Sympatric Occurrence of Two Species of Humpback Whitefish in Squanga Lake, Yukon Territory

1963 ◽  
Vol 20 (3) ◽  
pp. 749-767 ◽  
Author(s):  
C. C. Lindsey
Keyword(s):  
Gonad Development ◽  
Morphological Characters ◽  
Yukon Territory ◽  
The Other ◽  
Coregonus Clupeaformis ◽  
Early Winter ◽  
High Count ◽  
Morphometric Characters ◽  
Yukon River ◽  
Gill Raker

Squanga Lake in the Canadian headwaters of the Yukon River contains two species of humpback whitefish, characterized by modal first arch gill raker counts of 23 and 28 but with overlap in the range of counts. The species can be separated more sharply by raker counts of the second arch, also with modes of 23 and 28. Seven other morphometric characters not correlated with gill raker count each have significantly different means, but some overlap, between the species.In June the species with high raker count mainly occupies the pelagic zone, while the low count species occupies the bottom layers at all depths. The high count species feeds mainly on plankton, the low count species on bottom organisms. The high count species spawns in inlet and outlet streams in November and December. Gonad development in June suggests that the low count form spawns later, in localities unknown. Samples from early winter spawning runs contained exclusively high count individuals. A few fish, probably hybrids, had raker count corresponding to one species and most other morphological characters corresponding to the other. Tentative names for the species are Coregonus clupeaformis (high gill raker count) and Coregonus pidschian.

Stocks are Chameleons: Plasticity in Gill Rakers of Coregonid Fishes

1981 ◽  
Vol 38 (12) ◽  
pp. 1497-1506 ◽  
Author(s):  
C. C. Lindsey
Keyword(s):  
Gene Flow ◽  
Northern Hemisphere ◽  
Phenotypic Variation ◽  
Morphological Characters ◽  
Yukon Territory ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Gill Rakers ◽  
Gill Raker ◽  
Coregonid Fishes

The characters that apparently render a stock of fish distinctive may in reality be a reflection of the presence or absence of other fish species with which the stock shares its environment. Over the northern hemisphere, the whitefish genera Coregonus, "Leucichthys," and Prosopium offer striking examples of morphological characters being displaced because of coinhabiting species. Whenever one of the groups is missing, another tends to shift its gill rakers so as to fill in the vacant part of the spectrum in gill-raker counts. Plankton-feeding lake whitefish (Coregonus clupeaformis) having many long gill rakers exist in several lakes sympatrically with bottom-feeding lake whitefish having fewer and shorter gill rakers, but only if the even more specialized plankton-feeding species of ciscoes are absent. Lake whitefish in Yukon Territory have on the average fewer rakers in those lakes that contain ciscoes than in those that do not. Artificial transplants demonstrate that gill-raker characteristics can change quickly in a new environment. Gill-raker count is less subject to phenotypically induced variation from environmental influences than are most morphological characters, but it is not immune. Partial hybridization, where bimodal populations are maintained by a balance between gene flow and selection, also poses special problems for the stock concept. When employing even relatively stable characters such as gill-raker counts, one should beware that the "stocks" may be chameleons which shift their appearance in response to the biological color of their surroundings.Key words: coregonids, whitefish, gill rakers, phenotypic variation, hybridization, selection, transplants, stocks

Phenotypic Variation in the Lake Whitefish, Coregonus clupeaformis, Induced by Introduction into a New Environment

1974 ◽  
Vol 31 (1) ◽  
pp. 55-62 ◽  
Author(s):  
J. S. Loch
Keyword(s):  
Feeding Habits ◽  
Morphological Characters ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Meristic Characters ◽  
Line Scale ◽  
Benthic Food ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Gill Raker ◽  
Electrophoretic Phenotype

Adult lake whitefish (Coregonus clupeaformis) from Clearwater Lake and second generation adults of offspring from Clearwater whitefish transplanted to Lyons Lake were compared with respect to morphometric and meristic characters and isozymes of L-glycerol-3-phosphate dehydrogenase (GPDH). Feeding habits and abundance of pelagic and benthic foods were compared in the two lakes.Gill raker number, lateral line scale count, and interorbital width remained constant between parental and offspring populations. Gill raker length was the main character found to differ between the populations. This was found to be related to the percentage and type of benthic food eaten. Abrasion of the gill rakers is offered as an explanation for the differences in gill raker length. Differences were found in various other meristic and morphological characters, as well as in electrophoretic phenotype frequencies of isozymes of GPDH.

Hemitriakis indroyonoi sp. nov., a new species of houndshark from Indonesia (Carcharhiniformes: Triakidae)

Zootaxa ◽  
2009 ◽  
Vol 2110 (1) ◽  
pp. 41-57 ◽  
Author(s):  
WILLIAM T. WHITE ◽  
LEONARD J. V. COMPAGNO ◽  
DHARMADI _
Keyword(s):  
New Species ◽  
Morphological Characters ◽  
The Other ◽  
Cranial Morphology ◽  
Morphometric Characters ◽  
Eastern Indonesia ◽  
Northwestern Australia ◽  
A New Species

A new species of the genus Hemitriakis Herre, 1923 (Family Triakidae, Order Carcharhiniformes), is described from off the islands of Bali and Lombok in eastern Indonesia. Hemitriakis indroyonoi is separable from the other congeners, H. abdita, H. complicofasciata, H. falcata, H. japanica and H. leucoperiptera, by a combination of vertebral counts, morphometric characters, and juvenile coloration. H. indroyonoi is most similar to H. falcata from northwestern Australia but differs in juvenile coloration, some meristic and morphological characters, size and cranial morphology. The new species is allopatric to other members of this genus.

Pleistocene Watershed Exchanges and the Fish Fauna of the Peel River Basin, Yukon Territory

1977 ◽  
Vol 34 (3) ◽  
pp. 388-395 ◽  
Author(s):  
R. A. Bodaly ◽  
C. C. Lindsey
Keyword(s):  
River Basin ◽  
Fish Fauna ◽  
Aquatic Organisms ◽  
River System ◽  
Yukon Territory ◽  
Glacial Refugium ◽  
Morphological Evidence ◽  
Coregonus Clupeaformis ◽  
Yukon River

The Peel River basin is a unique Canadian glacial refugium containing many relict fish populations. Peel River is presently tributary to the Mackenzie River system, but at least twice during Pleistocene glaciations it was diverted into headwaters of the Yukon River system, offering the possibility of two-way transfer of aquatic organisms between the Mackenzie and Yukon. Present fish distributions in the Peel basin are summarized. Biochemical and morphological evidence suggests that races of at least six species now inhabiting the area (Coregonus clupeaformis, Prosopium coulteri, Thymallus arcticus, Salvelinus namaycush, Esox lucius, Cottus cognatus) originated from types which either came from the Yukon River system or developed in situ in unglaciated parts of the Peel.

Jumbo spotted form of least cisco Coregonus sardinella in lakes of southern Yukon Territory

1982 ◽  
Vol 60 (11) ◽  
pp. 2783-2786 ◽  
Author(s):  
C. C. Lindsey ◽  
L. F. Kratt
Keyword(s):  
Yukon Territory ◽  
Sympatric Populations ◽  
Dissolved Solids ◽  
River Drainage ◽  
Yukon River ◽  
Gill Raker ◽  
Slow Growing

Four lakes on the upper Yukon River drainage contain a strikingly spotted jumbo form of least cisco, with fork lengths up to 452 mm, larger than all previously known lacustrine or anadromous forms. The jumbo fish, with high gill raker counts (48–52), are probably nonmigratory. They may in each lake represent parallel responses to high dissolved solids, little competition, and unusually favourable conditions for growth. Available material is insufficient to establish whether small specimens in these lakes are young or slow-growing individuals of the jumbo spotted form, or whether the lakes contain two sympatric populations.

Size At Sexual Maturity and Morphometric Variability in Three Populations of a Ustropotamobi Us Pallipes Pallipes (Lereboullet, 1858) According To a Restocking Strategy

Crustaceana ◽  
1997 ◽  
Vol 70 (4) ◽  
pp. 454-468 ◽  
Author(s):  
D. Romain ◽  
J.P. Mocquard ◽  
C. Souty-Grosset ◽  
F. Grandjean
Keyword(s):  
Sexual Maturity ◽  
Morphological Characters ◽  
Allometric Equation ◽  
Canonical Discriminant Analysis ◽  
The Other ◽  
Morphometric Characters ◽  
Relative Growth ◽  
Size At Sexual Maturity ◽  
Reference Parameter ◽  
Two Populations

AbstractSize at sexual maturity was determined by the allometric equation in three populations of Austropotamobius pallipes pallipes from the Poitou-Charentes region, France. Seven morphological characters were measured and POL (post orbital length) was used as a reference parameter. The puberal moult was identified by changes in the relative growth of CW (claw width) and CL (claw length) in both sexes. Males have shown variation of the relative growth of CW and CL at 19.15 mm of POL for the Gatineau (Gat) stream, 20.1 mm of POL for the Magnerolle (Mag) and 20.3 mm for the Fontaine Saint-Pierre (Fsp) populations, respectively. Sexual maturity of females occurred at 16.17 mm POL for the Fsp, 18.2 mm for the Mag and for the Gat. Geographic variation in A. pallipes was investigated using multivariate analysis of five morphometric characters on mature specimens. By canonical discriminant analysis, the Mag population was distinct from the other two populations. Results are discussed with regard to restocking strategy.

scholarly journals Assessment of Morphometric and Genetic Variation in Three Freshwater Fish Species of the Genus Garra (Osteichthyes: Cyprinidae)

2011 ◽  
Vol 3 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Arulraj DHINAKARAN ◽  
Nabeel Mannalamkunnath ALIKUNHI ◽  
Selvaraj CHINNATHAMBI ◽  
Ramaiya SORNAM ◽  
Murugaiyan KALAISELVAM ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Fish Species ◽  
Similarity Index ◽  
Morphological Characters ◽  
The Other ◽  
Morphometric Characters ◽  
Disc Width ◽  
Rapd Pcr ◽  
Finger Printing ◽  
First Time

The present study evaluated the patterns of morphometric and genetic variation using RAPD-PCR techniques for the first time on three species of Garra, viz. G. mullya, G. kalakadensis and G. gotyla stenorhynchus, collected from various river basins of South-India. The results of morphological analysis revealed that G. mullya and G. kalakadensis hold many similar characters compared to the other congener, G. gotyla stenorhynchus. However, the G. gotyla stenorhynchus fish species exhibited distinct variation in the morphological characters such as snout length, pre-nasal length, inter-nasal width, gap width, lower jaw to isthmus, head depth at pupil, dorsal fin length and disc width from the other two species of Garra. However, certain morphometric characters overlapped. Hence the RAPD finger printing was used to assess the levels of genetic variation in Garra spp. using RAPD-PCR technique. A total of 72 reliable fragments were detected using 10 Operon primers, ranging from 2600 molecular weight to 3100. The shared RAPD fragments found in both G. mullya and G. kalakadensis with fixed frequencies were observed with all the investigated primers, implying their genetically closer relationship. However, the similarity index observed for G. gotyla stenorhynchus was less with the other two species specifying a genetically distant link. The present investigation thus contribute to the knowledge on morphological and genetic variation in these three Garra species.

Morphological and Ecological Divergence Within the Lake Whitefish (Coregonus clupeaformis) Species Complex in Yukon Territory

1979 ◽  
Vol 36 (10) ◽  
pp. 1214-1222 ◽  
Author(s):  
R. A. Bodaly
Keyword(s):  
Lake Water ◽  
Species Complex ◽  
Yukon Territory ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Sympatric Populations ◽  
Gill Rakers ◽  
Growth Divergence ◽  
Gill Raker ◽  
Plankton Feeders

Two forms of lake whitefish (Coregonus clupeaformis species complex sensu McPhail and Lindsey [1970]) were found in each of five lakes in Yukon Territory. They are characterized by differences in gill raker counts. Low gill raker fish are benthic feeders and are found almost exclusively near the bottom while high raker fish are largely plankton feeders, being found throughout the lake water column. High raker fish have longer and more closely spaced gill rakers than low raker fish. They also have shorter life spans and mature earlier than low raker fish. Lakes supporting these sympatric populations of lake whitefish have no cisco populations. The low gill raker member of these sympatric populations seems to be equivalent to most other Yukon lake whitefish whereas the high raker member appears to be the unusual member of each sympatric pair. Key words: whitefish, lake, feeding, morphology, growth, divergence, Yukon Territory, sympatric populations

UV ability to inactivate microorganisms combined with factors affecting radiation

1997 ◽  
Vol 35 (11-12) ◽  
pp. 107-112 ◽  
Author(s):  
A. M. Shaban ◽  
G. E. El-Taweel ◽  
G. H. Ali
Keyword(s):  
Microbial Communities ◽  
Uv Radiation ◽  
Contact Time ◽  
Tap Water ◽  
Scenedesmus Obliquus ◽  
Morphological Characters ◽  
The Other ◽  
Bacterial Cells ◽  
Dark Repair ◽  
Nile Water

In the present study, the effect of UV radiation on the inactivation of a range of microorganisms was studied. Each organism was seeded into sterile tap water and exposed to UV in batch experiments with changing turbidities. In addition, the effect of UV on microbial communities in river Nile water was examined. It was found that 1min contact time (0.5L/min flow rate) was effective against vegetative cells levels almost reaching zero (except with Staphylococcus aureus). On the other hand, spore-forming bacteria, Candida albicans and coliphage were more resistant to UV. This contact time caused coenobia cells in single form with Scenedesmus obliquus while for Microcystis aeruginosa colonies broke into smaller groups. Exposure of Nile water microbial communities to UV showed that yeasts and Aeromonas survived better than the other organisms while in the phytoplankton partial fragmentation occurred in some algal groups. The protective effect of turbidity differed between organisms, with increased contact time under conditions of stable turbidity having no effect on the organisms. At 20 NTU the UV radiation had no effect on the morphological characters of algal cells. In reactivation experiments, it is clear that photoreactivation, and not dark repair, takes place with bacterial cells. Only coliphage had no photoreactivation and dark repair responses although with coliphage and host, both reactivation processes worked well. Moreover, the irradiated algae regained their normal shape after 3 days in suitable media and enough light.

Phylogenetic analysis of the subfamily Hylodinae (Anura, Leptodactylidae) based on morphological characters

2005 ◽  
Vol 26 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Francisca do Val ◽  
Paulo Nuin
Keyword(s):  
Phylogenetic Analysis ◽  
Phylogenetic Relationships ◽  
Maximum Parsimony ◽  
Morphological Characters ◽  
The Other ◽  
The Family

AbstractThe systematics and phylogenetic relationships of the family Leptodactylidae are controversial as is the intrafamilial phylogeny of the leptodactylids. Here we analyze the relationships of the leptodactylid subfamily Hylodinae. This subfamily has been considered to be monophyletic and composed of three genera, Hylodes, Crossodactylus and Megaelosia. In the present study 49 characters were used, based on different studies on Leptodactylidae phylogeny. Maximum parsimony methods with unweighted and successively weighted characters were used to estimate the phylogeny of the Hylodinae. Upon analysis, the data provided further evidence of the monophyletic status of the three genera, with Megaelosia being the basal genus and the other two genera being sister taxa. The analysis with successive weighting results in a more resolved topology of the species subgroups of the genus Hylodes and separates this genus from Crossodactylus and confirms that the hylodines are monophyletic.

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