Oyster ResearchProject Proposal 2011

Pavarni NaidooInstitute for Animal Production

An introduction to the oysterindustry

• 9 oyster farms in SA• R 8.5 mill industry• Smallholder farmers• ~100 employed full-time• WC consumes 61 %

oysters produced= local demand + export• Room for growth esp. at

Saldanha

From: AISA benchmarkingsurvey 2009

Current Industry Structure

Market Money$$$

Growout(3-6 months market size-

longlines)

South AfricaSaldanha outer bay, WC (Striker fishing)Algoa Bay, PE (Two Oceans Oysters)

Larger weaning /Nursery(ponds)

(20-30g seed)

South AfricaKleinzee Mariculture Ponds (N Cape)Paternoster Oyster Company (W Cape)

Hatchery spawn& Algae culture

Larvae rearing

Settlement

Weaning (2mm)

InternationalChile: Cultivos Marinos TongoyUK: Sea SalterUSA: Coast-Washington DC Research-Milford, Connecticut Whiskey CreekFrance: Satmar

Activity: Location:

Problem ID

• Currently no SA oysterresearchers

• From Industry:

– Climate changeTemp ; pH– Seasonal MortalitySummer: Mort ; quality– No local hatchery

Research Question 1

• Do growth rates of oysters fromcommercial suppliers in Chile; the USA theand naturalised Breede / GouKou river stock,differ between strains and between grow-outsites at Kleinzee (N. Cape),Saldanha Bay (W.Cape) and Algoa Bay (E. Cape)?

Research Question 2• In what way do key environmental

variables known to affect oyster growthdiffer between these 3 grow-out sites, andwhat is the temporal variation in theseparameters?

• What are the ratios of chlorophyll a to nitrate at

each grow-out sites, and how does this varyover time (within and between seasons)?

Research Question 3

• What is the geneticdiversity, mappedusing microsatelliteDNA markers (nullalleles-ProfHedgecock?), betweenand within cohorts ofoysters of these fourdifferent origins?

Research Question 4

• Synthesis: what is the interaction between theabove environmental variables, key growthtraits, and genetic variability among theoyster strains?

Aim

• ID stocks (genotypes) suitable for localconditions as broodstock for a future localhatchery that is crucial for the growth of thelocal oyster industry

Oyster spat(currentlyimported atsignificant cost/ risk/inconvenience)

Growth rate

SurvivalCondition

index

Summer

Winter

3strains

UKUSAChile

Environments

Measure/calculate

SaldanhaBay

AlgoaBay

Kleinzeeponds

Water qualitymeasures

Australia/New Zealand& naturalised SA??

Project Overview

Harvesting of oysters: Long lines

Materials & Methods 1• Oyster strains of

different origins(imported)– Chile– US– Breede– Australia/New Zealand?

• 3 Sites– Kleinzee– Saldanha Outer Bay– Port Elizabeth

Materials & Methods 2

• Pack labelled (someindividually tagged)batches of oysters intoOstriga cages

• Plant at each site• Weigh every 2 months

(i.e. Field trips to each sitefor 3 weeks out of every 8weeks for 2 years)

Materials & Methods 3

Environmental monitoring(samples taken every 2 weeks)

• Measure:– Nitrate– Particulate Organic Carbon and Nitrogen– pH– Particulate Inorganic and Organic Matter– Temperature– Chlorophyll a– Condition Index

Materials & Methods 4Genetics Study

Oyster tissue samples (min. 40 per strain per site = 360) • DNA Assays:

– DNA extractions– Microsatellite analyses (null alleles!!)– Mitochondrial gene sequencing and sequence alignments

to determine allele polymorphism

• Quantitative genetic analyses (GXE)interactions

Industry Contribution:

• Infrastructure (longlines)• Boat time & labour• Import of oysters (permits)• Ostriga cages & rope• Practical advice&assistance

Approximate cost ofthese contributions =R20 000/year

Industry Benefits:

• At 2-month intervals, reports on short termcomparisons of strains based on CI (conditionindex)

• Environmental monitoring (chlorophyll A andtemperature data)

• Recommendation on best oyster stock to use ateach location, in different seasons

• Info on genetic variation and key performancetraits

2010 Pilot study key findings

• Condition index (July):dry meat mass relativeto dry shells-

Saldanha & Kleinzee > PE(even though PE oysters grew faster; warmer water, food

availability is better at Saldanha)• Kleinzee oysters have a higher shell density

than other farms, suggesting high quality shells(NB for developing young oysters)

Budget $$$

• MCM: R300 000/year for 2011-2013 (3 years)+ access to labs & equipment (Dr GrantPitcher)

• Uni. Stell. : R30 000 + labs + 1 intern + 1 MSc.

student (supervised by my co-worker Dr SueJackson)

• WCDA: my salary + R60 000 ?