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
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
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
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
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)
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
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?
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
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.
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
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)
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
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
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
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
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
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
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
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).