Norman Ragg - Aquaculture New Zealand

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please!
NZ Aquaculture Conference 2010
RESEARCH BASED SOLUTIONS

listen
How to talk to shellfish
The role of physiological tools in developing a
deeper understanding of animals in aquaculture
Norman Ragg & Ellie Watts
NZ Aquaculture Conference 2010
RESEARCH BASED SOLUTIONS

Quantitative
understanding
Talk
&
listen
communicat
e
Qualitative
understanding
Appreciation &
empathy

Animal husbandry:
the importance of empathy and intuition

The enigmatic shellfish
Animals in aquaculture
tend to reveal little about
their welfare

Our form of communication:
Physiology… Getting beneath the shell
‘fitness’ (capacity to cope with stress) determined by:
-Resting/exercising heart rate and oxygen consumption
-Blood cell responses and biochemistry

Aquaculture physiology at Cawthron
Shellfish physiology lab 2010

Diverse interests…
New species:
•Establishing basic
requirements
Stress - cause & effect, e.g.:
•Optimising handling and harvesting
methods
•Identifying critical environmental tolerance
limits
•Effects of disease
Matching animal to environment
–either:
•Modify conditions in land-based systems
•Site selection for grow-out
•Species selection
•Appropriate phenotype (family) selection
Selective breeding -
identify family lines that:
•Optimise growth efficiency
•Resilient to stress
Climate change:
•Real effects
•Perceived effects

HSP genotyping
Shell strength
Fouling resistance
Fluctuating asymmetry
Stressor vs. histological changes
heritability
Stressor vs. immune function
Stressor vs. survival
simplification
thermotolerance
Feeding
performance
Growth
performance
Protein / lipid /
carbo turnover
Dynamic
Energy
Budgets
Correlation to
commercial
performance

Temperature tolerance and the heart
• Inescapable
• Key determinant of growth rate, efficiency and condition
• High temperature stress survival during seeding &
harvest
• Low temperature tolerance shelf life in live product
• Etc..etc…
• Heart-beat: vital physiological process directly
affected by temperature
Nasty graphs and algebra…

Calculating Arrhenius temperature
S. Arrhenius 1889:
k & ( T )
= k &
1
e
( T
A
/ T
1
−T
A
/ T )
family #1
Here k = heart rate
So gradient Ln k : 1/T gives –T A , Arrhenius temperature
Ln (heart rate)
5.0
4.0
3.0
-T A
2.0
1.0
0.0
0.0031 0.0032 0.0033 0.0034 0.0035 0.0036
1/absolute temp (K -1 )

How to measure heart rate

• 24 mussel heart monitor setup

Futures now…
intended outcomes

Relative family performance (preliminary conclusions)
Family no. Growth Air survival Temperatur
e sensitivity*
Upper temp
tolerance
1 + + + +
11 + - + -
19 + - - -
24 + - - -
32 - + + +
33 - - - -
35 - + 0 +
36 - + + +
* + = less sensitive

Acknowledgements
• Cawthron Aquaculture & Aquatic Biotechnologies group
• Staff at the Glenhaven Aquaculture Centre
• Andy Elliot, Bridget Alexander (Aotearoa Seafoods Ltd)
• Dan McCall (Marlborough Mussel Co.)
Funded by NZ Govt. Foundation for Research, Science &
Technology grants to Cawthron (contracts CAWX0303,
CAWX0802)

Slide Title Here – Arial 32

Survival in air
• 24 families (2009 cohort)
• 10 individuals x 4 containers
• 18ºC, 97% RH
• LT 50 determined by shell palpation

Results – survival in air
Fast growing
Slow growing
9
8
mean survival (d)
7
6
5
4
3
1 2 3 4 5 6 7 8 10 11 12 13 14 19 20 22 24 27 30 31 32 33 35 36
family no.