Aggressiveness and kinship in brown trout (Salmo trutta) parr

In a series of experiments, kin-biased behavior of young browntrout (Salmo trutta) was observed. The aggressiveness shownby groups of familiar siblings (siblings reared together sincefertilization) and groups of unfamiliar siblings (siblings rearedapart since fertilization) was significantly lower comparedto that of mixed groups of two unrelated sibling groups (offspringof two different pairs of parents). The evolution of kin-biasedbehavior, as shown by a reduction in aggressiveness, is assumedto have evolved through a kin-selective mechanism.[Behav Ecol7: 445-450 (1996)]     

Feeding by Arizona trout (Salmo apache) and brown trout (Salmo trutta) at different light intensities

Synopsis Brown trout (Salmo trutta) were more efficient than Arizona trout (Salmo apache) in eating brine shrimp at starlight (10^–4 fL) light levels. Arizona trout required light levels moonlight (10^–3 fL) to feed. In bright light (50 fL), brown trout utilized cover to a much greater extent in both field and laboratory. Our study indicates that factors other than competition for food or habitat are probably causing the displacement of Arizona trout by brown trout when browns are stocked into the native habitat of Arizona trout.     

MHC-mediated spatial distribution in brown trout (Salmo trutta) fry

Major histocompatibility complex (MHC) class I-linked microsatellite data and parental assignment data for a group of wild brown trout (Salmo trutta L.) provide evidence of closer spatial aggregation among fry sharing greater numbers of MHC class I alleles under natural conditions. This result confirms predictions from laboratory experiments demonstrating a hierarchical preference for association of fry sharing MHC alleles. Full-siblings emerge from the same nest (redd), and a passive kin association pattern arising from limited dispersal from the nest (redd effect) would predict that all such pairs would have a similar distribution. However, this study demonstrates a strong, significant trend for reduced distance between pairs of full-sibling fry sharing more MHC class I alleles reflecting their closer aggregation (no alleles shared, 311.5 ± (s.e.)21.03 m; one allele shared, 222.2 ± 14.49 m; two alleles shared, 124.9 ± 23.88 m; P<0.0001). A significant trend for closer aggregation among fry sharing more MHC class I alleles was also observed in fry pairs, which were known to have different mothers and were otherwise unrelated (ML-r = 0) (no alleles: 457.6 ± 3.58 m; one allele (422.4 ± 3.86 m); two alleles (381.7 ± 10.72 m); P<0.0001). These pairs are expected to have emerged from different redds and a passive association would then be unlikely. These data suggest that sharing MHC class I alleles has a role in maintaining kin association among full-siblings after emergence. This study demonstrates a pattern consistent with MHC-mediated kin association in the wild for the first time.     

Prey selection by young trout fry (Salmo trutta)

Factors influencing the choice of invertebrate food by early feeding trout are sought, special attention being given to the dimensions of the prey. The stomach contents of fish of similar age feeding on lake plankton and drifting stream fauna are compared. Little consistent preference was displayed for the smaller planktonic organisms but prey size was of importance in the distribution of stream benthos among predators of different lengths. The width of the prey was of greater significance to selection than the mean volume or the area of the largest surface of the food items. When the fish were in obvious competition for food the correlation between predator length and all prey dimensions improved.     

Morphological differentiation among local trout (Salmo trutta) populations

The trout (Salmo trutta) has been divided into three forms: sea-run trout, lake-run brown trout, and resident brown trout. They differ in their living environment, migratory behaviour, growth and appearance. As local trout populations are often isolated, and gene flow between them is minimal, differentiation between populations can be expected. The morphology of 1-year-old trout from ten populations representing all three forms was studied in a common-garden experiment. The fish were reared under similar environmental conditions, and 20 morphometric characters were measured from each individual fish. Marked morphological differentiation was found, and differences between populations were greater than differences between forms. The results suggest that the differences have a genetic basis, and they are likely to indicate adaptation to local environmental conditions in the native habitat of the trout.     

Glycine uptake by trout (Salmo trutta) red blood cells

The present study demonstrates the presence of different amino acid carriers in the membrane of trout red cells. Most glycine is taken up through the Na⁺-dependent system ASC, although the nearly specific Gly system is also active. Besides these carriers, glycine is taken up by means of Na⁺-independent transporters, system l being the most important. A system asc of high affinity and low capacity has been found, and band 3 is unable to transport glycine under physiological conditions. These results suggest that although all these carriers are already present in primitive vertebrates, several differences exist in their properties with respect to those found in mammalian cells.We would like to express our sincere thanks to Mr. Antonino Clemente (Piscifactoria de Bagà, Medi Natural, Generalitat de Catalunya) for his help and logistical assistance and to Mr. Robin Rycroft for his editorial help.This work was supported by a grant of Comisió Interdepartamental de Recerca i Technologia (AR90-3.3394). M.A.G. is recipient of a fellowship from the Generalitat de Catalunya.     

Toxicity of fluoride to brown trout fry (Salmo trutta)

The toxicity of fluoride to brown trout fry (Salmo trutta) was tested using groups of 100 animals in tapwater containing 29 ppm calcium with sodium fluoride added. Resultts obtained were similar to published work on S. gairdnerii although, taking into account the ‘calcium effect’, it appears that the animals used in this investigation may be more sensitive.     

Glucose metabolism by trout (Salmo trutta) red blood cells

Summary Glucose metabolism has been studied in Salmo trutta red blood cells. From non-metabolizable analogue (3-O-methyl glucose and l-glucose) uptake experiments it is concluded that there is no counterpart to the membrane transport system for glucose found in mammalian red blood cells. Once within the cells, glucose is directed to CO₂ and lactate formation through both the Embden-Meyerhoff and hexose monophosphate shunts; lactate appears as the most important endproduct of glucose metabolism in these cells. From experiments under anaerobic conditions, and in the presence of an inhibitor of pyruvate transfer to mitochondria, most of the CO₂ formed appears to derive from the hexose monophosphate pathway. Appreciable O₂ consumption has been detected, but there is no clear relationship between this and substrate metabolism. Key enzymes of glucose metabolism hexokinase, fructose-6-phosphate kinase and, probably, pyruvate kinase are out of equilibrium, confirming their regulatory activity in Salmo trutta red blood cells. The presence of isoproterenol, a catecholamine analogue, induces important changes in glucose metabolism under both aerobic and anaerobic conditions, and increases the production of both CO₂ and lactate. From the data presented, glucose appears to be the major fuel for Salmo trutta red blood cells, showing a slightly different pattern of glucose metabolism from rainbow trout red blood cells.Abbreviations EM Embden-Meyerhoff pathway - G6D glucose-6-phosphate dehydrogenase - GOT glutamate oxalacetate transaminase - GPI glucose phosphate isomerase - HK hexokinase - HMS hexose monophosphate shunt - IP isoproterenol - LDH lactate dehydrogenase - MCB modified Cortland buffer - OMG 3-O-methyl glucose - PFK fructose-6-phosphate kinase - PK pyruvate kinase - RBC red blood cells - TAC tricarboxylic acid cycle     

Recruitment as a driver of production dynamics in stream-resident brown trout (Salmo trutta)

1. The objective was to assess the role of recruitment as a determinant of the production dynamics of stream-resident brown trout ( Salmo trutta ) across replicate habitats of contrasting quality and population attributes. A total of 128-year-classes (YC) at 12 stream sites were examined along four tributaries of the Rio Esva drainage (northwestern Spain).
2. A meta-comparison revealed that growth, density, mortality and production were essentially site-specific. However, when all data were pooled, recruitment (as a delayed density-dependent process) affected both growth and mortality in a way such that individuals in YC with high recruitment grew less and had higher mortality.
3. The value of total YC production recorded covered the global range of variation in the production of stream salmonids reported in the literature. Linear regressions of log-transformed data revealed that 89.0%, 58.9% and 70.7% of the variation in YC density, biomass and production, respectively, were explained by variations in recruitment.
4. The inclusion of growth and mortality, together with recruitment, into a multiple regression increased the variance explained of the total YC production by 13.3%, from 70.7% to 84.0%.
5. The functional relationships between recruitment and the population attributes elucidated in this study appear to provide a useful tool for management applications, including forecasting population status.     

Basic physico-chemical parameters of milt from sea trout (Salmo trutta m. trutta), brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss)

The aim of the study was to compare the physico‐chemical parameters of milt from sea trout (Salmo trutta m. trutta), brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss). Milt was collected by stripping and spermatozoa concentrations, were determined and compared with sperm motility and spermatocrit values along with seminal plasma indices (pH, osmolality, sodium, potassium, chlorine, calcium, magnesium, glucose and protein concentrations). The highest spermatozoa concentration of 22.3 ± 6.7 × 10⁹ ml^?1 was found in the sea trout milt, and was significantly different of those observed in brook trout (11.9 ± 3.3 × 10⁹ ml^?1) and rainbow trout (10.7 ± 4.4 × 10⁹ ml^?1). The values for pH and K⁺ did not differ significantly among species. The mean pH was 8.0 in the milt of each species and the K⁺ concentrations ranged from 24.8 ± 7.2 to 30.5 ± 7.6 mm L^?1. Considerable differences were determined for the Ca²⁺ ions concentrations. The highest value was found in sea trout (1.7 ± 0.3 mm L^?1), while in the rainbow trout it was 0.7 ± 0.5 and in the brook trout 0.4 ± 0.1 mm L^?1. The most pronounced differences were found in the glucose concentration cause of its unnaturally low concentration in rainbow trout of the mean value of 6.0 ± 15.2 mg L^?1. The mean value in sea trout and brook trout was 185.0 ± 172.4 and 231.2 ± 148.4 mg L^?1 respectively. For all species, protein mean values were below 1.3 g L^?1. The mean osmolality was between 230.6 ± 98.6 and 272.0 ± 26.4 mOsm kg^?1 in the species studied. No correlation was found between any components determined in milt and the spermatozoa motility (P > 0.05). The sperm concentration was positively correlated with the protein content in the milt of the three species studied, other less exhibited correlation was found.     

Standard karyotype of sea trout (Salmo trutta morpha trutta) based on replication banding patterns

Replication banding patterns have been obtained from in vivo treatment of Salmo trutta morpha trutta chromosomes using a modification of the 5-BrdU technique and in kidney cultures using the fluorochrome photolysis Giemsa (FPG) staining method. Each chromosome pair was identified in the karyotype based on the banding pattern, chromosome size, and centromere position. The standard karyotype of sea trout has been proposed. Similarities of replication, and restriction enzyme banding patterns of chromosomes 8 and 9, and of chromosomes 11 and 12, are discussed. Fluorescence in situ hybridization was used to determine the location of telomeric sequences.     

Life history and habitat use of Norwegian brown trout (Salmo trutta)

SUMMARY. 1. Brown trout ( Salmo trutta) life history and habitat use were studied in two Norwegian rivers: the Vosso river system, western Norway, and the Søre Osa, eastern Norway.
2. Age-groups were partly segregated in feeding habitats, the youngest fish living mainly in running water and in the littoral zone of lakes, the older fish also exploiting pelagic waters and deeper epibenthic habitats. In a population with free access to and from the sea, some individuals smoltified and became sea-run migrants, performing yearly migrations to the coastal sea, whereas others stayed as freshwater residents throughout their entire life span.
3. Within local populations, females were larger and less variable in size than males. This was partly because females matured at an older age than males, partly because the sexes tended to exploit feeding habitats with different food and growth Conditions. Within age-groups, females were more pelagic and migrated more than males, whereas males were more confined to running water and epibenthic areas than females. In the pelagic zone, males were more abundant in near-surface water, and females more abundant in deeper areas. When exploiting the same feeding areas, the two sexes grew at the same rate. There therefore appears to be a connection between feeding habitat and the reproductive ecology of brown trout.     

Variability in swimming performance and underlying physiology in rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta)

We investigated intra- and interspecific variation in swimming performance and related physiological parameters in two members of the salmonid family. For our comparisons, we sourced juvenile brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) from one hatchery and a second strain of rainbow trout from another. The hatcheries maintain genetic stocks obtained several decades ago from very different environments. We tested competing hypotheses: that there would be greater interspecific (across species) variation or that there would be greater intraspecific (within species) variation, owing to regional adaptations. To test these hypotheses, individual and small schools of five fish were taken to fatigue using the critical swimming speed test (U(crit)), and three post-exercise physiological metrics, packed red cell volume (hematocrit), citrate synthase and lactate dehydrogenase activity, were assessed. The majority of the results in swimming performance and hematocrit support that intraspecific variation was greater than interspecific variation, i.e. the location had a stronger effect than did genus. Variation in lactate dehydrogenase activity supported neither intra- nor interspecific variation as determining factors. In sum, our findings suggest that the performance of different species of salmonids from the same locale can be more similar than those of the same species from different areas.     

Suboptimal growth among individuals of brown trout (Salmo trutta) in a temperate river

This study assessed growth of individually tagged brown trout Salmo trutta in a temperate system of north-west Spain (2010–2012). This study identified notable individual variation in fish growth with individuals growing sub-optimally compared with laboratory-based growth-model predictions in most cases (85.5% of individuals). The present observations of suboptimal growth need to be considered in view of intraspecific competition or limiting food resources instead of thermal regimes.     

Phenotypic differentiation analysis: A case study in hybridizing Çoruh trout (Salmo coruhensis), Rize trout (Salmo rizeensis) and brown trout (Salmo trutta fario)

The aim of this study was to determine and compare the phenotypic variation in Çoruh trout (Salmo coruhensis), Rize trout (Salmo rizeensis), brown trout (Salmo trutta fario) and their native hybrids (S. rizeensis × S. t. fario; S. t. fario × S. coruhensis; S. rizeensis × S. coruhensis). The numbers and diameters of red and black spots were determined on operculum, fins and above and below the lateral line. The results from this study indicate that there were differences in spotting pattern, colour pattern or fin pigmentation traits between S. rizeensis, S. t. fario, S. coruhensis and their hybrids. Consequently, native S. rizeensis, S. t. fario and S. coruhensis were affected by interaction and phenotypic plastic aspects of traits in S. rizeensis were dominant in their hybrids (S. rizeensis × S. t. fario; S. rizeensis × S. coruhensis).     

The calpastatin/calpain system in trout Salmo trutta trutta muscle

Many recent reports suggest that the calpastatin/calpain system plays a role in cellular growth and differentiation. Defects of the calpastatin/calpain system have been linked to cellular dysfunctions, apoptosis, myocardial infarct, and dystrophies. The calpastatin/calpain system has also been implicated in post‐mortem tenderization of skeletal muscle through degradation of key myofibrillar and associated proteins, a process of key importance to meat quality. In the present study we investigate the presence and activity of the calpastatin/calpain system in trout muscle samples, collected at 0, 3, 18 and 28 h post‐mortem, by immunohistochemistry method. Calpastatin is a specific endogenous enzyme of cytosol, modulating the ubiquitous calpains. Calpastatin was found in samples obtained in vivo and immediately post‐mortem, but its concentration declined rapidly in samples obtained 3, 18 and 28 h post‐mortem. The ubiquitous m e m‐calpains, which are localized on Z line proteins and activated by intracellular Ca²⁺ increase, showed a rapid decline within 3 h post‐mortem. By contrast p94 calpain, which is specific to skeletal muscle, showed a slow decrease post‐mortem which was independent of intracellular Ca²⁺ increase. Our results suggest that the mechanism of activation and activity of the calpastatin/calpain system in trout is similar to that described in mammals.     

Epizootics in brown trout (Salmo trutta fario) caused by VHSV-F1

Epizootics in brown trout have been observed in the course of the last three years in a fish farm in the North West of the Fed. Rep. Germany. Only in 1988 sick fish exhibited the typical pathological signs as described for the viral hemorrhagic septicemia of trout. The virus isolated from moribund and healthy looking brown trout was identified as VHSV strain F1.

Zusammenfassung

VHSV-F ₁ bedingte Fischsterhen hei Bachforellen (Salmo trutta fario)
Fischsterben während der letzten drei Jahre bei unter teichwirtschaftlichen Bedingungen produzierten Bachforellen, wurden in einem Forellenzuchtbetrieb im Nord-Westen der Bundesrepublik Deutsch-land beobachtet. Während der ersten zwei Jahre (1986/1987) zeigten die Fische keine eindeutigen klinischen Symptome und waren virologisch und bakteriologisch negativ; 1988 zeigten die erkrankten Fische pathologisch anatomische Anzeichen, wie sie für die virale hämorrhagische Septikämie beschrieben worden sind. Das von kranken sowie von gesundaussehenden Bachforellen isolierte Virus wurde als VHSV-F1 identifiziert.

Résumé

Epizooties causées par VHSV-F1 chez la truìte de rivière (Salmo trutta fario)
Des épizooties ont été observées au cours des trois dernières années chez la truite de rivière dans une aquaculture dans le nord-ouest de la R.F.A. C'est seulement en 1988 que les poissons montraient les signes pathologiques typiques décrits pour la septicémic hémorragique virale de la truite de rivière. Le virus isolé chez des truites moribondes et apparemment saines a été identifié comme étant VHSV, souche F1.     

The old trout Salmo trutta in the pond

The last of 12 brown trout Salmo trutta stocked in a small pond in south‐east Norway in 1979 were caught in July 2011. These fish represent a curiosity regarding longevity and growth pattern, and ageing from otoliths was consistent with the known life history of this specimen. Despite almost total stagnation in growth since the age of 16 years, the testes were fully developed.     

Induction, isolation and a characterization of the lipid content of plasma vitellogenin from two Salmo species: rainbow trout (Salmo gairdneri) and sea trout (Salmo trutta)

Vitellogenin synthesis is induced in juvenile rainbow trout (Salmo gairdneri) and juvenile sea trout (Salmo trutta) by estradiol-17 beta. A purification procedure for vitellogenin from trout plasma by precipitation with MgCl2-EDTA and subsequent anion exchange chromatography on DEAE-Sephacel is described. The total lipid contents of purified rainbow trout and sea trout vitellogenins are 18 and 19%, respectively. Approximately 2/3 of the lipids are phospholipids, while the remainder consists of triglycerides and cholesterol. Phosphorus determinations on delipidated vitellogenin yield a phosphorus content of 0.63% in rainbow trout and 0.58% in sea trout vitellogenin. Native (dimeric) vitellogenins from rainbow trout and sea trout both have an apparent molecular weight of 440,000, when estimated by gel filtration on Sepharose 6B.