Forums

Back

Question on how fish age in SS3

RSS (Opens New Window)(Opens New Window)
MS
Michelle Sculley, modified 5 Months ago.

Question on how fish age in SS3

Youngling Posts: 9 Join Date: 3/21/17 Recent Posts

It is my understanding that all fish age to the next year class on Jan-1 in an SS3 model. If, for example, fish are born in July, they are subject to half a year of age-0 natural mortality. Do they then experience age-1 natural mortality starting Jan-1 of the next year or do they experience age-0 natural mortality until they turn 1 in July of that year?

 

Thanks!
Michelle Sculley

Richard Methot, modified 5 Months ago.

RE: Question on how fish age in SS3

Youngling Posts: 219 Join Date: 11/24/14 Recent Posts

Hi Michelle,

Thanks for using the Forum to post this question.

It probably is the former, but I need a little more info before responding.  Is your model annual time step with recruitment in July, or do you have explicit seasons?  Are you using natural mortality option 3=agespecific; or 4=agespec_withseasinterpolate?  Or perhaps you are using Lorenzen M.

Suggest you look in report.sso for this table:  Natural_Mortality report:43

Rick

 

MS
Michelle Sculley, modified 5 Months ago.

RE: Question on how fish age in SS3

Youngling Posts: 9 Join Date: 3/21/17 Recent Posts

Thanks Rick, The model is set up with an annual time step and four seasons, and age specific natural mortality. Fish recruit in Q3 and then go through fishing and natural mortality for Q3 and Q4. In the numbers at age file there are 0 age-zero fish in Q1 and Q2. So I guess that might answer my own question since there are  no age zero fish in Q1 and Q2, so they would all have turned one on Jan-1 and are undergoing age-1 natural mortality. Thank you!

 

Michelle