Oyster Farming Fundamentals, Class One, Mississippi 2018

Transcript

1. Oyster Farming Fundamentals OFF/Class of 2018 Mississippi Department of Marine Resources, Auburn University, Alabama Cooperative Extension
2. Class Topics — Class One — Introductions — What is off-bottom oyster farming and why do it? — Oyster Biology and Life Cycle — Understanding Triploidy — Introduction to Business Planning — Field Visit to Hatchery in Pass Christian — Class Two – Starting an Oyster Farm — Site Selection — Gear Options — Gear Assembly and Installation — Business Planning – Part Two — Permitting — Field Visit to Oyster Farm
3. Class Topics — Class Three – Operating an Oyster Farm — Grading & Splitting — Controlling Bio-Fouling — Nursery Options — Class Four – Operating an Oyster Farm — Storm Preparation — Mitigating Hazards — Inventory Management — Harvest Requirements — Protecting Public Health
4. Class Topics — Class Five – Making the Most of an Oyster Farm — Best Management Practices — Marketing and Branding — Basics od Distribution — Risk Management — Business Planning - Conclusion
5. My Background — With Auburn University’s Department of Fisheries & Allied Aquacultures and Alabama Cooperative Extension System since Jan. 2009 — Prior to working here, I worked as an Extension agent on Cape Cod, Massachusetts, working with shellfishermen, shellfish farmers and resource managers — On the weekends, had a small oyster farm in Cape Cod Bay for 5 years — Produced Bees River oysters
6. Communication — Email — Do you want a class website? — Pictures will be on Facebook, Twitter and Instagram — https://www.facebook.com/AUShellfishLab — Walton Lab Website — https://mifralabgroup.wixsite.com/home — E-newsletter
8. Shellfish Culture in USA — Oysters, clams, mussels – a success story for US aquaculture — But in 2008, very limited oyster culture in Southern US
9. Two Means of Traditional Oyster Production in the Gulf — ‘Wild’ public oyster reefs — Private ‘oyster beds’
10. Both Rely upon Natural Set — ‘Cultching’/shell planting is done to improve the habitat for oyster settlement to improve set — On private beds, oyster seed may be moved to different areas
11. Primarily Commodity Market — Focused on the commodity, shucked product market — Gulf prices vary widely with supply — In the shell, bought by weight or volume, not by the piece Credit: Scott Mowbray
12. Why Off-Bottom Oyster Farming? — Intended for the premium, high value niche markets — Primarily live, raw half-shell market that emphasizes quality — Off-bottom farming has very high survival, allowing culture of bred lines and/or triploid oysters – which do not suffer from poor summer condition — Branded oysters reduce variation in quality — Not competition with shucked product or even less expensive sacks of oysters — Rather, adds high value niche product that could help overall perceptions — Stability of income with possible limited season harvest
13. Why Farm instead of Bottom Plant? — But … — Bottom planting can allow much higher production — Production cost per oyster is much lower — Can promote faster growth — Increases survival — Allows control of fouling — Improves shell shape and appearance — Increases product consistency
14. Off-Bottom Oyster Farming is Not … — A public commercial fishery — Traditional on-bottom oyster leasing — Oyster restoration
15. How Does this Differ? — Usually relies on hatchery- reared native seed — Gear is used to protect oysters from predators, burial and other losses — Requires $ investment — Requires time — Bottom cage, suspended, floating — Can be established in areas where oysters on the bottom don’t survive (high salinity, soupy bottom)
16. Why Weren’t We Doing More Off-Bottom Oyster Farming? — Why Farm Something that Nature Provides in Abundance? — Problems of Fouling and Overset — Concerns about Potential Price for Regional Farmed Oysters — Risk of Hurricanes — Risk of Theft, Vandalism
17. We Can Now Provide Consistently High Quality that Nature Does Not — South historically has had a lot of relatively inexpensive oysters — Quantity and quality vary — Target high-end market with beautiful, branded oysters
18. Solving Problem of Fouling & Overset Cost Effectively — In Alabama, collaboratively tested 4 types of gear, of which 3 control fouling through air drying — Australian long-lines — Floating cages — Floating bags — Bottom cages — Needed to produce oysters that at most needed a rinse
19. Air Drying Takes Oysters Fully Out of Water: Control Frequency and Duration of Low Tide Fernando DeCillis
20. Markets and Price — In 2009, advised that top price would be 15 cents per oyster — Currently, wholesale prices of 35 to 70 cents per oyster — Focused on high end markets in US Southeast — New Orleans, Atlanta, Houston, Birmingham, Nashville, etc. — Opportunity/challenges in outside markets?
21. New Wave of Oyster Bars — Within the South, new emphasis on oyster varieties — Outside region, interest in what is being produced — Certainly seasonal opportunities
22. Why Weren’t We Doing More Off-Bottom Oyster Farming? — Why Farm Something that Nature Provides in Abundance? — Problems of Fouling and Overset — Concerns about Potential Price for Regional Farmed Oysters — Risk of Hurricanes – Developing strategies and insurance options — Risk of Theft, Vandalism – To be determined
23. Opportunities and Needs for Research and Outreach — Improving production methods and product quality (reduce costs, increase profits) — Improving product safety — Understanding and predicting water quality issues, harmful algal blooms, etc. — Understanding ecological interactions and managing environmental impacts — Training and technical advice
24. Hands-On Training — 34 farmers trained over three years — Provided classes and hands-on instruction — Each farmer chose a gear type and was given 10,000- 20,000 oyster seed to raise
25. Alabama Growth — In 2008, no farming — In 2016, Situation & Outlook Report — 14 oyster aquaculture — Farm gate at least $1.9 million — At least 2.6 million oysters harvested — Oyster market prices ranged from $0.30 to $0.80 with an average price of $0.45 — At least 20 full-time employees and 10 part-time employees — At least 28 acres permitted for oyster aquaculture with at least 18.1 acres used in production.
26. Five Growing ‘Areas’
27. Where Has This Gotten Us Regionally? — In Louisiana, now 4 oyster farms — In Florida, at least 30 farms now raising oysters — Working with colleagues in NC, SC and GA as well
28. Oyster ‘Gardening’
29. Pier Farming Photos from al.com
30. Going Forward — Exciting growth of off-bottom oyster farming in the region — Typically family farms — Creating jobs, allowing people to make a living on the coast — Potential for spat on shell in the region — We will continue to provide: — Science-based advice — Demonstration of new techniques — Training for individuals
31. Oyster Biology and Life History
32. Cultured Oyster Taxonomy Phylum: Mollusca Class: Bivalvia (Pelecypoda) Order: Eulamellibranchia Family: Ostreidae Genera: Crassostrea Ostrea Pycnodonta Saccostrea Family: Unionidae (all freshwater) Order: Unionoida Family: Mytilidae (mussels) Family: Pectinidae (scallops) Order: Veneroida (zebra mussels, corbicula, etc.)
33. •Change sex from year to year • Usually start first year as male and switch to female after the first or second spawn. May switch back again. •Factors controlling sex reversal • food availability…males may predominate under low food conditions • parasites • pheromones, sex and proximity of nearby oysters • pollutants – nonylphenol may induce females and simultaneous hermaphrodites (Nice et al. 2003)
34. Reproductive Strategies — Two basic strategies. — Ostrea. — Eggs released from gonad, fertilized and then retained in mantle cavity for the first half of larval life (ovoviviparity). — Crassostrea. — Both eggs and sperm are discharged directly into the water and all of larval life is planktonic. www.umces.edu/2002Session/oyst er.html
35. Crassostrea — Eggs small — Many eggs (100 X 106) — Not incubated — Males and females are broadcast spawners
36. Oyster Life Cycle
37. Trochophore — Start to swim within 15-20 min. from fertilization. — Phase lasts 24 - 48 hours (22 – 24OC) — Tend to swim toward the surface.
38. D-Stage Veliger — Early veliger stage — Region of hinge is straight http://www.youtube.com/watch?v=- • Stage starts when the shell begins to calcify. • Velum, well developed and distinct. • Planktonic • Begins feeding • Stage lasts several days depending on temp. ~ 90 um
39. Umbonal-stage veliger velum Umbo Feeding Locomotion Respiration
40. Eyed Larvae — Eye spots develop on both sides of the body. — Umbo becomes more distinct. — Takes 2-3 weeks to reach this stage — Marks beginning of transformation to pediveliger stage
41. Pediveliger — Late veliger stage — Prominent foot — Begins to look for suitable place to set. Settlement: exploratory activity before attachment and during which attachment is reversible. Cues: chemicals, bacterial film Metamorphosis: irreversible developmental process…permanent attachment, loss of velum, and foot..etc. Cues: light, chemicals (bacteria, ~ 275 um
42. Oyster settlement and metamorphos 1. Settlement: Pediveligers use byssal gland to secrete “tethering line” and initial attachment to surface (left valve) 2. Metamorphosis: Foot and associated byssal gland reduced/lost. Mantle secretes cement to attach new shell to substrate
43. Spat — Glues itself (Sets) permanently to substrate. — Clean (but with biofilm), hard substrate is required (Cultch). — Cultch free from: — Silt — Grease — Always glues the Left valve to the substrate.
44. Hatcheries Maximize Steps of Oyster Life Cycle — Spawning — Fertilization — Larval Growth and Survival — Metamorphosis — Early growth of oysters after metamorphosis (typically considered ‘nursery’)
45. BroodStock Conditioning Crassostrea virginica Females > 3 inches (76 mm)
46. — Collect early before natural spawning (February in the Gulf of Mexico; < 18 C for C. gigas). — # Brooders depends on goals. — Should be “fat” (high levels of glycogen). — Water supply: — >20‰ Salinity — Low turbidity or good filtration. — Hold for 2 Weeks at 20ºC . Brood Conditioning
47. Fat Oyster Photo #1 Examine subset of brooders for “ripeness Mature eggs = pear shaped: 55-75 um long and 35-55 um wide
48. Spawning stimuli • increased temperature, chemical stimuli from algae stimulate males • Released sperm stimulates both males and females to spawn (species specific), eggs stimulate only males to spawn (across species) •(Rice et al. 2002) Synchronized Spawning
49. Fertilization: Controlled 1)Induce Spawning – temperature, food, oyster gametes, chemicals
50. Temperature Shock
51. Fertilization: Controlled 1)Induce Spawning 2)Move spawning adults to separate aerated containers 1) Sieve eggs thru 50 um screen to remove debris 2) Combine eggs from several females in aerated containers 3) Fertilize with small volume sperm (20-50 ml) from >3 males 4) Examine eggs under scope after 15 minutes 5) If < 10% have a polar body, add more sperm 1) Subsample and count eggs for stocking into larval – rearing tanks
52. Larvae Culture in Tanks
53. •48 hours after fertilization •Larvae are ~65 μm and have already entered D- stage •Filter screen size 50 μm used to collect larvae •Placed in rearing tanks (5/ml) •Water changed and larvae sorted 3 times / week •Look for disease, measure growth, segregate size-classes, remove slow growers
54. Larval Food — Available food must be the right size and quality. — Diet consists of : — Bacteria — Diatoms — Flagellates — Detritus — Food size: — 10μm or less.
55. Ambient Food 1)Filter (10 -25 um) seawater to remove zooplankton and large algae. Provide filtered water directly to larvae 2)Filter seawater and then fertilize to stimulate algal growth and reproduction Problems: 1) Inconsistent results 2) Disease 3) Dominance by wrong algae 4) Zooplankton may slip through
56. Cultured Algae Chaetocerus gracilis Isochrysis galbana Pavlova spp. Nannochloropsis spp. Live Problems: labor, contamination Commercial Concentrates Example: Reed Mariculture Shellfish diet Problems: cost, growth/survival may be somewhat lower than optimum growth on live foods
57. At 24 – 28 C, development to eyed larval stage occurs in 12 – 21 days (250 – 300 um) • Eye spots develop on both sides of the body. • Umbo becomes more distinct. • Marks beginning of transformation to pediveliger stage
58. Pediveliger — Late veliger stage — Prominent foot — Begins to look for suitable place to set. Settlement: exploratory activity before attachment and during which attachment is reversible. Cues: chemicals, bacterial film Metamorphosis: irreversible developmental process…permanent attachment, loss of velum, and foot..etc. Cues: light, chemicals (bacteria, conspecifics), texture ~ 275 um
59. Oyster settlement and metamorphosis 1. Settlement: Pediveligers use byssal gland to secrete “tethering line” and initial attachment to surface (left valve) 2. Metamorphosis: Foot and associated byssal gland reduced/lost. Mantle secretes cement to attach new shell to substrate
60. Two Hatchery ‘Products’ — Singles for ‘off-bottom’ culture — Spat on Shell for ‘on- bottom’ culture
61. On-Bottom Culture — This to produce a lot of oysters at low cost Diagram from Cosgrove et al. (2009). Full process detailed in Supan (1992), ‘Using remote setting to produce seed oysters in Louisiana and the Gulf coastal region’.
62. Eyed Larvae are Shipped to Setting Stations
63. Spat on Shell Are Then Planted
64. On-Bottom Culture Going Forward — Several states are considering using spat on shell for stock enhancement (Louisiana, Mississippi, Alabama) — Number of individuals trying spat on shell on private leases in several states
65. Off-Bottom Culture — Nursery Required for micro cultch set oysters and cultchless oysters — Expensive — Used only for premium oysters — Many Methods
66. Microcultch •Micro cultch in downwellers (convert to upweller after metamorphosis: 24-48 hrs for settling and metamorphosis) •Particle size: 250-300 μm crushed oyster shell •100 eyed larvae per cm2 • initial mesh size = 150 um
67. Diploid vs. Triploid oysters Diploid Triploid • 2 sets of chromosomes • 3 sets of chromosomes • Fecund • Full to partial sterility (reduced gametogenesis) • Wild caught or hatchery produced • Chemically produced or produced through mating
68. The Triploid Oyster — Stanley et al. (1981) with C. virginica and Allen & Downing (1984) with C. gigas were some of the first to produce triploid oysters. — In 1985, commercial production of triploids began in the Pacific Northwest (Shatkin 1992). — Around 1994, the first mated triploid was produced in C. gigas (Guo & Allen 1994). — By 1999-2000 triploids were 1/3 of production in Pacific Northwest and breeding programs started in Europe and Australia (Nell, 2002).
69. Chemical vs. Mated induction — Main pathways to produce triploids: — Chemical induction: cytochalasin B (CB) or 6-dimethyl- aminopurine (6-DMAP) — Mated induction: diploid x tetraploid (From Callum, 2013)
70. Questions