It seems also to be the case in charr and trout populations which migrate to
estuaries : smaller migrants stay in shallow bays while larger ones move
into deeper and more saline water. In brook charr (at least), this
"segregation"  is associated with differences in salinity tolerance, which
increases with size, and successive shifts in diet (from invertebrate drift
to estuarine benthic invertebrates and then fish).


Sophie Lenormand
Centre Interuniversitaire de Recherche sur le Saumon Atlantique
Université Laval
Canada

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----- Original Message -----
From: "Ron Heintz" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, July 08, 2002 1:30 PM
Subject: Re: lengths of fish using estuaries


> Try contacting Alex Wertheimer ([log in to unmask]). He studied the
> movement of juvenile pink salmon through estuaries. I believe he showed
that
> juveniles reared in the near shore until they reached a size threshold and
> then moved to the deeper water. After rearing there for a while they began
> migrating seaward.
> Ron Heintz
>
> Marin Greenwood wrote:
>
> > Greetings to all FISH-SCI members
> >
> > I am interested if anyone would be please be able to point me in the
> > direction of literature dealing with whether individuals of a single
> > species of fish inhabit different parts of estuaries according to their
> > body length. In particular whether anyone has experience of consistent
use
> > of the shallower (or nearer to shore) areas being used by larger/smaller
> > individuals contrasting with use of deeper (or further offshore) parts
by
> > smaller/larger conspecifics.
> >
> > Thanks in advance for any suggestions.
> >
> > Dr Marin Greenwood
> > Forth Estuary Ecology Group
> > University of Stirling
> > UK
> >
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