Riverine and near coastal migration performance of hatchery brown trout <i>Salmo trutta</i>

Davidsen, Jan Grimsrud; Daverdin, Marc; Arnekleiv, Jo Vegar; Rønning, Lars; Sjursen, Aslak Darre; Koksvik, Jan Ivar

doi:10.1111/jfb.12439

Cited by 13 publications

(15 citation statements)

References 29 publications

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“…The return rate in this study was high compared to those reported in previous studies. Davidsen et al (2014 a ) found that 16% of tagged hatchery‐reared S. trutta post‐smolts returned to the river after the first summer at sea, while a long‐term study conducted by Jonsson & Jonsson () in the River Imsa from 1976 to 2005, found that on average 15% of wild S. trutta post‐smolts survived the annual marine migration.…”

Section: Discussionmentioning

confidence: 99%

“…A variety of explanations for this have been proposed. Post‐smolts may primarily occupy their home river estuary and nearby shallow waters, which may be due to better feeding opportunities than in the open pelagic waters masses (Lyse et al , ; Davidsen et al , 2014 a ). Predation on salmonid post‐smolts in the early marine phase can be high, particularly in open water (Hvidsten & Møkkelgjerd, ), and predation risk may confine post‐smolts to shallow waters where shelter can provide protection from predators (Werner & Hall, ).…”

Section: Introductionmentioning

confidence: 99%

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The first months at sea: marine migration and habitat use of sea trout Salmo trutta post‐smolts

Flaten

Davidsen

Thorstad

et al. 2016

Journal of Fish Biology

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The early migration and habitat use of brown trout Salmo trutta post-smolts tagged with acoustic transmitters (n = 50) were investigated in a fjord system in central Norway from 30 April to 26 November 2014. The main aims were to investigate return rate, marine residence time and spatial use of the fjord system. Median seaward migration and return to fresh water dates were 22 May and 4 July, respectively. Of the 40 seaward migrating smolts, 26 returned to fresh water, giving a minimum return rate to fresh water of 65%. Entrance to the fjord from the river occurred mainly at night (80% of the S. trutta), however, no such diurnal pattern was observed during the return migration. Mean marine residence time was 38 days, but with large individual variation (22-99 days). The innermost parts of the study area were more utilized than the outer part of the fjord system during the sea residency, and with more use of the near shore habitat than the open, pelagic areas. Many post-smolts also utilized the outer part of the fjord system, however, and 94% of the post-smolts were recorded at least 14 km from the home river mouth. Marine survival and distribution in the fjord were size dependent with the largest individuals utilizing outer fjord areas and having higher return rates to fresh water. As far as is known, this is the first published study on temporal and spatial behaviour in the marine environment of first-time S. trutta migrants during the full course of their first trip to sea.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The first months at sea: marine migration and habitat use of sea trout Salmo trutta post‐smolts

Flaten

Davidsen

Thorstad

et al. 2016

Journal of Fish Biology

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“…Such behaviour was also observed in studies of hatchery S . trutta in the River Nidelva (Davidsen et al , ), the River Gudenåen (Aarestrup et al , ) and the River Sävarån (Serrano et al , ). The River Nidelva estuary is more saline than both the River Gudenåen and the River Sävarån estuaries.…”

Section: Discussionmentioning

confidence: 99%

“…In response to declining fish populations, hatchery programmes have been implemented to supplement fish already present in the wild (Kostow, 2009). For instance, as a compensation measure for decreases in many S. trutta populations in catchments influenced by hydropower regimes, hatchery smolts are released annually into some of these rivers (Davidsen et al, 2014). The intention is often to support the sea run part of the population, with the aim of producing fish that undergo one or several marine feeding migrations and return to the river for spawning after a period in the sea.…”

Section: Introductionmentioning

confidence: 99%

Does reduced feeding prior to release improve the marine migration of hatchery brown trout Salmo trutta smolts?

Davidsen

Daverdin

Sjursen

et al. 2014

Journal of Fish Biology

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The aim of this study was to test the hypothesis that hatchery brown trout Salmo trutta smolts, with 50% reduced or no feeding over the last 5 months before release, were more likely to migrate to the sea than individuals with standard feeding ratios. The juvenile fish were divided into three groups 176 days before release: (A) with no feeding, (B) with 50% and (C) with 100% feeding. To study their seaward migration, 40 fish from each feeding group were tagged with acoustic transmitters and tracked by automatic listening stations in the River Nidelva, Trondheim, Norway, its estuary and in the nearest marine environment. At the time of release, mean condition factor was significantly lower in group A and the fish from groups A and B had higher levels of Na+, K+-ATPase. Significantly more fish from group A migrated to the sea, but the rate of downstream progression from release to the estuary did not differ between the three groups. In conclusion, the S. trutta smolts with no access to food in the last 176 day before release were more likely to migrate to the sea. Fish from all three feeding groups, however, appeared to smoltify and had the same rate of downstream progression to the estuary. This indicates that differences in migratory behaviour between individuals from the three feeding groups begin from the time when the fish reach saline waters. It is suggested that feeding in hatcheries has to be greatly reduced (by 50% or more) over several months to have a pronounced effect on the migratory behaviour in S. trutta.

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“…Anadromous brown trout typically feed close to the coast, not far from their home stream, but with variation among populations (Davidsen et al, 2014;Degerman et al, 2012;Flaten et al, 2016;Jensen, 1968;Jonsson & Jonsson, 2014;Pemberton, 1976). In the present study, approximately half of the recaptures were from within 1 km of the mouth of the home stream, and few were recaptured more than 30 km from the mouths of the streams.…”

Section: Discussionmentioning

confidence: 51%

Water level influences migratory patterns of anadromous brown trout in small streams

Jönsson

Jonsson

2018

Ecology of Freshwater Fish

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Habitats modify the population ecology of species. Here, we show how low water level influences abundance and size of adult anadromous brown trout (Salmo trutta) entering a small, South Norwegian stream for spawning. After smolting, the fish appear chiefly to feed within 10 km of the home stream. In the autumn, South Norwegian streams typically flood because of heavy rainfall, when the anadromous brown trout entered from the sea. Mean annual duration of the upstream migration period was 34 days and ended when the flooding ended and the water temperature dropped to below 4°C. During most of the migration period, on average two trout ascended the river per day. The sexes entered the spawning area concurrently, and the male:female ratio of the anadromous trout was 1.27. No fish entered when the water depth just downstream of the spawning area was below 5 cm, and mean number of fish increased with increasing water depth to ca. 30 cm, but not at higher flows when the ascent gradually decreased. Mean and maximum size of the entering spawners increased with water depth between 5 and 16 cm. Among those that had been to sea, most were recaptured in the home stream, 4% in other streams, but only two of the strays were caught close to spawning time. The present results illustrate that population traits of anadromous brown trout from a small stream differ from those in larger rivers, probably because of selection associated with water flow.

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Riverine and near coastal migration performance of hatchery brown trout Salmo trutta

Cited by 13 publications

References 29 publications

The first months at sea: marine migration and habitat use of sea trout Salmo trutta post‐smolts

The first months at sea: marine migration and habitat use of sea trout Salmo trutta post‐smolts

Does reduced feeding prior to release improve the marine migration of hatchery brown trout Salmo trutta smolts?

Water level influences migratory patterns of anadromous brown trout in small streams

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