Use of long‐term (40+ year) trend data to evaluate management actions on brown trout, Salmo trutta, populations in groundwater‐fed streams

2020 ◽  
Vol 27 (6) ◽  
pp. 551-566
Author(s):  
Douglas J. Dieterman ◽  
R. John H. Hoxmeier ◽  
Jason Roloff ◽  
David F. Staples
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Management Actions ◽  
Brown Trout Salmo Trutta ◽  
Trend Data

Between-watershed movements of two anadromous salmonids in the Arctic

2015 ◽  
Vol 72 (6) ◽  
pp. 855-863 ◽  
Author(s):  
Arne Johan Jensen ◽  
Ola Håvard Diserud ◽  
Bengt Finstad ◽  
Peder Fiske ◽  
Audun Håvard Rikardsen
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Salvelinus Alpinus ◽  
Habitat Preferences ◽  
Arctic Region ◽  
Arctic Char ◽  
The Arctic ◽  
Long Term Study ◽  
Brown Trout Salmo Trutta

A long-term study in the River Halselva in the Arctic region of Norway demonstrated that movements between watersheds were considerably higher in anadromous brown trout (Salmo trutta) than anadromous Arctic char (Salvelinus alpinus). Fourteen smolt year classes of both species were captured in a fish trap, individually tagged, and thereafter registered each time they passed the trap during their migration between the sea and fresh water every summer. Annual mean survival (i.e., recovery rate) after the first entry to sea as smolts was estimated as 31.4% in Arctic char and 26.6% in brown trout. Most surviving Arctic char returned to the River Halselva to overwinter after the same summer that they migrated to sea as smolts. However, several brown trout overwintered one to four times in other watersheds, mainly the considerably larger River Altaelva, before most eventually returned to the River Halselva upon maturation. The substantial difference in movement rate between watersheds between Arctic char (2.2%) and brown trout (39.6%) is expected to be a consequence of local geographic conditions combined with different habitat preferences of the two species.

Fillet texture and muscle structure in brown trout (Salmo trutta ) subjected to long-term exercise

2003 ◽  
Vol 34 (14) ◽  
pp. 1287-1295 ◽  
Author(s):  
Jérôme Bugeon ◽  
Florence Lefevre ◽  
Benoit Fauconneau
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Muscle Structure ◽  
Brown Trout Salmo Trutta

Explorative behavior increases vulnerability to angling in hatchery-reared brown trout (Salmo trutta)

2014 ◽  
Vol 71 (12) ◽  
pp. 1900-1909 ◽  
Author(s):  
Laura Härkönen ◽  
Pekka Hyvärinen ◽  
Juuso Paappanen ◽  
Anssi Vainikka
Keyword(s):  
Body Condition ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Natural Environments ◽  
Behavioral Differences ◽  
Rearing Method ◽  
Brown Trout Salmo Trutta ◽  
Size Standard ◽  
In The Beginning

Animals, including fish, display individually consistent behavioral differences that may affect an individual’s vulnerability not only to predation, but also to fishing. Compared with complex natural environments, plain hatchery environments might induce development of behaviors that increase vulnerability to fishing, which would in turn have major implications for the management of stocks by supportive releases. We studied whether the vulnerability of hatchery-reared brown trout (Salmo trutta) to angling could be predicted by rearing method (standard versus enriched) or behavioral variation that was assessed using long-term observations of moving activity in groups. High moving activity in the beginning of the behavioral tests (i.e., exploration behavior) predicted increased vulnerability to angling independently of fish body size. Standard rearing promoted high exploration rate among fish, whereas enriched rearing promoted improvement in body condition in (semi-)natural conditions. However, the driving influence of hunger on vulnerability could not be ruled out, as the most explorative standard-reared fish appeared unable to maintain their body condition during the experiments. This study provides direct evidence that standard hatchery rearing method promotes behaviors that directly predict vulnerability to angling.

Nonnative brook trout (Salvelinus fontinalis) and the demise of native brown trout (Salmo trutta) in northern boreal lakes: stealthy, long-term patterns?

2007 ◽  
Vol 64 (4) ◽  
pp. 654-664 ◽  
Author(s):  
Johan Spens ◽  
Anders Alanärä ◽  
Lars-Ove Eriksson
Keyword(s):  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salvelinus Fontinalis ◽  
Time Lag ◽  
Boreal Lakes ◽  
Extinction Rate ◽  
Average Maximum ◽  
Brown Trout Salmo Trutta

This study of 193 boreal lakes of northern Sweden suggests a long-term detrimental impact of introduced brook trout (Salvelinus fontinalis) on brown trout (Salmo trutta) populations. Thirteen of 65 (20%) brown trout populations in lakes exposed to brook trout went extinct, whereas the extinction rate in unexposed lakes was significantly lower (2%). We verified other studies that indicate that altitude strongly affects the distribution of the two species; brown trout populations in our higher altitude lakes were more sensitive to impact from brook trout. In 28 lakes above 285 m, 12 trout populations exposed to brook trout went extinct, while only one population became extinct in 37 lakes below 285 m. No effects of other environmental factors were detected (e.g., water chemistry, stocking of rainbow trout (Oncorhynchus mykiss), fish species community assembly, migration barriers, or lake morphometry on brown trout extinction). The time lag between the first record of brook trout introduction and subsequent extinction of brown trout was two decades on average (maximum 70 years). Even though further stocking of brook trout has been stopped, our analysis suggest that existing sympatric populations may continue to pose an extinction threat to brown trout.

scholarly journals Spatial assemblage and interference competition of introduced Brown Trout (Salmo trutta) in a Himalayan river network: Implications for native fish conservation

2021 ◽  
Vol 24 (2) ◽  
pp. 33-42
Author(s):  
Aashna Sharma ◽  
Vineet Kumar Dubey ◽  
Jeyaraj Antony Johnson ◽  
Yogesh Kumar Rawal ◽  
Kuppusamy Sivakumar
Keyword(s):  
Brown Trout ◽  
Relative Abundance ◽  
Salmo Trutta ◽  
Propagule Pressure ◽  
Interference Competition ◽  
Fish Fauna ◽  
Native Fish ◽  
Management Actions ◽  
Snow Trout ◽  
Brown Trout Salmo Trutta

Abstract Often regarded as a potential threat to the native fish fauna worldwide, the Brown Trout (Salmo trutta), has successfully established its population in the majority of the Himalayan rivers post its introduction dating back to the eighteenth century. Over the years, the species has gained infamy as a sport fish and is considered a profitable source of income to the locals ensuing a heightened propagule pressure due to lack of appropriate management actions. No comprehensive study has been conducted to date in order to understand the mechanism by which the Brown Trout poses threat to the native fish populations. Through the present study, we could assess its competition with the native Snow Trout (Schizothorax richardsonii) to understand the spatial assemblage of both the species across space in Tirthan, a pristine high-altitude river of the western Himalaya. River Tirthan is one of the major tributaries of River Beas traversing for most of its stretch within the protected boundaries of the Great Himalayan National Park Conservation Area. A total of 108 sampling points were chosen from confluence to origin of rivers/streams, ranging from 989 to 3677msl. A total of 28 explanatory variables were recorded at each point. Overall, the Brown Trout adults were found to be greater in relative abundance (66.1%) than the Snow Trout adults (33.9%). The fingerlings of Snow Trout on the other hand, were distinctively high in relative abundance (61.9%) than those of the invasive Brown Trout (38.1%). Non-native trout showed higher abundance in the higher stream orders i.e. in the main streams while natives mostly restricted themselves to the lower order streams. Redundancy analysis (RDA) for species and environmental covariates resulted in 40.75% of constrained variance with higher eigen values for Redundancy analysis1 and Redundancy analysis2. Ward’s minimum variance clustering of Hellinger transformed data revealed sites agglomerating into six reasonable distinct subgroups with respect to species abundances. Immature individuals of non-native and native trout used similar habitat conditions, but they differed in using habitats at adult stage. Our results show a competitive dominance of Brown Trout in terms of higher abundance and maximum space utilization that highlight an urgent action for preventing its introductions to new areas. We recommend a national policy of ‘The Indian Invasive Species Act’ and management level interventions to control overstocking in the areas of established population.

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