David (Say hello to Tom Dresser) and Wes,
I sent that person an e-mail, but it was returned- the account was
expired.
In regards to correctly identifying bull trout from Dolly Varden, It is
extremely difficult to differentiate the two species in the field
(Although its easy to send a fin clip to the lab). The only scientific
way to do this in the field is to use the Hass Linear Discriminate
Function (see below). I do not recommend that anglers try and count and
measure the variables because it takes quite a long time and you would
probably stress the fish beyond its limit to recover (Branchiostagal and
anal fin rays are very difficult to count).
This summer I caught some small resident native char (<190 mm) above Sol
Duc Falls, which are known to be pure Dolly Varden (Not all Dolly Varden
are anadromous). These Dolly Varden had small heads that looked like
rainbows, and did not look at all like the bull trout I have seen in
Eastern Washingtin! When I fish the Skagit system, which is known to
contain both char species, I cannot I.D. the char to species with 100%
certainty!
The article from the Skagit Valley Herald was in response to the USFWS
proposal to utilize a provision in section 4(e) of the Endangered Species
Act "Similarity of Appearance"; see Federal Register 66:1628 (Jan 9,
2001). Karolee had the reporter call me, and I talked to her for 1/2
hour about the fish. It seems as though IUve missed my chance of being
quoted in the Skagit Valley Herald- I'm crushed. The USFWS proposes to
use the provision, because we foresee people utilizing misidentification
as a way to try and get out of enforcement violations. The reporter
thought that this proposal was aimed at anglers- it is not! When the bull
trout was listed, the USFWS determined that "existing" fishing regulations
were adequate to "conserve" the species. As you know, the State treats
bull trout and Dolly Varden as "Native Char", so if catch and keep is
allowed, such as in the Skagit, Snohomish and one small eastside river, it
does not matter what species you retain. The proposal is intended for
"harm and harass" type violations, such as destruction of habitat.
I'm not a taxomomist, but I personally feel that bull trout and Dolly
Varden should be subspecies. As most of you know, cutthroat trout have
10+ subspecies. Kurt Kraemer (WDFW) believes that bt/DV are spawning
together in the Skagit system, this would indicate that a "biological
species" type approach in identifying them as separate species is
incorrect. The American Fisheries Society (1980) concluded that
morphological and genetic work from Ted Cavender (1978) and others was
sufficient to separate bt/DV.
Here is an abstract from a true bull trout/Dolly Varden expert- Gordon
Hass.
Haas, G. R. and J. D. McPhail (1991). "Systematics and distributions of
Dolly Varden (Salvelinus malma) and bull trout (Salvelinus confluentus) in
North America." Canadian Journal of Fisheries and Aquatic Sciences 48(11):
2191-2211.
"Dolly Varden char in North America separate into two species: Doll Varden
(Salvelinus malma (Walbaum)) and bull trout (Salvelinus confluentus
(Suckley)). Principal component analyses reveal two distinct
morphotypes, and a linear discriminate function is derived (based on three
field measurable variables) for their consistent classification. No single
character can always distinguish both species, although branchiostegal ray
number often will. The morphology of the two species remains relatively
constant across their large ranges. The two species occur in strict
sympatry in several areas with no evidence of interbreeding. The two
species also exist parapatrically or syntopically and appear to exhibit
broad scale competitive exclusion in these situations. Dolly Varden are
distributed largely along the coast and range further north, while bull
trout are mostly interior and range further south. Laboratory crosses
demonstrate that the morphology of both species distinctive when they age
reared under similar conditions and that their artificial hybrids are
morphologically intermediate. No such natural hybrids were conclusively
found, and there is no evidence of introgression."
I'm sure that by now, you are dying to see the Linear Discriminate
Function. Here it is-
LDF=.629BR + .178AFR + 37.10 UJL/SL - 21.8
Where BR represents the total Branchiostagal Rays (both sides), AFR =
total Anal Fin Rays, UJL = Upper Jaw Length and SL = Standard Length.
When you measure the four parameters and compute the equation, values
greater than zero are bull trout, values less than zero are Dolly Varden.
The main problem with the Hass LDF is that people are more likely to count
fewer than actual branchiostagal or anal fin rays. Since Dolly Varden
have lower numbers of branchiostagal rays, and sometimes lower counts of
anal fin rays; miscounts almost always favor a Dolly Varden conclusion.
If anyone catches "Native Char" in the salt, please let me know!
___________________________________________________________________
On Sat, 27 Jan 2001, David Duvall wrote:
> Scott,
>
> Several weeks I sent you an email of a guy who spent considerable time
> fishing and catching bull trout/dollies in the salt. Perhaps a year ago, you
> mentioned on this list that you were looking for info on these species in
> the salt. I was just wondering if this guy was a flake or if he was able to
> help you out. A couple of weeks ago the "Skagit Valley Herald" ran an
> article on bull trout/dollies. They quoted Karolee Owens (you probably know
> her since she is a USFW'er too) and Curt Kraemer, but I am still confused.
> I have talked to Dr. Paul James at CWU and he said it is virtually
> impossible to distinguish between the two, yet many people say they can. I
> am somewhat fascinated by these two species and would love to be able to ID
> them each when I see them, if possible. I am a temp bio for Grant Co. PUD
> and I currently have another month before I go back to work (lots of time on
> my hands). You got any suggestions?
>
> David Duvall
>
>
>
>
>
>
>
> ----- Original Message -----
> From: Scott Craig <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Wednesday, January 24, 2001 7:13 PM
> Subject: FYI- WDFW FF angling proposal
>
>
> > WDFW is seeking comments on the following propsal-
> >
> > see http://www.wa.gov/wdfw/do/newreal/jan2201a.htm
> >
> > Proposal would allow anglers with certain disabilities to use spin gear in
> > fly fishing-only waters
> >
> > Olympia- At its next regular meeting in February, the Washington Fish and
> > Wildlife Commission will hear public testimony and consider a proposal
> > that would allow anglers with permanent disabilities to their upper
> > extremities reasonable access to waters designated fly fishing-only.
> > The meeting is scheduled for Feb. 9 and 10 at the Best Western
> > Southcenter, 15901 West Valley Road, Tukwila. The exact time the issue
> > will appear on the agenda is still to be set; check the agency's web site
> > for details later this month or call the Commission office at (360)
> > 902-2267.
> > Current fishing regulations allow only fly-fishing gear, which typically
> > requires two hands and mobility, to be used in waters designated as "fly
> > fishing-only." There are 20 waters in Washington designated for fly
> > fishing-only. Under current regulations, anglers with disabilities cannot
> > effectively take advantage of the opportunities these waters provide.
> > Allowing anglers with disabilities use of spinning gear to fish on these
> > waters will provide them access to these opportunities, because spin gear
> > may be operated with one hand.
> > The issue was raised this past fall when an angler with a permanent
> > disability protested changing North Silver Lake in Spokane County to a fly
> > fishing-only water, contending that restrictions on fly fishing gear limit
> > his ability to fish in fly fishing-only water. Subsequent discussions
> > between the angler, USFWS, the state Attorney General's Office and the
> > WDFW resulted in an agreement to modify the agency's fly fishing-only
> > definition.
> > Commissioners are expected to take testimony, then discuss and decide on
> > the proposed regulation change. The proposed rule would allow anglers with
> > the inability to use one or both upper extremities to apply for a
> > fly-fishing special use permit by presenting a letter from a physician.
> > The fisher would be issued a special use permit in the form of a letter,
> > which he or she would be required to carry while using spin-casting gear
> > in fly fishing-only waters.
> > Gear regulations with the special permit would include:
> >
> > * Spin-casting gear with a casting bubble would be allowed.
> > * Monofilament line with no limit on the breaking strength of the
> > line would be allowed.
> > * The leader beyond the bubble could not exceed 15 feet in length or
> > have a breaking strength greater than 12 pounds.
> >
> > Hook size and barb restrictions, fly fishing requirements and bait and
> > weight prohibitions would not change.
> >
> >
> >
> ****************************************************************************
> > Scott D. Craig The members of this genus (Salvelinus)
> > Fisheries/Aquatic Biologist are by far the most active and handsome
> > U.S. Fish & Wildlife Service of the trout, they live in the coldest,
> > Lacey, WA. cleanest and most secluded waters.
> >
> > Check out the homepage No higher praise can be given to a
> > http://www.eskimo.com/~craigs Salmonid than to say, it is a charr.
> > (Jordan and Evermann 1896)
> >
>
>
****************************************************************************
Scott D. Craig The members of this genus (Salvelinus)
Fisheries/Aquatic Biologist are by far the most active and handsome
U.S. Fish & Wildlife Service of the trout, they live in the coldest,
Lacey, WA. cleanest and most secluded waters.
Check out the homepage No higher praise can be given to a
http://www.eskimo.com/~craigs Salmonid than to say, it is a charr.
(Jordan and Evermann 1896)
