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

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