# S a l mo n in t h e E s t u ary
b y K e nn Ob errec h t



### In the Pac ifi c N o rth w e st , s a l mon a r e the mo st i mpo rtan t o

f

a ll comme r c i a land

s

po rt fis he s , ye t w e
s eem t o have tri ed ou r be st t o p l ace eve r y
conce i vab l e ob str uc ti on i n t he pa th o f t he ir

s u r v i va l . We ' ve de str oyed t he ir hab it a t , bu ilt ba rri e rs t o the ir

m i g r a ti on, po ll u t ed the ir w a t e rs , and

ove rfis hed them. O r egon au t ho r An t hony N e t boy ha s ca ll ed

s a l mon the w o rl d 's

mo st ha r a ss ed fis h.

Of t he si x s pec i e s of P ac i f i c s a lm on, f i ve occur a l ong the P ac i f i c Nor thwe stcoa st: p i nk, chu m , s ockeye, coho, and ch i nook. Of t ho s e, coho and ch i nook are t he m o stp l en ti fu l i n Oregon wa t er s , bu t chu m s a lm on u s e
s evera l of our coa st a l r i ver s

. S ockeye s e l do m appear s ou th of t he C o l u mb i a Ri ver, and t here t he run s have been a ll bu tw i ped ou t

. Pi nk

s a lm on don' t s pawn i n Oregon bu tare s o m e tim e s par t of the offs hore

ca t ch.

A ll P ac i f i c s a lm on are anadro m ou s , m ean i ng t ha t t hey s pend m o stof the i r li ve s i n t he ocean bu tre t urn t o fre s h wa t er t o s pawn and d i e. In a s much

a s e st uar i e s are t he l ower reache s of coa st a l r i ver s , where s a lt and fre s h

wa t er mi x, a ll P ac i f i c s a lm on u s e t he e st uar i e s t o s o m e ex t en t . They m u st pa ss through t he m on the i r way t o s pawn i ng ground s . The mi gra ti ng young, known a s sm o lt
, mu sta ls o m ove through t he e st uary on t he i r way t o the s ea. M any u s e the e st uar i e s i n o t her way s a s we ll

.
A lthough s o m e genera liti e s app l y t o each s pec i e s of P ac i f i c s a lm on,
cer t a i n st ock s or race s w ith i n a s pec i e s mi gh td i ffer con si derab l y i n one or
s evera l hab its

. F or exa mp l e, we s ay genera ll y tha ta ll P ac i f i c s a lm ons pawn i n fre s h wa t er, bu t s o m e race s of chu m s a lm on ac tua ll y s pawn i n
e st uar i e s , i n ti da l area s near upwe lli ng s of ground wa t er. M o sto t her chu m
s a lm on s pawn on l y a s hor t d ist ance fro m t he e st uary, and the i r young
s pend abou t t hree m on t h s feed i ng i n t he ti da l m ar s he s and ee l gra ss bed s before mi gra ti ng t o t he ocean.

S ockeye fry nor m a ll y mi gra t e i n t o fre s hwa t er l ake s where they s pend one t o three year s feed i ng before head i ng for t he ocean. S o m e st ock s , however, i n st ead of m ov i ng i n t o t he s o-ca ll ed nur s ery l ake s , head down st rea m t o t he brack is h sl ough s and backwa t er s of e st uar i e s , where t hey gorge on abundan tfood for m on t h s pr i or t o the i r s eaward mi gra ti on.

C oho fry re m a i n i n t he i r b i r t h st rea ms un til t hey undergo t he t ran s for m a ti on tha tw ill enab l e the m t o adap t t o s a ltwa t er. Then a s sm o lts t hey de s cend t o t he e st uary. M o st li nger t here for a few week s , forag i ng and grow i ng rap i d l y, bu t s o m e m ay st ay for a s l ong a s a year.

L i ke t he coho, ch i nook fry re m a i n i n fre s h wa t er un til they beco m e sm o lt and head for t he e st uary. F a ll ch i nook mi gh t s pend on l y a few week s or
m on th s i n t he e st uary, wh il e s pr i ng ch i nook genera ll y re m a i n a s l ong a s 18

m on th s before mi gra ti ng t o s ea.

Pi nk s a lm on probab l y s pend the l ea st tim e i n t he e st uary on the i r s eaward mi gra ti on. B u t t hey and o t her s , st ud i e s have s hown, s pend a t l ea st t wo week s feed i ng and grow i ng i n t he r i ch e st uar i ne wa t er s

. P erhap s one of the grea t e st va l ue s of t he e st uary t o the s e young s a lm on is t he abundan tfood tha t enab l e s the m t o doub l e or even tr i p l e i n si ze before mi gra ti ng t o s ea. Si ze is one of t he be stdefen s e s aga i n st preda ti on. S o
e st uar i e s are e ss en ti a l t o t he very s urv i va l of t he s e f is he s

.



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