scholarly journals Saltwater spawning grounds of sea-run brown trout (Salmo trutta) in tidal waters of a major Norwegian river

2021 ◽  
Author(s):  
Sven-Erik Gabrielsen ◽  
Robert J. Lennox ◽  
Tore Wiers ◽  
Bjørn T. Barlaup
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Pink Salmon ◽  
River Mouth ◽  
Competitive Balance ◽  
Spawning Grounds ◽  
Sea Trout ◽  
Spawning Areas ◽  
Brown Trout Salmo Trutta ◽  
Spawning Behaviour

AbstractSea-run brown trout (Salmo trutta) have a highly phenotypically plastic life history that allows them to be effective colonizers and competitors in freshwater. This paper documents a previously unknown spawning behaviour in a brackish, tidally influenced estuary 14 km from the mouth of the Vosso River, a major Atlantic salmon- and sea-run brown trout–producing river in western Norway. Putative spawning gravel was observed, and sea-run brown trout deposited eggs that hatched in April. Survival of recruits was high (> 95%) in the tidal spawning gravel. These areas are strongly tidally influenced with a peak of 23.17 psu recorded at the lowest spawning ground. The observation of spawning so far from the river mouth may be unique in such a system with a long estuary but provides important insight into the biology of sea trout. Invasion of pink salmon, also known to spawn in estuaries, may negatively affect the competitive balance of sea trout with other salmonids in rivers where sea trout populations rely on recruitment from these relatively extreme spawning areas. Restoration of estuaries that have been modified by dredging or channelization may be important to ensure quality and heterogenous habitat for sea trout spawning given that haline spawning grounds could contribute to population resilience.

Spawning behaviour and sex hormone levels in adult and precocious brown trout (Salmo trutta L.) males and the effect of anosmia

Chemoecology ◽  
1998 ◽  
Vol 8 (1) ◽  
pp. 9-17 ◽  
Author(s):  
K. Håkan Olsén ◽  
J. Torbjörn Järvi ◽  
Ian Mayer ◽  
Erik Petersson ◽  
Frederieke Kroon
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Sex Hormone ◽  
Hormone Levels ◽  
Brown Trout Salmo Trutta ◽  
Spawning Behaviour

scholarly journals Marine migration and habitat use of anadromous brown trout (Salmo trutta)

2015 ◽  
Vol 72 (9) ◽  
pp. 1366-1378 ◽  
Author(s):  
Sindre Håvarstein Eldøy ◽  
Jan Grimsrud Davidsen ◽  
Eva Bonsak Thorstad ◽  
Fred Whoriskey ◽  
Kim Aarestrup ◽  
...  
Keyword(s):  
Residence Time ◽  
Brown Trout ◽  
Salmo Trutta ◽  
River Mouth ◽  
Temporal Distribution ◽  
Long Distance ◽  
Migration Distance ◽  
Marine Migration ◽  
Brown Trout Salmo Trutta ◽  
River Mouths

The biology and ecology of anadromous brown trout (Salmo trutta) at sea is poorly understood. This study provided information on spatial and temporal distribution of sea trout in the ocean. The behaviour of 115 individuals (veteran migrants, 270–700 mm) was tracked by using acoustic telemetry in a fjord system during April–September in 2012–2013. Overall, fish spent 68% of their marine residence time close to river mouths (<4 km). Most fish registrations (75%) were in nearshore habitats, but pelagic areas were also used. The maximum migration distance of tagged fish was categorized as short (<4 km from river mouth, 40% of fish), medium (4 – ∼13 km, 18% of fish), or long (>∼13 km, 42% of fish). Long-distance migrants had poorer body condition in spring prior to migration, used pelagic areas more often, and returned earlier to fresh water than short- and medium-distance migrants. Marine residence time was 7–183 days and was positively correlated to body length and smolt age, but negatively correlated to the date of sea entry.

Inter- and intra-specific variability in female salmonid spawning behaviour

1994 ◽  
Vol 72 (4) ◽  
pp. 636-642 ◽  
Author(s):  
Bjørn T. Barlaup ◽  
Harald Lura ◽  
Harald Sægrov ◽  
Rolf C. Sundt
Keyword(s):  
Atlantic Salmon ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Water Discharge ◽  
Selective Advantage ◽  
Data Series ◽  
Discharge Rates ◽  
Random Occurrence ◽  
Brown Trout Salmo Trutta ◽  
Spawning Behaviour

Egg pocket characteristics determined from the excavation of 29 stranded redds made by Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) in the River Vosso in western Norway are presented. The egg pockets of Atlantic salmon were, on average, deeper (27.0 vs. 14.8 cm) and contained more eggs (707 vs. 148) than those of brown trout. An adaptive "test-digging" behaviour was indicated by the finding of a significant association between false redds and gravel classified as low-quality spawning substrate. Based on fecundity data and number of eggs per redd, it was estimated that individual Atlantic salmon and brown trout deposited their eggs in 8.4 and 5.7 different redds, respectively. A 100-year data series indicates that the high proportion of stranded salmon redds (23%) can be attributed to the high frequency (27% of the years) and random occurrence of low water discharge rates. Estimated probabilities of extinction and associated variances in fitness assigned different spawning behaviours suggest that the temporal and spatial variation in offspring survival produces a selective advantage for the multiple-redd tactics over the single-redd tactic. Moreover, in contrast to iteroparous salmonids, semelparous Oncorhynchus species invariably place all their offspring in one redd. This dichotomy can most likely be ascribed to the provision of parental care (i.e., redd guarding) by semelparous salmonids.

scholarly journals A comparison of trends in population size and life history features of Atlantic salmon (Salmo salar) and anadromous and non-anadromous Brown trout (Salmo trutta) in a single catchment over 116 years

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Colin E. Adams ◽  
Hannele M. Honkanen ◽  
Ellen Bryson ◽  
Isabel E. Moore ◽  
Malcolm MacCormick ◽  
...  
Keyword(s):  
Time Series ◽  
Atlantic Salmon ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Relative Proportion ◽  
Population Trends ◽  
Sea Trout ◽  
Salmon Population ◽  
Brown Trout Salmo Trutta ◽  
Long Time

AbstractWe use a long time series of catch abundance from a recreational fishery over 116 years to look for population trends in Atlantic salmon, and anadromous (sea trout) and non-anadromous (brown) trout for a single catchment, Loch Lomond, west central Scotland. Year strongly predicted variation in catches but catch effort did not meaningfully increase explained variation. Salmon showed periods of increasing and decreasing trends, for sea trout and brown trout there was an overall declining trend. Since 1952, Lomond salmon population trends differed from both wider Scotland and southern Europe, indicating that the Lomond population is partially buffered from drivers of change in salmon populations more widely. In contrast Lomond sea trout showed a similar declining trend to that of populations from the wider west of Scotland over this period. The Lomond populations showed some evidence of shorter-term cycling patterns; the drivers for which are unknown. Body size in salmon and sea trout declined but increased in brown trout; salmon returned to freshwater later, and the relative proportion of all caught trout that were anadromous increased across the time series. This study shows a long and protracted period of fundamental change to populations of these two species over 116 years.

scholarly journals Characteristics of sea trout spawners (Salmo trutta) in the Vistula River mouth in reference to the previous Vistula River stocks

2020 ◽  
Vol 28 (3) ◽  
pp. 166-174
Author(s):  
Paweł Buras
Keyword(s):  
Age Structure ◽  
Salmo Trutta ◽  
Length Distribution ◽  
River Mouth ◽  
Spawning Grounds ◽  
Sea Trout ◽  
Vistula River ◽  
Management Interventions

AbstractThe age structure and length distribution of sea trout spawners caught in the Vistula River mouth in the 1984–1986 period were analyzed in reference to previous Vistula stocks of summer spawning and winter spawning runs, and also to silvering sea trout. The comparison took into consideration two variants: the period when the sea trout summer spawning and winter spawning runs ascended the Vistula and when they gathered at spawning grounds. Statistically significant differences were confirmed in the age structure and length distribution of sea tout spawners caught in the Vistula River mouth in the 1980s and the previous Vistula stocks. The reason for these difference must be sought in management interventions and especially in the permanent cycle of smolt production, sea trout spawner selection when they ascended the Vistula, catches made for artificial spawning, and the periodic stocking of sea trout with material originating from Pomeranian rivers.

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