Assessment of Fin Erosion by Comparison of Relative Fin Length in Hatchery and Wild Trout in Utah

1994 ◽  
Vol 51 (3) ◽  
pp. 636-641 ◽  
Author(s):  
Thomas Bosakowski ◽  
Eric J. Wagner
Keyword(s):  
Rainbow Trout ◽  
Body Length ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Cutthroat Trout ◽  
Total Body Length ◽  
Wild Fish ◽  
Fish Length ◽  
Total Body ◽  
Fin Length

We measured all fins of 600 hatchery trout sampled from all 10 state fish hatcheries in Utah, and of wild fish sampled as controls comprising 58 rainbow trout (Oncorhynchus mykiss), 33 cutthroat trout (O. clarki), and 54 brown trout (Salmo trutta). A strong linear correlation was found between fin length and total body length (100–300 mm) for all fins of wild rainbow trout. "Relative fin length" (fin length/total body length × 100) proved to be a useful comparative measure, as this statistic was not biased by fish length in the wild fish sampled (all slopes <0.01%). Interspecific comparison of wild rainbow, cutthroat, and brown trout showed slight but statistically significant differences in some fin lengths. In intraspecific comparisons, hatchery fish had significantly shorter (10–50%) rayed fins than wild fish. The dorsal fin was most severely eroded in rainbow and brown trout, followed by the pectoral, anal, ventral, and caudal fins, in cutthroat trout the pattern was the same except that pectoral fins had more extensive erosion than dorsal fins. No species was clearly more susceptible to fin erosion in hatcheries, but the Fish Lake – DeSmet strain of rainbow trout had significantly shorter fins than other rainbow trout strains.

Trends in the Distribution and Abundance of Yellowstone Cutthroat Trout and Nonnative Trout in Idaho

2014 ◽  
Vol 5 (2) ◽  
pp. 227-242 ◽  
Author(s):  
Kevin A. Meyer ◽  
Erin I. Larson ◽  
Christopher L. Sullivan ◽  
Brett High
Keyword(s):  
Rainbow Trout ◽  
River Basin ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Cutthroat Trout ◽  
Snake River ◽  
Trout Population ◽  
Yellowstone Cutthroat Trout ◽  
Over Time

Abstract The distribution and abundance of Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri across their native range is relatively well-known, but evaluations of trends in distribution and abundance over time are lacking. In 2010–2011, we resurveyed 74 stream reaches in the upper Snake River basin of Idaho that were sampled in the 1980s and again in 1999–2000 to evaluate changes in the distribution and abundance of Yellowstone cutthroat trout and nonnative trout over time. Yellowstone cutthroat trout occupied all 74 reaches in the 1980s, 70 reaches in 1999–2000, and 69 reaches in 2010–2011. In comparison, rainbow trout O. mykiss and rainbow × cutthroat hybrid occupancy increased from 23 reaches in the 1980s to 36 reaches in 1999–2000, and then declined back to 23 reaches in 2010–2011. The proportion of reaches occupied by brown trout Salmo trutta and brook trout Salvelinus fontinalis was largely unchanged across time periods. Yellowstone cutthroat trout abundance declined from a mean of 40.0 fish/100 linear meters of stream in the 1980s to 32.8 fish/100 m in 2010–2011. In contrast, estimates of abundance increased over time for all species of nonnative trout. Population growth rate (λ) was therefore below replacement for Yellowstone cutthroat trout (mean  =  0.98) and above replacement for rainbow trout (1.07), brown trout (1.08), and brook trout (1.04), but 90% confidence intervals overlapped unity for all species. However, λ differed statistically from 1.00 within some individual drainages for each species. More pronounced drought conditions in any given year resulted in lower Yellowstone cutthroat trout abundance 1 y later. Our results suggest that over a span of up to 32 y, the distribution and abundance of Yellowstone cutthroat trout in the upper Snake River basin of Idaho appears to be relatively stable, and nonnative trout do not currently appear to be expanding across the basin.

Role of the crayfish Cherax destructor clark as food for trout in Lake Eucumbene, New South Wales

1983 ◽  
Vol 34 (3) ◽  
pp. 407 ◽  
Author(s):  
RA Faragher
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Salmo Trutta ◽  
New South ◽  
New South Wales ◽  
Water Levels ◽  
Size Analysis ◽  
Fish Length ◽  
Freshwater Crayfish ◽  
South Wales

The freshwater crayfish C. destructor was a major dietary item for brown trout, Salmo trutta L., and rainbow trout, S. gairdneri Richardson, in Lake Eucumbene, New South Wales. The incidence of crayfish in the diet increased, particularly in brown trout, over the period 1972-1977. The proportion of the trout's diet comprising C. destructor increased with length of brown trout but not with length of rainbow trout. The size of crayfish ingested was postively correlated with fish length for both species of trout, although rainbow trout tended to ingest smaller crayfish than brown trout of equivalent size. Analysis of the crayfish's diet revealed predominantly plant material. Spawning by the crayfish was apparently confined to the period December-April. The abundance of C. destructor in Lake Eucumbene was apparently low until about 1970 but increased between 1972-1977. A decline in the average size of brown and rainbow trout in the angler catch occurred from 1959-1960 until 1977-1978. Hypotheses are suggested for the increase of the crayfish population since impoundment of the lake (1957). Factors considered include predation by trout and the biology of the crayfish, particularly related to its occurrence in this lake, which has fluctuating water levels and a short season suitable for growth and spawning.

Transmission of Bacterial Kidney Disease from Wild to Stocked Hatchery Trout

1981 ◽  
Vol 38 (5) ◽  
pp. 547-551 ◽  
Author(s):  
Douglas L. Mitchum ◽  
Loris E. Sherman
Keyword(s):  
Rainbow Trout ◽  
Kidney Disease ◽  
Brown Trout ◽  
Disease Transmission ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Horizontal Transmission ◽  
Wild Fish ◽  
Salmo Gairdneri ◽  
Bacterial Kidney Disease

Natural, horizontal transmission of bacterial kidney disease (BKD) from infected wild brook trout (Salvelinus fontinalis) to newly stocked hatchery brook trout, brown trout (Salmo trutta), and rainbow trout (Salmo gairdneri) was shown in a small lake and stream system in southeastern Wyoming, USA. Stocked trout were infected naturally and died in 9 mo or less after exposure to infected wild fish. Dead and live fish collected from each of three stations were necropsied. Fluorescent antibody techniques (FAT) were used to detect the BKD organism in all samples. Low severity infections were often detected by FAT at a higher rate when feces were examined as compared to kidney tissues from the same fish. Because other known pathogens were essentially absent, BKD was diagnosed as the cause of all deaths in both stocked hatchery fish and wild fish. Rainbow trout were found to be the most refractory species.Key words: bacterial kidney disease, natural disease transmission, wild trout, brook trout, brown trout, rainbow trout, epizootics

scholarly journals Modelling the factors influencing ontogenetic dietary shifts in stream-dwelling brown trout (Salmo trutta)

2018 ◽  
Vol 75 (4) ◽  
pp. 590-599 ◽  
Author(s):  
Javier Sánchez-Hernández ◽  
Fernando Cobo
Keyword(s):  
Body Length ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Prey Availability ◽  
The Body ◽  
Habitat Characteristics ◽  
Water Current ◽  
Fish Length ◽  
Water Current Velocity ◽  
Brown Trout Salmo Trutta

Biotic and abiotic variables shape ontogenetic trajectories of animals. This study modelled (i) the body length related timing of the ontogenetic switch from aquatic to surface prey and (ii) the impacts of habitat characteristics, prey availability, and fish densities on the relative contribution of surface prey to the overall diet of native brown trout (Salmo trutta). We used individual-based models of dietary data for 170 fish (length range 48–343 mm). There was a high degree of individual variation in the use of surface prey, but logistic regression suggested that the shift from aquatic to surface prey was established at a body length of 81 mm (range 36–127 mm). Results of linear mixed-effects models highlighted the importance of fish length, benthic invertebrates, brown trout density, and water current velocity to the switch to surface prey by riverine brown trout, with fish length being the most influential variable. Our study provides evidence of the importance of ontogeny (intrinsic features of individuals linked to fish length) and individual differences in feeding behaviour to understand water-column use for feeding by stream-dwelling salmonids.

scholarly journals Population Estimation of Oncorhynchus mykiss, Salmo trutta and Schizothorax plagastimous in Upper River Swat, Khyber Pakhtunkhwa, Pakistan

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Ullah F ◽  
◽  
Khan T ◽  
Hayat S ◽  
Ali S ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Body Length ◽  
Brown Trout ◽  
Salmo Trutta ◽  
The Body ◽  
Population Status ◽  
Khyber Pakhtunkhwa ◽  
Wet Weight ◽  
The Mean

This study was designed to assess the population status of Oncorhynchus mykiss (Rainbow trout), Salmo trutta (brown trout) and Schizothorax plagastimous (swati fish) in river Swat. Data were collected from four Sub- Areas (SAs) namely Madyan (SA1), Mankiyal (SA2), Kalam (SA3) and Mahoo Dhand (SA4). Fishes captured with electrofisher were identified morphologically and the wet weight and body length were determined. A total of 502 fishes were captured and identified. The highest capture (206) was recorded at SA4 whereas the lowest (64) at SA1. Similarly the highest captured specie (276) was Salmo trutta while the lowest (22) was Schizothorax plagastimous. The body length ranged from 15-36 centimeters whereas the wet weight varied from 47- 304 grams. Out of 502 fishes, 64, 104, 124 and 206 were from SA1, SA2, SA3 and SA4, respectively. The mean wet weight of Oncorhynchus mykiss, Salmo trutta and Schizothorax plagastimous 137.15g, 124.57g and 138.85g, respectively.

Effects of Fish Introductions and Hydroelectric Development on Fishes in the Kananaskis River System, Alberta

1965 ◽  
Vol 22 (3) ◽  
pp. 721-753 ◽  
Author(s):  
J. S. Nelson
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Cutthroat Trout ◽  
River System ◽  
Hydroelectric Development ◽  
Fish Introductions ◽  
Longnose Suckers ◽  
Abundance And Distribution

Changes occurred in the abundance and distribution of fishes in the Kananaskis River system, Alberta, in conjunction with fish introductions and hydroelectric development. Data from surveys from 1936 to 1961 indicate the probable chronology of events.Dolly Varden (Salvelinus malma), brook trout (S. fontinalis), cutthroat trout (Salmo clarkii), and rainbow trout (S. gairdneri) decreased in abundance, probably due to the introduction of brown trout (Salmo trutta), longnose suckers (Catostomus catostomus), and white suckers (C. commersonii), to the cooling of the Kananaskis River from reservoir construction, and to sport fishing. Hybridization between rainbow and cutthroat trout was also important in the decrease of the latter species. After introduction by man, brown trout, rainbow trout, longnose suckers, white suckers, lake chub (Hybopsis plumbea), and longnose dace (Rhinichthys cataractae) greatly increased in abundance. Prior to the increase in numbers of white suckers, a reduction in the numbers of longnose suckers occurred in Lower Kananaskis Reservoir. Little change in the distribution of mountain whitefish (Prosopium williamsoni), longnose dace, and brook sticklebacks (Culaea (= Eucalia) inconstans) occurred over the 25 years. Changes in the physicochemical environment and invertebrate fauna in the reservoirs appeared to be of secondary importance to the interaction among fish in causing the changes in species abundance and distribution.

Reflecting materials in the eyes of three teleosts, Orthopristes chrysopterus, Dorosoma cepedianum and Anchoa mitchilli

1973 ◽  
Vol 184 (1074) ◽  
pp. 15-27 ◽  
Keyword(s):  
Body Length ◽  
Pigment Epithelium ◽  
Total Body Length ◽  
Gizzard Shad ◽  
Dorosoma Cepedianum ◽  
Anchoa Mitchilli ◽  
First Report ◽  
Total Body ◽  
Bay Anchovy

The tapeta lucida of three species of teleosts were examined to determine the composition of the reflecting material. The fishes were bay anchovy Anchoa mitchilli (Engraulidae), gizzard shad Dorosoma cepedianum (Clupeidae) and pigfish Orthopristes chrysopterus (Haemulidae). The tapetum of each species was situated in the pigment epithelium of the eye. That of the pigfish contained triglycerides identified as chiefly glyceryl tridocosahexaenoate. A reduced pteridine, 7, 8-dihydroxanthopterin, occurred in the tapetum of the gizzard shad. Guanine occurred in the tapetum of the bay anchovy. The tapetum of the shad contained brightly reflecting particles about 0.5 μm in diameter There were 10.8 mg of dihydroxanthopterin in the tapetum of a shad (total body length 23 cm) and 0.46 mg of guanine in the tapetum of an anchovy (total body length 9 cm). This is the first report of a pteridine acting as a retinal reflector in vertebrates. Various aspects of retinal reflectors of teleosts are discussed and their variety and common characteristics commented upon.

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