Feeding habit of Brown trout (Salmo trutta fario) in upper parts of river Swat, Pakistan

Salmo trutta fario is the most important fish species of family Salmonidae inhibited in cool waters all over the world including the nortern parts of Pakistan. This study was aimed to find out the prey selection and feeding habits of the species. One hundred and eighty five Salmo trutta fario were captured from March 2016 to April 2017. Feeding intensity as represented by a fullness index (FI), changing with various length groups and season. Out of 185 Brown trout 24 fish stomaches were found empty. The most important and common food items of brown trout were Brachycentridae, Blepharocera, Hydropsychidae, ephemerella spp. Kruskal Wallis H-test were applied on feeding intensity groups consisting of three month group. The test statistic for K.W-H-test were (H=8.13 with df =3) had a p-value of 0.043 < (alpha=0.05 indicates favor of the alternative hypothesis of at least one difference among the feeding intensity groups. The linear relationship of N with index of relative importance and %IRI denoted by least square regression line (N = 35.2 + 22.1%IRI), shows that for 22 prey there is 1% change in IRI. The relationship between total length (mm) and fish body weight (gm) is expressed by Pearson correlation coefficient (r = 0.976), showed that total length (mm) and fish body weight (gm.) is highly correlated. Descriptive statistics are used for the stomach fullness, which shows that feeding intensity was recorded higher from March to May. A total of 2289 preys was recorded including the most common were; Trichoptera, Hydropsychidae, Brachycentridae, diptera, blepharocera, ephemerala, chironomida, honey bees, grass hopper, locust, trout egg, trochanter, plant tissue, stones were retrieved from the gut contents of brown trout. According to index of relative importance IRI% four preys represents major components of the diet. The highest IRI% was recorded in Brachycentridae (39.38%), followed by blepharocera (13.23%), Hydropsychidae (10.76%) and ephemerella spp (8.28%). The relationship between IRI and FO is (r =0.556) is moderately correlated with coefficient of determination (r2=0.31). This study will help in the development of an artificial diet for the species for better growth performance in captivity.

CHANGES IN MICROBIAL INTESTINE FLORA OF BROWN TROUT (SALMO TRUTTA FARIO) FED WITH PREBIOTIC ADDED FEEDS

In this research, Brown trout (Salmo trutta fario L., 1758) with 100±15 g from the fish production center of Aquaculture department of Fisheries Faculty at Ataturk university was used. The effects of addition of prebiotic (0 % prebiotic as control and 0.1 % prebiotic) to the fish diets was determined from a-90 days of feeding trial (Experiment 1) with 4 replications (2x4=8 tanks). Fish were distributed randomly to each group of tanks including 40 fish each. Fish were fed with experimental diets twice a day at 10±1°C water temperature. In the experiment treatment vs time interaction was investigated by taking samples from intestine for determination of intestinal bacterial flora and body proximate composition at 0, 30, 60 and 90. days. Feeding fish with prebiotic showed that there were significant changes in the number of all bacteria counted from intestinal flora and percentages of chemical composition from fish fillets (p<0.05).

Health Surveillance of Wild Brown Trout (Salmo trutta fario) in the Czech Republic Revealed a Coexistence of Proliferative Kidney Disease and Piscine Orthoreovirus-3 Infection

The population of brown trout (Salmo trutta fario) in continental Europe is on the decline, with infectious diseases confirmed as one of the causative factors. However, no data on the epizootiological situation of wild fish in the Czech Republic are currently available. In this study, brown trout (n = 260) from eight rivers were examined for the presence of viral and parasitical pathogens. Salmonid alphavirus-2, infectious pancreatic necrosis virus, piscine novirhabdovirus (VHSV) and salmonid novirhabdovirus (IHNV) were not detected using PCR. Cell culturing showed no viruses as well, and serological analysis of 110 sera did not detect any specific antibodies against VHSV or IHNV. Fish from two rivers were positive for the presence of piscine orthoreovirus-3 (PRV-3), subtype PRV-3b. However, none of the PRV-3-positive fish showed gross pathologies typically associated with PRV infections. By far the most widespread pathogen was Tetracapsuloides bryosalmonae which was confirmed in each of the examined locations, with a prevalence of up to 65% and 100%, as established by immunohistochemistry and PCR, respectively. Furthermore, up to 43.8% of fish showed signs of proliferative kidney disease caused by T. bryosalmonae, suggesting that this parasite is a main health challenge for brown trout in the Czech Republic.

The Usage of Non-Wood Forest Products - Culinary and Artisanal Traditions in Romania

Non-wood forest products are essential for numerous industrial branches, as well as for the creation of culinary and artisanal products. From this point of view, Romania has numerous such products. The present article succinctly describes ten products resulted from the local usage of some non-wood forest products: porcini soup in Bucovina (Porcinis mushrooms -Boletus edulis-); hârzobi in Neamt (trout fish- Salmo trutta fario); common beech trout in Covasna (Pleurotus ostreatus mushrooms); truffles-Tuber sp.- zacusca (stew) in Bucharest; holopchi with porridge and porcini or honey mushrooms in Moisei; fir bellows cheese in Bran Moeciu; brandy from bird cherry fruits (Prunus avium) in Brad; tinder mushroom (Inonotus obliquus) in Harghita; fir’s needles for dead wreaths in Sibiu; rattle, rich snowdrop flowers, dried crocus flowers, roots and bark (privet bark, black alder bark, buckthorn bark) in Botiza. Knowing and promoting (creating local brands) these products is extremely important.

Passability of Potamodromous Species through a Fish Lift at a Large Hydropower Plant (Touvedo, Portugal)

River fragmentation by large hydropower plants (LHP) has been recognized as a major threat for potamodromous fish. Fishways have thus been built to partially restore connectivity, with fish lifts representing the most cost-effective type at high head obstacles. This study assessed the effectiveness with which a fish lift in a LHP on the River Lima (Touvedo, Portugal), allows potamodromous fish—Iberian barbel (Luciobarbus bocagei), Northern straight-mouth nase (Pseudochondrostoma duriense) and brown trout (Salmo trutta fario)- to migrate upstream. Most fish (79.5%) used the lift between summer and early-fall. Water temperature was the most significant predictor of both cyprinids’ movements, whereas mean daily flow was more important for trout. Movements differed according to peak-flow magnitude: nase (67.8%) made broader use of the lift in the absence of turbined flow, whereas a relevant proportion of barbel (44.8%) and trout (44.2%) passed when the powerhouse was operating at half (50 m3s−1) and full-load (100 m3s−1), respectively. Size-selectivity found for barbel and trout could reflect electrofishing bias towards smaller sizes. The comparison of daily abundance patterns in the river with fish lift records allowed the assessment of the lift’s efficacy, although biological requirements of target species must be considered. Results are discussed in the context of management strategies, with recommendations for future studies.