Observations on Cyathocephalus truncatus Pallas, 1781 (Cestoda: Spathebothriidea) in its Intermediate and Definitive Hosts in a Trout Stream, North Wales

1966 ◽  
Vol 40 (1-2) ◽  
pp. 1-10 ◽  
Author(s):  
J. B. E. Awachie
Keyword(s):  
Brown Trout ◽  
Annual Cycle ◽  
Salmo Trutta ◽  
Feeding Habits ◽  
Age Groups ◽  
Older Age ◽  
Cottus Gobio ◽  
North Wales ◽  
Food And Feeding

Of the three species of fish which live in Afon Terrig (Salmo trutta, Cottus gobio and Nemacheilus barbatula), only S. trutta was infected by Cyathocephalus truncatus. The parasite has a clear annual cycle and hence a periodicity of occurrence in the brown trout.No age resistance of fish to infection by C. truncatus is found. The increase of incidence with age among l+—3+ year-old fish and decrease in the older age groups are correlated with the variation in the food and feeding habits of trout with age.

On the bionomics ofCrepidostomum metoecus(Braun, 1900) andCrepidostomum farionis(Müller, 1784) (Trematoda: Allocreadiidae)

Parasitology ◽  
1968 ◽  
Vol 58 (2) ◽  
pp. 307-324 ◽  
Author(s):  
J. B. E. Awachie
Keyword(s):  
Salmo Trutta ◽  
Time Lag ◽  
Ecological Factors ◽  
Life Cycles ◽  
Trophic Factors ◽  
Annual Cycles ◽  
Cottus Gobio ◽  
The United Kingdom ◽  
North Wales ◽  
History Of

The life-cycles of the two species ofCrepidostomumoccurring in a stream in North Wales are investigated. Both species share the same arthropod and definitive hosts, viz.Gammarus pulexandSalmo trutta, respectively, but have different molluscan hosts, viz.:Lymnaea peregraforC. metoecusandPisidium casertanumforC. farionis.C. metoecusandC. farionishave annual cycles, hence periodicity of occurrence in their hosts. InC. metoecusthe dynamics of occurrence in the three hosts are correlated. The inverse relationship inG. pulexandS. truttaas well as the existence of a time-lag of 3–4 months between the establishment of this worm inG. pulexand inS. truttaare discussed.Neither premunition nor age-resistance occurs in the parasitization ofS. truttaandG. pulexbyC. metoecus. The increase in the rate and degree of infestation with the age and length of fish, except in the oldest and longest group, is shown to be due to trophic factors.C. metoecusis more abundant and widely distributed in the stream thanC. farionis. This fact is associated with the occurrence of their molluscan hosts.Experimental observations were made on the stages in the life-history ofC. metoecus, including the mode of emergence of the cercaria, invasion of shrimps and encystment, as well as development of the metacercariae inG. pulex.More cercariae are shed by day and at higher temperatures, and they live for about 5 days at 8 °C. The metacercaria undergoes considerable development before becoming infective.C. metoecusdoes extensive damage toL. peregra, has no observed ill-effect on trout, and apparently affects the life-span of shrimps adversely only in cases of very heavy infestations.The non-parasitization ofCottus gobioby the two flukes is probably due to the prevailing ecological factors.My thanks are due to Professor H. B. N. Hynes and Dr J. C. Chubb for many helpful criticisms at all stages of this study; to Miss Joan Venn for helping with the sampling programme; and the Commonwealth Scholarship Commission in the United Kingdom for financial support.

Small-scale dispersal and population structure in stream-living brown trout (Salmo trutta) inferred by mark–recapture, pedigree reconstruction, and population genetics

2012 ◽  
Vol 69 (9) ◽  
pp. 1513-1524 ◽  
Author(s):  
Leif Asbjørn Vøllestad ◽  
Dimitar Serbezov ◽  
Arthur Bass ◽  
Louis Bernatchez ◽  
Esben Moland Olsen ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Isolation By Distance ◽  
Juvenile Fish ◽  
Age Groups ◽  
Small Scale ◽  
Mark Recapture ◽  
Small Stream ◽  
Brown Trout Salmo Trutta ◽  
Mature Fish

Many animals move among habitats, and even small-scale dispersal of individuals between habitat patches may have strong implications for population dynamics and structure. Here, we use long-term mark–recapture data combined with extensive genotyping and parentage assignment to investigate the importance of small-scale location change of resident brown trout ( Salmo trutta ) in a small stream (1500 m). During the first summer, juvenile fish dispersed downstream (mean displacement 200 m), with smaller juveniles dispersing longer distances. Downstream movement was also predominant during the first winter, but older fish moved little. This limited dispersal resulted in a significant isolation-by-distance structure for ages 1 and 2, but not for older age groups or for the mature fish. Individual pairwise relatedness coefficients decreased with waterway distance for mature fish during the 2002 and 2003 spawning seasons, but only weakly. Overall, between-site genetic differentiation was stronger for the younger age classes, and the signal decayed with age, indicating that the genetic structure observed in the stream is mainly driven by spatial aggregation of close relatives.

scholarly journals Influence of discharge, hydraulics, water temperature, and dispersal on density synchrony in brown trout populations (Salmo trutta)

2016 ◽  
Vol 73 (3) ◽  
pp. 319-329 ◽  
Author(s):  
Victor Bret ◽  
Benjamin Bergerot ◽  
Hervé Capra ◽  
Véronique Gouraud ◽  
Nicolas Lamouroux
Keyword(s):  
Water Temperature ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Age Groups ◽  
Negative Influence ◽  
Spawning Period ◽  
Emergence Period ◽  
Discharge Water ◽  
Brown Trout Salmo Trutta ◽  
Influence Of Substrate

Environmental factors may cause synchronous density variations between populations. A better understanding of the processes underlying synchrony is fundamental to predicting resilience loss in metapopulations subject to environmental change. The present study investigated the determinants of synchrony in density time series of three age groups of resident brown trout (Salmo trutta) (0+, 1+, and adults) in 36 stream reaches. A series of Mantel tests were implemented to disentangle the relative effects on trout synchrony of geographical proximity, environmental synchrony in key environmental variables affecting trout dynamics (discharge, water temperature, hydraulics, and spawning substrate mobility), and density-dependent dispersal. Results indicated that environmental synchrony strongly explained trout synchrony over distances less than 75 km. This effect was partly due to a negative influence on 0+ trout of strong discharges during the emergence period and a more complex influence of substrate mobility during the spawning period. Dispersal between reaches had a weak influence on results. Juvenile and adult densities were strongly driven by survival processes and were not influenced by environmental synchrony. The results suggest that the environment can have general effects on population dynamics that may influence the resilience of metapopulations.

Winter Habitat Utilization by Stream Resident Brook Trout (Salvelinus fontinalis) and Brown Trout (Salmo trutta)

1986 ◽  
Vol 43 (10) ◽  
pp. 1970-1981 ◽  
Author(s):  
Richard A. Cunjak ◽  
Geoffrey Power
Keyword(s):  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salvelinus Fontinalis ◽  
Focal Point ◽  
Age Groups ◽  
Habitat Utilization ◽  
Point Sources ◽  
Energetic Cost ◽  
Brown Trout Salmo Trutta

Habitat utilization by brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) is described from three winters of underwater observations in a southern Ontario river. Older trout (>age 1) generally occupied positions in deeper and faster water than age 0+ trout. In winter, at sites of sympatry, brown trout occupied greater focal point water depths than brook trout; both species had similar focal point water velocities. At all sites, and for both age groups and species, there was a strong preference for positions beneath cover. Relative to summer, trout positions in winter were characterized by slower water velocities and greater overhead cover, In winter, most trout were in aggregations, usually in pools beneath cover and close to point sources of groundwater discharge. Gregarious behaviour appeared to increase as water temperatures decreased; no such relationship was evident in the summer. Specific strategies for overwintering varied between sites and age groups but generally conformed to the theory of energetic cost minimization for position choice. These variable patterns appear to be adaptive.

Carry-over effects in brown trout (Salmo trutta): hypoxia on embryos impairs predator avoidance by alevins in experimental channels

2007 ◽  
Vol 64 (5) ◽  
pp. 786-792 ◽  
Author(s):  
Jean-Marc Roussel
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Saturation Level ◽  
Juvenile Period ◽  
Cottus Gobio ◽  
Brown Trout Salmo Trutta ◽  
Body Sizes ◽  
Carry Over ◽  
Similar Body ◽  
Early Juvenile Period

Laboratory experiments on brown trout (Salmo trutta) embryos suggest that sublethal stress in the gravel nest such as hypoxia may alter the behaviour and survival of fish during the early juvenile period. Eggs and embryos were incubated at constant temperature (8.2 °C ± 0.6 standard deviation) under nonlethal dissolved oxygen (DO) concentrations (3.0 mg·L–1; 26% air saturation level) and normoxia (10.3 mg·L–1 DO; 90% air saturation level). The average survival from fertilization to end of embryonic development was 70% and 85% for hypoxic and normoxic groups, respectively. Hypoxic embryos grew slowly compared with their normoxic counterparts, but similar body sizes were observed when yolk-sac absorption was completed. Fish incubated as hypoxic embryos delayed their emergence from the gravel in experimental channels. In presence of freshwater sculpin (Cottus gobio), their swimming activity was reduced by 20%, on average, and predation was enhanced by 14% compared with normoxic groups. Results support the view that subtle events early in a fish's ontogeny can have carry-over effects on later periods of its life cycle, and this phenomenon may be a significant source of variation in salmonid fitness.

scholarly journals Cottus gobio Linnaeus, 1758 Community Interest Species Conservation in Upper Târnava Mare River Basin, Through Fish Populations Rehabilitation for Brown Trout Zone Based on a Decision-Support Management System

2017 ◽  
Vol 9 (2) ◽  
pp. 5-10
Author(s):  
Cristina Cismaş ◽  
Doru Bănăduc ◽  
Voicu Răzvan ◽  
Curtean-Bănăduc Angela
Keyword(s):  
Brown Trout ◽  
Fish Species ◽  
Management System ◽  
Salmo Trutta ◽  
Conservation Status ◽  
Species Conservation ◽  
Management Decision ◽  
Cottus Gobio ◽  
Community Interest ◽  
Favourable Conservation Status

Abstract The ADONIS: CE software has been used for two fish species, Cottus gobio, of conservation interest and Salmo trutta fario, of economic interest, to design an on-site (upper Târnava Mare River) adapted support-system model for management decision-making. Habitat needs and indicators of favourable conservation status have been investigated, pressures and threats to these fish species have been determined, and management elements have been suggested. This management system allows the proper organization of management measures for the renaturation of the local natural fish associations in the local brown trout zone.

scholarly journals Assessment of trout populations inhabiting the Palena River, southern Chile

2021 ◽  
Vol 49 (1) ◽  
pp. 29-39
Author(s):  
Sandra Bravo ◽  
Ken Whelan ◽  
María Teresa Silva
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salvelinus Fontinalis ◽  
Feeding Habits ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Recreational Angling ◽  
Brown Trout Salmo Trutta ◽  
Gravid Females

A survey of trout species was carried out to assess the trout stocks' quality inhabiting the Palena River Basin, one of the most important rivers for recreational angling in Chilean Patagonia. Six sampling campaigns were carried out over 16 selected stretches of the river between February 2012 and June 2013. A total of 912 trout were collected, 57% rainbow trout (Oncorhynchus mykiss), 33.3% brown trout (Salmo trutta), and 9.6% brook trout (Salvelinus fontinalis). Also, one tiger trout (Salmo trutta × Salvelinus fontinalis) (a hybrid between brown and brook trout) was recorded. Results showed that both rainbow trout and brown trout shared the same reaches of the river, with very similar feeding habits, while brook trout inhabited smaller and more enclosed streams. Maturity stages (V-VI) were recorded from the fish sampled over the period spring-summer-autumn in the case of rainbow trout; autumn-winter for brook trout, and summer-autumn for brook trout. One of the study's most notable features was the small size of the mature brook trout, reaching 17.5 cm in length for gravid females and 12.4 cm for mature males at age 2+. The maximum age recorded for rainbow and brown trout was 6+, with a maximum length of 69.8 and 58.5cm, respectively, while for brook trout, the maximum age recorded was 3+ for a female with a length of 29.9 cm length and 2+ for a male of 16.6 cm.

scholarly journals Population status of the native Cottus gobio after removal of the alien Salmo trutta: a case-study in two Mediterranean streams (Italy)

2018 ◽  
pp. 22 ◽  
Author(s):  
Massimo Lorenzoni ◽  
Antonella Carosi ◽  
Massimo Giovannotti ◽  
Gianandrea La Porta ◽  
Andrea Splendiani ◽  
...  
Keyword(s):  
Brown Trout ◽  
Intraspecific Competition ◽  
Salmo Trutta ◽  
Central Italy ◽  
Fish Fauna ◽  
Inverse Correlation ◽  
Population Status ◽  
Mediterranean Streams ◽  
Cottus Gobio

In the Mediterranean area, one of the major threats to freshwater fish fauna is represented by the introduction of alien species. The bullhead, Cottus gobio, is a species of great conservation interest threatened by the massive introduction of hatchery-reared brown trout, Salmo trutta, for angling purposes. The aims of this research were: i) to present a case-study of interspecific and intraspecific competition in dwelling fish from two Mediterranean streams (central Italy); ii) to evaluate the bullhead population status before and after the alien brown trout removal, and iii) to investigate the influence of the environmental parameters on the abundance of both species. For the bullhead populations the abundances and the young-of-the-year percentage significantly increased after the removal activities. The growth analysis showed that, after the trout removal, bullhead were distinguished by greater performance and larger sizes in all age classes in comparison to the pre-removal period, while the condition factor (Kn) showed no differences, suggesting that the effects of trout population control acted mainly through predator-prey dynamics. An inverse correlation between the abundance of bullhead and its body condition suggested that the beneficial effects due to the reduction of predation could be compensated by the intraspecific competition due to the increase of the bullhead population density.

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