Diet of 0-group stages of capelin (Mallotus villosus), herring (Clupea harengus) and cod (Gadus morhua) during spring and summer in the Barents Sea

The Barents Sea stock of capelin ( Mallotus villosus ) has suffered three major collapses (>90% reduction) since 1985 due to recruitment failures. As capelin is a key species in the area, these population collapses have had major ecosystem consequences. By analysing data on spawner biomass and three recruitment stages (larvae, 0-group, and 1-year-olds), we suggest that much of the recruitment failures are caused by predation from herring ( Clupea harengus ) and 0-group and adult Northeast Arctic cod ( Gadus morhua ). Recruitment is furthermore positively correlated with sea temperatures in winter and spring. Harvesting of maturing capelin on their way to the spawning grounds reduced the abundance of larvae significantly, but this reduction to a large extent is compensated for later in life, as mortality is strongly density-dependent between the larval stage and age 1. Altogether, our study indicates a very high importance of trophic interactions, consistent with similar findings in other high-latitude marine ecosystems.

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Effects of predation from juvenile herring (Clupea harengus) on mortality rates of capelin (Mallotus villosus) larvae

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f09-105 ◽

2009 ◽

Vol 66 (10) ◽

pp. 1693-1706 ◽

Cited By ~ 26

Author(s):

Elvar H. Hallfredsson ◽

Torstein Pedersen

Keyword(s):

Barents Sea ◽

Fish Larvae ◽

Mortality Rates ◽

Clupea Harengus ◽

Mallotus Villosus ◽

Rate Estimate ◽

Predator Prey ◽

The Barents Sea ◽

Capelin Mallotus Villosus ◽

Larvae Density

Predation has been suggested as a cause of substantial mortality of fish larvae to the degree that it might influence recruitment. This field-based study concludes that juvenile herring ( Clupea harengus ) as small pelagic predator can significantly affect mortality rates of the planktonic larvae of capelin ( Mallotus villosus ) in the Barents Sea. Surveys were carried out in the summers of 2001 and 2003. In 2001, juvenile herring were widely distributed and overlapped with capelin larvae over a wide area, whereas in 2003, the herring were more aggregated. The study focused on predation in the areas of predator–prey overlap. Capelin larvae were observed in the herring stomachs at 11 of 24 stations and at 8 of 16 stations where herring were caught in 2001 and 2003, respectively. At those stations, an estimated 7.3% and 9.9% of the capelin larvae were eaten by herring per day in 2001 and 2003, respectively. Statistical models revealed that density of capelin larvae and copepods and occurrence of euphausiids in the stomachs affected the number of capelin larvae per predator stomach. A simplified model with only capelin larvae density as predictor was converted to a functional response relationship using an experimentally derived digestion rate estimate for capelin larvae in herring stomachs.

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Seasonal dynamics of spatial distributions and overlap between Northeast Arctic cod (Gadus morhua) and capelin (Mallotus villosus) in the Barents Sea

PLoS ONE ◽

10.1371/journal.pone.0205921 ◽

2018 ◽

Vol 13 (10) ◽

pp. e0205921 ◽

Cited By ~ 8

Author(s):

Johanna Fall ◽

Lorenzo Ciannelli ◽

Georg Skaret ◽

Edda Johannesen

Keyword(s):

Seasonal Dynamics ◽

Gadus Morhua ◽

Barents Sea ◽

Spatial Distributions ◽

Mallotus Villosus ◽

Arctic Cod ◽

The Barents Sea ◽

Capelin Mallotus Villosus

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Effects of predation from pelagic 0-group cod (Gadus morhua) on mortality rates of capelin (Mallotus villosus) larvae in the Barents Sea

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f07-137 ◽

2007 ◽

Vol 64 (12) ◽

pp. 1710-1722 ◽

Cited By ~ 17

Author(s):

Elvar H Hallfredsson ◽

Torstein Pedersen

Keyword(s):

Mortality Rate ◽

Stomach Content ◽

Gadus Morhua ◽

Barents Sea ◽

Stomach Contents ◽

Mortality Rates ◽

Mallotus Villosus ◽

The Barents Sea ◽

Predation Mortality ◽

Capelin Mallotus Villosus

Surveys were carried out in 2002 and 2003 to test whether predation from pelagic 0-group cod (Gadus morhua) juveniles affects mortality rates of Barents Sea capelin (Mallotus villosus) larvae. In 2002, capelin larvae were observed in 17% of the cod stomachs and predation was observed at 19 of 50 stations. In 2003, capelin larvae were observed in 8% of the cod stomachs and predation was observed at 19 of 37 stations. The stomach contents and zooplankton samples were dominated by copepods and krill. The number of capelin larvae in cod stomachs increased with increasing capelin larvae abundance and cod length and decreased with increasing stomach content of copepods and prey abundance of krill. The time when capelin larvae could be recognised after ingestion in the cod stomachs was estimated experimentally and depended on predator and prey lengths. The estimated overall predation mortality rate from juvenile cod on capelin larvae was about 1.5% per day for both years and can potentially have a significant effect on the survival of capelin larvae, depending on the overlap in the different years.

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