Stenohaline fishes are

Options

A. marine fishes only
B. those which tolerate narrow range of salinity
C. those which tolerate wide range of salinity
D. fresh water fishes only

Answer

**Step-by-Step Solution:**

1. **Understanding the Term "Stenohaline":**
- The term "stenohaline" is derived from two parts: "steno," which means narrow, and "haline," which refers to salinity. Therefore, stenohaline fishes are those that can tolerate only a narrow range of salinity in their environment.

2. **Salinity and Its Importance:**
- Salinity refers to the concentration of salts in water. Different aquatic organisms have varying tolerances to salinity levels, which is crucial for their survival.

3. **Characteristics of Stenohaline Fishes:**
- Stenohaline fishes are typically found in stable environments where salinity does not fluctuate significantly. For example, freshwater fishes are stenohaline because they can only survive in low salinity waters.

4. **Impact of Salinity Changes:**
- If a stenohaline fish, such as a freshwater fish, is exposed to a higher salinity environment (like marine water), it cannot adapt to the increased salt concentration. This can lead to physiological stress and ultimately death.

5. **Conclusion:**
- Therefore, stenohaline fishes are defined as those that can tolerate a narrow range of salinity levels in their aquatic environment.

**Final Answer:**
Stenohaline fishes are those that can tolerate a narrow range of salinity.

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