Trophic polymorphism in brook charr revealed by diet, parasites and morphometrics

Abstract

Stomach contents, parasite assemblages and morphometrics were compared in brook charr Salvelinus fontinalis from the littoral and pelagic zone of two adjacent lakes on the Canadian Shield. In lac Baie des OnzeÎles, fish from the littoral zone had greater abundance of benthic prey in their stomach and were more heavily infected by parasites that use intermediate hosts associated with the littoral zone than fish captured in the pelagic zone. Littoral and pelagic brook charr from this lake also differed in regard to body shape and fin length, with each group being anatomically adapted to exploit their respective habitats. The highly significant correlation between morphometric and parasite canonical scores supports the hypothesis of functional diversification of individuals within lac Baie des OnzeÎles. While fish from littoral and pelagic zones of lac Caribou did not differ in terms of diet, parasite assemblages or morphometrics, they were different to fish from lac Baie des OnzeÎles in that they were less frequently infected with parasites that use gastropods as intermediate hosts, and had shorter pectoral fins. The inter-lake comparisons suggested that parasite assemblages and morphometrics of brook charr reflected the dominance of the limnetic and littoral habitats in lacs Caribou and lac Baie des OnzeÎles, respectively. # 2008 Her Majesty the Queen (Environment Canada)

RETRACTED ARTICLE: Advancements in morphometric differentiation: a review on stock identification among fish populations

“…In the presence of northern pike, Esox lucius, predatorinduced changes in body shape of crucian carp, Carassius carassius provide a shrinking example of adaptive plasticity by developing a deeper body (Bronmark and Miner 1992). Adaptive plasticity may also contribute to the morphological differences between the benthic and limnetic forms observed in a variety of fish taxa (Robinson and Wilson 1994;Robinson and Parsons 2002;Sacotte and Magnan 2006;Knudsen et al 2007;Bertrand et al 2008). The limnetic forms have more and longer gill rakers; shallower bodies and heads; longer heads, snouts, and upper jaws; and larger eyes than the benthic forms (McPhail 1984(McPhail , 1992.…”

The role of Salvelinus in contemporary studies of evolution, trophic ecology and anthropogenic change

“…Of particular interest was the fascinating number of sympatric forms of S. alpinus from Lake Tinnsjøen in Norway (four, as in Lake Thingvallavatn in Iceland), with an exotic profundal form found at 450 m depth that parallels that reported in Gander Lake, Newfoundland, (O'Connell et al, 2005). Additional studies of intraspecific variation in Brook charr (Bertrand et al, 2008;Samways et al, 2015), Dolly Varden (Oleinik & Skurikhinal, 2010), and Lake charr (Eshenroder, 2008;Chavarie et al, 2016) have similarly demonstrated the high degree of polymorphism observed in Arctic charr, such that one can conclude it to be characteristic of the genus Salvelinus.…”

Vertebrate diets derived from trophically transmitted fish parasites in the Bothnian Bay

“…Parasites were a more signiWcant predictor of the trophic position and stable isotope ratio of yellow perch (Perca Xavescens) in Canadian Shield lakes compared to gut contents (Johnson et al 2004). In a parallel study, parasites could predict the trophic position of brook charr (Salvelinus fontinalis) better than observed diet or morphometrics in Quebec lakes Table 2 ( Bertrand et al 2008). Thus, parasites are indeed eVective information units with which trophic relationships can be constructed (Marcogliese 2003(Marcogliese , 2004(Marcogliese , 2005.…”