Scallop Fisheries
Current projects
Closed Area Monitoring
The Isle of Man has a series of closed or restricted areas within the 3 mile inshore limit, most of which are in place to provide protection or enhancement for the scallop fishery (e.g. Port Erin Closed Area and Ramsey Bay Fisheries Management Zone), or to act as trial reseeding or ranching areas (e.g. Laxey Bay and Niarbyl Bay Restricted Areas).
Working with DEFA, surveys are carried out onboard either the government enforcement vessel FPV Barrule or using chartered commercial fishing vessels. Recent surveys have primarily focused on assessing king and queen scallop stocks in the Fisheries Management Zone (FMZ) within the Ramsey Bay Marine Nature Reserve (RBMNR). The fishing industry has direct involvement in the management of this site and scientific data helps the fishermen to make decisions about the appropriate levels of fishing or the extension of closures within the FMZ.
The closure of three of these areas (Douglas, Niarbyl & Laxey) was recently extended by DEFA under a temporary order to allow an additional two years of data to be collected. During these two years (2016 – 2017) scientific monitoring of these areas is a high priority and will include assessment of the seabed habitat types, along with scallop density and age and size distributions. The results of this monitoring will give an indication of the areas of suitable scallop habitat that exist within each bay, along with identification of any key conservation features that may be present, together with patterns of scallop growth rates and recruitment. Monitoring these protected areas will also enable comparisons with unprotected areas to be made. The data can also provide general scientific information about how effective the closed areas are and how they respond to the absence or reduction of fishing activity.
Click image to enlarge:
Image: Fisheries closed areas and Marine Nature reserves around the Isle of Man - Isle of Man Government Document
Fishery
Fisheries for both king (Pecten maximus) and queen scallops (Aequipecten opercularis) operate within the Isle of Man’s territorial waters. These are the two most valuable fisheries to the Isle of Man fleet. The different behaviours of these two species mean that different fishing methods are used with a dredge fishery for king scallops and otter trawl fishery for queen scallops (with a small dredge fishery for queen scallops operating at limited times and within limited fishing areas).
King Scallop, Pecten maximus
In 2015/16 the total number of vessels licenced to fish for king scallops is 157; in 2015 2,345 tonnes worth £4,502,385 (source: DEFA Economic Digest, 2015) were landed from ICES Rectangles 36E5 and 37E5 by Isle of Man vessels and by UK vessels into Isle of Man ports. As king scallops burrow in the sediment they are fished using a Newhaven dredge. This has teeth that rake through the substrate lifting the scallops into a chain mesh bag.
Queen Scallop, Aequipecten opercularis
In 2015/16 following a public consultation and the introduction of a track record period the number of vessels licenced to fish for queen scallops has been reduced to 48. In 2015 3,799 tonnes worth £2,369,023 (source: DEFA Economic Fisheries Digest, 2015) were landed from ICES Rectangles 36E5 and 37E5 by Isle of Man vessels and by UK vessels into Isle of Man ports. Queen scallops are active swimmers when disturbed so are fished using an otter trawl. A tickler chain disturbs the sea floor causing the scallops to swim up into the water column, where they are captured in the fishing net. This method is preferred mid-June to October with skid dredges being used in the winter months.
In 2011 the Queen scallop trawl fishery was awarded Marine Stewardship Council (MSC) accreditation as a result of being a well-managed and sustainable fishery. It is one of the largest and most valuable queen scallop fisheries in the world. There has been an increase in demand over the past few years highlighting the importance of continued management of this fishery to ensure its future sustainability. In May 2014 the MSC certification for the fishery was suspended following a decline in queen scallop stocks and a corrective action plan has been enacted to rebuild the stock. As part of the corrective action plan the Isle of Man Government have been participating in a Pan-Irish Sea queen scallop management project, in collaboration with the fisheries administrations of the UK. It is recognised by industry, fisheries scientists and the fisheries administrations that the wider queen scallop fishery is under significant pressure and is showing signs of decline, whilst at the same time lacking any significant control measures. It is the objective of the project to develop and implement suitable management for this fishery in areas VIa and VIIa, which contribute the majority of landings.
Species Ecology
The King Scallop (Pecten maximus)
The king scallop is a large bivalve that can grow up to 15 cm long. The right valve is highly convex and off-white, yellowish, or light brown in colour. The left valve is flat and light pink to reddish brown in colour. Both valves have 15-17 radiating ribs.
Habitat & Distribution
King scallops are usually found in shallow depressions in the seabed. They prefer clean, firm sand, fine or sandy gravel, but are occasionally found in areas of muddy sand. It is found along the European Atlantic coast from northern Norway and south to the Iberian Peninsula. It has also been reported off West Africa, the Azores, Canary Islands and Madeira. King scallops are filter feeders and eat micro-organisms in the water column.
Life Cycle
Their lifespan can be up to 20 years and they reach sexual maturity between 3 and 5 years. King scallops have both male and female reproductive organs (hermaphrodites) and fertilization takes place externally. Their larvae develop in the water column and are dispersed in the currents. After 30 days they settle to the sea floor and attach to a suitable surface using their byssal threads (strong, silky fibres). Young scallops usually remain attached by byssal threads until they are between 4 and 13 mm in length and then settle on the seabed.
It is believed that adult king scallop do not migrate and only move when disturbed. Therefore, their distribution relies heavily on larval dispersion and consequently the local environmental conditions, such as currents and temperature.
The Queen Scallop (Aequipecten opercularis)
The queen scallop is a medium-sized scallop with two convex shells of variable colour. It is often light-pink to brown, orange or yellow, and may be overgrown with encrusting sponge. This species can grow to 9 cm in diameter.
Habitat & Distribution
Queen scallops are usually found between tidemarks up to depths of 100 m. They are often found in high densities on sand and gravel substrates and lie on top of the seabed instead of becoming settled in the sediment like the king scallop. They have also been found amongst horse mussel beds. This species is found from South of Norway to the Mediterranean and the Canary Isles. Queen scallops are filter feeders and eat micro-organisms in the water column.
Life Cycle
The lifespan of the queen scallop can be from 6-10 years and they reach sexual maturity at 1 year. Queen scallops have both male and female reproductive organs (hermaphrodites) and fertilization takes place externally. Their larvae develop in the water column and are dispersed in the currents. After 11-30 days the larvae settle from the water column and attach to suitable substrates by their byssal threads (strong, silky fibers). Young scallops remain attached by byssal threads for a period of time and then settle on the seabed.
Queen scallops are known to be quite mobile and swim readily in response to disturbances such as predators, divers, and fishing gear. They swim by rapidly opening and closing their shells which allows the scallop to rise off the seabed at a steep angle before swimming horizontally for a short distance and sinking back to the seabed.
Reports
Reports
- Isle of Man sustainable fisheries strategy – 2008
- Hydrodredge: reducing the negative impacts of scallop dredging – 2008 + additional documents 'Accepted manuscript'
- Sources and sinks of scallops (Pecten maximus) in the waters of the Isle of Man as predicted from particle tracking models – 2008
- Developing an ecosystem approach to the management of Manx fisheries
- Comparison of catch efficiencies for King and Queen Scallops between the RV ‘Prince Madog’ and the commercial trawler ‘Genesis’ – 2009
- Marine fisheries research report to DAFF 2007/2008
- Efficiency and environmental impacts of three different Queen scallop fishing gears – 2009
- The Isle of Man Aequipecten opercularis Fishery: Science and Management – 2009
- Genetic Connectivity and Marine Protected Areas. Progress Report – 26th November 2009.
- Seabed habitats around the Isle of Man
- Predicted impacts of proposed management measures in the Isle of Man’s Pecten maximus fishery – 2010
- The Isle of Man Aequipecten opercularis fishery: Research Update 2011
- The Isle of Man Aequipecten opercularis fishery stock assessment 2012
- Progress Report: Genetic investigation into the spill over of scallop larvae from Port Erin closed area - 2010
- Potential effects of stock enhancement with hatchery reared seed on genetic diversity and effective population size - 2013
- Spatial variation in the gonad condition of the scallop Pecten maximus L. - 2012
- Potential effects of stock enhancement with hatchery reared seed on genetic diversity and effective population size - 2013
- The Isle of Man Aequipecten opercularis fishery stock assessment 2013
- The Isle of Man Aequipecten opercularis consultation: Impact Assessment 2013
- December 2013 scallop fishery in Ramsey Bay fisheries management zone - Management Evaluation Report
- Environmental impacts of demersal otter trawls targeting queen scallops (Aequipecten opercularis) in the Isle of Man territorial sea - 2014
- Spatial variation in by-catch and energy subsidies generated by a trawl-caught queen scallop (Aequipecten opercularis) fishery - 2012
- The Isle of Man Aequipecten opercularis consultation: Impact Assessment 2014
Publications
- Hold, N., Murray, L.G., Hinz, H., Neill, S.P., Lass, S., Lo, M., Kaiser, M.J. (2013). Environmental drivers of small scale spatial variation in the reproductive schedule of a commercially important bivalve mollusc, Marine Environmental Research, 92: 144-153.
- Murray, L.G., Hinz, H., Hold, N., Kaiser, M.J. (2013). The effectiveness of using CPUE data derived from Vessel Monitoring Systems and fisheries logbooks to estimate scallop biomass, ICES Journal of Marine Science, 6: 70.
- Hold, N., Dawnay, L., Taylor, M.I. (2013). Development of microsatellite markers from 454 transcriptome derived sequences for the scallop Pecten maximus, Conservation Genetics Resources, 5: 663-666.
- Hold, N., Murray, L.G., Kaiser, M.J., Hinz, H., Beaumont, A.R., Taylor, M.I. (2012). Potential effects of stock enhancement with hatchery-reared seed on genetic diversity and effective population size, Canadian Journal of Fisheries and Aquatic Sciences, 70: 330-338.
- Hinz, H., Murray, L..G., Malcolm, F.R., Kaiser, M.J. (2012). The environmental impacts of three different queen scallop (Aequipecten opercularis) fishing gears, Marine Environmental Research, 73: 85-95.
- Murray, L.G., Hinz, H., Kaiser, M.J. (2011). Functional response of fishers in the Isle of Man scallop fishery, Marine Ecology Progress Series, 430: 157-169 .
Presentations
- Modelling sources and sinks for scallop populations in the Isle of Man – 2009
- The Isle of Man scallop fishery: Research and management – 2009
- Manx fisheries science – 2009
- How effective is management of the Isle of Man scallop fishery? – 2009
- Oceanographic and seabed surveys around the Isle of Man – 2009
- Spatial patterns in scallop fishing effort around the Isle of Man - 2010
MSc & PhDThesis
- Discarding in the Isle of Man Queen scallop, Aequipecten opercularis, fishery – 2008
- Spatial variation in king scallop, Pecten maximus, maturation state around Isle of Man – 2009
- Emission profile of a keystone fishery and recommendations for fuel management - A case study on the Isle of Man Scallop Fishery - 2010
- Survivability of target species discards in the Isle of Man Queen scallop (Aequipecten opercularis) fishery – 2011
- Discard analysis, damage and mortality of non-target species in a Queen scallop fishery – 2011
- An investigation of biotope distribution and susceptibility to fishing pressure in Manx territorial waters for the development of management recommendations for conservation – 2011
Additional documents
- Aequipecten opercularis fishery management plan
- Update on Aequipecten opercularis stock status and recommended Total Allowable Catch – 2010