Body pigmentation pattern to assess introgression by hatchery stocks in native Salmo trutta from Mediterranean streams

Abstract

Five qualitative and seven quantitative colouration and spotting pattern features were measured in 23 brown trout Salmo trutta populations and two hatchery stocks. Simultaneously, the LDH-C1*, a diagnostic locus fixed for *90 and *100 alleles in stocking and native populations from southern Europe, respectively, was analysed to classify the brown trout studied according to their origin: native, hatchery stock and hybrids. The three genotypes showed significant differences in the colouration and spotting features and a discriminant function analysis could correctly identify 79% of the individuals. The most discriminating variables were dorsal fin margin colour, number of opercular spots, presence of the preopercular mark and diameter of black spots. Given the low cost, ease and possibility of field identification of native fish, the results indicate great opportunities for the application of morphological-based classification models on the conservation and management of native brown trout stocks. # 2005 The Fisheries Society of the British Isles

Assessing fish metrics and biotic indices in a Mediterranean stream: effects of uncertain native status of fish

“…The basis for considering brown trout as introduced to Tordera basin was: (i) that at present the Tordera population is genetically very similar to those of hatchery origin (Aparicio et al, 2005), which are genetically and morphologically distinct to native stocks but have been stocked throughout the Iberian Peninsula to satisfy angling demands Length is fork length except for eel (total length). Stretch presence reports the sampling sites (see Table 1 for codes) where the species was detected (Aparicio et al, 2005;Almodóvar et al, 2006); and (ii) it is a low altitude population that was probably introduced long ago (A.…”

“…Stretch presence reports the sampling sites (see Table 1 for codes) where the species was detected (Aparicio et al, 2005;Almodóvar et al, 2006); and (ii) it is a low altitude population that was probably introduced long ago (A. de Sostoa, pers.…”

Comparison of number and shape of parr marks in three species of the genus Salmo and two ecotypes of cultured brown trout Salmo trutta from Turkey

“…Spots pattern and colouration characteristics are primarily used for identification of species or different strains within a population (Skaala and Jorstad, 1988;Largiader and Scholl, 1996;Lascaux, 1996;Aparicio et al, 2005) and often varies in different populations (Blanc et al, 1982(Blanc et al, , 1994Moran et al, 1989;Mezzera et al, 1997).…”

“…Parr marks may persist in young adults, but disappear in adults. Visible parr marks are important characteristics in several fishes for identification (Aparicio et al, 2005). Brown trout juveniles normally have visible parr marks on their sides as in many other salmonid species (Mezzera et al, 1997).…”

“…These morphological differentiations could be due to genetic drift in populations (Karaiskou et al, 2009). Mezzera et al (1997) reported that the number of parr marks were between 11 and 13 in S. trutta but according to Aparicio et al (2005) it ranged between 8 and 12. The present study recorded 5 to 12 parr marks in all five groups.…”