Final answer:
True, extrinsic limiting factors can significantly impact fish by altering the external conditions of their environment, such as salinity levels and light availability, thus affecting their survival, growth, and reproduction.
Step-by-step explanation:
Extrinsic limiting factors are indeed factors that can affect fish populations in an ecosystem. The term 'extrinsic' refers to external or outside factors that affect an organism's ability to survive, grow, and reproduce. These can include aspects such as predation, food availability, water quality, and environmental changes. For instance, salinity and temperature are abiotic factors that significantly influence life in freshwater biomes. High salinity levels can lead to an accumulation of salts in the body of fish, which is deleterious to their health. On the other hand, low salinity (low osmolarity) can cause water to flood into the bodies of freshwater fish, also creating harmful conditions. Light availability is another extrinsic factor, where too much algal growth can block light, affecting photosynthetic organisms and causing imbalances in oxygen levels. Moreover, changes in these extrinsic factors, such as a decrease in fishing effort, can lead to rebounds in fish populations and contribute to healthier marine ecosystems.