fish hatchery techniques: quality fingerlings for offshore aquaculture michael rust northwest...

Fish Hatchery Techniques: Quality Fingerlings for

Offshore Aquaculture

Michael Rust

Northwest Fisheries Science Center

Seattle, Washington

Outline

• What is quality from the Hatchery?– Healthy fish– Weaned to Pelleted Feeds– No defects– Uniform Size– Physiologically appropriate

Healthy Fish• Goal: Fish should be free of known diseases

– Approach - SPF hatcheries

• Goal: Fish should be protected from potential diseases– Approach:

VaccinationNutrition

Automatic Vaccination Lines

Fish Weaned to Pelleted Diets

• Goal: Fast Growth • Goal : Uniform Size• Goal: Cost Effective Feeding• Goal: Reduce Environmental Impacts• Goal: Healthy Fish

– Approach - Wean fish early and completely in Hatchery– Approach - Complete Compound Feeds– Approach - No Wet Fish (Trash Fish) Diets

No Defects

• Goal : High Product Quality– Approach - In

Hatchery Provide Optimal Environmental Conditions

– Approach - Provide high quality diets

0%

25%

50%

75%

100%

Tot

al h

atch

6 9 12

Temp (oC)

Developmental Anomalies (Temperature)

Other

Jaw

Spine

Normal

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Tot

al h

atch

15 20 25 30 35

Salinity (ppt)

Developmental Anomalies (Salinity)

Other

Jaw

Spine

Normal

Uniform in Size

– Approach - Start with uniform graded fish

– Approach - Genetic Selection for Uniform High Growth.

– Approach - Completely weaned to High Quality Pelleted diets.

• Goal: Uniform Product at Harvest

Physiologically Appropriate

• Goal - Excellent Growth and Survival under conditions in Offshore cages.– Perhaps lower Oxygen– Perhaps stronger currents– Approach - Species Selection

• Bioenergetics model under conditions likely to be found at site.

Simple Bioenergetics Model

E = G + R + L – Where:

– E is the total energy taken in by the fish from the diet

– G is the amount of energy going into growth

– R is the amount of energy used for everything that is not growh (movement, fighting diseases, reproduction, etc)

– L is the losses due from Feces, Urine and energy to digest the feed (SDA)

♀

♂

0

1

2

3

4

5

6

0 5 10 15 20 25 30

R F+U+SDAG Total

0

1

2

3

4

5

6

0 5 10 15 20 25 30Age (years)

Ye

arly

en

erg

y d

em

an

d (

MJ

)

Energy use curves for wild Blue Rockfish showing energy partitioning.

Female

Male

•Growth (G) represents a very small part of the energy budget of wild animals.

• Respiration (R) and Waste (F+U+SDA) represents a large portion of the energy budget

• Growth in farmed salmon can reach 50% of the total energy budget

Need to develop a simple bioenergetics model for species of interest in off shore

aquaculture• Conditions off shore are likely to be different than near

shore. In Washington State it is likely that they will have:– Lower Oxygen– Higher Currents

than traditional near shore aquaculture areas used by the salmon farming industry.

Potentially more energy will be needed for R making less available for G.

The cost/benefit to G from increased/reduced R is likely to be different among species

The cost/benefit to G from increased/reduced R is likely to be different among sites.

Bioenergetics models can be developed for different conditions

and species using respirametry

FlowDO inCO2 in

FlowDO outCO2 out

By measuring the uptake of Oxygen under various conditions you can determine R and predict G

Summary

• What is quality? It’s– Healthy fish– Weaned to Pelleted Feeds– No defects– Uniform Size– Physiologically appropriate

Thank you