Diet of the introduced pikeperchSander lucioperca(L.) (Osteichthyes, Percidae) in a recent colonised reservoir in south-western Iberian Peninsula

Abstract

The present study examines the diet of pikeperch (Sander lucioperca) in Iberian freshwaters. Food habits of Sander lucioperca were studied based on stomach content analyses of 376 specimens (12.22-52.52 cm total length) collected in 2009 on a south-western Iberian reservoir. A total of 265 stomachs (79.52%) contained food, and fifteen taxonomic levels of prey were identified. The most important prey was fish according to the Relative Importance Index (IRI). Trophic level analysis revealed that S. lucioperca is a top predator throughout its life history. There were no differences between sexes (p = 0.573, ANOSIM) and seasons (p = 0.266) in the diet composition, but minor dietary shifts with ontogeny were found. The Levins' standardized index indicated wider niche breadth for small pikeperch, whereas larger pikeperch specimens showed a narrow niche breadth with a specialization in congeners. The graphical analysis (Amundsen method) of the diet confirmed that pikeperch feed mainly on congeners in Alcántara reservoir; however some native species were also consumed.

Variation in Diet Patterns of the Invasive Top Predator Sander lucioperca (Linnaeus, 1758) across Portuguese Basins

“…However, the results presented here are generally consistent with other studies conducted in Spain and France, supporting the current observed patterns adjusted to Iberian watersheds [36,60]. The sampling period of this study might have influenced the results; however, most of the studied populations were lentic ones, related to reservoirs that are more stable environments with a limited community seasonal change [36]. Specifically, it would be important to widen the study period to encompass the entire year in riverine populations, to evaluate the predation effect on anadromous fish that spawn during the winter months [20].…”

“…The current work evaluates pikeperch dietary patterns from different populations that were collected across a wide spatial gradient, using different methodologies, encompassing distinct months and involving a limited number of individuals in some populations. However, the results presented here are generally consistent with other studies conducted in Spain and France, supporting the current observed patterns adjusted to Iberian watersheds [36,60]. The sampling period of this study might have influenced the results; however, most of the studied populations were lentic ones, related to reservoirs that are more stable environments with a limited community seasonal change [36].…”

“…Ontogenetic fluctuations in prey use were also found, with small individuals feeding predominantly on insects, small macroinvertebrates and fish, while large specimens foraged mainly on fish and crayfish and with both size classes showing signs of cannibalism in six populations. These results are coincident with those found in lakes [58,59] and reservoirs [36,60], suggesting that fish prey constitute a staple prey for pikeperch across its non-native range. Furthermore, the majority of the pikeperch diet was composed of non-native species, although the presence of native fish preys (e.g., Mugilidae, Big-scale sand smelt, Unidentified nase, European seabass, European flounder) was found but in low numbers, but in lotic populations could reach half of the preys.…”

“…Despite exhibiting ontogenetic shifts in its diet, it rapidly attains piscivory during its first year of life [32,33]. The predatory behavior of pikeperch has been well studied both within their native and non-native ranges (e.g., [34][35][36][37][38]). However, there is little information on the trophic ecology of pikeperch in relation to novel environments, which could depict distinct impacts and effects on native fish communities.…”

Variability in Population Traits of a Sentinel Iberian Fish in a Highly Modified Mediterranean-Type River

“…In general, predation by non-native fish could affect the population structures and dynamics of native fish species in the Iberian Peninsula [95]. Some studies from other Iberian rivers confirmed the inclusion of different barbel species in the diet of top predator fish such as E. lucius [100,101] and S. Lucioperca [102]. Predatory fish (E. lucious, S. lucioperca and M. salmoides) showed a higher occurrence in the lower reaches of the study area.…”