Question

Inflammed gills, excessive mucous secretions and accelerated respiration in fishes is due to infections of

• A. Dactylogyrus
• B. Pyrodactylus
• C. Dactylus
• D. Meloidogyne

Hint:

Dactylogyrus is a monogenean parasite that targets fish gills. Distinguish it from Gyrodactylus, which is a monogenean parasite that targets fish skin and fins.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Parasitic infestations are a major concern in fisheries and aquaculture, with gill parasites directly affecting the respiratory efficiency of fish hosts.
Detailed Explanation:
- Dactylogyrus (commonly known as the gill fluke) is a genus of monogenean flatworms that act as ectoparasites on the gills of freshwater fish.
They attach to host tissue using a specialized posterior anchoring organ called the haptor.
This attachment damages the gill filaments, causing inflammation and triggering defense responses like excessive mucus secretion.
The layer of excess mucus limits gas exchange, leading to respiratory distress (hypoxia).
To compensate, fish exhibit accelerated respiration and may swim to the surface to gulp air.
- Meloidogyne is a genus of plant-parasitic nematodes (root-knot nematodes) and does not parasitize aquatic animals.
- Pyrodactylus and Dactylus are incorrect taxonomic names used as distractors in this question.

Step 2: Final Answer:
The symptoms of inflamed gills and respiratory distress in fish are caused by infections of the parasite Dactylogyrus.