 Aurora Trout Photos Courtesy of Robert McFarlane. |
 Aurora Trout |
 Aurora Trout Photos Courtesy of Robert McFarlane. |
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Content for this site written by Tyler Dunn.
1925 Story of the discovery of the Aurora Trout The Aurora's Recovery Strategy
Ontario Fishing
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Aurora TroutDESCRIPTION OF THE AURORA TROUT
(SALVELINUS TIMAGAMIENSIS) We have recently returned from the Timagami region of Ontario with specimens of a species of charr belonging to the S. alpinus - group, which upon examination and comparison appears to be new. The species is locally known as "Rainbow Trout," "Land-locked Salmon," and "Salmon-trout." Since none of the local names are truly applicable, we suggest that this beautifully. colored trout be known as the Aurora Trout. It may be described as follows: Salvelinus timagamiensis sp. nov. (Aurora Trout).
Type: 7969 Carnegie Museum Catalog of Fishes, 10.75 inches in total length. Paratypes 7970a-k, Car. Museum. Cat. of Fishes, ten specimens from 8.63 to 13.5 inches in total length; and one, head only, of a specimen 16.0 inches in total length. DESCRIPTION. Scales 47 to 50 about 240 to 250--41 to 44; scales from adipose fin to lateral line, 27; scales with pores about 130 to 137. Lower jaw (distance from tip to junction with the quadrate) in head, 1.43 to 1.60 (av., 1.50). Upper jaw (distance from tip of snout to end of maxillary) in head, 1.57 to 1.72 (av., 1.65). Maxillary extremely elongate. In large specimens (13·5 and 16 inches in total length) the maxillary extends beyond the vertical from the posterior margin of the eye a distance equal to the total length of the orbit, as measured from the anterior tip of the triangular orbital membrane to the posterior edge of the eyeball. In a specimen of S. namcycush (Lake Trout) of about the same size (U. S. N. M., 77,866) the maxillary extends beyond the posterior margin of the eye a distance equal to about only three-fourths of the length of the eyeball. In smaller specimens of the present species (8.5 to IO inches in total length) the maxillary extends beyond the vertical from the posterior margin of the eye a distance about equal to, or slightly less than, the length of the eyeball. This proportion is similar in specimens of S. fontinalis of the same size.
Distance from tip of snout to end of maxillary in smaller specimens about equal to the length of the pectoral fin and to the length of the longest caudal rays. In the larger specimens this distance is greater than the pectoral length. In species with a short maxillary, such as S. oquassa, this distance is much less than the pectoral length. Body robust; profile arched; and head
relatively broad and flattened or depressed. Depth at origin of
the dorsal, 1.04 to 1.18 (av.,1. I I) in length of head; and
this depth 4-44 to 4.90 (av., 4.65) in The distance from the posterior end of the base of the dorsal to the origin of 'the adipose fin is about equal to the length of the head. The distance from the tip of the snout to the base of the pectoral, 0.96 to 1.25 (av., I.II) in the distance from the dorsal to the adipose and 1.9 to 2.43 (av., 2.1 I) in the distance from the tip of snout to the origin of the dorsal. Pectoral 13-14; the pectoral is the longest of the fins, its length being about equal to that of the longest caudal rays and 1.4 to I.76 (av., 1.59) in head. The distance from the base of the pectoral to the base of the ventral is 3.01 to 3.42 (av., 3.28) in the length to the base of the caudal.
Ventral with 8-9 rays. The ventral is situated slightly anterior to the median line from the base of the dorsal; its origin being very slightly nearer the tip of the snout than to the base of the middle caudal rays. The distance from the base of the ventral to the origin of the anal is slightly less than the length of the head, being about equal to the length of the head, less half of the total orbital diameter, and is contained from 4-48 to 5.10 (av., 4.71) in the length to the base of the caudal. Anal with 9 rays. The height of the anal fin (measured from in front of the anterior base, or origin, to the tip of the third, and longest, ray) equals 0.6 to 0.77 (av., 0.67) of the distance from the ventral to the anal. The length of the anal base equals 0.58 to 0.69 (av., 0.64) of the height of the anal, The height of the anal in the younger specimens is greater than the distance from the posterior base of the anal to the lower base of the caudal, and in the larger specimens it is about equal to this distance. The anal fin is of about the same length as the pectoral fin, or slightly less. The distance from the posterior base of the anal to the lower base of the caudal (this measure men t cannot be accurately taken) is slightly greater than the distance from the posterior base of the adipose to the upper base of the caudal, containing the least depth of the caudal peduncle from I. to 1.63 (av., 1.28) times. The caudal in specimens of all sizes is slightly lunate or truncate, being very similar to that of S. fontinalis. It is never notched, or forked. The coloration we record is based upon notes made in the field from freshly captured specimens. A small specimen, sex indeterminate, about nine inches in length, has the dorsal surface uniformly iridescent dark olive-green which has a golden glint in the' sunlight. The sides become paler, below the lateral line becoming silvery, and gradually shading into the pure white abdomen. Alcoholic specimens, when revolved in the light, give off a steel-blue iridescence, indicating that this coloration is structural rather than pigmentary. Coloration uniform ,.ie., without spots, only one small specimen (797oc) showing faint traces of a darker dorsal mottling, I ris oval and black; margin of iris greenish golden. Belly pure white. Fins colored as in the adult, except that their inner border is white, instead of light lemon-yellow. A sexually mature female (7970j C. NI. Cat. Fishes) 13.5 inches ill total length has the dorsal coloration similar to younger specimens, but darker; the plumbeous color being uniform, progressively lighter ventrally, . Dorsal and caudal fins uniformly bluish or colorless. In some cases black pigment overlies the fin-rays of the dorsal; never, however, producing black spots, as in S.fonl1:nalis. Pectorals, ventrals, anal, and lower lobe of caudal. margined with clear white, then a solid ivory-black patch which tapers terminally to form a narrow bl<ick streak, which follows the white outer margin to its tip. Balance of all fins (except dorsal and caudal) bright crimson-madder, except ,inner third, which fades to a very pale lemon-yellow. Lower jaw and abdomen pure white; throat and branchiostegals outlined with dusky. Lateral spots, characteristic of most species of trout, are lacking in all of our specimens, except C. lVI. Cat. Fishes No. 7970j. On the left side, just below the lateral line this specimen has two spots, the anterior just above the tip of the pectorals, and the posterior anterior to the vertical from the ventrals. 1 Although our field-notes indicate that the dorsal region is colored dark olivegreen, no trace of this coloration is evident in the alcoholic specimens, which cause it to appear that the coloration of this region is dark bluish-silvery, or plum-colored These spots are
quite
similar to the typical ocelli of S. fontinalis , consisting of a
central
spot of crimson-madder surrounded by a very light blue aureola.
It
is our belief, based on observations made by the junior author
in
September, 1923, that, as the colder weather and, presumably,
the
breeding season approach, faint indications of the presence of
the
bicolored (red and blue) ocelli appear, and can be detected on
very
close examination. After several months of preservation in
alcohol,
several of our specimens show faint, irregular, colorless
blotches that
are in no wise similar to the sharply defined, yellow spots of
S. fontinalis
preserved under exactly similar conditions. There was, however,
no indication of these colorless areas at the time of capture.
DIFFERENTIATION. Although a member of the arctic or alpine charrs, (5. atpinus-
group of Regan), having the clear, or unmottled fins, and the
dentition,
of that group, this species has many resemblances to the
Brook trout (S. fontinalis), especially in the size and shape of the
maxillary
and in the truncate caudal fin, As pointed out in the
description of
the coloration, this similarity is enhanced by the presence in
one specimen (7970j) of two of the typical crimson spots of S.
fontinalis. The Canadian Red Trout, S. marstoni (Garman), the geographic range of which approaches most nearly that of the present species, is the only form of the "S. alpinus-group" which is not extremely restricted in its habitat. It has been recorded frOI11 a number of lakes in Quebec between Lac de Marbre or Marble Lake in Wakefield township, Ottawa County, north of the Ottawa River, down along the St. Lawrence River to Rimouski County on the south shore. A full list of localities for this species is given by Evermann and Goldsborough (Proc. BioI. Soc. Wash., XX, 1907, p. 104). S. marstoni is not at all closely allied to S. timagamiensis, since it has a relatively short maxillary, sharp recurved teeth on the tongue, which are quite feeble in , and a deeply cleft or forked tail. As emphasized in the original description by Garman (Science, XXII, 1893, p. 23) in S. mars/ani, "the caudal notch is deeper ... than in any other of the American forms, except S. namo.ycu.sli." The dorsal and anal fins arc also longer, each having thirteen rays. Differences in color would doubtless also be evident in living specimens. Colorplates of both sexes of S. 11Ia1'sl01l'i from drawings by Denton were published in the "Fifth Annual Report of the Com missioners of Fisheries, Game, and Forests of the State of New York" for 1899 (I900), under the caption, "The Canadian Red Trout." In the same series for the following year (Sixth Ann. Rept., 1900 (190r), pp. 353- 356), Mr. John Titcomb gave an interesting treatise on the life history and habits of this trout. For purpose of direct comparison we have received a specimen of S. marstoni, determined by Mr. Samuel Garman, from the Museum of Comparative Zoology and another Irorn the U. S. National Museum (No. 72,292) from the Laurentides National Park (Lake St. John District) of Quebec. From the Silver Trout of Monadriock Lake (S. agassieii Garman) S. timagamiensis differs considerably. In S. timagamiensis the maxillary is much longer and, as in S. fontinalis, the form is essentially depressed; while S. agassizii is a much slenderer fish, with a pointed snout and slightly notched caudal, contrasting with the blunt snout and truncate caudal of S. timagamiensis and S. fontinalis From the Blue-back Trout of the Rangeley Lakes (5. oquasso], S. timagamiensisis differentiated in several important structural details. In addition to having a longer l~laxillary S. timagamiensishas the ventral fins more anterior; the distance from the tip of the snout to the base of the ventral fins being less than that from this point to the base of the caudal. In S. oquassa these distances are approximately equal. The fact that S. timagamiensis possesses this extremely elongate maxillary serves to differentiate it immediately from all other species of Saloelinus of northeastern North America such as S. a/pinus, S. ali-pes, and S. aureolus, without a further consideration of structural and color-differences, which are numerous in each case. We have been enabled to make direct comparisons with most of the above species through the loan of a nice series of North American trouts by the U. S. National Museum, received through the courtesy of Professor Barton A. Bean.
DISTRIBUTION. Although our specimens of this trout are all from White Pine Lake, we saw small specimens of what were undoubtedly S. timaganrieu.sis in Clearwater Lake and know that specimens were caught in the small lake to the southwest of White Pine Lake. We were informed by Mr. Dick, of Gowanda, that this species occurs in the small pond formed by the creek running from Clearwater to Smoothwater Lake. Forest-rangers report its occurrence in Smith Lake, which is west of Smoothwater Lake. These bodies of water are all small lakes draining into Smoothwater Lake. Therefore this species may occur also in Apex, Parent, Lulu, Okiniada, Lady Dufferin, and Kennedy Lakes; thus constituting a total area of probable distribution of about eighty square miles. It is not known to occur in Smoothwater Lake. White Pine Lake (Fig. 4) is a body of clear water approximately three miles long and one-sixth of a mile wide. The region surrounding . it is an uninhabited wilderness of forest, consisting of pine, spruce, balsam, cedar, silver birch, and poplar, growing upon the almost bare Huronian diabase, which is the general rock-formation of this region. The lake-bottom is practically free of sediment, the stones being imbedded in a coarse sand and scantily covered with a growth of algai. There is but little growth of water-weeds, and the white and yellow pond-lilies, common in this region, are conspicuously absent. From these waters we have also taken specimens of S. fontinalis and of a Sucker We have been informed that S. namaycush (Lake Trout) has been taken in Srnoothwater Lake, where we have taken a few walleyed pike i Stizostediou) All of the smaller specimens of the Aurora Trout taken by
us
were
infested by a parasitic copepod, identified by Professor Charles
Branch Wilson as Satmincola edwardsii (Olssen). These parasites
were abundantly attached to all fins, especially to the dorsal.
The
caudal fins of the larger specimens, which, when taken, were
free
from this parasite. nevertheless showed scars or markings,
proving
earlier infestation. HISTORICAL. All of these specimens were not less than twelve inches or more than eighteen 'inches in total length. Not recognizing the species, but assuming that it was what was commonly and vaguely referred to as "Gray Trout" and "Salmon Trout," no attempt was made to preserve specimens, the salted skin of only one being brought out as a trophy. A search of the literature by the junior author failing to
positively
identify the fish, the senior author was consulted. Upon his
advice,
the matter was taken up with Dr. William C. Kendall of the U. S.
Bureau of Fisheries. In commenting, Dr, Kendall wrote that he
was
unable to make an identification but said: "For several
reasons, I do
not believe it to be a hybrid. It is quite possible that in
those waters
there is a hitherto unrecognized species." Acting upon this
suggestion,
on May IS, 1924, the junior author, accompanied by Mr. Charles
O. Goulding jr , of Pittsburgh, made a trip to Timagami to
collect
for the Carnegie Museum specimens of this and other trouts
native
to the region. However, because of extremely cold weather and
consequent poor angling, it was found impossible to carry out
the On July 31, 1924. the authors left with the same purpose in view. After travelling to Latchford, Ontario, it was necessary for five days to proceed by canoe and trail until White Pine Lake was reached. We there remained in camp for Four days, taking the specimens listed on August 7, 8, and 9. These were preserved in four percent. formaldehyde. Natural color photographs of several of the specimens, as well as of specimens of S. fontinalis from the Lady Evelyn River were taken. While encamped at this spot, we met Messrs. Marrit and Bruno, government rangers, stationed on Smoothwater Lake. They gave us general information concerning the distribution of S. timagamiensis. Mr. Dick of Gowganda visited Smoothwater and White Pine Lakes during our presence and gave us information concerning methods by which other anglers had taken numbers of this fish. These people, of course, were unaware that this was a distinct species, referring to them as "Rainbow Trout." HABITS. REPRODUCTION. Perhaps the best safeguard against its extinction lies in the long and difficult journey between the railroad and its habitat. DATA.
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