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Pecten Maximus) Sea-Ranching in Norway – Lessons Learned

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Pecten Maximus) Sea-Ranching in Norway – Lessons Learned Scallop (Pecten maximus) sea-ranching in Norway – lessons learned Ellen Sofie Grefsrud, Tore Strohmeier & Øivind Strand Background - Sea ranching in Norway • 1990-1997: Program to develop and encourage sea ranching (PUSH) • Focus on four species • Atlantic salmon (Salmo salar) • Atlantic cod (Gadus morhua) • Arctic char (Salvelinus alpinus) • European lobster (Homarus gammarus) • Only lobster showed an economic potential Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Background - Scallop sea ranching • 1980-90’s – a growing interest on scallop Pecten maximus cultivation in Norway • Based on suspended culture (1980’s) – labour costs high • European concensus that seeding on bottom was the most viable option • First experimental releases i Norway in mid-1990’s Photo: IMR Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Production model Pecten maximus • Hatchery + nursery – larvae + 2-20 mm shell height • Intermediate culture – 20-55 mm • Grow-out on seabed – 55->100 mm Photo: IMR Three production steps to lower risk for investors and increase the profit in each step Time aspect – four-five years from hatchery to market sized scallops Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Hatchery + nursery • Established a commercial hatchery, Scalpro Photo: S. Andersen • Industry + research developed methodolgy for producing spat on a commercial scale • Larvae phase • Antibiotics and probiotica to prevent bacterial outbreaks (early phase) • Continous flow-through in larvae tank and increased volume • No use of antibiotics in commercial production • From hatching to spat in about three weeks Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Hatchery + nursery • Transferred from hatchery to nursery in the sea at 2-4 mm • Land based race-way system – 2-20 mm Photo: IMR • Flow-through filtered sea water • Reduced predation and fouling • The commercial hatchery, Scalpro, covered both the hatchey and nursery phase Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Intermediate culture • Suspended culture or bottom cages • Interaction between transport method and site selection • Expected survival 75-90% Photo: IMR • Most scallops reach a size of 45-55 mm SH within a year • Fouling challenges Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Grow-out on sea bed • Transport – stress impact recessing behaviour and mortality • Site selection • Many areas considered suitable for scallop sea ranching • Growing into commercial size (100 mm SL) within 3-4 years • Rotational system removing large scallops • Majority of scallops should be harvested within a three-year period • Predator control • Great loss to crab and starfish predation • Need of predator control Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Predator vs scallop Two strategies • Release large scallops (> 60 mm SH) • Negative effect of intermediate culture on viability Photo: Ø. Strand • Increased labor costs • Develop predator control systems • Physical installations (fences) • Release in areas with low predator density and/or when predator activity is low Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA • 1200 crabs caught outside fenced area and 4 crabs caught inside Fence • 89% survival within the fenced area, 5% in the site with no predator control • Do not keep out seastars Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Harvest at grow-out site • Dredging not allowed in in-shore areas • Diver based (reference level fishery: 200-300 kg/diver/day) • ROV-technology – no success (less cost-effective compared to diving, 47 kg/hour) Photo: Ø. Strand Photo: S. Mortensen Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Later phase (mid 2000’s) Idustry role Government based research • Technology • Environmental impact on benthic • Husbandry operations communities • Predator control • Product marketing • Evaluation of site suitability Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Laws & regulations • 2001 – The Act on Sea Ranching • 2006 – became part of the Aquaculture Act • Restricted to sedentary species • Provides licence holders exclusive right to harvest released animals within a defined area • Licence holders resposibility • Ecological impact on biological diversity • Risk of disease transmission • Use of local broodstock for juvenile production • Document technical qualifications • Plan to remediate licence area Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA 2006: 16 licences for scallop sea ranching given under the Aquaculture Act 2014: 9 licences, none in commercial operation Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Commercialisation of scallop sea-ranching failed – but why? Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Lessons learned • Site selection • Research and industry trial generated knowledge • But - farmers chose areas based on practical considerations, not necessarily based on best grow-out conditions • Result - Production time exceeded due to slower than expected scallop growth rates • Predator control • Labour intensive • High costs Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Lessons learned • Conflicts with local interests • Municipality plans • Sea ranching did not fit into any of the existing area-planning categories • Resistance against structures on the sea bottom (fences) • Fishing activity • Recreational activity • Environmental interests (protected areas) • Lack of industry support from authorities to develop scallops as a new aquaculture specie (long production time and non-fish issues) Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA Future prospects • More focus on biomass production lower in the food Photo: IMR chain i.e. low throphic aquaculture • More focus on sustainable production and harvesting • Hatchery + undersized scallops from wild fishery in holding areas (put and take) • Low density seeding strategy (stock enhancement) Photo: IMR • May be an opportunity for a renewed interest of scallop sea ranching – knowledge base is good, but governmental support and financial willingness is needed! Photo: IMR Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA # BeMoreScallop Photo: R. Olssøn Production challenges Pecten maximus • Hatchery + nursery • Survival and growth / bacterial control • Continuous larvae culture • Predation • Intermediate culture • Transportation and handling stress • Optimize growth in cages • Grow-out on seabed • Site selection • Predator control • Harvest Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA .
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