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Papers by Eduardo Grimaldo

PLOS ONE

The introduction of the Nordmøre grid in shrimp trawls has reduced the bycatch of non-target spec... more The introduction of the Nordmøre grid in shrimp trawls has reduced the bycatch of non-target species. In the Norwegian Northern shrimp (Pandalus borealis) fishery, the mandatory selective gear consists of a Nordmøre grid with 19 mm bar spacing combined with a 35 mm mesh size diamond mesh codend. However, fish bycatch in shrimp trawls remains a challenge and further modifications of the gear that can improve selectivity are still sought. Therefore, this study estimated and compared the size selectivity of Nordmøre grids with bar spacings of 17 and 21 mm. Further, the effect of applying these two grids on trawl size selectivity was predicted and compared to the legislated gear configuration. Experimental fishing trials were conducted in the Barents Sea where the bottom trawl fleet targets Northern shrimp. Results were obtained for the target species and two by-catch species: cod (Gadus morhua) and American plaice (Hippoglossoides platessoides). This study demonstrated that reducing ba...

Estuarine, Coastal and Shelf Science

Målsettingen med toktet var å undersøke hvordan de forskjellige delene i nota beveger seg under f... more Målsettingen med toktet var å undersøke hvordan de forskjellige delene i nota beveger seg under fangstprosessen i snurrevadfiske, og hvordan dette påvirker overlevelse, stressnivå og fangstskader på fisken. I tillegg var det ønskelig å relatere bevegelsene i sekken til fangstmengden, operasjonene på brua og hivehastigheten brukt av skipperen. Det ble også utført noen studier som var en oppfølging av det arbeidet som ble gjort på tokt på Gunnar K. i 2011. Følgende studier ble utført: - Ombordtaking av levende fisk, hvor pumping og sekking ble sammenlignet. - Effekt av elektrobedøving av torsk og hyse. Resultatene viste at sensorer som ble brukt var godt egnet til å undersøke hvordan nota flyttet seg i vannmassen. Videre at det var forskjeller i kvaliteten på fisken, spesielt for hyse, ved de to ulike vinsjehastighetene. Generelt var det tendens til at sekket fisk hadde en høyere andel fangstskader enn pumpet fisk. En spenning på 28V var for lav til å gi konsistent bedøvelse av fisken

Ocean & Coastal Management

Scientia Marina, 2016

Most selectivity experiments employ either the covered codend or paired gear methods. It is not a... more Most selectivity experiments employ either the covered codend or paired gear methods. It is not always possible, however, to use these methods. Owing to operational, biological and/or environmental considerations, there may be no obvious way or it may be inappropriate to pair the test and control data. Hence, it will not be possible to estimate the selectivity of the gear and its uncertainty using standard statistical methods. This study presents a methodology for analysing the selectivity of fishing gears from unpaired test and control data. The uncertainty in the control and test population structures is accounted for by using a double bootstrapping procedure that takes into account both between-haul and within-haul variation. This bootstrapping approach is used to assess the selectivity of two different devices, a 139.5 mm T90 codend and a 135.9 mm codend with 140.9 mm lateral exit windows, in the Barents Sea pelagic cod trawl fishery. The purpose of the experiment was to test and compare the performance of the two devices in pelagic trawl fisheries, where high densities of fish can be encountered. Significant differences were detected between the T90 codend and the codend with the exit windows but only for sizes of cod between 55 and 76 cm.

Marine Pollution Bulletin, 2022

During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we collected samples of mes... more During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we collected samples of mesopelagic species down to a depth of 600 m and analysed the chemical composition of the catch samples. We present gross proximate composition (g /100 g fresh weight) and fatty acid composition (% of total fatty acids) in mesopelagic raw material samples (values are mean ± standard deviation of 2–4 samples).

During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we studied the biomass of m... more During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we studied the biomass of mesopelagic fish down to a depth of 600 m and identified and quantified the species composition of the catches. The biomass density was estimated considering the volume of water filtered by the cross-sectional area of the trawl blinded with 16 mm meshes (130 m–2), the distanced covered by the trawl (m) at a towing speed (transformed to m s–1) the effective tow time (min) and the catch (kg).

The Norwegian Research Council The Norwegian Seafood Research fund (FHF) Rolls-Royce Marine AS Mo... more The Norwegian Research Council The Norwegian Seafood Research fund (FHF) Rolls-Royce Marine AS Morenot AS

The present study reports results of a small-scale preliminary experiment to evaluate whether lif... more 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 doors and sweeps clear of the seabed (semi-pelagic rigging). The study focused on the by-catch of American plaice (Hippoglossoides platessoides) and showed that the gear was significantly less efficient at catching this species when rigged in the semi-pelagic mode. When rigged this way, the gear captured 52%–66% fewer American plaice between 10 and 40 cm compared to traditional rigging. Moreover, this difference was significant for sizes between 12 and 31 cm, and it increased with fish size. The herding efficiency of doors and sweeps for American plaice was estimated to be 100% and signif...

Fisheries Research, 2019

In the commercial pot fishery for snow crab (Chionocetes opilio), size selection by the pots is i... more In the commercial pot fishery for snow crab (Chionocetes opilio), size selection by the pots is important for reducing catch sorting and unintended mortality. In addition to mesh size and shape, selection in the pots relies on every crab contacting the netting meshes, which makes the process complex because the odour of the bait tends to keep all sizes of crab in the pots. Thus, soak time may affect the extent of the use of the selective potential of the pots. This study was designed to assess the influence of soak time on size selectivity, and the methodology was applied to snow crab data collected in the Barents Sea. The results showed that a minimum soak time is required to reach the full size-selective potential of the pots. Specifically, a fraction of the small crabs inside a pot will not attempt to escape through the pot meshes when the pots are soaked for short periods of time (under nine days). Further, with short soak time, some of the crabs inside a pot will not make selectivity contact with the netting. Therefore, some crabs will not utilize the escape options through the pot meshes. This finding confirms the need for using a selection model that explicitly accounts for such a process when assessing snow crab size selection. Lastly, this study outlines how the concept of selectivity contact can formally be applied to model the effect of soak time on the size selectivity of the snow crab pot fishery.

During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we collected samples of mes... more During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we collected samples of mesopelagic species down to a depth of 600 m and evaluated the presence of unwanted substances. Except for Cd and As, toxic compounds were present at levels far lower than the limits set by European Union regulations.

During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we studied Maurolicus muell... more During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we studied Maurolicus muelleri (Mueller's pearlside) wet mass, length, sex and maturity stages per size class.

During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we collected samples of mes... more During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we collected samples of mesopelagic species down to a depth of 600 m and analysed wax esters, triglycerides, free fatty acids, cholesterol and phospholipids (g/100 g oil) of four catch samples.

Regional Studies in Marine Science, 2022