Search results for "trout"

Spines and behaviour as defences against fish predators in an invasive freshwater amphipod.

2006

7 pages; International audience; Selective predation may be an important proximate cause of the success or failure of invader species. Gammarus roeseli is an invasive amphipod, for which the causes of establishment in rivers where the native species, Gammarus pulex, predominates remain unstudied. Freshwater amphipods are important prey for numerous fish predators, but empirical evidence of lower predation rates on exotic prey is scarce. In laboratory experiments, we compared the susceptibility of G. pulex and G. roeseli to fish predation, determined the mechanisms influencing prey selection, and studied the interaction between behavioural and morphological defences. Fish predators (brown tr…

Anaphylatoxin-like molecules generated during complement activation induce a dramatic enhancement of particle uptake in rainbow trout phagocytes.

2004

Here we have identified a serum fraction containing approximately 8-kDa molecules with an unexpected capacity to greatly enhance particle uptake in trout head kidney leukocytes (HKLs). This approximately 8-kDa particle-uptake enhancing fraction (PUEF-8) was purified from complement-activated serum by gel filtration chromatography. Mass spectrometric analysis and reactivity of anti-trout C3-1 and C4 antibodies, indicated the presence of C3a, C4a and C5a molecules in PUEF-8. Using a newly developed flow cytometric assay that measures the capacity of cells to ingest fluorescent beads, we showed that PUEF-8 induced a striking enhancement (344+/-50% higher than the PBS control value) in the numb…

Accelerated Solvent Extraction and Pulsed Electric Fields for Valorization of Rainbow Trout (Oncorhynchus mykiss) and Sole (Dover sole) By-Products: …

2021

Fishery by-products are rich in biologically active substances and the use of green and efficient extraction methods to recover these high-added-value compounds is of particular importance. In this study, head, skin and viscera of rainbow trout and sole were used as the target matrices and accelerated solvent extraction (ASE) (45–55 °C, 15 min, pH 5.2–6.8, 103.4 bars) and pulsed electric fields (PEF) (1–3 kV/cm, 123–300 kJ/kg, 15–24 h) were applied as extraction technologies. The results showed that ASE and PEF significantly increased the protein extract efficiency of the fish by-products (p < 0.05) by up to 80%. SDS-PAGE results showed that ASE and PEF treatments changed the molecular size…

Muhos- ja Sanginjoki lohikalojen elinympäristöinä

2006

A link between ectoparasite infection and susceptibility to bacterial disease in rainbow trout

2006

Rainbow trout, Oncorhynchus mykiss, were infected concomitantly with Argulus coregoni and Flavobacterium columnare and their survival was compared with that of fish infected with either the parasite or the bacterium alone. The mortality of fish challenged with A. coregoni was negligible while infection with F. columnare alone led to significantly lower survival. However, compared with single infections, the mortality was significantly higher and the onset of disease condition was earlier among fish, which were concomitantly infected by A. coregoni and F. columnare. This data presents, for the first time, experimental support for the hypothesis that an ectoparasite infection increases suscep…

Complementary methods assessing short and long-term prey of a marine top predator ‒ Application to the grey seal-fishery conflict in the Baltic Sea.

2019

The growing grey seal (Halichoerus grypus) population in the Baltic Sea has created conflicts with local fisheries, comparable to similar emerging problems worldwide. Adequate information on the foraging habits is a requirement for responsible management of the seal population. We investigated the applicability of available dietary assessment methods by comparing morphological analysis and DNA metabarcoding of gut contents (short-term diet; n = 129/125 seals, respectively), and tissue chemical markers i.e. fatty acid (FA) profiles of blubber and stable isotopes (SIs) of liver and muscle (mid- or long-term diet; n = 108 seals for the FA and SI markers). The methods provided complementary inf…

Impact of trace metals from past mining on the aquatic ecosystem: a multi-proxy approach in the Morvan (France).

2014

10 pages; International audience; This study seeks to determine to what extent trace metals resulting from past mining activities are transferred to the aquatic ecosystem, and whether such trace metals still exert deleterious effects on biota. Concentrations of Cd, Cu, Pb and Zn were measured in streambed sediments, transplanted bryophytes and wild brown trout. This study was conducted at two scales: (i) the entire Morvan Regional Nature Park and (ii) three small watersheds selected for their degree of contamination, based on the presence or absence of past mining sites. The overall quality of streambed sediments was assessed using Sediment Quality Indices (SQIs). According to these standar…

Cardiovascular, ventilatory and total activity responses of brown trout to handling stress

1994

Changes in total activity, heart and ventilation rates were observed in 2-year-old brown trout, following handling stress, using non-contact bioelectronic monitoring equipment. Experiments were carried out in laboratory conditions at water temperatures below 4° C, Transfer between tanks as well as 5 min restraint stress increased the total activity of fish for 24 to 48 h, after which it declined to near the pre-stress level. The transfer and struggle both elevated the heart rate for 3 to 4 days. Ventilation rate was elevated to a maximum of about 30% above the nominal level and recovered within 3 to 4 days. Both heart and ventilation rates were higher in feeding fish relative to fasting fis…

Mortality of pike-perch (Stizostedion lucioperca), brown trout (Salmo trutta) and landlocked salmon (Salmo salar m. sebago) caught as by-catch in pel…

2000

Altogether 146 pike-perch, 49 brown trout and 19 landlocked salmon were caught in 23 exploratory trawl-hauls in lake Pyhaselka, Finland. Brown trout and salmon were caught only in surface trawling, whereas pike-perch were taken also in mid-water trawling. Most of the fish were smaller than the minimal legal size of 40 cm. To estimate their post-trawling mortality, 129 fish were kept in net cages for 1 week. Less than 15% of the pike-perch and brown trout caught by surface trawl died during 1 week caging, whereas every caged salmon died. Mid-water trawling was far more lethal to pike-perch than surface trawling. We conclude that pike-perch and brown trout can recover from surface trawling. S…

Hepatic responses of gene expression in juvenile brown trout (Salmo trutta lacustris) exposed to three model contaminants applied singly and in combi…

2007

Chemical pollution of the aquatic environment is almost always the result of multiple rather than single toxic compounds. The possibility of separating the effects of key risk chemicals from those of others, including their joint effects, is of clear theoretical interest and high technical importance. We addressed this goal using multiple gene expression profiling in the liver of juvenile brown trout (Salmo trutta lacustris) exposed to three model chemicals (cadmium, carbon tetrachloride [CCl4], and pyrene) administered singly, in binary and trinary combinations at low acutely sublethal concentrations, and in the partial dose–response manner. Differentially expressed genes were grouped by c…