Murray Cod question (1 Viewer)

[5ephyd]

how would you approach this question??

Explain the implication of increased water salinity for the survival of the Murray Cod (freshwater fish).

If freshwater fish needs to get rid of water because there is a gradient concentration of more salt in the body than the environment hence it would need to maintain homeostasis, wouldn't an increase in salinity level balance out the concentration gradient between the environment and its body which would be advantageous to the fish as it would not need to go through all these process of balancing out the concentrations of water and urea

 

[s-tressed]

i'm not 100% sure

Increasing salt in the water would mean that this salt will move from a high concentration in the water to a low concentration in the fish (through diffusion). This salt movement would also involve the movement of water from the surroundings into the fish. Now, I believe that fresh water fish have different structures to marine fish? Meaning that fresh water fish cannot excrete salts as efficiently as marine fish (their existing structures aim to conserve salt). For example, in marine fish they have chloride secretory cells in the gills that remove salts from the fish to the surrounding, where as, in fresh water fish, the cells in the gills absorb salt. Also, fresh water fish have a larger glomeruli to remove excess water, leaving salt to accumulate altering the internal environment blah blah -> death.

I hope that's what you're after/it's the right info haha.

 

[5ephyd]

yes it makes sense now thanks

 

[Rhinoz8142]

Increased water salinity would upset the water balance in the Murray Cod because freshwater fish normally have a higher salt concentration than the environment and this result in the increase of uptake of osmosis and the production of dilute urine. Increase salinity in the enviroment would lead to an increased loss of water from the fish and so they would dehydrate and eventually die

 

[2016yr12]

Your answer is quite helpful, however there are a few sections in it that do not make sense or need to be worded correctly. Thanks and keep updating!