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How to Participate

1. Create one post describing a broodstock evaluation method for either crustaceans or bivalves

2. For each method, include:

Name/title of the practice

Brief description of the method

Species it applies to

Key advantages

Any relevant images or diagrams

3. Review other posts and use the voting reaction to support methods you find most efficient and sustainable

4. You may comment on posts to discuss the pros and cons of each method

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Source: Selim, S., Harun-Ur-Rashid, M., Jahan, I., & Mostafa, E. M. (2024). Culture-independent molecular techniques for bacterial detection in bivalves. The Egyptian Journal of Aquatic Research.

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Quantitative Polymerase Chain Reaction (qPCR)

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Quantitative Polymerase Chain Reaction (qPCR)

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Brief Description:

In this method, tissue samples are collected from brood stock and preserved appropriately. DNA or RNA is then extracted from the samples using a commercial kit or lab protocol. Specific primers and probes targeting known pathogens are added, and the qPCR machine amplifies and quantifies the genetic material. Results are analyzed to determine the presence and load of pathogens, allowing hatchery managers to exclude infected individuals from the breeding population.

Species Applied To:

Oysters (Crassostrea gigas, C. virginica)

Clams (Ruditapes philippinarum)

Mussels (Mytilus spp.)

Key Advantages:

Detects low levels of pathogens before clinical signs appear, enabling proactive brood stock selection.

Provides quantitative data, helping assess the severity of infection and make informed breeding decisions.

Minimizes false positives/negatives, ensuring reliable results that support hatchery biosecurity.

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The Gonadosomatic Index (GSI) is a non-lethal, quantitative method to evaluate broodstock quality by measuring the gonad-to-body weight ratio.

Method:

1. Weighing the whole animal

2. Carefully extracting and weighing the gonad tissue

3. Calculating: GSI = (Gonad Weight / Total Body Weight) × 100

Species it applies to in Malaysia:

Penaeus vannamei (Whiteleg shrimp)

Penaeus monodon (Black tiger shrimp)

Scylla spp. (Mud crabs)

Key Advantages

1. Simple and Cost-Effective - Requires only basic lab equipment (scale, dissection tools)

2. Standardized Metric - Allows comparison across different farms and regions

3. Non-Destructive - Can be used on live animals when done carefully

4. Correlates with Spawning Success - Higher GSI values indicate better reproductive potential