Brine Shrimp (Artemia salina / Artemia franciscana): The newly hatched free-swimming Artemia nauplii represent the most universal and indispensable live food used across commercial shrimp hatcheries.
From the mysis stage through early post-larval development (PL1 to PL10), Artemia nauplii provide the optimal prey size, slow motility, high protein content, and essential lipids required for larval survival.
Correct Option: Option 1 (Brine shrimp).
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22
ICAR JRF Fish Nutrition And Feed Technology 29 Jun 2024Shift 1
MCQ (Single Correct)+4−1
The inconsistent survival from the later zoea to megalopa stage is the major problem in mud crab hatchery due to
Moult Death Syndrome (MDS) in Mud Crab Hatcheries:
In mud crab (Scylla serrata) hatcheries, larval metamorphosis from late Zoea (Zoea 5) to the Megalopa stage represents the most vulnerable developmental bottleneck.
Moult Death Syndrome (MDS): The primary cause of catastrophic mortality, wherein larvae fail to completely cast off their old exuviae during ecdysis, becoming trapped and dying.
It is precipitated by nutritional deficiencies (polyunsaturated fatty acids, cholesterol), bacterial epibiont loads, and hormonal ecdysone imbalances.
Correct Option: Option 4 (MDS).
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23
ICAR JRF Fish Nutrition And Feed Technology 29 Jun 2024Shift 1
MCQ (Single Correct)+4−1
In mud crab hatching occurs in days after spawning at temperatures of 26.5-31°C
In female mud crabs (Scylla serrata), fertilized eggs are extruded and carried beneath the abdominal flap as a compact egg mass ("berry" or "sponge").
Under optimal tropical water temperatures of $26.5^\circ\text{C} - 31^\circ\text{C}$ and salinity of $30-34\text{ ppt}$, embryonic incubation requires $7 - 14\text{ days}$ (typically 9–12 days).
The eggs change color from bright yellow-orange to deep brown and finally dark grey before releasing thousands of free-swimming Zoea-1 larvae.
Correct Option: Option 3 (7-14 days).
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24
ICAR JRF Fish Nutrition And Feed Technology 29 Jun 2024Shift 1
MCQ (Single Correct)+4−1
Which one of the following is harmful for the carp spawns?
Newly hatched carp spawn ($5-7\text{ mm}$) possess poor swimming mobility and thin cuticles, making them highly vulnerable to aquatic hemipteran and coleopteran insect predators.
Anisops spp. (Backswimmers, family Notonectidae): Voracious aquatic predatory bugs that grasp carp spawn with their raptorial forelegs and inject piercing-sucking digestive enzymes, killing hundreds of carp larvae within hours.
Brachionus, Keratella, and Ceriodaphnia are beneficial non-predatory zooplankton that serve as primary food.
Correct Option: Option 1 (Anisops).
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25
ICAR JRF Fish Nutrition And Feed Technology 29 Jun 2024Shift 1
MCQ (Single Correct)+4−1
In which of the carp culture systems fishes are cultured mostly under natural feed?
Extensive Carp Culture: Characterized by low stocking densities ($1,000 - 3,000\text{ fingerlings/ha}$), minimal or no external artificial feeding, and reliance almost entirely on natural pond food organisms (phytoplankton, zooplankton, benthos) generated through basic pond fertilization.
Semi-intensive incorporates supplementary feeds, and intensive relies $100\%$ on formulated balanced pellets.
Correct Option: Option 3 (Extensive).
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