Intensive Fish Production 1 - Intro to the Industry PDF

Intensive Fish Production 1 Intro to the Industry Carrick Anderson With thanks to the staff at Institute of Aquaculture, University of Stirling Learning Objectives • Understand the basics of the global aquaculture industry, and who the prominent producers are. • Have an understanding of the facto...

Intensive Fish Production 1 Intro to the Industry Carrick Anderson With thanks to the staff at Institute of Aquaculture, University of Stirling Learning Objectives • Understand the basics of the global aquaculture industry, and who the prominent producers are. • Have an understanding of the factors that change with intensification • Understand the salmonid lifecycle and be able to describe key stages • Have an understanding of the salmonid production cycle and how it can be manipulated to provide benefits to the industry • Understand some of the challenges facing the aquaculture industry • Understand where future opportunities lie within the industry Poll Everywhere PollEv.com/carrickander333 The global aquaculture industry • Aquaculture is a new, and quickly expanding industry, making up almost half of global seafood production in 2020. • With the demand for protein set to double by 2050, high quality, sustainable production approaches are essential (GSI, 2016). The UK (Scottish) Aquaculture industry • The aquaculture industry is worth nearly £600 million per year to the UK economy • Atlantic salmon (Salmo salar) dominates production almost exclusively in Scotland. • Scottish salmon is UK’s biggest fresh food export. • Exports: USA 34%, France 23%, China 12% • Directly employs over 2,500 people in Scotland • Globally, Norway is the largest producer by a significant margin, accounting for about 1/2 of production, Chile follows, and then Scotland Comparisons to terrestrial farming (GSI, 2016) • The feed conversion ratio of farmed fish is one of the huge driving factors towards its sustainability. • In some systems, you can even achieve an FCR of <1.0 • The scope for genetic improvement in aquaculture is huge. Selective breeding has only occurred for 14 generations. • Think about how long terrestrial animal production has been refined for? • There is now huge research and funding behind optimising genetics of farmed fish. Salmon is the focus, but research into other species suitable for production is ongoing So, what species of fish are farmed? • More than 600 different species are farmed globally, on a scale of extensively to intensively. • Here, you can see that global production is dominated by carp and tilapia, two major species produced in Africa and Asia, largely in extensive systems. (Hua et al., 2019) How can we produce fish? The majority of the world’s fish are produced extensively in Africa and Asia in freshwater ponds. • As we transition from extensive to intensive: • Stocking density increases • Natural productivity (algae, phytoplankton etc. decreases) • Exogenous feeding increases • Think of it in the same way as extensive dairy farming vs more intensive systems. In European intensive aquaculture there is a predominance for cage aquaculture, and an increases Recirculating Aquaculture System (RAS) sector. Intensive production considerations As with other intensive food production systems there are additional considerations to ensure success: • A complete diet that meets all nutritional requirements • Additional supply of oxygen • Many methods including increasing water flow, increasing aeration, and oxygenation (most effective at high stocking densities) • Risk – mechanical failure can cause big problems. • Removal of metabolic waste and uneaten feed • Pathogen control • Behaviour and welfare considerations. In aquaculture, many of these can be achieved through improving technology and research, coupled with meticulous and accurate site selection. The Salmon Lifecycle 1) 2) Adult broodstock carefully selected Females stripped of eggs, males stripped of milt. Usually based on strict genetics to maintain healthy stocks 3) Fertilisation 4) 250ºD to eyed eggs 5) 250ºD to hatching 6) 300ºD to first feed (yolk sac runs out and alevins become fry 7) Fry become parr at roughly 5-10cm long 8) Smoltification occurs, depending on system. Can be achieved in 6-9 months by altering light and photoperiod. These stages are commonly in RAS facilities 9) Once fish are smolts, they need to be transferred to seawater. It is common at this stage to move fish from RAS facilities to sea or loch sites 10) By 2 years old salmon should be around 5-5.5kg and ready for harvest, or selection as brood stock. 11) If selected as broostock, a series of genetic tests will happen, and only the best will be retained. Can reach as big as 15kg by stripping 12) Whole cycle of egg to egg currently takes 3-4 years Photo taken from Benchmark Genetics The concept of ‘Degree days’ • Since they are poikilothermic (cold-blooded) the rate of metabolism in fish depends on the temperature of the environment in which they are kept. • The higher the temperature, the faster the metabolism • ‘Degree days’ is a term used to incorporate these differences, in the breakdown of drugs, as well as developmental stages in life. • Statutory minimum withdrawal of antibiotics in fish is 500 °𝐷. • Example – Atlantic Salmon eggs take 250°𝐷 to reach ‘eyed’ stage (Neural chord visible) à 25 days at 10ºC = 250ºD à 50 days at 5ºC = 250ºD Hatcheries A fundamentally key aspect of any fish production unit • Year round production is key to profitable production • Most systems need 2-3 egg inputs per year • Varies hugely dependent on system type. Key factors • High quality genetics • Exceptional biosecurity (Fungus is a huge issue, more later) • High quality brood stock • High quality environment • High quality management and husbandry Once selected, a 10kg female can produce upwards of 20,000 eggs This hatchery in Iceland has the capacity to hold upto 400 million eggs at one time. Eggs are disinfected in an iodine solution (0.01%) for 10 mins prior to being ‘laid down’ at 3-5ºC. Dead eggs should be removed to avoid fungus proliferation Hatch time varies hugely between species Eggs hatch around 500ºD later. Manipulating the lifecycle There are 2 main areas the lifecycle is manipulated. Early sexual maturation of salmon is a problem in the aquaculture industry • Once fish mature, energy is directed toward gondadogenesis, rather than growth, and the quality of the carcass drops dramatically. • Therefore, to allow fish to continue growth to harvest weight, maturation must be delayed. But how? • Production of sterile fish, or monosex cultures The other area the lifecycle is manipulated is smoltification. • The conversion of Parr à Smolt occurs with some anatomical changes. • Smoltification is initiated by a decreasing daylength (Autumn/Winter) • It is then completed on an increasing daylength (Spring/Summer) • Therefore, most systems (RAS facilities) alter daylight and temperature provided to the tanks, and give an artificially short winter of 6-8 weeks. • This can result in smolts being ready for sea transfer in 6-9 months, an advance of 3-6 months. Smoltification Parr A smolt is at the stage of the lifecycle where anatomical changes occur, to adapt it to living in saltwater. • A metamorphosis occurs in response to increasing daylight following the winter. Main changes • Chloride cell proliferation • Actively transport Na+, Cl- and K+ out of the tissue. • Sodium-Potassium-ATPase pump reversed • Endocrine changes • Molecular isoform changes alpha to beta Are the smolts ready for sea? • Must be sure, if they are not – HUGE economic losses • Measure gill Na-K-ATPase activity – enzyme assay • Measure plasma Chloride levels via blood sample • Historically, took a few, put them in salt water. Do they live? • Advanced testing now available Smolt • • • Molecular testing Gene testing Ratio calculations. How do we alter smoltification to benefit production? Natural Light cycle à Smoltification occurs with rising daylight following winter Manipulated Light cycle à Advances smoltification by 3-6 months Producing sterile fish – ‘neo-males’ Generation 1 XY Cock XX Hen Converted males are retrieved, with deformed gonads, and handstripped of milt Generation 2 XX Cock Eggs hatch Swim up fry (roughly 0.14g) are fed 17a methyltestosterone for 75 days until roughly 2g Now, all fish are phenotypically male, despite a genotype mix of XX and XY. NOTE: these fish are not harvested for human consumption XX Hen Eggs hatch All offspring have genotype XX Heat or pressure shock Results in production of only females Why only females? • Male aggression • Males anatomy changes and can cause more damage • These are harvested before maturation New research has shown triploid fish experience higher susceptibility to disease and subsequent poorer welfare. Producing sterile fish - Triploidy Triploid fish are very common nowadays. 3 full sets of chromosomes. • They are entirely sterile • Achieved by heat or pressure shocking eggs that have been fertilized as normal. • Advantageous higher growth rates, as no energy is channeled into maturation • Although it has been seen that males can develop secondary sexual characteristics and larger gonadal growth. • This is also an advantage for salmon farms, as in the event of escaped fish, there can be no genetic introgression to wild salmon stocks. Grow out The most common system used currently is: • Freshwater RAS systems transferred to seawater systems at smoltification At any given site, there can be upwards of 30-50,000 fish per pen, and as many pens as 20 per site. (Sometimes upwards of 1 million fish per site!) Stocking densities typically <15kg/m3, resulting in a 98.5:1.5 ratio A variety of cage/pen types, metal squares are typically used in sheltered sites, and polar circles are used in exposed sites. Huge technological and engineering inputs – work boats, well boats, treatment boats, lighting, automated feeders, cameras, feed barges etc. Feeding can be either at the surface or at depth Fish are cropped, harvest of the largest fish, allowing smaller fish to grow quicker. General harvest weight will be 5-5.5kg Grow out - Video Credit: James Sibley The grow out phase is a huge logistical operation Photo credit: Salmon Scotland The grow out phase is a huge logistical operation Photo credit: Salmon Scotland Challenges to the industry Infectious disease/Parasites • Sea lice – a huge issue, estimated to cost the Scottish salmon industry over £50 million each year. • More depth covered in next lecture Predators • Seals – another large problem • How do you get a seal out of a salmon pen ethically? • Illegal to shoot or intervene in any way. • Can cause huge losses in a single event - stress and direct mortality. Treatments and environmental impacts • Historically, some questionable practices occurred. • However, now the aquaculture industry is one of the most tightly regulated industries. • It is important to try and find alternatives, but antibiotic use in the industry is next to nothing. Food sourcing • Another key aspect of sustainability. • Historically reliant on fish oil and fish meal for food production • Is it possible to produce pellets from other, more sustainable protein sources to meet demands? Huge research into: • Insect protein sources • Plant based protein sources • Terrestrial animal-based protein sources Climate Change • Warming seas is bringing unprecedented challenges to the health and welfare of fish. Future of the industry There is currently huge investment into alternative production systems – some of which are gigantic. • Offshore systems • Closed containment systems • Semi-closed containment systems There is also huge investment in RAS technology and completing the entire lifecycle on land. Advantages of this: • Complete control over disease and water quality. • Generalised improved biosecurity • No lice • Minimal environmental impact However, currently this is only achieved at a small scale. Atlantic Sapphire in the USA are currently pioneers, however they are experiencing economical issues. Common misconceptions about aquaculture “Fish Farming is the reason wild salmon stocks are declining” • There is SOME impact, however this is vastly exaggerated by communities and individuals opposed to fish farming • There is very little significant evidence of disease transfer to wild fish from farms • Hugely multifactorial issue: Overfishing at sea, river pollution, climate change all contribute “Farmed salmon is dyed to get the pink fillet colour” • Incorrect. Astaxanthin is a natural pigment obtained by the salmon from feed “Salmon Farming is bad for the environment” • One of the most highly regulated industries out there. Scottish Sea Farms was audited 347 times in 2022 alone. • All regulations are enforced by independent third parties • Fish waste and food waste are organic matter. Historically problematic, but with improved site selection and stocking understanding, dispersion of waste is now very effective “It still takes too many wild fish to feed farmed salmon, contributing to fisheries depletion” • Wild salmon: 10:1 FCR. • Fish used to produce salmon food is of low consumer preference (sardines, anchovies) and at Mowi, FCRs of 0.68 have been reached. • Partnerships with accredited sustainability fisheries ensure sustainable provision of raw materials for food production The salmon production industry, particularly, is undergoing rapid change, with huge amounts of research. There are, without doubt, challenges, but the long-term goal of improving global food security sustainably is constantly considered. Key Points • Every species is different. • Production works on a completely different scale to any other food production system. (Only poultry is comparable) • Aquaculture is a growing, and hugely diverse industry across the world • Egg à Alevin à Fry à Parr à Smolt à Adult • Intensification requires increased energy, feed, stocking densities • Fish have low FCRs which can be exploited for hugely efficient production. • Norway, Chile, Scotland are all world leaders in the industry. Any Questions? Thanks!