scholarly journals Nutritional correlates of spatiotemporal variations in the marine habitat use of brown trout (Salmo trutta) veteran migrants

2018 ◽  
Vol 75 (10) ◽  
pp. 1744-1754 ◽  
Author(s):  
Xavier Bordeleau ◽  
Jan G. Davidsen ◽  
Sindre H. Eldøy ◽  
Aslak D. Sjursen ◽  
Fred G. Whoriskey ◽  
...  
Keyword(s):  
Habitat Use ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Life Stage ◽  
Nutritional State ◽  
Long Distance ◽  
Marine Habitat ◽  
Species Population ◽  
Brown Trout Salmo Trutta ◽  
Feeding Migration

The brown trout (Salmo trutta) is an iteroparous, anadromous salmonid that exhibits a complex continuum of feeding migration tactics, ranging from freshwater residency, to potamodromy, to estuarine migration, as well as short- to long-distance coastal migrations. While anadromous migrants are believed to play an important role in the species’ population dynamics, little is known about the factors driving differences in the extent of individual marine habitat use. In this study, 32 brown trout veteran migrants were acoustically tagged prior to their seaward migration and sampled for indices of their nutritional state. Our findings suggest that (i) body condition factor differed among fish adopting different migratory tactics, with outer fjord migrant being in poorer condition; and (ii) within migratory groups, plasma triglyceride concentration was negatively correlated with the duration of marine residency. Results support the idea of condition-dependent migration in veteran migrants, with individual variation in nutritional state influencing the spatiotemporal aspects of marine habitat use. Furthermore, overall marine minimum survival during the summer feeding migration was 86%, the highest reported estimate for this life stage.

The effects of brown trout (Salmo trutta morpha fario) on habitat selection by larval Fire Salamanders (Salamandra salamandra): a predator-avoidance strategy

2018 ◽  
Vol 96 (3) ◽  
pp. 213-219
Author(s):  
Aneta Bylak
Keyword(s):  
Habitat Use ◽  
Brown Trout ◽  
Predator Avoidance ◽  
Salmo Trutta ◽  
Predatory Fish ◽  
Heterogeneous Habitats ◽  
Microhabitat Distribution ◽  
Brown Trout Salmo Trutta ◽  
Salamandra Salamandra ◽  
Avoidance Strategy

Predatory fish can have a major impact on aquatic amphibian assemblages. Knowledge regarding the influence of habitat heterogeneity on predator–prey dynamics is extensive, but not much is published on how the habitat structure influences the co-occurrence of brown trout (Salmo trutta Linnaeus, 1758 morpha fario) and Fire Salamander (Salamandra salamandra (Linnaeus, 1758)). I examined the microhabitat distribution of larval salamanders relative to the presence of brown trout and stream morphology, hypothesizing that larval salamanders will increase their habitat use in the presence of trout to avoid predation. Fish and salamanders were sampled with an electroshocker in 62 instream habitat patches. In the stream zone populated by brown trout, larval salamanders avoided high-quality habitats such as pools, whereas they strongly preferred them in the fishless zone (their densities were ∼10 times lower in pools than in riffles). Brown trout mainly occupied deeper pools. The co-occurrence of larval Fire Salamanders with trout suggests the presence of an effective predator-avoidance strategy. The predator-avoidance response and habitat-use pattern decreased interspecific overlap, leading to the use of different instream spaces. Heterogeneous habitats enable habitat partitioning between larval salamanders and brown trout, which means that the natural characteristics of streams promote coexistence between fish and amphibians.

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.

Brown trout (Salmo trutta) habitat use and life history in Swedish streams: possible effects of biotic interactions

1998 ◽  
Vol 55 (4) ◽  
pp. 1034-1042 ◽  
Author(s):  
Ingemar Näslund ◽  
Erik Degerman ◽  
Fredrik Nordwall
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Brown Trout ◽  
Fish Species ◽  
Salmo Trutta ◽  
Adult Survival ◽  
National Database ◽  
Juvenile Growth ◽  
Growth And Survival ◽  
Brown Trout Salmo Trutta

To test if habitat use and life history of stream-dwelling brown trout (Salmo trutta) differed between allopatric and sympatric situations, we compared three streams with differing fish communities and used data from a large national database containing electrofishing results from Swedish streams. In the three-creek study, allopatric brown trout used all habitats and shifted from nursery areas in riffles to pool habitats, where adult growth and survival were higher. Mainly females shifted habitat and this was undertaken after age 1. Sympatric brown trout under intense pressure from other fish species remained in the riffles throughout their life cycle. Under moderate pressure from other species, larger brown trout used slow-flowing habitats. Early growth was more rapid in sympatry. Sympatric brown trout also had a lower adult to juvenile growth ratio and lower adult survival and matured earlier than allopatric brown trout. The data from the nationwide database showed that frequency of occurrence and abundance of brown trout were negatively associated with the number of coexisting fish species. It was also verified that the habitat shifts between riffles and pools were more common and possibly more beneficial in terms of growth and survival in allopatry. In addition the existence of differences in juvenile growth between allopatric and sympatric populations was verified.

Sign in / Sign up

Export Citation Format

Share Document