Question

2. Coastal rainbow trout (Oncorhynchus mykiss) move between marine and freshwater systems yet are homoiosmotic organisms. What is meant this? What physiological challenges do these fish have to meet in each environment (marine and freshwater)? How does their physiology change to overcome these challenges?

Answer 1

Trout is the name given for a species of freshwater fish belonging to Salmonidae. The word trout is used for non-salmonid fish such as Cynoscion nebulosus.

there are two types of trout. one is lake trout . the other is rainbow trout. lake trout lives in freshwater lakes and rivers while rainbow trout lives in sea before it rturns to fresh water.

The rainbow trout (Oncorhynchus mykiss) is a trout and species of salmonid . The steelhead ("steelhead trout") is an anadromous form of the coastal rainbow trout or Columbia River redband trout that usually returns to fresh water to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead.

homoiosmotic are organisms having a bodily osmotic regulating mechanism and body fluids that differ in osmotic pressure from the surrounding medium or from seawater . so these coastal rainbow trout have a osmotic regulating mechanism in their bodies to differ when they live in both fresh and sea water

In freshwater, they prefer cool water but have been known to tolerate water temperatures up to 24°C (native climates have water temperatures around 12°C in the summer). Productive streams have a good mixture of riffles and pools and overhanging vegetation for shade. Most importantly, they require gravel beds to lay their eggs, and therefore, are sensitive to sedimentation and channel scouring.

marine trout prefer protective cover and low velocity water and have been known to be swept away and killed in water that is too fast. Since they are native to the western U.S., then tend to be found in coastal streams and rivers which naturally have reduced flow in summer months

In freshwater, they prefer cool water but have been known to tolerate water temperatures up to 24°C (native climates have water temperatures around 12°C in the summer). Productive streams have a good mixture of riffles and pools and overhanging vegetation for shade. Most importantly, they require gravel beds to lay their eggs, and therefore, are sensitive to sedimentation and channel scouring. Juvenile trout prefer protective cover and low velocity water and have been known to be swept away and killed in water that is too fast. Since they are native to the western U.S., then tend to be found in coastal streams and rivers which naturally have reduced flow in summer months