Harvest Quality‘Reducing Stress’

Mark Porter

• Industry threats• Differentiating Australian Barramundi• Harvest methods• Stress• Measuring harvest stress• NGO’s & legislation• Conclusions

Content

What are the threats to the barramundi industry

How do we compete with these imports

DIFFERENTIATION!

High retail price Imports

Alternativeproducts

• Product quality• Animal welfare• Feed• Environmental responsibilities• Local employment• Harvest methods

“Scottish Quality Salmon operates above the regulatory framework imposed on the Scottish salmon farming industry. The salmon are strictly monitored and, as with any kind of animal production, only the use of authorised veterinary medicines and vaccinations to protect fish welfare and combat naturally occurring diseases or pest problems is permitted”

This quality brand was designed to differentiate the domestic product from cheaper alternatives and to highlight to customers that the fish they were buying was of a consistent high quality from an accredited farm.

• Traditional brailing and cosh harvesting of salmon in Scotland (1992)

• So what are the modern alternatives?

Harvest Methods

So what are the alternatives?

• Crowding methods to reduce

stress

• Rapid harvest of the fish before

stress parameters develop

• Percussive stunning

• Electrocution, CO2

• Ikejime (spiking the brain)

• Rested harvest which involves

conservative handling and the

use of anesthetics to minimise

pre-mortem stress in the

animal.

Acute and chronic stress

• Acute Stress (adaptive)– A single event for a short period. The stress response rapidly regains

the animals natural state within hours.

• Chronic Stress (maladaptive)– A constant long term stress which the fish has no way of avoiding has

an adverse effect on health, growth and reproductive

STRESS CORTISOL

LACTIC ACID

GLUCOSE

PROTEIN DENATURATION

WATER HOLDING CAPACITY

TEXTURE+

+

Creatine PhosphateATP

AMP

RIGOR MORTIS ODOUR

TASTE

Physiological response:

Physical consequences of stress at harvest

Gaping and blood spotting are due to several factors but primarily increased flesh and blood pH. This attacks the collagen fibers and artery walls which then allows muscle blocks to separate and blood vessels to rupture. This is compounded by increased blood flow due to rapid swimming activity prior to harvest.

Physiological Consequences of Rested Harvest in barramundi

Time to Rigor Onset

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0 1 2 3 4 5 6 7 8 9 10 11 12 13

Time (hrs)

Rig

orIn

dex

% (

Mea

n S

E)

d

bc

ab aab

ff f

cd

e

f

a

RESTED

CONVENTIONAL

Harvest Method

delayed rigor onset-increase time to process pre-rigor

maintain higher physiologicallyflesh pH

– Improved visual appearance • External colour• Flesh colour• Reduced gaping• Eye clarity

Flesh pH

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Time (hrs)

Fle

sh p

H (

Mea

n S

E) RESTED

CONVENTIONAL

a*

a

a a

a*a*

a*

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a*

Harvest Method

bb

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bb a

a

b*

Plasma Cortisol Immediately Post-harvest (t=0)

0

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RESTED CONVENTIONAL

Harvest Method

Co

rtis

ol

(ng

.ml-1

)

a

b

Plasma Cortisol Immediately Post-harvest (t=0)

0

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RESTED CONVENTIONAL

Harvest Method

Co

rtis

ol

(ng

.ml-1

)

a

b

Harvest Quality and fish physiology

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1st crowd(dip net)

1st crowd(stunner)

2nd crowd(stunner)

3rd crowd(stunner)

What are the threats to the barramundi industry

How do we compete with these imports

DIFFERENTIATION!

High retail price Imports

Farmed Fish Welfare (proactive dialogue with NGO’s & Government)

Main impacts of aquacultureThe seven key environmental and social impacts are:• Benthic impacts and siting: Chemicals and excess

nutrients from food and feces• Chemical inputs: Excessive use of chemicals - such

as antibiotics and pesticides – • Escapes: Can compete with wild fish and

interbreed with local wild. • Feed: Reduce dependency on fishmeal and fishoil • Nutrient loading and carrying capacity: Excess

food and fish waste increase the levels of nutrients in the water

• Social issues: labor practices and worker rights under public scrutiny. Additionally, conflicts can arise among users of coastal environments.

Farmed Fish Welfare (proactive dialogue with NGO’s & Government)

Demand in the UK increased by 31.7% between 2008 and 2009 alone which also saw Waitrose, Marks & Spencer, Sainsbury’s and Little Chef all stop selling or using caged eggs.

Public opinion is a very powerful tool!

Farmed Fish Welfare – the alternative Public pressure

If you don’t think this will happen in Australia

Farmed Fish Welfare – E.U. legislation- banning ice slurry slaughter

Supermarkets are already aligning with NGO’s

Conclusion

• Why spend 16 months growing a fish to reduce its value in the last 60 minutes of its life?

• There is a fantastic opportunity to differentiate Australian barra from cheap foreign imports

• A high quality consistent Australian alternative to foreign imports should be an industry imperative in the future

• I’d suggest the barramundi industry should be engaging with NGOs and Government to:• Set a standard• Then voluntarily exceed these regulations• Market the welfare and clean green aspects of

the product

Thank you