Authors: María J. Cabrera-Álvarez, Jenny Volstorf

Mullus surmuletus is a popular species from waters off Norway to the Canary islands and in the Mediterranean and Black sea. In some regions, its catch statistic is combined with that of the related M. barbatus (Red mullet), as the market does not differentiate between the two. As a BENTHIC carnivore foraging in depths of 2-80 m, it is caught by DEMERSAL fisheries, predominantly of small scale, among them (bottom-)set nets. The second most frequent capture method is bottom trawl.

After being caught and held in the (gill or trammel) net during soaking and hauling – which can take several hours – the IND can already emerge dead or very weak from exhaustion or depredation by crustaceans or cetaceans. A shorter soak time could decrease suffering. Avoiding bycatch of the target species will only be able through mesh size that reduces catching undersized IND. Once on board, IND then will endure exposure to air, disentangling, experiencing their own weight, and throwing during release from gear, sorting, and storing. This could be avoided through stunning as soon as they arrive on board, followed by slaughter while still unconscious. Such a protocol does not exist, though.

Another possibility to reduce the contact with predating cetaceans could be to close the fishing for certain times or areas which would also benefit the local M. surmuletus populations. To prevent non-target species (usable and non-usable including ETP) being accidentally caught, the mesh size is decisive, but it might also need an adjustment of the minimum conservation reference size. Installing guarding nets for trammel nets is another option. Since non-target bycatch will probably not be completely avoided, a landing obligation and a campaign to encourage consumption of the less popular species could be pursued. Set nets are to be preferred over bottom trawl to catch M. surmuletus, since set nets seem to have a higher size selectivity and since their impact on the benthos is relatively low, as set nets are usually not dragged along the seafloor.

To find the fishes in their habitat, there are different techniques to localise them (e.g., echosound/sonar, chasing).

What is the probability of avoiding a decrease in welfare during the process of searching for the species?

Likelihood

Potential

Certainty

Catching methods differ in the way they are set up and consequently in the time it takes for setting them.

What is the probability of avoiding a decrease in welfare during the process of setting the catching method?

Likelihood

Potential

Certainty

Given the principle of the catching method, the gear (with the fishes caught) may be hauled vertically or horizontally in the water for a certain amount of time and distance.

What is the probability of avoiding a decrease in welfare during catching?

Likelihood

Potential

Certainty

Not all specimens of the target species are equally sought after, e.g., when they are undersized, of wrong sex, wrong age, damaged, over quota, or mixed with a high proportion of undersized or unwanted non-target fishes. Measures to prevent this bycatch still in the water may include slipping in purse seine, window in net, opening in trap, etc.

What is the probability of avoiding a decrease in welfare with the help of bycatch-avoiding measures?

Likelihood

Potential

Certainty

The process of bringing the fishes out of the water also depends on the catching method and may, thus, differ in duration and impact (e.g., netting, brailing, pumping, lifting).

What is the probability of avoiding a decrease in welfare during emersion?

Likelihood

Potential

Certainty

There are different ways to remove the fishes from the gear (e.g., unhooking, disentangling, dropping).

What is the probability of avoiding a decrease in welfare during release from the gear?

Likelihood

Potential

Certainty

Given the species specificity of the method, sorting might be necessary once the catch arrives on deck.

What is the probability of avoiding a decrease in welfare during sorting?

Likelihood

Potential

Certainty

If bycatch of the target species could not be prevented, the individuals could still be returned from the gear/deck to the water.

What is the probability of avoiding a decrease in welfare during discarding?

Likelihood

Potential

Certainty

Given how long it takes the vessel to return to the harbour, the caught fishes have to be stored for a certain amount of time. This storing happens most frequently with the fishes still being alive, but differing in the type of storage containers and medium (ice, brine, air, etc.).

What is the probability of avoiding a decrease in welfare during storing?

Likelihood

Potential

Certainty

Ideally, slaughter a) immediately follows stunning (i.e., while the individual is unconscious), b) happens according to a clear and reproducible set of instructions verified under catching conditions, and c) avoids pain, suffering, and distress.

What is the probability of avoiding a decrease in welfare during stunning/slaughter?

Likelihood

Potential

Certainty

Sometimes the literature does not specify the welfare hazards and the catching step that lead to hazard consequences.

What are consequences that decrease welfare during uncategorised steps of the catching process?

The focus of this WelfareCheck | catch is the welfare of the target species. There could be improvements to the catching method that are not covered by the criteria and could include prevention of overexploitation, prevention of bycatch of non-target species, e.g., pingers to deter cetaceans, and avoiding damage to the environment, though.

What are these improvements?

• Target species: measures to manage population besides minimal landing size and minimum mesh size (→ 4.2. Contact with the gear): in another DEMERSAL species caught with set nets in the Northern Atlantic and Mediterranean, Merluccius merluccius, total allowable catch is recommended and closure of areas to prevent catch of JUVENILES because minimum mesh size cannot avoid entangling of small IND by teeth 37 which M. surmuletus loses in the upper jaw only from >9 cm TOTAL LENGTH on 38. Further research needed to determine whether this applies to M. surmuletus as well.
  Fishing season: Mar-Aug 18, spring-autumn 14, May-July up to year round 22, July-Dec 21, Sep-Dec 23, Oct-Apr 3 4, year round 16 20 25. In M. merluccius, to avoid overexploitation, recommended to regulate fishing days per year, close areas or seasons, especially during the spawning season 39. Further research needed to determine whether this applies to M. surmuletus as well.
  With bottom-set gill nets, mesh size 50-90+ mm, off France, during 2009-2015: <5% bycatch of IND >40 g (ca 18 cm TOTAL LENGTH) minimal commercial landing weight; for trammel nets >15%, probably indicating a risk for overexploitation of the population 20.
  Trammel nets off Egypt, Mediterranean, caught IND of 9.1-30 cm TOTAL LENGTH which is partly <15.4 cm age at maturity and thus a risk for overexploitation, since the JUVENILES cannot reproduce before being caught. Possible mitigation measures need to be researched: larger mesh size, closure of fishing areas 40.
  Management regulations for trammel nets, off Mallorca: limitation to 6 fishing days per week, forbidden to catch >50 m depth 21.
  In Mediterranean, bottom trawl was more detrimental for population of M. surmuletus than gill nets 12 or trammel nets 18 due to worse size selectivity 12 including JUVENILES 18.
  • How to improve: prefer set nets over bottom trawl and possibly gill nets over trammel nets, limit fishing days, limit fishing depth (<50 m), possibly closure of fishing areas (further research needed)
• Non-target species: given the principle of set nets to be passive gear floating or standing in habitat that other species use or traverse, there is the risk to also catch co-existing, preyed-on, and predating species 0.
  Usable bycatch: with gill nets of 300 m length × 1.8 m height, 36 mm mesh size, in northern Aegean Sea, Greece: 20.7% biomass catch of (mostly) JUVENILES of Pagellus acarne, Diplodus annularis, and Pagellus erythrinus threatened these species' populations 14. Given that in northern Aegean Sea, Greece, fishing season (spring-autumn) fell in reproductive season for these species, risk for overexploitation of the population due to extraction of SPAWNERS of Diplodus annularis, Mullus barbatus, Sphyraena sphyraena, and Trachurus trachurus is probable 14. Recommended to specify lengths at maturity and adjust minimum conservation reference size 14.
  With gill nets of 1,000 m length × 3 m height and commercial mesh size 53 mm, in Asturias, northwest Spain: M. surmuletus caught together with other species of high economic value representing 33.5% IND of catch (mostly Merluccius merluccius, some Serranus cabrilla, Pagellus acarne, rarely Trisopterus luscus, Pagellus erythrinus, Sepia officinalis, Pagellus bogaraveo, Belone belone, Octopus vulgaris, Trachurus trachurus, Auxis rochei, Chelidonichthys lucerna, Coris julis, Oblada melanura, Pollachius pollachius, Sarda sarda, Scorpaena porcus, Symphodus melops, Zeus faber), another 53.3% IND for use as bait (Trachurus trachurus, Boops boops). Higher number of IND and weight of catch used for bait with 5 m high net instead which is not allowed and cannot be recommended 15. Encouraging consumption of species (so far) used as bait and implementing a landing obligation could reduce the amount of bycatch 15.
  With gill nets, in Northern Atlantic, at 68 mm mesh size: pollocks, streaked gurnards, cuckoo wrasses, lesser spotted dogfishes 7 8, scads, poutings, lings, one octopus, horse mackerels 7, one sea cucumber 8.
  With shore netting, in Northern Atlantic, at 108 mm mesh size: bycatch of bass, Gilthead seabream (Sparus aurata), mullet 3 4, jellyfish 3.
  With trammel nets of 500 m length and mesh sizes in 36-40 mm, out 240 mm, in Izmir Bay, Aegean Sea, Turkey: bycatch of commercial species (mostly Diplodus annularis, some Boops boops, Spicara flexuosa, Diplodus vulgaris, Pagellus erythrinus, rarely Sepia officinalis, Octopus vulgaris, Trachurus trachurus, Trigla lucerna, Pagellus acarne) 16.
  Non-usable bycatch: with gill nets with 60-75 mm mesh size, off the southern Portuguese coast (the Algarve): ~0.9% bycatch of Tursiops truncatus 26.
  With gill nets of 1,000 m length × 3 m height and commercial mesh size 53 mm, in Asturias, northwest Spain: 13.2% IND discarded due to commercial species being damaged (36.3% IND) or being undersized (21.1% IND) or of too little numbers (12.7% IND) or exceeding total allowable catch (4.6% IND) or due to non-commercial species (25.3% IND) (mostly Polybius henslowi, Sardina pilchardus, Boops boops, Trachurus trachurus, some Trachinus draco, Chelidonichthys cululus, Scorpaena scrofa, Trisopterus luscus, rarely Scomber colias, Scorpaena notata, Callionymus lyra, Serranus cabrilla, Chelidonichthys obscurus, Scomber scombrus, Arnoglossus imperialis, Pagellus acarne, Trisopterus minutus, Chelidonichthys gurnadus, Corystes cassivelaunus, Diplodus vulgaris, Echinaster sepositus, Engraulis encrasicolus, Holothuria forskali, Labrus bergylta, Labrus mixtus, Octopus vulgaris, Pagellus bogaraveo, Sarda sarda, Scyliorhynus canicula, Symphodus bailloni). Higher number of IND damaged and higher number of non-commercial species with 5 m high net instead which is not allowed and cannot be recommended 15. Implementing a landing obligation and encouraging consumption of (so far) non-commercial species could reduce the amount of discards – also because FISHES used as bait (Trachurus trachurus, Boops boops) are not treated carefully during disentangling due to their low appreciation 15.
  With trammel nets of 500 m length and mesh sizes in 36-40 mm, out 240 mm, in Izmir Bay, Aegean Sea, Turkey: 77.4-81.4% IND discarded (Anomura spp., Maja squinado, Hexaplex trunculus, Serranus scriba, Symphodus tinca, Arnoglossus materna, Coris julis, Bolinus brandaris, Aporrhais pespelecani, Serranus cabrilla, Eledone moschata, Sardina pilchardus, Symphodus ocellanus, Serranus hepatus, Blennius ocellaris, Gobius niger, Chromis chromis). Highest discards in May-Oct, probably due to more FISHES inhabiting seagrass. Attaching guarding nets (selvedge) decreased discards to 18.6-22.6%, especially of decapod crustaceans Anomoura spp. and Maja squinado and gastropods Hexaplex trunculus, Bolinus brandaris, Aporrhais pespelecani 16.
  General bycatch: with bottom-set trammel nets of 500-2,000 m × 1.6 m height, 27 mm mesh size, off Sardinia: the following other non-target species caught of which unclear whether they are used (commercially or at sea) or discarded: mostly Diplodus vulgaris, Scorpaena porcus, Diplodus annularis, Scorpaena scrofa, Serranus cabrilla, Pagellus erythrinus, Sepia officinalis, some Symphodus tinca, Phycis phycis, Sciena umbra, Spodyliosoma cantharus, Spicara maena, Sepia orbignyana, Symphodus roissali, Dentex dentex, rarely Octopus vulgaris, Labrus merula, Diplodus puntazzo, Trigloporus lastoviza, Uranoscopus scaber, Zeus faber, Boops boops, Labrus viridis, Sarpa salpa, Palinurus elephas, Diplodus sargus, Scyliorhinus canicula, Trachinus draco, Trisopterus minutus capelanus, Loligo vulgaris, Pagellus acarne, Conger conger, Symphodus mediterraneus, Dasyatis pastinaca, Labrus micaculatus, Sepia elegans, Sphyraena sphyraena, Seriola dumerili, Trachinus radiatus, Trachinus araneus, Scomberesox saurus, Raja clavata, Raja brachyura, Maja squinado 23.
  • How to improve: prefer mesh size that avoids catching non-target species, adjust minimum conservation reference size, install guarding net (selvedge) for trammel nets, encourage consumption of non-commercial species, landing obligation
• Non-target species: given that M. surmuletus is a BENTHIC carnivore 41, catching takes place at the bottom 25 12 23 20 26 3 31 24 29 1 4. The net is not dragged along the seafloor 3 4, though, so seabed damage or huge impact on benthos is relatively low 0. Recommended to monitor the benthic habitat before deploying the net 2.
  • How to improve: impact on benthos relatively low, recommended to monitor the benthic habitat before deploying the net
• Non-target species: non-usable bycatch: in ghost-net experiments (gill net: 60 mm mesh size, trammel net: in mesh 60 mm and out mesh 100) off the southern Portuguese coast (the Algarve), that catch several FISHES including M. surmuletus, 15-20 weeks effective fishing lifetime of the net. The nets caught 39 species belonging to 4 main groups (crustaceans: Galathea strigosa, Maja squinado, Macropipus puber, Scyllarus arctus; gastropods: Charonia lampas; molluscs: Cybiun olla, Sepia officinalis; FISHES: Alistes carolinensis, Parablennius gattorugine, Callionymus lyra, Caranx rhonchus, Trachurus trachurus, Conger conger, Phycis phycis, Trisopterus luscus, Pomadasys incisus, Labrus merula, Symphodus bailloni, Symphodus spp., Merluccius merluccius, Mugil spp., Mullus surmuletus, Scomber spp., Scomber japonicus, Scorpaena notata, Serranus spp., Serranus cabrilla, Buglossidium luteum, Dentex gibbosus, Diplodus annularis, Diplodus bellottii, Diplodus cervinus, Diplodus puntazzo, Diplodus sargus, Diplodus spp., Diplodus vulgaris). Estimated 344 FISHES/100 m length caught in 120 days. Probable depredation by Conger spp., Muraeinadae, and Coris julis on the ghost netted FISHES, especially soft bodied species like M. surmuletus 42.

How much is this species targeted annually?

Authors: María J. Cabrera-Álvarez, Jenny Volstorf

As a consequence of welfare hazards, fishes may suffer from physical damage (e.g., barotrauma, abrasions/lacerations/wounds, ecchymosis, desiccation).

Where in the catching process does physical damage occur and how to avoid it?

Physical damage may occur most frequently through contact with the gear, handling/dropping, and predation pressure. To avoid or decrease it during catching/hauling, a) prefer mesh size that reduces catching undersized IND (given body ∅ in season and region), b) prefer shorter soak time which also reduces depredated IND (which needs to be verified for the catching context), and c) to further deter cetaceans: amend or switch gear to avoid recognisable sounds, close fishing for certain times or areas or switch up areas, apply "stealth fishing", attach dolphin deterrent devices or, favourably, dolphin interactive devices to the gear which all need to be verified for the catching context. To avoid it during emersion, further research needed. To avoid it during release from gear, sorting, and storing, prefer immediate stunning followed by slaughter while still unconscious. Decreasing distance to neighbour is probably not an issue in set nets. Further research needed.

1.1 Barotrauma

Extruded eyes/guts: no data found yet.

Ruptured swim bladder: no data found yet.

Bleeding: no data found yet.

• Given catching depth of 2-68 m 22, 10-65 m 23, 12-70 m 15, 15-21 m 16, 16-86 m 1, 18-60 m 12, 20-80 m 24, 15-30 fathoms (~27.4-54.9 m) 25 and unknown speed of hauling, barotrauma is possible 0.
  • Catching step:  Catching

1.2 Damages/abrasions/lacerations/wounds

Eye damage: no data found yet.

• During soaking, IND may be damaged 6 14, probably by scavenging crustaceans 3 or predating cetaceans 14. Depredation rate by Tursiops truncatus ~21-25%/haul 26. Given that depredated IND are most likely discarded after manual disentangling, depredation should be avoided or at least decreased 0.
  During soaking, interactions with 1-12 bottlenose dolphins Tursiops truncatus 12/88 times (13.6%), during hauling 17/88 times (19.3%), spending average 20 min and reducing catch of M. surmuletus. Negative correlation between catch volume and duration of soak time and interactions with dolphins 23 indicates probable reduction of lost catch through lower soak time 0. Of those IND still caught in the net when hauled on board, without interaction with dolphins, mainly bite injuries 23, probably by cuttlefishes Sepia spp., common octopus Octopus vulgaris, European conger Conger conger, Mediterranean moray Murena helena 27↶23; with interaction with dolphins, roughly equal amount of bite injuries, only head remaining, only tail remaining, and fragments remaining 23. As dolphins are probably lured by sounds that the gear make, recommended to amend or switch up gear; dolphins could also hear if vessels leave for the sea at night, so recommended to close fishing for certain times or areas or switch up areas 23 or apply "stealth fishing" 28↶23.
  Using dolphin deterrent devices reduced depradation by T. truncatus by 48%, using dolphin interactive devices reduced depradation by 50%, but their efficiency gradually reduces over time 29.
  • Catching steps:  Catching Bycatch avoidance Discarding
  • How to improve: prefer shorter soak time (further research needed), amend or switch gear to avoid recognisable sounds, close fishing for certain times or areas or switch up areas, apply "stealth fishing", attach dolphin deterrent devices or, favourably, dolphin interactive devices to the gear

Mouth damage: no data found yet.

Opercular/gill damage: no data found yet.

Scale loss: no data found yet.

Broken spine: no data found yet.

• Given the principle of set nets to catch IND 5 6 7 8 3 by the head region (called “snagging”) 9, by the gills (called "gilling") 3, by the mid body (called “wedging”) 9, or by wrapping the whole body or attaching protruding body parts like teeth (called “entangling”) 9, hazard consequences are probable 0. During catching, substantial scale loss (26-50% of body surface) in IND, indicating a high risk of external injuries 1.
  Catching SPAWNERS with gill nets and transportation caused skin damage resulting in mortality within 2-3 weeks; more IND dead without external injuries 10.
  • Catching steps:  Catching Bycatch avoidance Emersion
• The following mesh sizes assure good size selectivity, i.e., the listed sizes of IND will have contact with the gear:
  bottom-set gill nets at 18-60 m depth, after soaking from 2 h prior to 2 h after sunset: decreasing number of IND and increasing catching length with increasing mesh size (17, 19, 21, 23 mm). Of 10-21 cm FORK LENGTH caught, all IND were >10 cm FORK LENGTH minimal landing size 11↶12, indicating good size selectivity of currently used mesh sizes and better size selectivity than bottom trawls 12.
  Gill nets at 20 m isobath with mesh size 36 mm, after soaking for 1.5 h, caught IND of 9.4-23.1 cm TOTAL LENGTH, mostly above minimum conservation reference size (11 cm 13↶14) and partly below 50% size at maturity (15.5 cm 13↶14) 14. Recommended mesh size for Mediterranean (38.5 mm 13↶14) might eliminate these issues 0.
  Gill nets at 12-70 m, after soaking 3-5 h from before sunrise: decreasing number of IND with increasing mesh size (53, 60, 75, 87 mm); highest weight at 60 mm. Of 18-39 cm TOTAL LENGTH caught, all IND were >15 cm minimal landing size, prompting recommendation to increase allowed mesh size from 50 to 60 mm. No difference in number of IND and weight with 5 m high net instead which is not allowed and cannot be recommended 15.
  Trammel nets at 15-21 m depth with 36-40 mm in mesh and 240 mm out mesh, after soaking for 2 h caught IND of 14.1-21.7 cm TOTAL LENGTH, all >11 cm minimal landing size 16.
  Trammel nets with 40-52 mm mesh size caught IND of 11-27 cm TOTAL LENGTH, mostly above size at maturity (15-16 cm 17↶18) and with better size selectivity than bottom trawls (5-23 cm TOTAL LENGTH) 18.
  • Catching steps:  Catching Bycatch avoidance
  • How to improve: prefer mesh size that assures good size selectivity given body ∅ in season and region
• The following mesh sizes potentially cause bycatch, i.e., they should be avoided to prevent those IND from having contact with the gear:
  With bottom-set gill nets, mesh size 50-90+ mm, during 2009-2015: <5% bycatch of IND >40 g (ca 18 cm TOTAL LENGTH) minimal commercial landing weight, for trammel nets >15%, probably indicating a risk for overexploitation of the population 20.
  Trammel nets with minimum mesh size 50 mm, during 2000-2012 caught IND of 9-29 cm TOTAL LENGTH, partly <14 cm size at 50% first maturity, probably indicating a risk for overexploitation of the population 21.
  • Catching steps:  Catching Bycatch avoidance
  • How to improve: prefer mesh size that reduces catching undersized IND given body ∅ in season and region
• No crowding step before hauling the net on board, but IND remained caught and with the same distance to other con-specifics under and above water when net was continuously hauled 5 6 7 8 or when IND were collected lying on the shore 3 4, probably not resulting in decreasing distance to neighbour 0.
  • Catching steps:  Catching Emersion
  • How to improve: no risk of hazard consequences, as decreasing distance to neighbour is unlikely compared to catching methods with crowding step
• Given short distance between water surface and aboard vessel and thus hardly any occasion 5 7 8, predation pressure during emersion is probably low 0. More time and more convenient occasion during soak time or hauling → 3.7. Predation pressure.
  • Catching step:  Emersion
  • How to improve: low predation pressure during emersion, rather during soaking or hauling (→ 3.7. Predation pressure)
• When the net is hauled onboard, IND may be catapulted on deck, and given how the effect of gravity interacts with the type of catching (snagging, gilling, wedging, entangling) and therefore how the net affects the skin and given contact with several reels along which the net is guided 5 6 7 8 and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  Catching SPAWNERS with gill nets and transportation caused skin damage resulting in mortality within 2-3 weeks; more IND dead without external injuries 10.
  • Catching step:  Emersion
• Given that during manual disentangling, IND may fall to the floor 5 7 8 and that after disentangling, IND are thrown into buckets 5 6 7 1 3 4 and assuming IND are not already dead, hazard consequences are probable 1 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching steps:  Release from gear Sorting
• Given that manual disentangling happens fast and rough 5 6 7 8 1 and assuming IND are not already dead, hazard consequences are probable 1 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching steps:  Release from gear Sorting Discarding
• Given that undersized IND are discarded after manual disentangling 8 and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences.
  • Catching steps:  Release from gear Sorting Discarding
  • How to improve: prefer mesh size that reduces catching undersized IND given body ∅ in season and region (→ 4.2. Contact with the gear)​
• Given that surviving discarded IND are probably disoriented, stressed, and weakened after the catching process and release 30, and given that seabirds 5 6 8 and other predators might gather near fishing boats, predation pressure is probable 30. Predation on several FISHES 31, including M. surmuletus 32, by seabirds like Morus bassanus – which was reduced through use of a visual deterrent in the form of a bird of prey ("scarybird") – and by Larus spp. – which was reduced through retaining to-be-discarded IND in buckets until after hauling the net 31. Given the use of small buckets resulting in crowded conditions, hazard consequences are probable 0. Further research needed on types of hazard consequences.
  • Catching step:  Discarding
  • How to improve: use visual scarybird device as deterrent against predatory seabirds
• Discarding probability is assumed to be low due to high commercial value of M. surmuletus 33↶34 35↶34.
  Gill nets at 12-70 m, after soaking 3-5 h from before sunrise: at commercial mesh size 53 mm, 1.4% discarded due to damage 15.
  • Catching step:  Discarding
• Given that IND were thrown into buckets 5 6 7 1 3 4 with water 7, later placed on and under ice 3 4, and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching step:  Storing
  • How to improve: prefer immediate stunning followed by slaughter while still unconscious

1.3 Ecchymosis

Bruising and discoloration of the skin due to squeezing: no data found yet.

1.4 Desiccation (surface issue)

Unspecified: no data found yet.

Stress is a likely consequence of various welfare hazards. It may be measured via physiological parameters (cortisol, glucose, lactate, etc.) or behavioural observations (e.g., opercular movement).

Where in the catching process does stress occur and how to avoid it?

Stress may occur most frequently through contact with the gear, lack of oxygen, handling/dropping, and predation pressure. To avoid or decrease it during catching/hauling, a) prefer mesh size that reduces catching undersized IND (given body ∅ in season and region), b) prefer shorter soak time which also reduces depredated IND (which needs to be verified for the catching context), and c) to further deter cetaceans: amend or switch gear to avoid recognisable sounds, close fishing for certain times or areas or switch up areas, apply "stealth fishing", attach dolphin deterrent devices or, favourably, dolphin interactive devices to the gear which all need to be verified for the catching context. To avoid it during emersion, further research needed. To avoid it during release from gear, sorting, and storing, prefer immediate stunning followed by slaughter while still unconscious. Decreasing distance to neighbour is probably not an issue in set nets. Further research needed.

Cortisol, glucose, lactate, other physiological stress parameters: no data found yet.

Opercular movement: no data found yet.

• Fishers use fish finder devices to determine the depth 1, which helps determine the presence of IND 2. Further research needed on types of hazard consequences.
  • Catching step:  Prospection
• With shore netting (Oct-Apr), fishers deploy net in dropping tide in bay and trap IND when they want to leave the bay just at a foot of water 3 4. Given that setting does not include active chasing or passive ways to direct IND (noise, light, FADs, etc.), hazard consequences during setting are unlikely 0.
  • Catching step:  Setting
  • How to improve: hazard consequences unlikely
• Given the principle of set nets to catch IND 5 6 7 8 3 by the head region (called “snagging”) 9, by the gills (called "gilling") 3, by the mid body (called “wedging”) 9, or by wrapping the whole body or attaching protruding body parts like teeth (called “entangling”) 9, hazard consequences are probable 0. During catching, substantial scale loss (26-50% of body surface) in IND, indicating a high risk of external injuries 1.
  Catching SPAWNERS with gill nets and transportation caused skin damage resulting in mortality within 2-3 weeks; more IND dead without external injuries 10.
  • Catching steps:  Catching Bycatch avoidance Emersion
• The following mesh sizes assure good size selectivity, i.e., the listed sizes of IND will have contact with the gear:
  bottom-set gill nets at 18-60 m depth, after soaking from 2 h prior to 2 h after sunset: decreasing number of IND and increasing catching length with increasing mesh size (17, 19, 21, 23 mm). Of 10-21 cm FORK LENGTH caught, all IND were >10 cm FORK LENGTH minimal landing size 11↶12, indicating good size selectivity of currently used mesh sizes and better size selectivity than bottom trawls 12.
  Gill nets at 20 m isobath with mesh size 36 mm, after soaking for 1.5 h, caught IND of 9.4-23.1 cm TOTAL LENGTH, mostly above minimum conservation reference size (11 cm 13↶14) and partly below 50% size at maturity (15.5 cm 13↶14) 14. Recommended mesh size for Mediterranean (38.5 mm 13↶14) might eliminate these issues 0.
  Gill nets at 12-70 m, after soaking 3-5 h from before sunrise: decreasing number of IND with increasing mesh size (53, 60, 75, 87 mm); highest weight at 60 mm. Of 18-39 cm TOTAL LENGTH caught, all IND were >15 cm minimal landing size, prompting recommendation to increase allowed mesh size from 50 to 60 mm. No difference in number of IND and weight with 5 m high net instead which is not allowed and cannot be recommended 15.
  Trammel nets at 15-21 m depth with 36-40 mm in mesh and 240 mm out mesh, after soaking for 2 h caught IND of 14.1-21.7 cm TOTAL LENGTH, all >11 cm minimal landing size 16.
  Trammel nets with 40-52 mm mesh size caught IND of 11-27 cm TOTAL LENGTH, mostly above size at maturity (15-16 cm 17↶18) and with better size selectivity than bottom trawls (5-23 cm TOTAL LENGTH) 18.
  • Catching steps:  Catching Bycatch avoidance
  • How to improve: prefer mesh size that assures good size selectivity given body ∅ in season and region
• The following mesh sizes potentially cause bycatch, i.e., they should be avoided to prevent those IND from having contact with the gear:
  With bottom-set gill nets, mesh size 50-90+ mm, during 2009-2015: <5% bycatch of IND >40 g (ca 18 cm TOTAL LENGTH) minimal commercial landing weight, for trammel nets >15%, probably indicating a risk for overexploitation of the population 20.
  Trammel nets with minimum mesh size 50 mm, during 2000-2012 caught IND of 9-29 cm TOTAL LENGTH, partly <14 cm size at 50% first maturity, probably indicating a risk for overexploitation of the population 21.
  • Catching steps:  Catching Bycatch avoidance
  • How to improve: prefer mesh size that reduces catching undersized IND given body ∅ in season and region
• Given soak time of 60-75 min and hauling of 150 min 1, soaking ~1.5 h 14, soaking 2 h from just before dusk 16, average 172 min soaking from before dawn, average 42 min hauling at sunrise 23, soaking 3-5 h from before sunrise 15, soaking from 2 h prior to 2 h after sunset 12, soaking from sunset to sunrise 25, average 5.8-9.4 h 26, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  With bottom-set gill nets, after soak time of 60-75 min and hauling of 150 min, almost 50% IND arrived on board inactive, another ca 25% were lethargic with maximum duration of activity 4 min 1.
  During soaking, interactions with 1-12 bottlenose dolphins Tursiops truncatus 12/88 times (13.6%), during hauling 17/88 times (19.3%), spending average 20 min and reducing catch of M. surmuletus. Negative correlation between catch volume and duration of soak time and interactions with dolphins 23.
  • Catching step:  Catching
  • How to improve: prefer shorter soak time (further research needed)
• No crowding step before hauling the net on board, but IND remained caught and with the same distance to other con-specifics under and above water when net was continuously hauled 5 6 7 8 or when IND were collected lying on the shore 3 4, probably not resulting in decreasing distance to neighbour 0.
  • Catching steps:  Catching Emersion
  • How to improve: no risk of hazard consequences, as decreasing distance to neighbour is unlikely compared to catching methods with crowding step
• During soaking, IND may be damaged 6 14, probably by scavenging crustaceans 3 or predating cetaceans 14. Depredation rate by Tursiops truncatus ~21-25%/haul 26. Given that depredated IND are most likely discarded after manual disentangling, depredation should be avoided or at least decreased 0.
  During soaking, interactions with 1-12 bottlenose dolphins Tursiops truncatus 12/88 times (13.6%), during hauling 17/88 times (19.3%), spending average 20 min and reducing catch of M. surmuletus. Negative correlation between catch volume and duration of soak time and interactions with dolphins 23 indicates probable reduction of lost catch through lower soak time 0. Of those IND still caught in the net when hauled on board, without interaction with dolphins, mainly bite injuries 23, probably by cuttlefishes Sepia spp., common octopus Octopus vulgaris, European conger Conger conger, Mediterranean moray Murena helena 27↶23; with interaction with dolphins, roughly equal amount of bite injuries, only head remaining, only tail remaining, and fragments remaining 23. As dolphins are probably lured by sounds that the gear make, recommended to amend or switch up gear; dolphins could also hear if vessels leave for the sea at night, so recommended to close fishing for certain times or areas or switch up areas 23 or apply "stealth fishing" 28↶23.
  Using dolphin deterrent devices reduced depradation by T. truncatus by 48%, using dolphin interactive devices reduced depradation by 50%, but their efficiency gradually reduces over time 29.
  • Catching steps:  Catching Bycatch avoidance Discarding
  • How to improve: prefer shorter soak time (further research needed), amend or switch gear to avoid recognisable sounds, close fishing for certain times or areas or switch up areas, apply "stealth fishing", attach dolphin deterrent devices or, favourably, dolphin interactive devices to the gear
• Given short distance between water surface and aboard vessel and thus hardly any occasion 5 7 8, predation pressure during emersion is probably low 0. More time and more convenient occasion during soak time or hauling → 3.7. Predation pressure.
  • Catching step:  Emersion
  • How to improve: low predation pressure during emersion, rather during soaking or hauling (→ 3.7. Predation pressure)
• Given that when the net is hauled on board 5 6 7 8 or the IND are collected lying on the shore 3 4, IND are exposed to air and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid them.
  • Catching step:  Emersion
• When the net is hauled onboard, IND may be catapulted on deck, and given how the effect of gravity interacts with the type of catching (snagging, gilling, wedging, entangling) and therefore how the net affects the skin and given contact with several reels along which the net is guided 5 6 7 8 and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  Catching SPAWNERS with gill nets and transportation caused skin damage resulting in mortality within 2-3 weeks; more IND dead without external injuries 10.
  • Catching step:  Emersion
• Given that when the net is hauled on board 5 6 7 8 or the IND are collected lying on the shore 3 4, IND are exposed to gravity and given no evolutionary adaptation to experiencing own weight in air 30, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching step:  Emersion
• Given that during manual disentangling, IND are exposed to air 5 6 7 8 1 3 4 and assuming IND are not already dead, hazard consequences are probable 1 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching steps:  Release from gear Sorting Discarding
• Given that during manual disentangling, IND may fall to the floor 5 7 8 and that after disentangling, IND are thrown into buckets 5 6 7 1 3 4 and assuming IND are not already dead, hazard consequences are probable 1 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching steps:  Release from gear Sorting
• Given that manual disentangling happens fast and rough 5 6 7 8 1 and assuming IND are not already dead, hazard consequences are probable 1 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching steps:  Release from gear Sorting Discarding
• Given that undersized IND are discarded after manual disentangling 8 and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences.
  • Catching steps:  Release from gear Sorting Discarding
  • How to improve: prefer mesh size that reduces catching undersized IND given body ∅ in season and region (→ 4.2. Contact with the gear)​
• Given that surviving discarded IND will have to return to their natural living depth, vertical displacement is probable 30. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching step:  Discarding
• Given that surviving discarded IND are probably disoriented, stressed, and weakened after the catching process and release 30, and given that seabirds 5 6 8 and other predators might gather near fishing boats, predation pressure is probable 30. Predation on several FISHES 31, including M. surmuletus 32, by seabirds like Morus bassanus – which was reduced through use of a visual deterrent in the form of a bird of prey ("scarybird") – and by Larus spp. – which was reduced through retaining to-be-discarded IND in buckets until after hauling the net 31. Given the use of small buckets resulting in crowded conditions, hazard consequences are probable 0. Further research needed on types of hazard consequences.
  • Catching step:  Discarding
  • How to improve: use visual scarybird device as deterrent against predatory seabirds
• Discarding probability is assumed to be low due to high commercial value of M. surmuletus 33↶34 35↶34.
  Gill nets at 12-70 m, after soaking 3-5 h from before sunrise: at commercial mesh size 53 mm, 1.4% discarded due to damage 15.
  • Catching step:  Discarding
• Given that IND were thrown into buckets 5 6 7 1 3 4 with water 7, later placed on and under ice 3 4, and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching step:  Storing
  • How to improve: prefer immediate stunning followed by slaughter while still unconscious

The difference between temperature in water and air may induce a thermal shock.

Where in the catching process does temperature shock occur and how to avoid it?

Unspecified: no data found yet.

The quick transition from one salinity level to another may lead to osmoregulatory distress.

Where in the catching process does osmoregulatory distress occur and how to avoid it?

Unspecified: no data found yet.

Removing an individual from its home ground and social group and subjecting it to a potentially stressful catching event may result in disorientation.

Where in the catching process does disorientation occur and how to avoid it?

Unspecified: no data found yet.

Lack of oxygen is a likely consequence for aquatic species facing removal from the water.

Where in the catching process does asphyxia occur and how to avoid it?

Asphyxia may occur from emersion on. To avoid it, prefer immediate stunning followed by slaughter while still unconscious. Further research needed.

Behaviour indicating lack of oxygen (gulping, tail beating, etc.): no data found yet.

• Given that when the net is hauled on board 5 6 7 8 or the IND are collected lying on the shore 3 4, IND are exposed to air and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid them.
  • Catching step:  Emersion
• Given that during manual disentangling, IND are exposed to air 5 6 7 8 1 3 4 and assuming IND are not already dead, hazard consequences are probable 1 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching steps:  Release from gear Sorting Discarding
• Given that IND were thrown into buckets 5 6 7 1 3 4 with water 7, later placed on and under ice 3 4, and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching step:  Storing
  • How to improve: prefer immediate stunning followed by slaughter while still unconscious
• Given that IND were thrown into buckets 5 6 7 1 3 4 with water 7, later placed on and under ice 3 4, probably resulting in asphyxia 1 0 or hypothermia 0. Recommended to percussively stun with a fishing priest or captive bolt pistol, followed by cutting gill, immersing in ice water, or storing on ice 36.
  • Catching step:  Slaughter
  • How to improve: prefer immediate stunning followed by slaughter while still unconscious, e.g., percussive stunning followed by exsanguination

Unspecified: no data found yet.

Loss of water is another likely consequence of exposing aquatic species to air.

Where in the catching process does dehydration occur and how to avoid it?

Unspecified: no data found yet.

In an attempt to escape the situation of being caught, many individuals struggle and resist until they are exhausted.

Where in the catching process does fatigue/exhaustion occur and how to avoid it?

Fatigue/exhaustion may occur during catching (depending on the duration). To avoid or decrease it, prefer shorter soak time. Further research needed.

Inactivity/low vitality: no data found yet.

Oxidative stress: no data found yet.

• Given soak time of 60-75 min and hauling of 150 min 1, soaking ~1.5 h 14, soaking 2 h from just before dusk 16, average 172 min soaking from before dawn, average 42 min hauling at sunrise 23, soaking 3-5 h from before sunrise 15, soaking from 2 h prior to 2 h after sunset 12, soaking from sunset to sunrise 25, average 5.8-9.4 h 26, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  With bottom-set gill nets, after soak time of 60-75 min and hauling of 150 min, almost 50% IND arrived on board inactive, another ca 25% were lethargic with maximum duration of activity 4 min 1.
  During soaking, interactions with 1-12 bottlenose dolphins Tursiops truncatus 12/88 times (13.6%), during hauling 17/88 times (19.3%), spending average 20 min and reducing catch of M. surmuletus. Negative correlation between catch volume and duration of soak time and interactions with dolphins 23.
  • Catching step:  Catching
  • How to improve: prefer shorter soak time (further research needed)

The process of being caught probably induces states not unlike emotions.

Where in the catching process do emotion-like states occur and how to avoid them?

9.1 Fear (continuum up to panic)

Freeze: no data found yet.

Avoidance behaviour: no data found yet.

Escape manoeuvres: no data found yet.

Startling behaviour: no data found yet.

Unspecified: no data found yet.

9.2 Other

Unspecified: no data found yet.

Although killing is the ultimate goal of fisheries, many mortalities happen unwanted - even resulting in discards - and unregulated, without avoiding prolonged suffering.

Where in the catching process does mortality occur and how to avoid it?

Mortality may occur most frequently through contact with the gear, lack of oxygen, handling/dropping, and predation pressure. To avoid it during catching/hauling, a) prefer mesh size that reduces catching undersized IND (given body ∅ in season and region), b) prefer shorter soak time which also reduces depredated IND (which needs to be verified for the catching context), and c) to further deter cetaceans: amend or switch gear to avoid recognisable sounds, close fishing for certain times or areas or switch up areas, apply "stealth fishing", attach dolphin deterrent devices or, favourably, dolphin interactive devices to the gear which all need to be verified for the catching context. To avoid it during emersion, further research needed. To avoid it during release from gear, sorting, and storing, prefer immediate stunning followed by slaughter while still unconscious. Further research needed.

• Given the principle of set nets to catch IND 5 6 7 8 3 by the head region (called “snagging”) 9, by the gills (called "gilling") 3, by the mid body (called “wedging”) 9, or by wrapping the whole body or attaching protruding body parts like teeth (called “entangling”) 9, hazard consequences are probable 0. During catching, substantial scale loss (26-50% of body surface) in IND, indicating a high risk of external injuries 1.
  Catching SPAWNERS with gill nets and transportation caused skin damage resulting in mortality within 2-3 weeks; more IND dead without external injuries 10.
  • Catching steps:  Catching Bycatch avoidance Emersion
• The following mesh sizes assure good size selectivity, i.e., the listed sizes of IND will have contact with the gear:
  bottom-set gill nets at 18-60 m depth, after soaking from 2 h prior to 2 h after sunset: decreasing number of IND and increasing catching length with increasing mesh size (17, 19, 21, 23 mm). Of 10-21 cm FORK LENGTH caught, all IND were >10 cm FORK LENGTH minimal landing size 11↶12, indicating good size selectivity of currently used mesh sizes and better size selectivity than bottom trawls 12.
  Gill nets at 20 m isobath with mesh size 36 mm, after soaking for 1.5 h, caught IND of 9.4-23.1 cm TOTAL LENGTH, mostly above minimum conservation reference size (11 cm 13↶14) and partly below 50% size at maturity (15.5 cm 13↶14) 14. Recommended mesh size for Mediterranean (38.5 mm 13↶14) might eliminate these issues 0.
  Gill nets at 12-70 m, after soaking 3-5 h from before sunrise: decreasing number of IND with increasing mesh size (53, 60, 75, 87 mm); highest weight at 60 mm. Of 18-39 cm TOTAL LENGTH caught, all IND were >15 cm minimal landing size, prompting recommendation to increase allowed mesh size from 50 to 60 mm. No difference in number of IND and weight with 5 m high net instead which is not allowed and cannot be recommended 15.
  Trammel nets at 15-21 m depth with 36-40 mm in mesh and 240 mm out mesh, after soaking for 2 h caught IND of 14.1-21.7 cm TOTAL LENGTH, all >11 cm minimal landing size 16.
  Trammel nets with 40-52 mm mesh size caught IND of 11-27 cm TOTAL LENGTH, mostly above size at maturity (15-16 cm 17↶18) and with better size selectivity than bottom trawls (5-23 cm TOTAL LENGTH) 18.
  • Catching steps:  Catching Bycatch avoidance
  • How to improve: prefer mesh size that assures good size selectivity given body ∅ in season and region
• The following mesh sizes potentially cause bycatch, i.e., they should be avoided to prevent those IND from having contact with the gear:
  With bottom-set gill nets, mesh size 50-90+ mm, during 2009-2015: <5% bycatch of IND >40 g (ca 18 cm TOTAL LENGTH) minimal commercial landing weight, for trammel nets >15%, probably indicating a risk for overexploitation of the population 20.
  Trammel nets with minimum mesh size 50 mm, during 2000-2012 caught IND of 9-29 cm TOTAL LENGTH, partly <14 cm size at 50% first maturity, probably indicating a risk for overexploitation of the population 21.
  • Catching steps:  Catching Bycatch avoidance
  • How to improve: prefer mesh size that reduces catching undersized IND given body ∅ in season and region
• Given soak time of 60-75 min and hauling of 150 min 1, soaking ~1.5 h 14, soaking 2 h from just before dusk 16, average 172 min soaking from before dawn, average 42 min hauling at sunrise 23, soaking 3-5 h from before sunrise 15, soaking from 2 h prior to 2 h after sunset 12, soaking from sunset to sunrise 25, average 5.8-9.4 h 26, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  With bottom-set gill nets, after soak time of 60-75 min and hauling of 150 min, almost 50% IND arrived on board inactive, another ca 25% were lethargic with maximum duration of activity 4 min 1.
  During soaking, interactions with 1-12 bottlenose dolphins Tursiops truncatus 12/88 times (13.6%), during hauling 17/88 times (19.3%), spending average 20 min and reducing catch of M. surmuletus. Negative correlation between catch volume and duration of soak time and interactions with dolphins 23.
  • Catching step:  Catching
  • How to improve: prefer shorter soak time (further research needed)
• During soaking, IND may be damaged 6 14, probably by scavenging crustaceans 3 or predating cetaceans 14. Depredation rate by Tursiops truncatus ~21-25%/haul 26. Given that depredated IND are most likely discarded after manual disentangling, depredation should be avoided or at least decreased 0.
  During soaking, interactions with 1-12 bottlenose dolphins Tursiops truncatus 12/88 times (13.6%), during hauling 17/88 times (19.3%), spending average 20 min and reducing catch of M. surmuletus. Negative correlation between catch volume and duration of soak time and interactions with dolphins 23 indicates probable reduction of lost catch through lower soak time 0. Of those IND still caught in the net when hauled on board, without interaction with dolphins, mainly bite injuries 23, probably by cuttlefishes Sepia spp., common octopus Octopus vulgaris, European conger Conger conger, Mediterranean moray Murena helena 27↶23; with interaction with dolphins, roughly equal amount of bite injuries, only head remaining, only tail remaining, and fragments remaining 23. As dolphins are probably lured by sounds that the gear make, recommended to amend or switch up gear; dolphins could also hear if vessels leave for the sea at night, so recommended to close fishing for certain times or areas or switch up areas 23 or apply "stealth fishing" 28↶23.
  Using dolphin deterrent devices reduced depradation by T. truncatus by 48%, using dolphin interactive devices reduced depradation by 50%, but their efficiency gradually reduces over time 29.
  • Catching steps:  Catching Bycatch avoidance Discarding
  • How to improve: prefer shorter soak time (further research needed), amend or switch gear to avoid recognisable sounds, close fishing for certain times or areas or switch up areas, apply "stealth fishing", attach dolphin deterrent devices or, favourably, dolphin interactive devices to the gear
• Given short distance between water surface and aboard vessel and thus hardly any occasion 5 7 8, predation pressure during emersion is probably low 0. More time and more convenient occasion during soak time or hauling → 3.7. Predation pressure.
  • Catching step:  Emersion
  • How to improve: low predation pressure during emersion, rather during soaking or hauling (→ 3.7. Predation pressure)
• When the net is hauled onboard, IND may be catapulted on deck, and given how the effect of gravity interacts with the type of catching (snagging, gilling, wedging, entangling) and therefore how the net affects the skin and given contact with several reels along which the net is guided 5 6 7 8 and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  Catching SPAWNERS with gill nets and transportation caused skin damage resulting in mortality within 2-3 weeks; more IND dead without external injuries 10.
  • Catching step:  Emersion
• Given that undersized IND are discarded after manual disentangling 8 and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences.
  • Catching steps:  Release from gear Sorting
  • How to improve: prefer mesh size that reduces catching undersized IND given body ∅ in season and region (→ 4.2. Contact with the gear)​
• Given that surviving discarded IND are probably disoriented, stressed, and weakened after the catching process and release 30, and given that seabirds 5 6 8 and other predators might gather near fishing boats, predation pressure is probable 30. Predation on several FISHES 31, including M. surmuletus 32, by seabirds like Morus bassanus – which was reduced through use of a visual deterrent in the form of a bird of prey ("scarybird") – and by Larus spp. – which was reduced through retaining to-be-discarded IND in buckets until after hauling the net 31. Given the use of small buckets resulting in crowded conditions, hazard consequences are probable 0. Further research needed on types of hazard consequences.
  • Catching step:  Discarding
  • How to improve: use visual scarybird device as deterrent against predatory seabirds
• Discarding probability is assumed to be low due to high commercial value of M. surmuletus 33↶34 35↶34.
  Gill nets at 12-70 m, after soaking 3-5 h from before sunrise: at commercial mesh size 53 mm, 1.4% discarded due to damage 15.
  • Catching step:  Discarding
• Given that IND were thrown into buckets 5 6 7 1 3 4 with water 7, later placed on and under ice 3 4, and assuming IND are not already dead, hazard consequences are probable 0. Further research needed on types of hazard consequences and on how to avoid or decrease them.
  • Catching step:  Storing
  • How to improve: prefer immediate stunning followed by slaughter while still unconscious

When it is difficult to assign an observed behaviour to one of the above categories, we report it here.

Where in the catching process do uncategorised behavioural changes occur and how to avoid them?

Unspecified: no data found yet.