Question

Hatchlings grown in nursery ponds form:
A. Fingerlings
B. Fries
C. Adults
D. Spawns

Answer 1

Hint: Hatchlings are the larvae that emerges from the fertilized eggs after hatching, which belongs to a fish, amphibian, reptile or bird.

Complete Answer:
Let's have an analysis through the options for a correct answer.

Option A: When the small fish grow up to 10 - 15 cm size or a size roughly equal to a finger, it is termed as a fingerling. Fingerlings are formed after passing the fry stage. It takes approximately 30 - 60 days for a fry to grow as a fingerling. They are not directly formed from hatchlings. Therefore, this is the incorrect option.

Option B: When the larvae starts to shape like a fish, that stage is normally known as a fry. A fry is formed after becoming a spawn. It grows about a size of 1-2 cm after becoming a fry. It takes 7 - 10 days for the spawn to become a fry. In the fry stage, they are primarily smaller size zooplankton feeders. Since fry is not directly formed from hatchlings, this is the incorrect option.

Option C: Adults are the last stage of a fish before its senescence. Therefore, this is the incorrect option.

Option D: Spawns are formed, when the yolk sac of a hatchling gets absorbed. During this stage, mouth develops and zooplanktons like rotifers are taken as food. Egg yolks, powdered oil cake, rice bean etc are also given as food. Since spawns are directly formed from hatchlings, this is the correct option.

Thus, the correct option is D) Spawns.

Note: Hatchlings draws its nutrition with the help of a yolk sac hanging below from it. Mouth is not formed during this stage and food is not taken from outside.