Question

Which of the following (with respect to trouts) can be transported to long distances without losing viability?

• A. Unfertilized eggs
• B. Alevins
• C. Fertilized eggs
• D. Fry

Hint:

Trout "seed" is almost always sold and transported as Eyed Eggs. They are tough enough to survive being shipped in a cardboard box across the world, provided they stay cool and moist.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question identifies the life stage of trout (like Rainbow trout) that is most suitable for long-distance transport, specifically when viability and ease of handling are considered.
Detailed Explanation:

• Sensitivity of Stages: Unfertilized eggs are extremely delicate. Fry and alevins are living, swimming organisms that require large volumes of oxygenated water and produce metabolic waste, making their long-distance transport difficult and expensive.

• The Eyed-Egg Stage: Fertilized trout eggs reach a specific stage known as the "eyed-egg stage" (where the eyes of the embryo are visible as black spots). At this stage, the eggs become remarkably hardy.

• Transport Method: Eyed-eggs can be packed in moist cotton or moss in insulated boxes with ice. Because they have very low metabolic rates compared to fry, they do not require a continuous supply of bulk water. They can survive for several days in this "moist air" environment, making them the preferred stage for international and domestic trade.

• Viability: Once they reach the destination hatchery, they are placed back in water and usually hatch with very high success rates.

Step 2: Final Answer:
Fertilized eggs (specifically at the eyed-egg stage) are the most suitable for long-distance transport.