Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017

Erindi/veggspjald / Talk/poster E72

Feeding pattern of juvenile Atlantic cod (Gadus morhua) and saithe (Pollachius virens)

Höfundar / Authors: Anja Nickel (1), Guðbjörg Ásta Ólafsdóttir (1)

Starfsvettvangur / Affiliations: 1. University of Iceland, Research Center of the Westfjords

Kynnir / Presenter: Anja Nickel

The current study investigates the diets of 0-group Atlantic cod (Gadus morhua) and saithe (Pollachius virens) juveniles and discusses the relevance of trophic preferences and trophic competition for nursery ground conservation and management. The juveniles of both species settle in the shallow coastal waters in the north and the north-west of Iceland in late summer and share the same habitats during their first years. The settlement stage is described as a critical period for both species as growth in the first summer and fall may determine their winter survival. For the case study, samples were taken in autumn 2015 and 2016, and the stomach contents of 0-group cod and saithe were qualitatively and quantitatively analyzed. Dietary composition showed that copepods constituted the main diet for both species. Further important prey organisms were cladocera, insects (Chironomidae), gastropoda, cyprid larvae, amphipoda and ostracoda. The feeding patterns of the 0-group juveniles revealed that both species are opportunistic feeders with a wide range of prey organisms. Despite that, there is high overlap in the foraging niche of cod and saithe, suggesting the potential for trophic competition between and within the two species. The dietary overlap Results from the sampling period during July until November indicated a high dietary overlap between the two species. From late October on, cod and saithe feeding patterns started to diverge, which indicates more specialized foraging habits.