HI presentation blue english– lessons learned
& Øivind Strand
• 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)
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
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: IMR Photo: IMR
Production model Pecten maximus
• Intermediate culture – 20-55 mm
• Grow-out on seabed – 55->100 mm
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
Photo: IMR
Hatchery + nursery
• Established a commercial hatchery, Scalpro
• 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
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: S. Andersen
Photo: IMR
Hatchery + nursery
• Transferred from hatchery to nursery in the sea at 2-4 mm
• Land based race-way system – 2-20 mm • Flow-through filtered sea water
• Reduced predation and fouling
• The commercial hatchery, Scalpro, covered both the hatchey and nursery phase
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: IMR
Photo: IMR
Intermediate culture
• Interaction between transport method and site selection
• Expected survival 75-90%
• Most scallops reach a size of 45-55 mm SH within a year
• Fouling challenges
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: IMR
Photo: IMR
• 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
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: IMR
Two strategies
• Release large scallops (> 60 mm SH) • Negative effect of intermediate culture on viability
• Increased labor costs
• Develop predator control systems • Physical installations (fences)
• Release in areas with low predator density and/or when predator activity is low
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: Ø. Strand
Photo: IMR
• 1200 crabs caught outside fenced area and 4 crabs caught inside
• 89% survival within the fenced area, 5% in the site with no predator control
• Do not keep out seastars
Fence
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Harvest at grow-out site
• Diver based (reference level fishery: 200-300 kg/diver/day)
• ROV-technology – no success (less cost-effective compared to diving, 47 kg/hour)
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: Ø. Strand Photo: S. Mortensen
Later phase (mid 2000’s)
Idustry role • Technology
communities
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
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
2006: 16 licences for scallop
sea ranching given under the
Aquaculture Act
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
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 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)
• May be an opportunity for a renewed interest of scallop sea ranching – knowledge base is good, but governmental support and financial willingness is needed!
Grefsrud et. al, 6th ISSESR, 11-14 November, Sarasota FL, USA
Photo: IMR
Photo: IMR
Photo: IMR
• 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