Vitality insights of fish escaping from a sorting grid installed on a bottom trawl net.

Sorting grids to exclude the juveniles of species targeted by bottom trawl fisheries from the catch are among the most promising solutions to reduce discards. We tested a two-sections Juveniles' Sorting Grid (JSG) in a Mediterranean fisheries restricted area. First, we provided information on the vitality of individuals escaping from the JSG bars during towing, by analysing underwater footage.

Effect on catch efficiency and bycatch by introducing an Excluder device in the trawl fishery for lesser sandeel (Ammodytes marinus).

Sampling of the North Sea trawl fishery for lesser sandeel (Ammodytes marinus) showed that 96% of the catch weight consisted of the target species, and experimental sea trials demonstrated that the observed small bycatch percentages of haddock (Melanogrammus aeglefinus), mackerel (Scomber scombrus) and grey gurnard (Eutrigla gurnardus) could be significantly lowered by inserting a netting-based sorting device, an Excluder, in front of the codend. The sandeel fishery is conducted with small meshes in the codend, due to the small size and elongated body shape of this species. It is not mandatory for sandeel trawls to have any other selection devices than the small-meshed codend, and this can potentially cause problems with bycatch of unwanted species, if these are abundant on the fishing grounds.

Ghost fishing efficiency in swimming crab (Portunus trituberculatus) pot fishery.

Abandoned, lost, or otherwise discarded fishing gear (ALDFG) is a global challenge that negatively affects marine environment through plastic pollution and continued capture of marine animals, so-called "ghost fishing". In different pot fisheries, ghost fishing related to ALDFG is of concern, including pot fishery targeting swimming crab (Portunus trituberculatus). This study quantified the ghost fishing efficiency by comparing it to the catch efficiency of actively fished pots of the commercial fishery.

Effect of gillnet mesh size on the capture probability and capture patterns in the Asian paddle crab () fishery.

In the Asian paddle crab () gillnet fishery in the Yellow Sea, China, the minimum mesh size (MMS) regulation has been of a major importance due to high bycatch rates of undersized crabs. In this study, we evaluated how gillnet mesh size can affect the capture probability of and capture patterns in this fishery by comparing the performance of gillnets with four different mesh sizes (60, 70, 80, and 90 mm). Our results showed that changes in gillnet mesh size significantly affect the capture probability of different sizes of crabs.

Improving the size selectivity and exploitation pattern of cocktail shrimp (Trachypenaeus curvirostris) in shrimp trawl fishery of the South China Sea.

In order to improve the size selectivity and exploitation pattern for cocktail shrimp (Trachypenaeus curvirostris) in shrimp trawl fishery of the South China Sea (SCS), selective properties of four codends were tested and compared. These experimental codends involved two mesh sizes, 30 and 35 mm, and two mesh shapes, diamond-mesh (T0) and diamond-mesh turned by 90 degree (T90), respectively. Our results demonstrated that increasing the mesh sizes in T0 codends or/and applying T90 codends would improve the selective properties for cocktail shrimp in the SCS.

Comparison of physical properties and fishing performance between biodegradable PLA and conventional PA trammel nets in grey mullet (Mugil cephalus) and red-lip mullet (Liza haematocheila) fishery.

Marine plastic pollution and continuous capture of marine animals, so-called "ghost fishing", by abandoned, lost, or otherwise discarded fishing gear (ALDFG) are global concerns. This study investigated whether biodegradable polylactic acid (PLA) monofilaments can be used to replace conventionally used non-biodegradable polyamide (PA) in trammel net fishery for limiting ALDFG associated effects. It evaluated the physical properties of PLA and PA monofilaments and compared fishing performance of PLA and PA trammel nets in a commercial mullet fishery in the Yellow Sea, China.

Ghost fishing efficiency by lost, abandoned or discarded pots in snow crab (Chionoecetes opilio) fishery.

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 fishing gear loss.

Effect of gillnet twine thickness on capture pattern and efficiency in the Northeast-Arctic cod (Gadus morhua) fishery.

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.

Every animal matters! Evaluating the selectivity of a Mediterranean bottom trawl fishery from a species community perspective.

Bottom trawl fisheries often catch several species simultaneously. However, most studies addressing the catch performance and selectivity of a specific trawl focus on a few commercially important or most vulnerable species requiring management measures. By contrast, the present study considers the multispecies nature of Mediterranean bottom trawl fisheries through a holistic approach that accounts for the full species community in the catches.

Increasing sustainability in food production by using alternative bait in snow crab () fishery in the barents sea.

The use of food grade wild-captured species as bait for other fisheries questions the sustainability of food production. In pot fisheries, bait is an important factor determining the effectiveness of the gear. In snow crab () fishery, the pots are normally baited with squid ( sp.

Effect of the Nordmøre grid bar spacing on size selectivity, catch efficiency and bycatch of the Barents Sea Northern shrimp fishery.

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.

Comparison of the efficiency and modes of capture of biodegradable versus nylon gillnets in the Northeast Atlantic cod (Gadus morhua) fishery.

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.

Can biodegradable materials reduce plastic pollution without decreasing catch efficiency in longline fishery?

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.

Optimizing size selectivity and catch patterns for hake (Merluccius merluccius) and blue whiting (Micromesistius poutassou) by combining square mesh panel and codend designs.

Gear modifications in fisheries are usually implemented to obtain catch patterns that meet management objectives. In the Basque bottom trawl fishery, gear regulations include the use of a square mesh panel (SMP) placed at the top panel of the extension piece of the trawl to supplement diamond mesh codend selectivity. However, the catch patterns obtained with this combination have raised concern among scientists and authorities.

Comparing size selectivity and exploitation pattern of diamond-mesh codends for Southern velvet shrimp () in shrimp trawl fishery of the South China Sea.

In this study, size selectivity and exploitation pattern of six diamond-mesh codends with different mesh sizes, ranging from 25 to 54 mm, for Southern velvet shrimp () were tested and compared in a shrimp trawl fishery of the South China Sea (SCS). We used a codend with a mesh size of 25 mm (D25) as a starting point, which is the minimum mesh size (MMS) currently regulated in the studied area. Four different fishing population scenarios were applied to quantify and compare how mesh sizes of codends used would impact the size selectivity and exploitation pattern for the target shrimp species.

The effect of white and green LED-lights on the catch efficiency of the Barents Sea snow crab (Chionoecetes opilio) pot fishery.

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 increases the catch efficiency for snow crab over the minimum landing size of 95 mm carapace width of up to 76% when using green LED, and by 52-53% on average when using white LED.

Effects of six codend meshes on the size selection of juvenile white croaker (Pennahia argentata) in demersal trawl fishery of the South China Sea.

White croaker (Pennahia argentata) is a commercially important but overexploited species that is often caught in trawl fishery of the South China Sea (SCS). The codend size selectivity for this species in the local commercial trawl fishery is of concern when considering the established minimum landing size (MLS). This study investigated the size selectivity of white croaker for six different diamond-mesh codends with mesh size from 25 to 54 mm.

Can vertical separation of species in trawls be utilized to reduce bycatch in shrimp fisheries?

Several shrimp trawl fisheries use a Nordmöre sorting grid to avoid bycatch of fish. However, small fish can pass through the grid. Therefore, the retention of juvenile fish often remains an issue during shrimp trawling.

A netting-based alternative to rigid sorting grids in the small-meshed Norway pout (Trisopterus esmarkii) trawl fishery.

A new bycatch reduction device, termed "Excluder", is presented as an alternative to a traditional rigid sorting grid, mandatory in the small-meshed Norway Pout (Trisopterus esmarkii) trawl fishery in the North Sea. The fishery is a high-volume fishery with large vessels, large demersal trawls and catches up to 100 tons per haul of this small forage fish. The Excluder is a 30 m long netting-based sorting system, developed to reduce bycatch (70 mm square meshes) and improving on board gear-handling and safety.

Size-dependent escape risk of lumpfish (Cyclopterus lumpus) from salmonid farm nets.

In the last decade, the salmon aquaculture industry has considerably increased the use of lumpfish juveniles as cleaner fish. Potential escape of reared lumpfish into the wild may spread diseases or genetically contaminate wild stocks. The guidelines for minimum sizes of cleaner fish to use in aquaculture cages are currently based on simple mesh penetration tests.

The effect of long-term use on the catch efficiency of biodegradable gillnets.

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, as they caught 18.

Effect of mechanical properties of monofilament twines on the catch efficiency of biodegradable gillnets.

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.

Quantification of gear inflicted damages on trawl-caught haddock in the Northeast Atlantic fishery.

External damages are indicators of the overall quality of fish and fish welfare. Haddock is an important commercial species widespread in the North Atlantic, but few studies related to quality have been carried out on this species. We studied the levels of external damages on haddock captured with a demersal trawl in the Northeast Atlantic.

Quantification of bell-shaped size selectivity in shrimp trawl fisheries using square mesh panels and a sorting cone after a Nordmøre grid.

Shrimp trawlers in the Barents Sea use a Nordmøre sorting grid ahead of a small-mesh codend to avoid bycatch while catching shrimps efficiently. However, small fish can still pass through the grid to enter the codend, which increases their risk of being retained. In this study, we quantified the selectivity of a standard Nordmøre grid used together with one of two different codend designs, namely a diamond mesh codend with square mesh panels and a codend with a square mesh sorting cone section, for deep-water shrimp (Pandalus borealis), redfish (Sebastes spp.

Effect of pot design on the catch efficiency of snow crabs (Chionoecetes opilio) in the Barents Sea fishery.

The snow crab (Chioneocetes opilio) fishery in the Barents Sea is carried out by large offshore vessels, as the fishing grounds are located far from shore and the gear must be transported back and forth over long distances. Therefore, fishers use stackable conical pots that allow large numbers of pots to be carried on deck for each trip. One of the drawbacks of using stackable pots is that the entrance is at the vertex of the conical pot, which fishers claim does not provide the desired fishing efficiency.