Scotland's Future Catching Policy: Selectivity Proposals Consultation 2026

5. Technical Proposals for reducing unwanted catches of fish

As a result of our technical workshops and further stakeholder engagement and following on from our review of current measures, innovations, and best practises, the Scottish Government are proposing a number of changes to technical and management measures across Scottish waters.

The proposed measures for individual fleet segments are outlined below. The proposals aim to support a reduction in unwanted fish catch and also to simplify where possible and consolidate conflicting or converging existing legislation. The following section represents the joint work conducted with stakeholders over the last few years – this is by necessity technical and complex.

What do we mean by “technical”?

Throughout this consultation we reference technical workshops, and technical conservation measures, but what do we mean? Technical measures in the context of this consultation, this policy, and wider fisheries management can be more simply defined as “fishing gear requirements”.

As already discussed, fishing gear (e.g. trawls, creels, gill nets) is regulated through a long list of legislation which has been developed, amended and built upon over decades of management. Technical conservation measures are elements of this long list designed to deliver a stock or species sustainability benefit, more commonly known as “selectivity measures” (e.g. square mesh panels which allow small fish to ‘escape’ the fishing net, and acoustic deterrents which can deter marine mammals from approaching a fishing net). When we talk about technical measures, we are referring to the legislation or licence requirements in place that define what type of fishing gear is used and how it must be modified or constructed to meet legal standards e.g. the size of the mesh in a net. These measures are usually dependent on several additional factors such as fishing area, targeted species, vessel size, and vessel power.

For a basic introduction into demersal fishing nets, their component parts and construction, please see Annex A.

With specific reference to this consultation document, when we refer to “codend mesh size” assume that this also covers the mesh size of the extension piece of the net, in keeping with current legislation.

5.1 Large mesh demersal fleet segment

a) What is the large mesh demersal fleet segment?

• This fleet segment comprises of approximately 96 fishing vessels in Scottish waters who use large mesh demersal trawls as their primary method of fishing*. Of this, 66 are Scottish registered vessels, 11 are UK registered and 19 are non-UK vessels^[6].
• These vessels operate all over Scotland, mainly outside the 12 nautical mile line^[7]
• These vessels use demersal bottom trawls to catch whitefish (demersal) species and have a codend mesh size of 120mm or over (hence “large mesh”)

b) What measures do we have in place now?

• A requirement for demersal bottom trawls to have a minimum of 120mm mesh size in the codend. These are almost universally rigged in a diamond mesh format.
• An additional 120mm square mesh panel in the top of the extension piece if fishing east of the Cod Recovery Line in ICES Via (French line)

c) What needs to change?

• The 120mm mesh size in the codend is the legal minimum standard for whitefish targeting vessels^[8]. However, we have identified that square mesh codends may offer improved selectivity for small fish, given that meshes stay more open in comparison with diamond mesh codends. Feedback from fishers has suggested they would like the option to use square mesh codends, however, some legislative barriers to selectivity exist which can prevent them from considering a switch to square mesh codends i.e. the 120mm mesh stipulation outlined above in a square mesh format would result in the loss of too much marketable fish.
• Evidence shows, and trials are currently ongoing to prove, that a 100mm square mesh codend used in demersal trawls can be as selective as a 120mm diamond mesh codend, and maybe more so. However current legislation dictates a minimum of 120mm mesh size in the codend.

d) What are we proposing will change?

• Subject to the conclusion of successful gear trials, we propose to amend current requirements to allow for use of square mesh in codends below the current legal limit of 120mm for whitefish fishing.
• We propose to allow codends with square mesh of a minimum of 100mm.
• Diamond meshes would still need to be above this limit, but we would add a stipulation for a smaller allowed mesh if using the square configuration.

e) Proposed outcome

• To keep the minimum requirement for diamond mesh at 120mm but allow for use of square mesh codends at smaller mimimum mesh size e.g. 100mm. This will result in the potential wider spread use of square mesh codends, with potential to result in less retention of small fish.

Questions for this section:

Q3: Do you agree that we should amend the legislation to permit the use of square-mesh codends of less than 120mm?

Q4: If the use of square-mesh codends below 120mm are permitted, do you agree that the permitted size should be set at a minimum of 100mm?

Q5: Are there are other measures that may support further reduction of unwanted catches?

5.2 Mixed demersal fleet segment

a) What is the mixed demersal fleet segment?

• This fleet segment comprises of approximately 71 fishing vessels in Scottish waters who use a combination of large mesh and small mesh trawls as their primary method of fishing. Of this, 62 are Scottish registered vessels, 7 are UK registered and 2 are non-UK vessels^[9].
• These vessels operate all over Scotland, both inside and outside the 12nm but are often found off the east coast of Scotland in the North Sea, for example, Fladdens Grounds.
• These vessels use demersal bottom trawls to catch both whitefish, ground fish and Nephrops and utilise nets with a codend mesh size of both under 120mm and over 120mm depending on what they are targeting (hence “mixed”).

b) What measures do we have in place now?

• A one-net rule that prohibits the carriage of nets both above and below 100mm codend mesh size on a vessel at once, but does not prevent vessels from carrying 120mm codend mesh minimum for whitefish, and 100mm+ codend mesh minimum for directed fisheries (such as Nephrops) at the same time. The one net rule is discussed in more detail below.
• Existing measures for large mesh demersal and small mesh demersal apply to this segment, dependent on the size of gear they chose to use.

c) What needs to change?

• The current one-net rule can often lead to high catches of unwanted juvenile whitefish as nets with a mesh size of under 120mm cod end mesh size may be used erroneously to target whitefish as well as directed species.
• Measures were updated in 2019 to reflect the difference between whitefish fishing (120mm> codend mesh size) and “directed fishing” (<120mm codend mesh size). The one-net rule that is still applied today through fishing vessel licence conditions has not yet been updated to keep pace with this change.
• Further steps need to be taken to reduce unwanted catches of whitefish in small mesh demersal gear.

d) What are we proposing will change?

• To amend the one net rule to ensure the clear division between the targeting of whitefish and the targeting of directed fisheries, given that there are different selectivity requirements for either.
• Moving the rule to above or below the 120mm mesh size - meaning that vessels are either classified as a directed fishery or targeting whitefish, with only one category of net allowed to be carried on board at any one time.
• If partaking in a directed fishery (under 120mm), vessels will be required to install small mesh demersal selectivity measures (i.e. square mesh panels) as per current legislation.
• If partaking in a directed fishery catch-composition rules (outlined below) will apply (requiring vessels will be required to move-on and/or return to port if they cannot meet their catch composition requirements).
• We propose to amend the one net rule to allow for the use of dual-codend separator gear to pursue both whitefish and directed species without breaching the one net rule changes.

e) Proposed outcome

• No targeted or inadvertent whitefish fishing with small mesh, therefore fewer discards
• A more accountable and manageable mixed fishery with a new standard for selectivity
• Higher uptake of dual codend separator gear and the associated benefits it brings i.e. the ability to separate Nephrops and whitefish species while actively fishing, the ability to utilise selectivity methods for both while fishing for both simultaneously, and the ability to continue fishing for Nephrops with the top cod end open to avoid nearly all fish bycatch.

5.2.1 One-Net Rule

For fishers in Scottish waters the size of the mesh which is permissible for them to use in a codend is related to the type of species which they are targeting. Over 120mm codend mesh sizes are the minimum requirement for targeting whitefish, due to anything below this retaining too many undersized fish. Under 120mm codend mesh sizes are allowed when targeting “directed” species i.e. species that may require a smaller mesh to catch effectively, such as Nephrops, but these smaller mesh nets are supplemented by requirement to use additional selectivity measures.

A one net rule is currently in place in fishing vessel licence conditions which stipulates that multiple nets may be carried aboard a fishing vessel, provided they are both above 100mm or both below 100m. As per the paragraph above, current legislation draws the line at 120mm, meaning the current one net rule is no longer fit for purpose. With the proposals laid out above, we would be updating this one net rule i.e. a vessel is either fishing purely for whitefish, in which case they are using 120mm and over nets, or they are a “directed fishery”, in which case they are allowed to use under 120mm nets but will be subject to additional selectivity measures e.g. square mesh panel, catch-composition and spatial measures e.g. move-on rules.

As an example, under the current system, a vessel currently targeting both Nephrops and whitefish may carry a 105mm net and a 120mm net and claim to fish only Nephrops with the 105mm, and only whitefish with the 120mm, but in reality could use the smaller of the two to target both. Under the new proposed measures below, this would no longer be an option, therefore ensuring that the minimum standard for selectivity is met, dependent on the targeted species.

An exemption to this one net rule would be applied when using the dual-codend separator gear allowing fishers to utilise the varying sizes in the top and bottom codend for mixed fishing while ensuring effective separation between the directed species in the bottom and whitefish in the top.

5.2.2 Catch Composition

Prior to the implementation of the Landing Obligation, catch-composition rules were tightly linked to discarding, and in some cases discarding was required in order for a vessel to remain legally compliant. These rules specified the proportion of target to non-target species that had to be present in the retained catch in order to classify a vessel as operating in a particular fishery. For example, certain Scottish Nephrops fisheries required that at least 30% of the landed catch be Nephrops, while the combined weight of key whitefish species such as cod, haddock, and whiting could not exceed a defined threshold.

Catch composition rules in Scottish waters were designed to support sustainable stock management, reduce unwanted catches, and improve precision in reporting and enforcement.

In certain areas (for example, to the west of Scotland in ICES Division VIa) special catch composition rules applied alongside gear regulations^[10]:

• Vessels targeting Nephrops must ensure their retained catch contains at least 30% Nephrops and no more than 10% combined of cod, haddock and whiting.
• Vessels targeting whitefish in that same area must ensure their catch contains no more than 30% combined cod, haddock and whiting.

These rules aimed to limit the catch of stocks under pressure by ensuring that fishing operations remain focused on target species (or at least avoid excessive by‐catch of sensitive stocks) and hence improve selectivity.

However, under the Landing Obligation^[11], regulated quota species must be landed and counted against quota rather than discarded at sea. Because of this, “catch composition rules” (which historically set by‐catch thresholds) are no longer enforced in the same way for quota species (i.e., species for which the Landing Obligation applies).

In practical terms this means that while there was a catch composition framework in place to help steer fishers towards sustainable catch profiles (percentages of target species with sustainable levels of “other” species), the Landing Obligation made this difficult to adhere to for fishers and fisheries managers.

We are proposing that catch composition rules are used in a way that removes the interaction with the Landing Obligation and allows for fishers to meet catch composition targets by utilising selective gear and spatial consideration.

What would this look like?

• Catch composition rules for all directed fisheries (i.e. using trawls under 120mm codend mesh size).
• These rules would stipulate an expected percentage or ratio of the targeted catch (e.g. Nephrops) alongside a realistic margin of expected unwanted or unavoidable catches.
• If the fisher could not meet this expected target within a specific time period in a certain area, they would be expected to ’move-on’, meaning they would change location to try and minimise bycatches of unwanted or unavoidable species and maximise catches of their target species.
• If the fisher failed to meet their target species percentage after a specified total time period, they would be expected to return to port and change their gear to non-directed fishing gear (i.e. 120mm and over codend mesh size) for a set number of days – in an escalating format depending on the number of failed catch composition trips.
• Vessels would be exempt from this new system if they chose to use the dual-codend separator gear.

Primarily, those that are deemed a ‘directed’ fishery will be expected to meet defined catch composition thresholds. These rules will ensure that fishers using codends of below 120mm diamond mesh will target a specific designated species i.e. Nephrops and will be required to change their gear if they are unable to avoid large quantities of whitefish or other bycatch.

Introducing updated catch composition rules will define more robustly what constitutes a ‘directed’ fishery, with improved selectivity and, spatial and temporal measures to decrease instances of whitefish bycatch.

Questions for this section:

Q6: Do you agree that the one-net rule should be updated to distinguish between whitefish and directed fisheries, by prohibiting vessels from carrying nets of both above and below 120mm codend mesh size?

Q7: Do you agree that we should permit the use of the dual-codend separator gear, to enable fishers to prosecute a mixed fishery in one trip whilst delivering individual selectivity benefits?

Q8: Do you agree that vessels who do wish to target “directed fisheries” e.g. Nephrops with smaller than 120mm mesh should be subject to additional management measures (including updated catch composition requirements) as proposed?

Q9: Do you agree with the proposed approach to applying catch composition to directed fisheries?

5.3 Small mesh demersal fleet segment

a) What is the small mesh demersal fleet segment?

• This fleet segment comprises of approximately 246 fishing vessels in Scottish waters who use small mesh trawls as their primary method of fishing*. Of this, 186 are Scottish registered vessels, 57 are UK registered and 3 are non-UK vessels^[12].
• These vessels operate all over Scotland, mainly inside the 12nm line
• These vessels use demersal bottom trawls to catch mainly Nephrops and some ground fish and utilise nets with a codend mesh size of between 80mm – 119mm (hence “small mesh”)
• This fleet segment is subject to the installation of selectivity devices given the relatively smaller mesh sizes in the codend e.g. square mesh panels.

b) What measures do we have in place now?

• Demersal bottom trawls with codend mesh sizes between 80mm and 120mm specifically pursuing directed fisheries (i.e. Nephrops)
• A suite of additional selectivity requirements such as square mesh panels or other selectivity attachments
• These selectivity requirements are often accompanied by power or vessel size exemptions, for example, most vessels in the Firth of Clyde using 80mm – 119mm codends, must have a square mesh panel installed of 3m length and 300mm mesh size – however if the vessel is below 112kw or 12m in overall length, they may use a square mesh panel of 2m and 200mm.

c) What needs to change?

• Increasing minimum codend mesh size to 100mm in high fish abundant areas would result in less small fish being caught but could potentially lead to loss of marketable Nephrops
• There are many fishers who have sought to pursue the use of coverless trawls to minimise their fish bycatch but have been unsure whether this is allowed.

d) What are we proposing will change?

• Consideration of a move to a minimum mesh size of 100mm in directed fisheries, for high fish abundant areas.
• Unifying square mesh panel requirements across the small mesh demersal fleet segment so that all directed fisheries are fishing at the same standard (i.e. 80mm diamond mesh codend minimum, with a square mesh panel in the top of the extension piece of at least 300mm at 3m long).
• Consideration of the low power exemption outlined above.
• Clarify the position surrounding the use of covers in trawls to allow for their removal or use. If a cover is still wanted by a fisher, provide the necessary requirements to make them fit for purpose.
• As outlined under the mixed fleet segment measures, all directed fishing vessels be subject to additional management measures, and catch composition rules. However, we understand that there is great variance in the small mesh fleet and so we would look to tailor these rules depending on the type of operation (e.g. varying reporting requirement thresholds depending on the length of the trip).

e) Proposed Outcome

• Simplified legislation and therefore a more simplified suite of technical measures for fishers to use and officials to enforce
• A higher minimum standard of selectivity and catch composition requirements

5.3.1 Square Mesh Panels

The square mesh panel is one of the most commonly used selectivity devices. In this, the diamond mesh is turned through 45 degrees to the water flow thereby ensuring the meshes in the panel remain fully open throughout the fishing operation, allowing for the release of small fish. The current requirements in Scotland for square mesh panels are varied and complex. For example, in directed fisheries in the West of Scotland the standard is 300mm square mesh as part of a 3m panel, fitted in the top side of the fishing net, no more than 9-15m from the cod-line. There is an exemption to this standard however for lower powered, or lower length vessels (i.e. 200mm in a 2m panel instead of 300mm in a 3m panel, for vessels below 12 m in length and/or with engine power of 112 kW or less).

• We are proposing that these standards for square mesh panels of 300mm for 3m for all vessels fishing with codends under 120mm, should be applied across all of Scottish waters.

A study^[13] has outlined that removal of the low power exemptions for square mesh panels should not cause any issues in terms of selectivity or retention of wanted catch. Removing these power exemptions would help to simplify rules for all fishers, ensuring everyone is fishing the same standard of selectivity gear regardless of the size and power of the vessel. However, another study^[14] suggests that an increase to 300mm square mesh panel for these smaller, low powered vessels may result in a loss of medium sized marketable catches of Nephrops.

• Given the mixed evidence, we are seeking views on whether a legislative change is worthwhile in order to deliver a simplification of the rules.

Current rules state that a square mesh panel, when installed must have no more than two open diamond meshes between the longitudinal side of the panel and the adjacent selvedge in the West of Scotland and no more than five in the North Sea. This can cause some confusion for fishers and inhibits the ability for fishers to move across the North/West line without changing their gear.

• We are proposing to unify this measure across all of Scottish waters. Data suggests^[15] that we must ensure the rear most edge of the square mesh panel is not greater than 2 meshes from selvedge (stitched “seam” that joins the bottom and top half of the fishing net) as this prevents the panel being incorrectly inserted up the tapered section of the net.

Current legislation states that the overall length of the panel will be positioned no further than 9-15 metres from the cod-line (i.e. the rearmost row of meshes of the panel shall be no more than 15 metres from the cod-line). Data suggest that the closer the panel is inserted towards the cod-line, the more effective it will be at selecting out fish. However through detailed discussion with industry and gear technologists it is apparent that if the square mesh panel is brought too far back towards the codline, there is high potential for fishers to lose marketable catches of Nephrops through the panel when hauling the gear. The current standard of no less than 15m can be improved upon, but bringing the panel as close as 3-6m could be economically detrimental. Therefore:

• We propose that this range should be reduced from t9-15m to 6-12m.

Flotation buoys are often used around the Square Mesh Panel in order to keep the larger meshes open to better facilitate the escape of fish, however there is no legislation regulating their use and this can cause issues with selectivity if attached incorrectly.

• We are proposing to allow floats to be used around the square mesh panel, provided they do not block the openings of the square mesh or are attached directly to it.
• We propose to increase the twine thickness allowed in the square mesh panel when the mesh size exceeds 300mm.

5.3.2 Strengthening bags/straps

A lifting strap is a piece of rope or wire loosely encircling the circumference of the codend or the strengthening bag, if any, and attached to it by means of loops or rings. More than one lifting strap may be used at any time.

• We propose to require lifting straps be made of a non-elastic material in order to prevent the use of bungee cords as a means of circumventing the measurement stipulations.

Questions for section:

Q10: Do you think low power exemptions for square mesh panels should be removed in order to unify measures across all fishers?

Q11: Do you agree that requirements for square mesh panels should be the same no matter where in Scottish waters they are being used?

Q12: Do you agree that we should clarify the position surrounding the use of covers in trawls (i.e. minimum mesh size when in use)

Q13: Do you think that the minimum standard codend mesh size for directed fisheries should be raised from 80mm to 100mm in high fish abundance areas?

Q14: Do you agree that fishers using square mesh panels in excess of 300mm should be able to use thicker twine, as long as this does not affect selectivity of the Square Mesh Panel?

Q15: Do you agree that the range for the square mesh panel insertion from the codline should be reduced to 6-12m?

Q16: Do you agree that fishers should be able to use flotation buoys to help keep their square mesh panels open provided these buoys do not block the openings of the panel itself?

Q17: Do you agree that lifting straps should be required to be made of a non-elastic material in order to ensure accurate measurement and non-restriction of a fishing net?