King Scallop in Shetland inshore waters

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1 King Scallop in Shetland inshore waters Content last updated 22nd Feb 2017 Stock: King Scallop Shetland stock Management: Shetland Shellfish Management Organisation (SSMO) King Scallop in Shetland inshore waters Overview King scallops (Pecten maximus) (here after referred to as scallop 1 ) are filter-feeding bivalve molluscs that prefer mixed sediments consisting of muddy sand, sandy gravel or gravel, possibly interspersed with small stones, rocks, boulders and low-lying reef from extreme low-water down to 100m+. Most individuals are found between 20-70m and, being highly-adapted filter feeders, they prefer moderately strong tidal flows and reduced exposure to strong wave action. They feed on suspended phytoplankton, algae and other micro-organisms that arrive through the water column (Brand, 1991). Their asymmetrical shells the right valve is convex allow them to nestle securely in to softer sediments as they create a recess for their cup-shaped shells. They lie stationary and slightly open on the seabed, filtering the water that passes over their gills. The animals can swim using water jets ejected around the hinge of the shell and use this unusual movement as an escape strategy. However after an initial phase in the plankton adult scallops are considered to be relatively sedentary (Marshall and Wilson, 2009). Figure 1. Scallop dimensions; the length is the dimension used to define the Minimum Landing Size Scallops are hermaphrodites (i.e. both male and female) and can become fully mature at about 3 years old (at least 60mm to 90mm in shell length; see Figure 1). Spawning occurs in the warmer months, from April to September. Specimens up to 210mm shell length have been recorded, but become commercially viable at around 100mm 160mm shell length. Growth rates vary depending on depth, season and bottom-type but they have been seen to take between three and six years to reach 110mm in length. Specimens can be long-lived, with some being recorded over 20 years of age. It is more common for them to achieve years of age in exploited populations. 4-6 year olds are the most abundant year class in exploited populations (Minchin, 2003). Scallops occur widely around the waters of the North West Atlantic, from along the European Atlantic coast from Northern Norway to the Azores, Canary Islands and Madeira. They are common in the waters around Scotland, being found at depths up to 100+m in more sheltered sea loughs. Figure 2. Distribution of king scallops (Pecten maximus) in Atlantic waters (Source: Oceana) For Marine Scotland, the Shetland stock assessment unit is comprised of the twelve ICES statistical rectangles surrounding Shetland and is situated in ICES area IVa (Baretto and Baily, 2014, ICES, 2015). However, this profile is for scallops from inshore waters around Shetland, i.e. within the six mile limit under the remit of the Shetland Shellfish Management Organisation (SSMO, 2016). The Scottish scallop fleet now has two main components: a fleet of larger boats (>20m) which range in a nomadic fashion exploiting inshore and offshore stocks; the smaller inshore boats (<15m) that are restricted in range to certain areas within inshore waters (Cappell et al., 2013). This accounts for 56% of the nomadic UK fleet and 18% of the UK under 15m dredge fleet (Cappell et al., 2013). Most boats in the Scottish scallop fishery use Newhaven Dredges with their spring-loaded teeth and metal belly-rings. Of these over 90% are over 10m in length (Cappell et al., 2013). The majority of the Scottish fleet is over 15m in length, however the vast majority of Shetland scallop fleet (fishing within SSMO area) are under 15m (ICES, 2013; SSMO, pers comms). Commercial scallop dredging has taken place in Scottish waters for decades and scallops now represent a highly prized fishery in Scotland, second only in value as a shellfish to Nephrops. In 2014 the value of scallops landed into the UK by Scottish vessels was 32.5 million, 1.9 million of this was landed into Shetland (Scottish Government, 2014) Baretto, E., Bailey, N Fish and shellfish stocks 2014 Edition. Marine Scotland Science, 65 pp. Brand, A.R., (1991). Scallop ecology: Distributions and behaviour. In Scallops: biology, ecology and aquaculture (ed. S.E. Shumway), pp Amsterdam: Elsevier. [Developments in Aquaculture and Fisheries Science, no.21.] Cappell, R., Robinson, M., Gascoigne, J. and Nimmo, F. A. (2013) review of the Scottish Scallop Fishery. Poseidon report to Marine Scotland, December ICES Official Nominal Catches Version February ICES, Copenhagen. [ [Accessed ]. Marshall, C. and Wilson, E. (2009). Pecten maximus. Great scallop. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 11/07/2014]. [ [Date accessed: 31- Dec-15] Minchin, D., (2003). Introductions: some biological and ecological characteristics of scallops. Aquatic Living Resources, 51, Scottish Government, Scottish Sea Fisheries Statistics-Landings Tables [ Fisheries/PubFisheries/2014LandingsTables] [Date accessed: 8/01/2016] Shetland Shellfish Management Organisation (SSMO), Regulations, Shetland Shellfish Management Organisation [ accessed: 8/01/2016]

2 Stock Status less risk more risk The SSMO managed stock is scored as moderate risk. This is because the population and fishing mortality estimates show that both are around the long term average. The vulnerability score is also moderate (26 of 100 on Recruitment is thought to be stable. Management less risk more risk The management of Scallops up to the six mile limit has been scored as low risk. There is a suite of management controls that are implemented as well as back up controls that can be implemented if LPUE or SSB is found to be outside reference points. The enforcement of management controls is mostly done via VMS and logbook data. Bycatch less risk more risk The bycatch risk for this fishery has been assessed as high risk. This is because of the potential of the gear to cause significant bycatch and associated damage. Whilst fin-fish bycatch levels are relatively low it is known that many species are affected, but not retained, by the gear, and it is the juveniles of species that are often present in the dredge-belly. Habitat less risk more risk The seabed effects of the fishery are scored moderate. The gear has the potential to cause significant damage to benthic habitats, however the fishery is managed via a spatial management plan which includes mapping habitats and closing vulnerable areas in order to keep damage to vulnerable habitats to a minimum. As part of the SSMO Spatial Management Plan there are currently approximately 15 areas closed to scallop dredging as well as two additional voluntary closed areas (SSMO, 2015). This enables a much reduced interaction with vulnerable habitats. Outlook Type Current Risk Status Outlook Reason Stock Moderate Stable Population estimates are around the long term average as is fishing mortality. Management Low Stable Management controls in place are advised by analytical stock assessments, they are not precautionary but prevent over fishing and are designed to keep the fishery sustainable. Bycatch High Improving Evidence from the scallop survey around Shetland in 2010 indicates that bycatch ranges from approximately 19% to 53% of the catch depending on the area. In total across all areas bycatch made up 37.4% of the catch. Habitat Moderate Stable / Improving Dredging damages the seabed. However spatial management has been in place since 2010, and the fishery has less interaction with vulnerable habitats.

3 Stock Status Details less risk more risk The inshore Shetland Scallop stock is defined as within the six mile limit around Shetland (Fig. 1). This stock is managed and assessed annually by the Shetland Shellfish Management Organisation (SSMO). In addition to this there is an assessed Shetland stock assessment area as defined by Marine Scotland that encompasses the 12 ICES rectangles around Shetland, including the SSMO area (Fig. 1). Figure 1. Map showing the Shetland scallop stock assessment area as defined by Marine Scotland (light blue polygon) and the six mile limit around Shetland (black line) within which scallops are managed by the Shetland Shellfish Management Organisation (SSMO) Time-trends Shetland Shellfish Management Organisation (SSMO) stock assessment results up to 2014 indicate that landings and LPUE (catch per hour per metre dredge, where metre dredge = number of dredges x dredge width) have increased since 2000 but in the last few years since 2010 they have been stable. Effort also appears to show a similar trend of increasing since 2000 but stabilising from 2010 onwards (Fig. 2). Figure 2. Landings, Effort and LPUE of scallop vessels within the SSMO managed area and collected by SSMO logsheets. 95% confidence intervals are shown for LPUE Population analysis (Viable Population Analysis) of scallops within the SSMO area indicated that the population increased dramatically (likely due to a strong recruitment event) from around 2005 and was stable till 2012 when the population began to decline again as recruits from 2005 left the population (Fig.3) (NAFC, pers comm). The population now appears to be at around the long term average. Fishing mortality estimates for 4 to 6 year old scallops have fluctuated over the 14 year period of analysis but mortality estimates are also at the long term average (Fig. 3) (SSMO, 2016a). Figure 3. Estimated population number and fishing mortality (ages 4-6) for scallop stock within SSMO area, as estimated using a viable population analysis (VPA) Stock structure and recruitment Shetland inshore scallops can be defined as the stock within the six mile limit around Shetland. Under a regulating order the Shetland Shellfish Management Organisation (SSMO) manages this scallop fishery, assesses the stock and aims to promote sustainability of the shellfish fisheries around Shetland (SSMO, 2016b). Whilst managed and assessed as a separate stock, this stock is encompassed by the larger Marine Scotland Shetland stock assessment area (SSMO area is included as part of this) and there is likely to be a large degree of mixing between scallops found inside or outside the SSMO managed area. There is little information on the recruitment of king scallop populations in Scottish waters. For scallops it is generally accepted that the number of larvae available for settlement in an area is largely dictated by the SSB, however there are a number of biological and physical factors that affect localised recruitment such as ocean currents and available habitat. In general though recruitment is more frequent when stocks are higher. After settlement, Scallops are mostly sedentary and there is little mixing of adults across larger areas (Orensanz et al., 2006). In the wider Marine Scotland Shetland stock assessment unit the recruitment appears to be relatively stable in recent years (Baretto & Bailey, 2014). Data gaps and research priorities Information on the recruitment of the Shetland inshore scallop stock would be useful, in order that annual variability in recruitment within the six mile limit around Shetland could be estimated. Wider research is also currently being done on redefining stocks all over the EU. Marine Scotland Science provides the Scottish government with science and advice on scallop stocks. There are eight defined scallop stock assessment areas in Scotland, based on historical fisheries distribution. More work is being done by ICES, however, on defining spatial areas for scallop stocks across the EU based on fishing grounds and VMS data and the scallop assessment areas broadly comply with each other (Cappell et al., 2013). Baretto, E., Bailey, N. (2014). Fish and shellfish stocks 2014 Edition. Marine Scotland Science, 65 pp. Cappell, R., Robinson, M., Gascoigne, J. and Nimmo, F. (2013). A review of the Scottish Scallop Fishery. Poseidon report to Marine Scotland, December 2013

4 Dobby, H., Millar, S., Blackadder, L., Turriff, J. & McLay, A., (2012). Scottish scallop stocks: results of 2011 stock assessments. The Scottish Government, Scottish Marine & Freshwater Science, Volume 3, Number 10. ICES. (2013). Report of the Scallop Assessment Working Group (WGScallop), 2 5 September 2013, Galway, Ireland. ICES CM 2013/ACOM: pp. Shetland Shellfish Management Organisation (SSMO) (2016a). Stock assessment results [restricted access] Shetland Shellfish Management Organisation (SSMO) (2016b). Aims and Objectives, Shetland Shellfish Management Organisation [ accessed: 8/01/2016] Orensanz, J.M., et al (2006). Dynamics, assessment and management of exploited natural populations, in Scallops: Biology, Ecology and Aquaculture: [ Marine Management Organisation Annual Fisheries Statistics for [Data accessed: 31-Dec-15]

5 Management Details less risk more risk Advised and agreed catches According to the Scottish government statistics 990 tonnes of scallops were landed into Shetland in 2014 (Scottish Government, 2014). Stock harvesting strategy The management of scallops around Shetland up to the six nautical mile limit is the responsibility of the Shetland Shellfish Management Organisation due to a regulating order that allows them to manage shellfish within this area. Outside of this scallops are the responsibility of Marine Scotland and are under the same rules as the Inshore Fisheries Groups around Scotland. The SSMO objectives include managing and regulating shellfish fisheries within the six mile limit, using licence issuing, minimum landing size and other regulations to keep the fisheries sustainable in the long term (SSMO, 2016a). Management by the SSMO is seen as tighter than in other areas around Scotland as regulations include a curfew, the number of licences are limited, there are a number of closed areas and scope to implement more spatial or temporal measures if catch rates indicate a need to do so. The fishery gained MSC accreditation in 2011 (SSMO, 2016b). In the past LPUE was the only reference point used to assess the status of the stock. In the case of scallops and the recent harvest control rules SSB has also been introduced as a reference point. These reference points are used to indicate whether more management measures or stricter management measures need to be considered. Organised as a traffic light system values of LPUE and SSB have been chosen to assist management decisions in the future, i.e. if green then no extra management measures, amber requires consideration of extra management measures and if reference points are red this may result in closure or/and a more detailed monitoring of the fishery. In addition to this regional LPUE is also set as a reference point to consider but does not have any values assigned to it (SSMO, 2014). There are a number of regulations that vessels that have obtained a licence from the SSMO have to comply with. Some of these are similar to regulations for scallop dredging in the rest of Scotland. Main SSMO regulations : Tow bar/tow bars that the dredges are attached cannot be over 8.8 metres in combined total length Vessels are not allow to tow more than 10 scallop dredges (an exception to this is vessels that can show historical use of more than ten but no more than 14 dredges, in these instance vessels are allow to continue) Hydraulic, suction and French dredges are prohibited Vessels are only permitted to fish between the hours of 0600 and 2100 Minimum landing size for King Scallops is 100mm in width Fishermen are obliged to fill in logsheets to enable monitoring of the fishery Effort, LPUE and population (via VPA analysis) are monitored and if reference points are reached then additional management measures, such as no new licences issued or increasing minimum landing size, may be implemented (SSMO, 2014). Surveillance and enforcement Surveillance in the form of VMS if in force within the 6 mile limit, where if a vessel is found to be breaching curfew or fishing in closed areas then the SSMO are informed. Marine Scotland are also responsible for policing the regulating order where they see fit. Scottish Government (2014) Scottish Sea Fisheries Statistics-Landings Tables [ Fisheries/PubFisheries/2014LandingsTables] [Date accessed: 8/01/2016] Shetland Shellfish Management Organisation (SSMO) (2014) SSMO Harvest Control Rules [restricted access] Shetland Shellfish Management Organisation (SSMO) (2016a) Aims and Objectives, Shetland Shellfish Management Organisation [ accessed: 8/01/2016] Shetland Shellfish Management Organisation (SSMO) (2016b) Regulations, Shetland Shellfish Management Organisation [ accessed: 8/01/2016]

6 Bycatch Details less risk more risk Targeting and behaviour Scallops live recessed into gravelly, sandy and sometimes muddy seabed. However, many of these areas are surrounded by a wide variety of other seabed types so scallop dredges are deployed on ground favourable for scallops and suitable for towing a dredge over. This includes a wide range of bottom-types, from patchy boulders and rock through to gravel, sand and muddy-sand. The only bottom-type really excluded from this is prominent rocky-reef, as even low-lying rocky reef can be towed, and altered, by scallop dredges. Whilst a lot of the area around Shetland may be sporadically dredged, vessels mostly fish in the same general areas where scallops are known to be found. Vessels usually employ a strategy of fishing in the same area along the same tracks until catches begin to decrease. They then move on and this particular area will be rested for a time before being fished again. There are no dive caught scallops in the SSMO area, as it is thought that areas that are not dredged because they are inaccessible offer a refuge and contribute to the population. Evidence of bycatch risk Bycatch data are generally from limited areas and Scallop dredges have not been a priority for discard surveys (Enever et al., 2007) in European waters, so information on bycatch is mostly available from studies undertaken in research projects. Thus many of the results cited below are a generalisation from the studied fisheries, and raise the issue of risk due to the uncertainty relating to bycatch levels. Information on scallop dredge bycatch from research show retained scallop dredge bycatch dominated by commercial species such as spiny spider crab, monkfish, queen scallop, brown crab, cuttlefish, rays, plaice and sole and non-commercial fish and invertebrates such as starfish, Spiny starfish (Marthasterias glacialis), echinoderms, small crustaceans, bivalves, hydroids and bryozoans (Jenkins et al., 2001; Beukers-Stewart et al., 2012; Catherall et al., 2014). There has been one Shetland specific study on bycatch occurrence in the scallop dredge fishery that was conducted in 2010 as part of the MSC assessment process. Here it was found that catch from a scallop survey around Shetland consisted of up to 63 different species, 13 of which made up 98 % of the catch. On average, king scallops made up 62.6% of the weight of the catch, however only in two of the six areas surveyed did the catch to be king scallops average less than 70%. The analysis also revealed that bycatch of other potentially important commercial species such as Edible crab or Monkfish is low. The highest bycatch species in terms of weight were found to be Sea urchins, horse mussel and brown crab (Shelmerdine, 2010). Scallop dredging is known to be a form of fishing that has some of the most adverse effects on the seabed (Dayton et al., 1995, Collie et al., 2000). Studies have also shown that dredging generally causes high mortality in the benthic species it encounters (Kaiser et al., 2006). Scallops are known to survive the dredging process well and benefit from the use of measures to improve selectivity; minimum tooth spacing and ring size (Lart et al., 2003). Other organisms such as starfish and whelks were found also to be resilient to scallop dredging, but crabs were less likely to survive (Veale et al., 2000; Veale et al., 2001). There is also a risk of removal of organisms attached to the substrate such as fan corals. However since dredge fisheries are not a priority for discard sampling effects are uncertain. As was found around Shetland, Jenkins et al., (2001) also shows that most of the bycatch of the scallop fishery in the North Irish Sea consists of invertebrates. However they also found that a high proportion of those affected are not retained by the gear; capture efficiency was between 2 and 25% dependent on the species. Therefore there is mortality of organisms that are affected by the gear but not retained by it and there is differential between species in terms of the type and extent of damage and their survival. For most species this indirect mortality was found to be higher than that seen directly as bycatch in the dredge belly itself. Mitigation measures Mitigation of bycatch by vessels scallop dredging in the Shetland Shellfish Management Organisation (SSMO) area is currently done through the spatial and temporal restrictions that are in place. These include areas of protected habitat where dredging is prohibited under the spatial management plan (SSMO, 2015; SSMO, 2016). Beukers-Stewart B.D., Brand A.R., Craven H.R. (2012). Patterns and impacts of fish bycatch in a scallop dredge fishery. Aquatic Conservation: Marine and Freshwater Ecosystems Catherall, C.L., Murray, L.G., Bell, E. & Kaiser, M.J. (2014). English Channel King Scallops Research summary: Bycatch. Bangor University, Fisheries and Conservation Report No. 47, pp. 10. Collie, J. S., Hall, S. J., Kaiser, M. J., & Poiner, I. R. (2000). A quantitative analysis of fishing impacts on shelf sea benthos. Journal of animal ecology, 69(5), Dayton, P. K., Thrush, S. F., Agardy, M. T., & Hofman, R. J. (1995). Environmental effects of marine fishing. Aquatic conservation: marine and freshwater ecosystems, 5(3), Enever R., Revill A., Grant A. (2007). Discarding in the English Channel, Western Approaches, Celtic and Irish seas (ICES subarea VII). Fisheries Research 86: Jenkins, S.R., Beukers-Stewart, B.D., Brand A.R. (2001): Impact of scallop dredging on benthic megafauna: a comparison of damage levels in captured and non-captured organisms. Marine Ecology Progress Series 215, Kaiser M.J., Clarke K.R., Hinz H., Austen M.C.V., Somerfield P.J., Karakassis I. (2006). Global analysis of response and recovery of benthic biota to fishing. Marine Ecology Progress Series. 311: Lart, W. et al. (2003): Evaluation and improvement of shellfish dredge design and fishing effort in relation to technical conservation measures and environmental impact: [ECODREDGE FAIR CT ] Seafish Report CR Shelmerdine R.L. (2010). The occurrence of bycatch from scallop grounds around Shetland. NAFC Marine Centre. Shetland Shellfish Management Organisation (SSMO) (2015). SSMO Spatial Management Plan [restricted access] Shetland Shellfish Management Organisation (SSMO), Regulations, Shetland Shellfish Management Organisation [ accessed: 8/01/2016] Veale L.O., Hill A.S., Hawkins S.J., Brand A.R. (2000). Effects of long-term physical disturbance by commercial scallop fishing on subtidal epifaunal assemblages and habitats. Marine Biology 2000; 137: Veale L.O., Hill A.S., Hawkins S.J., Brand A.R. (2001) Distribution and damage to the bycatch assemblages of the northern Irish Sea scallop dredge fisheries. J Mar Biol

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8 Habitat Details less risk more risk Gear effects, targeting and behaviour Newhaven scallop dredges carry a heavy iron-ringed belly that needs to be suitably durable to withstand constant abrasion. This is covered on top by a synthetic fibre mesh. Each single dredge is attached to a dredge beam, which is a heavy steel tube with roller wheels at each end. A set of dredges will be attached to a further beam, and there may be up to 8 dredges for each side of the boat. This represents a very heavy set of gear, which can have a considerable impact on the seafloor. Scallops can be found on a variety of substrates, but substrates with a high level of gravel are favoured. Some scallop grounds contain patches of rocky ground or reef. The way in which scallops recess into the seabed means that the dredge teeth have to penetrate into the seabed in order to dig the scallops out of the sediment (approximately 25 mm is typical (Lart et al., 2013). The role of the sprung teeth is to absorb the shocks as the gear rides over the rocky parts of the habits and to enable it to shed stones successfully. The immediate physical effect of the gear on the seabed is high and in certain habitats, such as maerl beds, horse mussel beds and reefs, changes can be long lasting, permanent or more than 5 years (Brown 1989; Hall Spencer and Moore, 2000). However, it has proved more difficult to identify longer term effects of scalloping on more dynamic habitats (Sciberras et al., 2013) particularly as many of these areas have been dredged regularly for a number of years. Regular and intensive dredging could alter the composition of the seabed. Some seabed types are more sensitive to these impacts than others. Stable communities of marine wildlife build up around larger boulders, cobbles and larger gravels, which can also be attractive places for scallops. These complex communities are heavily impacted by scallop dredges. Other substrate types in high-energy environments, such as more mobile sand and gravels, are exposed to frequent change and attributing environmental and diversity damage solely to dredges in these areas is more difficult (Beukers-Stewart and Beukers-Stewart, 2009). Habitat risks The impacts of dredging gear have been well documented, but it can be seen that the slow-growing sessile organisms found in complex and stable seafloor types where rocks, boulders and even low-lying reef are found are the most vulnerable to encounters with fishing gear. Complex assemblages of species develop, and mortality is high from dredging both as bycatch and as indirect strikes of the dredge itself. These assemblages can take a long time to recover, but recovery is possible, as has been seen in Lyme Bay following closure of certain grounds in 2008 (Sheehan et al., 2005). The fishermen can target scallop grounds in a way that resembles rotational harvesting (Palmer, pers com). Fishing effort can be concentrated on areas of high abundance; fished down to a level which is uneconomic and then move on to other grounds. Returning to the grounds depends on the nature of recruitment and growth of young scallops. Where recruitment is regular and there is a seasonal closure, such as in the Isle of Man, fishermen tend to return annually to the same grounds. The majority of scallop dredging around Shetland is conducted in this fashion. In areas where recruitment of young scallops is more sporadic fishermen are likely to return when scallops are present, typically 3-5 years later. Effectively this means that scallop grounds in may not be affected continuously by dredging, there are periods when recovery can take place. The severity of impacts is closely related to the seabed type the gear is being fished over. For example, a complex mixed seabed of boulders, rocks, gravel and sand will be better for biodiversity and is therefore going to suffer more significant damage from dredging than a more uniform sand/muddy sand seabed where change is the norm for these more mobile sediments. Mitigation measures The EU habitats directive defines priority habitat types which include some features likely to be encountered by scallop gear (including biogenic reefs and maerl beds, horse mussel beds and other reef habitats) and a number of these areas have been protected or are in the process of being protected or are in the process of being protected under the UK response to this Directive and the implementation of the OSPAR convention. Under the Marine Strategy Framework Directive from the European Union (Council Directive 56/2008) the European nations have committed to aim towards Good Environmental Status for the seafloor habitat by the year In Shetland, the Shetland Shellfish Management Organisation (SSMO) has taken a proactive approach to spatial management and has had voluntarily closed areas for scallop dredging since The SSMO Spatial Management Plan states that a methodology for surveying and classifying sensitive seabed habitats has been developed and there is processes in place to protect these priority habitats such as maerl beds, horse mussels and sea grass beds. There are currently approximately 15 areas closed to scallop dredging as well two additional voluntary closed areas (SSMO, 2015). This enables a much reduced interaction with vulnerable habitats. There is the UK Good Practice guide for scallop fishermen which contains a guide to minimising the seabed effects of scallop fishing. The Guide represents best practice for responsible fishers and advises how best to fish for scallops whilst maintaining seabed integrity as far as possible. It includes co-operating with scientific research, and voluntary measures to protect vulnerable habitats. Many of the aspects of the good practice guide are found within the SSMO spatial management plan. Brown, RA (1989) Bottom trawling in Strangford Lough: Problems and policies. 3 rd North Sea Seminar. Hall-Spencer J.M., Moore P.G. (2000) Scallop dredging has profound, long-term impacts on maerl habitats. ICES Journal of Marine Science 57: Lart, W. et al Evaluation and improvement of shellfish dredge design and fishing effort in relation to technical conservation measures and environmental impact: [ECODREDGE FAIR CT ] Seafish Report CR Sciberras M., Hinz H., Bennell J.D., Jenkins S.R., Hawkins S.J., Kaiser M.J. (2013) Benthic community response to a scallop dredging closure within a dynamic seabed habitat. Mar. Ecol. Prog. Ser. 480, Sheehan E.V., Stevens T.F., Gall S.C., Cousens S.L., Attrill M.J. (2013) Recovery of a Temperate Reef Assemblage in a Marine Protected Area following the Exclusion of Towed Demersal Fishing. PLoS ONE 8(12): e doi: /journal.pone Shetland Shellfish Management Organisation (SSMO) (2015). SSMO Spatial Management Plan [restricted access] All content 2018 Seafish. Origin Way, Europarc, Grimsby, DN37 9TZ. This page created on 14th July 2018 at 04:00pm.