Food and feeding conditions of Norwegian spring-spawning herring (Clupea harengus) through its feeding migrations

Overlap in distribution and diets of Atlantic mackerel (Scomber scombrus), Norwegian spring-spawning herring (Clupea harengus) and blue whiting (Micromesistius poutassou) in the Norwegian Sea during late summer

“…This finding is in agreement with a range of previous observations (Dalpadado et al 2000;Gislason & Astthorsson 2002;Dommasnes et al 2004;Iversen 2004;Prokopchuk & Sentyabov 2006), and indicate that predators, at least to some extent, are able to utilize older stages of the new generation of C. finmarchicus before they migrate to deeper water for overwintering. Blue whiting diet, on the other hand, deviated from the other diets, especially from mackerel diet, and was dominated by amphipods and euphausiids as reported earlier in e.g.…”

“…Together, these factors indicate that herring only preyed in selected patches in 2004 while mackerel was more opportunistic. Another interesting observation was that diet overlap between herring and mackerel was lower than expected by chance in 2006, and that mackerel diet this year was totally dominated by C. finmarchicus, an assumed preferred prey for herring (Dalpadado et al 2000). In that same year, herring distribution was positively correlated with appendicularians and negatively correlated with mackerel distribution.…”

“…They also comprised a considerable weight in gut contents at some stations ( Table V), indicating that they were locally important prey items more than coincidental prey swallowed during search or filter feeding. These prey items may be an important supplement to Calanus (Dalpadado et al 2000;Purcell et al 2005;Prokopchuk & Sentyabov 2006). The great abundance of appendicularians, their high nutritional value, their slow swimming speed and lack of carapace make them attractive as prey for many predators (Purcell et al 2005).…”

“…Mackerel, herring and blue whiting are major consumers of zooplankton in the Norwegian Sea (Zilanov 1968;Dalpadado et al 2000;Iversen 2004;Prokopchuk & Sentyabov 2006). The dominant zooplankton group in terms of abundance in these waters is copepods, and Calanus finmarchicus Gunnerus, 1770 is the main contributor to the zooplankton biomass (Wiborg 1955;Marshall & Orr 1972;Aksnes & Blindheim 1996;Hirche et al 2001).…”

“…The dominant zooplankton group in terms of abundance in these waters is copepods, and Calanus finmarchicus Gunnerus, 1770 is the main contributor to the zooplankton biomass (Wiborg 1955;Marshall & Orr 1972;Aksnes & Blindheim 1996;Hirche et al 2001). Calanus finmarchicus is fed upon by all the three major pelagic species, and constitute a major part of mackerel and herring diets (Dalpadado et al 2000;Gislason & Astthorsson 2002;Dommasnes et al 2004;Prokopchuk & Sentyabov 2006). Euphausiids and Themisto spp.…”