Answer:
Low levels of dissolved oxygen would decrease the diversity of the fish population.
Explanation:
Salinity means an increase of the dissolved salt content in a water body.Water that has a high content of salt contains low amount of dissolved oxygen and therefore, it becomes a less appropriate environment for some aquatic organisms.
Although, most of the water bodies have specific optimal salinity range, They can adjust to live in that certain range, however, if salinity increases beyond that range , water bodies will shift from that environment to a new one that is more suitable for them to live. On the other hand, fish or other waterbodies that are more tolerant to salinity will migrate to this acquatic zone and will adapt there. But sometimes, an abrupt increase in salinity do not give alot of time to the fishes to relocate and they just die from salt stress. This has something to do with decreasing the diversity of fish population.
Hope it help!