-08)In the Northeast Atlantic deep-water shrimp (Pandalus borealis) trawl fishery, the bycatch of juvenile fish and shrimp represents a problem. This study evaluated if inserting a 200 mm mesh size top-panel in the last three sections of the tapered upper belly section of the trawl could reduce bycatch of juveniles while maintaining the catch efficiency for deep-water shrimp. The bycatch species ... -
Bycatch reduction in the Norwegian deep-water shrimp (Pandalus borealis) fishery with a double grid selection system
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-25)Trawlers targeting Deep-water Shrimp (<i>Pandalus borealis</i>) in the North Atlantic use a Nordmøre sorting grid ahead of a small-meshed codend. Based on experimental fishing, the effect of adding a 9 mm spaced release grid behind the mandatory 19 mm spaced Nordmøre sorting grid, was determined. The performance in terms of size selection of the release grid and the two grids combined were assessed ... -
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 ... -
Catch Efficiency of Groundgears in a Bottom Trawl Fishery: A Case Study of the Barents Sea Haddock
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-10)The catch efficiency of two types of groundgear—a conventional rockhopper and a new type of groundgear called the semicircular spreading gear (SCSG)—was investigated through experimental fishing for Haddock Melanogrammus aeglefinus conducted in the Barents Sea. A retainer bag was attached behind the footrope of the trawl, and the number of fish that were overrun by the trawl was compared with the ... -
Combination of a sorting grid and a square mesh panel to optimize size selection in the North-East Arctic cod (Gadus morhua) and redfish (Sebastes spp.) trawl fisheries
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-27)Sorting grids and square mesh panels are the two most-applied technical devices to supplement codend size- and species-selection in demer- sal trawls. In the Barents Sea gadoid fishery, the compulsory size-selectivity system comprises a mesh section with a sorting grid followed by a diamond mesh codend. We tested the size-selective performance of a new sorting section that comprised a sorting grid ... -
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 ... -
Does soak time influence the effect of artificial light on catch efficiency in snow crab (Chionoecetes opilio) pot fishery?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-09)In the Barents Sea commercial snow crab (Chionoecetes opilio) fishery, an increase in catch efficiency of the conical pots is important for the profitability of the industry. Light emitting diodes (LEDs) have previously been tested for increasing catch efficiency of the snow crab pots. These earlier experiments have shown varying results ranging from large increase in snow crab catches to no ... -
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 ... -
Effect of lifting the sweeps on bottom trawling catch efficiency on the Northeast arctic cod trawl fishery
(Research report; Forskningsrapport, 2014)Fuel consumption and environmental concerns have led bottom trawlers fishing for cod (Gadus morhua) in the Barents Sea to use semi-pelagic doors. However, this change may affect fish herding and consequently the catch efficiency of the gear. In this study we compared the catch efficiency of two different setups where the sweep length with bottom contact was different. This setup also enabled us to ... -
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 semi-pelagic trawling on american plaice (hippoglossoides platessoides) by-catch reduction in the northeast arctic shrimp fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017)The present study reports results of a small-scale preliminary experiment to evaluate whether lifting trawl doors and sweeps from the seabed can lead to a reduction of by-catch in the Northeast Arctic shrimp trawl fishery. We carried out a catch comparison and catch ratio analysis between two gear configurations: one with trawl doors and sweeps on the seabed (traditional rigging) and the other with ... -
The fate of conventional and potentially degradable gillnets in a seawater-sediment system
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-20)Abandoned gillnets in the marine environment represent a global environmental risk due to the ghost fishing caused by the nets. Degradation of conventional nylon gillnets was compared to that of nets made of poly- butylene succinate co-adipate-co-terephthalate (PBSAT) that are designed to degrade more readily in the envi- ronment. Gillnet filaments were incubated in microcosms of natural seawater ... -
Field demonstration of a novel towed, area bubble-plume zooplankton (Calanus sp.) harvesting approach
(Research report; Forskningsrapport, 2010)This paper presents field experiment results of using a new technology to harvest copepods (Calanus sp.) in the ocean by bubble upwelling. Two largo-scale bubble rafts, a 21 m2 and a flexible 75 m2 bubble raft with tow parallel and perpendicular sparger elements, respectively, were field tested in areas with high, upper 25-m water column Calanus densities. Measured bubble-driven upwelling velocities ... -
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 ... -
Ghost fishing efficiency by lost, abandoned or discarded pots in snow crab (Chionoecetes opilio) fishery
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-07-07)Marine pollution by lost, abandoned or otherwise discarded fishing gear (ALDFG) often has negative impact on the ecosystem through plastic pollution and continuous capture of marine animals, so-called “ghost fishing”. ALDFG in pot fisheries is associated with high ghost fishing risk. The snow crab (Chionoecetes opilio) pot fishery is conducted in harsh weather conditions increasing the risk of ... -
Governance implications for the implementation of biodegradable gillnets in Norway
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-15)Gillnets are among the most widely used fishing gear in global fisheries because of their simplicity, high operability, catch efficiency and low entrance cost for fishermen. In Norway, the Northeast Atlantic (NEA) cod (<i>Gadus morhua</i>) fishing industry represents the most important economic single species fishery and the gillnet fishery accounts for 24% of the national total allowable catch (TAC) ...
