The "other" thread prompted me to start this one.
On this site, and others, anglers tend to use the phrase "sea run" when referring to coastal cutthroat of the Fraser River basin, but are they really...?
From my handle, and my reports on this site, you can correctly surmise that I love chasing cutthroat . Although I primarily fish for them off the beach in the spring and summer months, I have also caught them from Maple Ridge to above Agassiz in sloughs, backwaters, creeks/streams/rivers, and lakes...but have never had any degree of certainty that these were sea run.
This crazy thought started rumbling around in my head after a trip many years ago to Pitt Lake and Red Slough. The many wild fish from the slough were dark green and heavily spotted while the one incidental fish that I caught off the dock just a mile or so from the slough was a chrome bullet. I started surmising that the different colouration of the fish was because they were resident fish of different marine enviroments and their colouration had adapted accordingly.
Over the years I've kept in touch with several bioloigsts who have held the coastal cutthroat portfolio for Ministry of the Environment. In a conversation with one many years ago, who is now retired, he said (edited slightly, however almost copied verbatim) there are no clear indications that any of the Fraser cutthroat are truly sea run. Some wild fish have been captured in test fisheries in the New Westminister portion of the river so there certainly could be some Fraser fish who are.
Hatchery cutthroat, which are stocked into tributary locations from Maple Ridge to Agassiz and originating from broodstock taken generally above Mission, are virtually absent from the very lower Fraser, possibly suggesting that we are mostly dealing with fish that are migratory but do not leave the confines of the big river for downstream marine areas. The Fraser provides abundant food and there is probably no need to leave the system. These fish reach moderate size because food and other conditions are quite favourable.
He went on to say that Fraser coastal cutthroat can exist in three forms: anandromous (sea run form), fluvial or potadromous (large river form: think Fraser residents that migrate within the basin) and lacustrine (large lake form: think Pitt or Harrison)
The lower Fraser area (including the large lakes) is incredibly complicated when it comes down to the lifestyles of coastal cutthroat. These fish don't organise themselves into neat and separate categories like we would wish in order to make the picture more clear. Undoubtedly there are lots of situations where fish with different lifestyles are together at the same time and place.
So, in summary, while there may be some Fraser River cutthroat that are sea run, I believe that the vast majority, that we think are, aren't.
What's your opinion and why?
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Topic: Fraser sea-run cutthroat. Are they? (Read 3029 times)