Stenohaline animals are those that can tolerate a narrow range of salinity. Salinity refers to the concentration of salt in water. These animals are unable to regulate their internal salt concentration in response to changes in the surrounding environment. Stenohaline animals are often found in either freshwater or marine environments, but not both.

Examples of Stenohaline Animals
- Most freshwater fish, such as trout and bass, are stenohaline animals. They are adapted to live in freshwater habitats where the salinity is low.
- Many marine invertebrates, such as corals and sea anemones, are also stenohaline. They are adapted to live in saltwater environments where the salinity is high.

Characteristics of Stenohaline Animals
- Stenohaline animals have limited ability to osmoregulate, which is the process of maintaining proper water and salt balance in their bodies.
- They are highly sensitive to changes in salinity. Even slight deviations from their preferred salinity range can be harmful or even fatal to them.
- Stenohaline animals are often restricted to specific habitats that provide the appropriate salinity conditions for their survival.

Comparison with Euryhaline Animals
- In contrast to stenohaline animals, euryhaline animals can tolerate a wide range of salinity. They are capable of osmoregulation, adjusting their internal salt concentration to match the surrounding environment.
- Euryhaline animals include many species of fish, such as salmon and tilapia, as well as some crustaceans, such as crabs and shrimp. They can move between freshwater and saltwater environments without experiencing significant physiological stress.

Importance of Salinity Adaptation
- Adaptation to specific salinity conditions is crucial for the survival and distribution of aquatic organisms. Salinity affects various physiological processes, including osmoregulation, metabolism, and reproduction.
- Stenohaline animals have evolved to thrive in specific salinity ranges, allowing them to occupy distinct ecological niches. This specialization contributes to the overall biodiversity and functioning of aquatic ecosystems.

In conclusion, stenohaline animals are those that can tolerate a narrow range of salinity, such as most freshwater fish and many marine invertebrates. They have limited ability to osmoregulate and are highly sensitive to changes in salinity. Understanding the salinity requirements of different species is essential for conservation and management of aquatic ecosystems.

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