Question

In the background section the authors wrote “Anadromous fishes such as Atlantic salmon (Salmo salar L.) exhibit a life history strategy that includes an initial phase in fresh water (FW) followed by migration to marine environments.” What is the osmotic pressure of salmon in freshwater? (1 point)

In the background section the authors wrote “Anadromous fishes such as Atlantic salmon (Salmo salar L.) exhibit a life history strategy that includes an initial phase in fresh water (FW) followed by migration to marine environments.” What is the osmotic pressure of salmon in marine environments? (1 point)

In the background section the authors wrote “The transformation of stream-dwelling parr to seawater (SW) tolerant ‘smolts’ entails the orchestrated development of physiological, morphological and behavioral traits that support migration to, and subsequent survival in, pelagic marine environments.” In terms of osmosis, what will happen to salmon because of this migration that they undergo? (1 point)

In the background section the authors wrote “The transformation of stream-dwelling parr to seawater (SW) tolerant ‘smolts’ entails the orchestrated development of physiological, morphological and behavioral traits that support migration to, and subsequent survival in, pelagic marine environments.” In terms of the diffusion of salt, what will happen to salmon because of this migration that they undergo? (1 point)

Based on your answer to question 3 and 4, what do salmon have to do to maintain homeostasis? Just saying “have salinity tolerance” is not an acceptable answer. (1 point)

In the “Plasma and gill analyses” section of the methods section the authors wrote “Plasma Gh levels were measured by a radioimmunoassay (RIA) validated for Atlantic salmon by Björnsson et al. [37].” What would a low radioactive level suggest about Gh levels? (1 point)

In the “Plasma and gill analyses” section of the methods section the authors wrote “Plasma Gh levels were measured by a radioimmunoassay (RIA) validated for Atlantic salmon by Björnsson et al. [37].” What would a high radioactive level suggest about Gh levels? (1 point)

How do you know that your answer to questions 6 and 7 are correct? (1 point)

In the “Developmental/seasonal patterns” section of the results section the authors wrote “We verified that parr-smolt transformation and subsequent loss of salinity tolerance occurred by profiling multiple morphological and ionoregulatory parameters.” Should there have been a loss of salinity tolerance? (1 point)

How do you know that your answer to question 9 is correct? (1 point)

In the discussion section the authors wrote “The ability of juvenile salmon to maintain ionregulatory balance upon direct transfer from FW to SW is readily employed as an operational definition of hyposmoregulatory capacity.” What does this quote mean for ions when salmon were in FW and when they were in SW? (1 point)

What one word in the quote of question 11 is evidence that your answer to question 11 is correct? (1 point)

Reference: https://bmcphysiol.biomedcentral.com/articles/10.1186/s12899-017-0028-5

Answer 1

The osmotic pressure of salmon in fresh water is 340 m-osmole/1.

The osmotic pressure of salmon in marine water is 410 m-osmole/1.

Due to the migration in terms of osmosis they undergo following observations are made:

• the changes in body shape along with utilization of lipid and glycogen stores
• rise in plasma chloride level
• raised plasma Gh levels

Due to the migration in terms of diffusion of salt they undergo following observations are made:

• Simultaneous branchial Nka activity and nkcc1 and cftr1 expression which is due to ionocyte employment in saline water salmons.

To maintain homeostasis salmons are helped by the molecular pumps present in gills have to change into opposite way pumping sodium ions out rather than in.

Low radioactive level suggest show low Gh level.

High radioactive level suggest high Gh levels.