Energetics and survival of virgin and repeat spawning brown trout (Salmo trutta)

1998 ◽  
Vol 55 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Ole Kristian Berg ◽  
Eivind Thronæs ◽  
Gunnbjørn Bremset
Keyword(s):  
Brown Trout ◽  
Specific Energy ◽  
Salmo Trutta ◽  
Energy Content ◽  
Survival Rates ◽  
Total Protein Content ◽  
Energy Expenditures ◽  
Brown Trout Salmo Trutta ◽  
Investment In Reproduction ◽  
First Time

Smaller virgin spawners of a stunted population of brown trout (Salmo trutta) had higher specific energy content than repeat spawners, indicating that once maturation has started, the trout does not completely recover from its first spawning. Males had higher amounts of total and specific energy after spawning compared with females (adjusted for length differences). The greatest energy expenditures were recorded among spawning females (specific total energy losses of about 20%, which were twice the losses of male spawners). Repeat females lost 40% of their fat content. The gonads of the females accounted for 20% of the total protein content. The loss in carcass protein and fat for the spawners was greater than the corresponding loss in visceral fat and protein. Survival rates paralleled the amounts of energy expended in reproduction. Overall survival rate of first-time spawning males (females) was about 0.90 (1.00), while the corresponding value for repeat spawners was about 0.65 (0.50). It is predicted that brown trout from a stunted population should make a relatively small investment in reproduction and thus represent a case of low investment among iteroparous fish species.

Recruitment and survival rate variability in fish populations: density-dependent regulation or further evidence of environmental determinants?

2014 ◽  
Vol 71 (2) ◽  
pp. 290-300 ◽  
Author(s):  
Javier Lobón-Cerviá
Keyword(s):  
Environmental Factors ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Survival Rates ◽  
Fish Populations ◽  
Data Set ◽  
Site Specific ◽  
Density Dependent ◽  
Long Term Study ◽  
Brown Trout Salmo Trutta

Recently, Minto et al. (2008) , based on a fishery data set including marine, estuarine, and freshwater fishes, described higher variability in the survival rates of juveniles at low rather than at high parental density in an inversely density-dependent fashion and suggested density-dependent mechanisms underpinning those patterns. This study, based on a long-term study of brown trout (Salmo trutta; a species and habitat not included in the Minto et al. (2008) analysis), documents that survival rates in these stream-living populations exhibit a pattern that matches exactly those reported by Minto et al. (2008) . Nevertheless, hypothesis testing rejected the occurrence of stock–recruitment relationships and the operation of density-dependent recruitment regulation. The patterns elucidated for these brown trout populations can be entirely explained by the operation of two single environmental factors, namely, stream discharge in March determining annual survival rates across streams and sites and site-specific depth determining site-specific survival rates. It is open to question that exactly the same patterns can be generated by two sets of opposing factors, density-dependent (i.e., Minto et al. 2008 ) and environmental factors (i.e., this study). The consistency of this pattern suggests that survival rates and recruitment are probably determined by environmental factors across fish populations and habitats.

Presence of rodlet cells in the intrahepatic biliary ducts of the brown trout, Salmo trutta fario Linnaeus, 1758 (Teleostei, Salmonidae)

1994 ◽  
Vol 72 (9) ◽  
pp. 1683-1687 ◽  
Author(s):  
Eduardo Rocha ◽  
Rogério A. F. Monteiro ◽  
Carlos A. Pereira
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Developmental Stages ◽  
Close Proximity ◽  
Brown Trout Salmo Trutta ◽  
Biliary Ducts ◽  
First Time ◽  
Pathological Reaction ◽  
Rodlet Cells ◽  
Salmo Trutta Fario

We report for the first time rodlet cells in the epithelium of intrahepatic biliary ducts of the brown trout (Salmo trutta fario Linnaeus 1758). Such cells have not been described in the liver of any salmonid. Several developmental stages of the rodlet cells were found, including mature, discharging elements. The number of rodlet cells decreased from June to April. Intra-epithelial macrophages were found in close proximity to rodlet cells, suggesting a mild pathological reaction.

Discharge-dependent covariation patterns in the population dynamics of brown trout (Salmo trutta) within a Cantabrian river drainage

2004 ◽  
Vol 61 (10) ◽  
pp. 1929-1939 ◽  
Author(s):  
Javier Lobón-Cerviá
Keyword(s):  
Population Dynamics ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Regional Scale ◽  
Survival Rates ◽  
River Drainage ◽  
Introduced Populations ◽  
Geographical Regions ◽  
Brown Trout Salmo Trutta ◽  
Positive Correlations

Patterns of spatial covariation in the population dynamics of brown trout (Salmo trutta) across Rio Esva (northwestern Spain) were explored by using the residuals from stock–recruitment relationships as indices of survival rates of spawner-to-recruit (STR), spawner-to-cohort size (STC), and spawner-to-spawner (STS). Positive correlations in pairwise comparisons among survival rates together with highly significant spatiotemporal variation in STC (74.3%) and STS (51.5%) explained by variation in STR provided evidence for persistent spatial covariation across the river drainage during the whole lifetime. Split-line regressions fitted to the survival rates versus river discharge in March (when trout emerge) highlighted the importance of discharge during, or just after, trout emergence as a major determinant of recruitment whose effects are reflected in the population over the lifetime and emphasized the synchrony between environmental processes and brown trout dynamics. Synchrony in recruitment is caused by hydrological synchrony that, in turn, is determined by climatic synchrony (rainfall) operating at the regional scale. The importance of discharge for recruitment is consistent with studies on native and introduced populations, suggesting its broad effect on the dynamics of stream brown trout across geographical regions.

scholarly journals Evidence for the linkage of survival of anadromous Arctic char and brown trout during winter to marine growth during the previous summer

2018 ◽  
Vol 75 (5) ◽  
pp. 663-672 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bengt Finstad ◽  
Peder Fiske
Keyword(s):  
Brown Trout ◽  
Critical Period ◽  
Salmo Trutta ◽  
Critical Size ◽  
Salvelinus Alpinus ◽  
Salt Water ◽  
Arctic Char ◽  
Brown Trout Salmo Trutta ◽  
First Time ◽  
Previous Summer

Data from a 25-year study of anadromous Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) in the River Halselva provided evidence that survival during winter was linked to marine growth during the previous summer. The study supported the “critical size and critical period” hypothesis, which postulates that regulation of the abundance of adult salmonids occurs in two major phases. The first phase is marine mortality that occurs shortly after smolts enter salt water, and the second is during the following winter, when individuals that have not attained a critical size are unable to meet minimum metabolic requirements and die. In the present study, growth during summer appeared to be more important to winter survival than body size. Size-selective mortality occurred both at sea during summer and in fresh water during winter and was more evident for first-time migrants than repeat migrants.

scholarly journals Application of multistate modeling to estimate salmonid survival and movement in relation to spatial and temporal variation in metal exposure in a mining-impacted river

2019 ◽  
Vol 76 (11) ◽  
pp. 2057-2068
Author(s):  
Mariah P. Mayfield ◽  
Thomas E. McMahon ◽  
Jay J. Rotella ◽  
Robert E. Gresswell ◽  
Trevor Selch ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Survival Rates ◽  
Cutthroat Trout ◽  
Spatial And Temporal Variation ◽  
Metal Exposure ◽  
Westslope Cutthroat Trout ◽  
Aquatic Life ◽  
Oncorhynchus Clarkii ◽  
Brown Trout Salmo Trutta

Multistate modeling was used to estimate survival and movement of brown trout (Salmo trutta) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) in relation to copper concentrations in the mining-impacted Clark Fork River, Montana. Survival probability in the uppermost river segment, where dissolved copper concentrations frequently exceeded acute criteria for aquatic life (range: 31–60 days > 13.4 μg·L–1), was 2.1 times lower for brown trout and 122 times lower for westslope cutthroat trout compared with survival rates in the lowermost segment that had relatively low dissolved copper (0 days exceedance of acute concentration). Lowest survival for both species occurred in the spring–summer period when dissolved copper concentrations were elevated coincident with higher discharge. Movement among study segments was generally low, and cutthroat trout showed low movement into the uppermost river segment with the most elevated copper levels. Both species showed high rates of movement into tributaries, which coincided with their respective spawning migrations rather than as an apparent avoidance of elevated copper levels. The linkage between survival rate and level of copper exposure for both trout species suggests that additional removal of tailings deposits could improve survival rates.

Selective Predation by Drift-Feeding Brown Trout (Salmo trutta)

1979 ◽  
Vol 36 (4) ◽  
pp. 392-403 ◽  
Author(s):  
Neil H. Ringler
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Prey Size ◽  
Energy Content ◽  
Feeding Strategy ◽  
Invertebrate Drift ◽  
Selective Predation ◽  
Heterogeneous Distribution ◽  
Brown Trout Salmo Trutta ◽  
Dominant Characteristic

Consumption of three species of prey by brown trout (Salmo trutta) in a laboratory stream was studied during 7-d experiments. Two drift rates (5 and 10 organisms/min) and three ratios (1:1, 2:1, 5:1) of small:large alternative prey were employed. Responses to prey species stabilized after 4–6 d and 800–1200 prey captures, but no prey was completely excluded from the diet. Size-selective predation was a dominant characteristic of the response. The fish appeared to alter the area (depth) searched in response to prey density; electivity was greatest when prey densities were high. Disproportionate predation on abundant prey ("switching") was a temporary phenomenon, which may have been masked by prey size. Brown trout ultimately achieved 54–91% of a hypothetical diet in which prey are ranked in order of size (energy content). Deviations from an optimal diet may be explained in terms of a feeding strategy that deals with heterogeneous distribution of prey, as well as with the behavioral capabilities of the predator. Key words: behavior, fish, invertebrate drift, optimal foraging, predation, prey size and abundance, Salmonidae, search image, streams

scholarly journals First record of Azygia robusta (Odhner, 1911) (Trematoda: Digenea: Azygiidae) in brown trout (Salmo trutta) in the VRBAS River

2018 ◽  
Vol 76 (2) ◽  
pp. 85-88
Author(s):  
Vera Nikolić ◽  
Branka Bilbija ◽  
Zlatko Nedić ◽  
Predrag Simonović ◽  
Vesna Djikanović
Keyword(s):  
Bosnia And Herzegovina ◽  
Brown Trout ◽  
Salmo Trutta ◽  
First Record ◽  
Fish Parasites ◽  
Image Analyzer ◽  
Trematode Parasite ◽  
Brown Trout Salmo Trutta ◽  
Banja Luka ◽  
First Time

Abstract The investigation of fish parasites in Bosnia and Herzegovina in recent years became significant, and therefore new records of parasitic trematodes and their hosts are important for better understanding of fish parasitology and pathology. In this study 41 parasitic specimens were collected and the basic taxonomical characters were measured (body length and width, diameter of oral and ventral sucker, length and width of pharynx, ovary length and width, testes length and width and eggs length and width). After the sampling of the parasites, they were collected and conserved in 70% ethanol. After that procedure the aforementioned characters were measured using Digimizer Image Analyzer Version 4.1. After all measurements, the trematode parasite Azygia robusta was confirmed for the first time on brown trout Salmo trutta. This first record was found in the Vrbas River near Banja Luka, Bosnia and Herzegovina (Sava River Basin). Former records of this parasite in Europe were observed on other salmonid fish species, as huchen Hucho hucho. This new record should be very important part of data of fish parasitology in Bosnia and Herzegovina.

scholarly journals Microanatomy and ultrastructure of kidney interstitial cells and nephron in brown trout (Salmo trutta Linnaeus, 1758) at different stages of the life cycle

2022 ◽  
Author(s):  
Ekaterina Flerova ◽  
Victoria V. Yurchenko ◽  
Yulia P. Sapozhnikova ◽  
Dmitry S. Sendek ◽  
Sergey F. Titov ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Structural Features ◽  
Ultrastructural Changes ◽  
Migration Process ◽  
Renal Interstitium ◽  
Specific Granules ◽  
Brown Trout Salmo Trutta ◽  
The Baltic ◽  
First Time

The study focuses on the microanatomy and ultrastructural changes in the trunk kidney interstitium cells and nephrons in parr, smolt and spawning brown trout Salmo trutta Linnaeus, 1758 sampled in Luga River and Solka River, the tributaries of the Baltic Sea. Regardless of the type of cells or their structure, there were changes in their areas and the number and structure of organelles responsible for the transport, synthetic and energetic function of cells. Our data on the morphology of the nephron combined with data on its physiology suggest a fundamental change in kidney function during the parr-smolt transformation before migration; this could be a preadaptation for a successful life in saltwater where urine output is sharply reduced. Thus, detected structural features of the trunk kidney in brown trout S. trutta are cytological markers of the migration process. The numbers of lymphocytes, neutrophils and eosinophils with segmented nuclei increased from parr to smolts and then to spawners; only monotypic specific granules in neutrophils were found in smolts and spawners. Cells with radially arranged vesicles were described for the first time in brown trout S. trutta renal interstitium. Their origin has not yet been established. The shape of these cells changed from spherical to trihedral during fish maturation. All the above ultrastructural changes of renal interstitium cells could be considered cytological markers of cell maturity.

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