King scallop

Information about Scottish North East king scallops is limited. There is not enough information to determine whether the population is at a healthy size, although it appears to be growing. Fishing effort has been decreasing, so there is not currently concern for fishing pressure. King scallop fishing in the north east coast of Scotland developed in the 1980s. Landings peaked at 3,500 tonnes in 1996 and have since declined to around 1,500t.Route 2 (data limited) scoring has been applied to this rating owing to the lack of a recent stock assessment. King scallops are considered to have high resilience to fishing pressure.The most recent stock assessments for scallops in Scottish waters were carried out in 2016. Annual scallop surveys have been carried out since then, but no stock assessments have been made available. The four survey areas are: Shetland, West Coast, North East Coast and East Coast. A fifth assessment area is in Orkney, where the first survey was carried out in 2019. Covid disruption has prevented additional surveys since then and there is no stock assessment for Orkney. Therefore, this rating covers both the North East and Orkney fisheries.The 2016 stock assessment did not provide reference points for fishing pressure or biomass for north east scallops. However, it did show that the spawning stock biomass (SSB) declined sharply, from over 14,329 tonnes in 2013 to 9,275 tonnes in 2016. SSB in 2016 was the lowest since 2006 and below the 10-year average of 11,720t. As a result, Marine Scotland Science advised that there should be no increase in fishing effort on this stock, and to consider measures to safeguard the spawning stock.From 2017-2021, fishing effort for scallops in Scotland in general declined, and scallop landings per unit of effort (kW Days) increased. This suggests a potential increase in stock sizes. Landings of king scallops from the North East stock averaged 993 tonnes between 2018 and 2022 - much lower than the 2013-2017 average of 1,764t. Landings from Orkney have been relatively stable and averaged 500 tonnes between 2018 and 2022.The changes in effort and the increase in LPUE suggest that scallop stocks have been able to grow under current levels of fishing pressure. Therefore, we consider there to be no concern for fishing pressure. However, there is no stock-specific data to indicate how effort or LPUE has changed for the North East and Orkney stocks, and no benchmark to indicate what a healthy stock size would be. As a result of these data limitations, we remain concerned for the biomass until stock assessments can be provided.

Some appropriate management measures are in place to control the scallop dive fishery in Orkney. Improvements are needed to improve understanding of the stock and the fishery.Most (over 99%) of the scallop catch from Orkney is by Scottish vessels, and the remainder is from England. Unlike the mainland fishery on the North east coast, less than half of catches in Orkney are by dredging, with passive gears, including diving, accounting for just over 50% of the recent (2018-2022) catch. This rating covers the dive fishery in Orkney.There is currently no Fishery Management Plan, harvest strategy, or quota for scallops in Scotland. There are also no recent stock assessments to inform management. Management cannot therefore be responsive to changes in stock, and does not adequately ensure that fishing is controlled to protect the species. As the last assessment in 2016 indicated concern for the scallop stock in the North East of Scotland, management requires considerable improvement. However, diving accounts for a relatively small proportion of total catches within the stock, and has little impact on habitats and other species. While improvements are needed, it does not require the same level of management as the dredge fishery.In the available catch data from the MMO, diving is not specified. ‘Passive gears’ is interpreted to mean ‘dive-caught’ in the case of scallops. The average catch by passive gears in Orkney from 2018-2022 was 255 tonnes. Landings have been relatively constant during that time, ranging between 240t in 2019 and 310 tonnes in 2022, with a low of 160t during 2020 which may have been the result of Covid restrictions. In the whole of Scotland, 539t of scallops were caught by diving in 2022.Scallop fisheries in Scotland, including in Orkney, are managed through the Regulation of Scallop Fishing (Scotland) Order 2017. Most measures relate to controlling the dredge fishery. The main measure that is relevant to the dive fishery is a minimum landing size (MLS) of 105mm to protect the breeding stock. Scallops are thought to mature at age 3 or around 80mm, although growth rates vary. Therefore, juveniles are protected. However, it is smaller than the MLS elsewhere in the UK, which is 110mm, and may not adequately protect the breeding stock.There are no controls on catches or effort, although a license is required for commercial fishing. There are currently no requirements for vessels under 12m, which is the majority of dive vessels, to carry tracking devices. The fishery is therefore not well understood or monitored. However, a consultation was held in 2023 on rolling out tracking systems for under 12m vessels.In the 0-6nm zone, there are also non-statutory Regional Inshore Fisheries Groups (RIFGs). They do not have powers to set byelaws or implement management measures. The Orkney Islands RIFG is Orkney Sustainable Fisheries (OSF). OSF published a Fisheries Management Plan in 2017 that set out suggestions for improved management and research projects, including scallop tagging with Heriot Watt University to better understand stock dynamics.

Hand-diving for scallops is a very low impact fishing method, with no unwanted bycatch of other animals and very little impact on habitats.The average scallop catch from diving in Orkney from 20186-2022 was 255 tonnes. This is over 50% of the total catch from Orkney, and 17% of the catch from north east Scotland and Orkney combined.Diving for scallops usually uses boats and scuba equipment. It involves gathering scallops from the seabed by hand, one at a time. Divers can ensure that they only remove scallops, and don’t affect any other species. The only potential damage would be from irresponsible practices, for example, making contact with seabed features such as biogenic reefs.It is important to note that shellfish can contain toxins, and therefore hand-dived scallops should be bought from processors that routinely undertake sampling of scallops for toxins. It can be dangerous to eat shellfish from areas where there is a high toxin, bacterial, or chemical contamination.