: Oncorhynchus Mykiss ... name going bye-bye?
02-19-2004, 06:03 AM
Quite a bit back in time now, there was some discussion as to whether Steelhead were, in fact, a specific enough specie (different enough from the rainbow trout0 to have its 'own name.'
Last I remember seeing it may not and there was strong consideration for lumping in steelhead into the trout family. Did this end up going anywhere??
I became convinced there's no difference in 1996. I was in Kamchatka with the Wild Salmon Center's Kamchatka Steelhead Project (KSP) for a few weeks. The scientists were in total agreement that it's all one species. One of the advantages of research in an untouched (by hatcheries, habitat degradation and lots of "management") wilderness steelhead fishery is to discover how things have naturally evolved.
On each of the three rivers we were on, there are three distinctive forms of O.Mykiss — resident rainbows, coastal steelhead and migratory (open sea) steelhead. But research showed that there was constant movement of fish from one group into the other — resident rainbows would become coastal steelhead, coastals would become residents and migratories, etc.
Even more interesting was this: on one of the rivers (in one year) the "steelhead" were 70% female, 30% male, the resident "rainbows" were the mirror opposite. Was this nature's way of protecting the species? . . . that if conditions "went to hell" in one environment (in the sea, in one year, for instance) the other "took up the slack"? Interesting question. It certainly suggests that it's nature's way of ensuring the health of a singular species.
Unfortunately, here we've pretty much destroyed nature's "wisdom". And we manage our rainbow and steelhead fisheries separately when we should possibly think of them as one.
02-19-2004, 12:39 PM
I suspect, most of 'us' already knew/guessed. In that thread the idea that all (vast bulk) of Adrom. fish 'un-erringly' return to their home river is another pipe dream.
As you noted above a lot of fish will go into a river system and go where conditions require for spawing purposes (think Toutle River/Mt. St. Helens as an over done example). I think these 'wandering fish' are a prime (as you noted above) insurance policy that continues runs even with a one-three year swing of 'bad' river conditions.
Only thing that bothers me about hatchery programs is they'll take a single brood-stock from one system and try to force feed it into another. That, IMHO, is the road to hell ... and completely against 'natures plan.'
But, back to the question: any 'news' on whether steelhead as a seperate group of fish will be dumped?
02-19-2004, 01:07 PM
Originally posted by wrke
Even more interesting was this: on one of the rivers (in one year) the "steelhead" were 70% female, 30% male, the resident "rainbows" were the mirror opposite.
This mirrors what hapens with brown trout/sea trout in Scotland. Most of the females migrate to sea and are classed as sea trout, while most of the males stay in the river and are classed as brown trout. The percentages vary according to food availability in the streams. If there is more food available in a given season, more of the females stay at home and become brown trout. If populations of fish decrease, the sea trout run falls dramatically and in some cases completely colapse, due to there being sufficient food to satisfy the fish in the river. There is also a Coastal form of brown trout these are refered to as Slob trout.
02-19-2004, 10:30 PM
I believe all cutts and rainbows (steelhead and src included) are now considered part of the Pacific salmon family Oncorhynchus. Salmo is reserved for European browns and atlantic salmon.
Nailknot is on the right track, the steelhead is considered to be the progenitor of all the Pacific salmonids. All salmonids wander and these "strays" are the means by which the species expand their range - as well as provide an policy in case of a natural disaster.
The rainbow is the landlocked version of the steelhead, they resulted from glacier related blockages of their spawning streams. These trapped fish residualized and continued to evolve in their landlocked habitats. This is contrary to the old belief that steelhead were rainbows "that went to sea", instead it is the other way around.
The other six Pacific salmon are "newer" species that evolved from the steelhead - hence the steelhead's re-classification as Onchorynchus. The Gairdeneri was replaced with Mykiss as research shows that the species was first classified in Russia well before it was documented in North America.
As for the males staying in the river, Nobuo (Cherry Pick) was just telling me the other day that with his favourite fish in Japan - the Cherry Salmon does just this. The females go to sea and return as 5-10 lb fish and the males stay in the river and are about 15" in length. Until a few days ago I had not heard this - now I see it again here in reference to other salmonids. Obviously this is just another twist from nature's bag of survival tricks! One learns something new all the time.
Kush is right about rainbows (steelhead) being the progenitors of Pacific salmonids.
The fish was first recorded in Kamchatka by George Wilhelm Steller and was classified by Johann Walbaum as Salmo Mykiss in 1792. More than forty years later, Meredith Gairdner collected specimens in the lower Columbia, sent them to the British naturalist Sir John Richardson in London in 1836. Richardson named the fish Salmo Gairdneri after it's donor. In 1990 all Pacific salmonids were classified as Oncorhynchus. And since the fish was initially discovered and classified in Russia it was renamed Oncorhynchus Mykiss.
The name Mykiss comes from the Koryak natives of Kamchatka, whose name for the fish was — is to this day — mikizha.
02-20-2004, 12:11 AM
Keep it coming!!
02-20-2004, 10:37 AM
Actually in 1990 the Pacific species in genus Salmo was combined with Oncorhynchus. The whitefish and char who are also salmonids were not included that move.
It is now know that rainbows are more than a landlock form of the species. Our anadromous streams downstream of all barriers have resident rainbows in the O. mykiss population complex. The literature is finding more and more examples of genetic exchange occurring between the resident and anadromous forms with examples of resident fish producing anadromous smolts and steelhead producing fish that remain all their lives in freswater. Steelhead and resident rainbows are behaving as a single species with multiple life histories that are less than rigid.
It is interesting in streams with summer steelhead we tend to find a large % of the population having the resident behavior. However on even winter streams resident fish are found. While in most of our winter streams it is rare to find a steelhead that is even 7 years old (a true giant) on the same streams I have seen rainbows as old as 10 years and as large as a small steelhead. As we see more restrictive harvest regulations (large minimum size limits, bait bans, and reduced bag limits) resident rainbows are becoming more common.
If you think about it having dual life histories is a good survival hedge against the variable survival conditions. For example; those population that have extremely low smolt to adult survival such as currently being experienced in the Georgia Straits and Puget Sound the population would have a safety net in the resident fish which would provide stability in recruitment of fry/smolts.
Smalma . . . right you are!
In my haste to write briefly, I forgot about the chars and whitefish as I was thinking only about the "trout".
Very interesting regarding residents becoming more common and the longevity differences in anadromous and residents. Also, are you aware of any change in management thinking that recognizes the anadromous and residents as a singular resource?
Also, as an interesting aside, back in 96, some (not all) of the Russian scientists were still a little skeptical about the Pacific trout being re-classified. They felt that there were still many similarities with Salmo, Mykiss especially with Salar. One was that all of the Pacific salmon are one-time spawners and all of the former Salmos are multiple spawners. I assume that by now they've accepted the reclassification.
I don't have my reference material at hand, but I remember an interesting "fact" about a difference between our NAmerican steelhead and the Kamchatka fish. Here, the normal percentage of mulitple spawners is fairly low (20%?), but in Kamchatka the percentage is very high (80%?) I can't remember the exact numbers, but I recall it was quite a significant difference. And the number of 3X spawners was also impressive (20%?).