Forums

Back

RE: Selectivity at size by sex

RSS (Opens New Window)(Opens New Window)
FI
Francisco Izquierdo, modified 1 Year ago.

Selectivity at size by sex

Youngling Posts: 9 Join Date: 10/30/20 Recent Posts


Dear SS experts,

I am working with a sex-separated length-based model for hake and I have a question regarding the report file output.

I have noticed that the majority of output tables by sex in the report file are provided at age and not at length (e.g. F, M or Catch). However, looking at the replist$sizeselex table I found the column "Sex". The thing is that both sexes (1 or 2) show exactly the same selectivity at length so I am wondering if this is an error or there is some way to get selex at length by sex.

I have read the section report in page 175 of the manual but I couldn't find the answer to this.

Many thanks in advance,

Fran

FI
Francisco Izquierdo, modified 1 Year ago.

RE: Selectivity at size by sex

Youngling Posts: 9 Join Date: 10/30/20 Recent Posts
La cuenta de correo francisco.izquierdo@ieo.es  dejará de estar disponible en breve. Para cualquier comunicación, por favor, envíe los mensajes a la nueva cuenta francisco.izquierdo@ieo.csic.es.   Los correos enviados a francisco.izquierdo@ieo.es serán desviados a la nueva cuenta, por lo que no será necesario el envío a ambos buzones.
Richard Methot, modified 1 Year ago.

RE: Selectivity at size by sex

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

Dear Francisco,

Selectivity-at-length can differ by sex in SS3, but only if your setup for selectivity requests sex-specific selectivity.  In the control file, it is the 3rd column of the selectivity setup and is labelled "male" and is described in the manual.

#_Pattern Discard Male Special
 24 0 0 0 # 1 Fishery
 24 0 0 0 # 2 Survey
 

Even if selectivity-at-length is the same for males and females, selectivity-at-age will differ between the sexes if growth is sex-specific.  This is because selectivity-at-age is partly determined by the combination of selectivity-at-length and distribution of length-at-age.

Rick

FI
Francisco Izquierdo, modified 1 Year ago.

RE: Selectivity at size by sex

Youngling Posts: 9 Join Date: 10/30/20 Recent Posts

Dear Rick,

Thank you for your quick response.

I had not realized about this option. As you mentioned, my selectivity was set as the same for males and females and that is why I found the same selex at size but different selex at age.

I will explore this option.

Thanks again,

Fran