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

Hallfredsson, Elvar H.; Pedersen, Torstein

doi:10.1139/f09-105

Cited by 42 publications

(37 citation statements)

References 47 publications

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“…2a). There is a potential competition between herring and cod juveniles as they have a dietary as well as a temporal and spatial overlap [57], [58], and the presence of juvenile herring reduces capelin recruitment and hence food availability in the Barents Sea [59]. In years with many capelin, these are preyed upon by cod, herring, haddock ( Melanogrammus aeglefinus ) and other demersal fish [60], such as Greenland halibut ( Reinhardtius hippoglossoides ) [61] and skates [62].…”

Section: Discussionmentioning

confidence: 99%

Change in Fish Community Structure in the Barents Sea

et al. 2013

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Change in oceanographic conditions causes structural alterations in marine fish communities, but this effect may go undetected as most monitoring programs until recently mainly have focused on oceanography and commercial species rather than on whole ecosystems. In this paper, the objective is to describe the spatial and temporal changes in the Barents Sea fish community in the period 1992–2004 while taking into consideration the observed abundance and biodiversity patterns for all 82 observed fish species. We found that the spatial structure of the Barents Sea fish community was determined by abiotic factors such as temperature and depth. The observed species clustered into a deep assemblage, a warm water southern assemblage, both associated with Atlantic water, and a cold water north-eastern assemblage associated with mixed water. The latitude of the cold water NE and warm water S assemblages varied from year to year, but no obvious northward migration was observed over time. In the period 1996–1999 we observed a significant reduction in total fish biomass, abundance, mean fish weight, and a change in community structure including an increase in the pelagic/demersal ratio. This change in community structure is probably due to extremely cold conditions in 1996 impacting on a fish community exposed to historically high fishing rates. After 1999 the fish community variables such as biomass, abundance, mean weight, P/D ratio as well as community composition did not return to levels of the early 90s, although fishing pressure and climatic conditions returned to earlier levels.

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Section: Discussionmentioning

confidence: 99%

Change in Fish Community Structure in the Barents Sea

et al. 2013

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“…(d) End of the 2002 season, based on Anon (2002b, 2004, 2006). (e) Start of the 2003 season, based on Hallfredsson and Pedersen (2009). (f) End of the 2003 season, based on Anon (2003a).…”

Section: Methodsmentioning

confidence: 99%

“…Capelin larvae mortality was modelled by means of natural mortality and predation from herring age 1–3. The rate of predation as a function of the prey density, i.e., the functional response (Murdoch, 1969), was assumed to follow the Holling type‐II (Holling, 1959) non‐linear relationship as proposed by Hallfredsson and Pedersen (2009): where N e refers to the number of capelin larvae eaten by one herring per day, and N c is the number of capelin larvae per m 2 . The value 0.42 is the Spearman rank correlation between the abundances of capelin larvae and herring, and the value 38.0 is the half‐saturation coefficient ( K s ).…”

Section: Methodsmentioning

confidence: 99%

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The recruitment process of the Barents Sea capelin (Mallotus villosus) stock, 2001–2003

Wiedmann

Pedersen

Nilssen

2012

Fisheries Oceanography

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Oceanographic and predation processes are important modulators of fish larvae survival and mortality. This study addresses the hypothesis that immature Norwegian spring‐spawning herring (Clupea harengus), when abundant in the Barents Sea, determine the capelin reproduction success through consumption of Barents Sea capelin (Mallotus villosus) larvae. Combining a hydrodynamic model and particle‐tracking individual‐based model, a realistic spatio‐temporal overlap between capelin larvae and predatory immature herring was modelled for the summer seasons of 2001–2003. Capelin larvae originating from western spawning grounds became widely dispersed during the summer season, whereas those originating from eastern spawning grounds experienced a rapid drift into the southeastern Barents Sea. Herring caused a 3% mortality of the capelin larvae population in 2001 and a 16% mortality in 2003, but the effect of predation from herring on capelin larvae was negligible in 2002. Despite a strong capelin larvae cohort and a virtual absence of predatory herring, the recruitment from the capelin 2002 year class was relatively poor from a long‐term perspective. We show that the choice of capelin spawning grounds has a major impact on the subsequent capelin larvae drift patterns, constituting an important modulator of the capelin larvae survival. Variation in drift patterns during the summer season is likely to expose the capelin larvae to a wide range of hazards, including predation from young cod, sandeel and other predators. Such alternative predators might thus have contributed to the poor capelin recruitment during 2001–2003, leading to the collapse of the capelin stock in the subsequent years.

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“…A fishing moratorium has been enacted three times when the population collapsed below the target escapement. The influence of fishing pressure seems to have been negligible in explaining the stock collapses which were primarily attributed to natural predation instead (Gjøsaeter 1998;Hallfredsson and Pedersen 2009;Hjermann et al 2004Hjermann et al , 2010. Indeed, the larval stage seems to be the most critical phase determining future capelin biomass (Gjøsaeter and Bogstad 1998;Hjermann et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Temporal stability of the maturation schedule of capelinMallotus villosusin the Barents Sea

Baulier

Heino

Gjøsæter

2012

Aquat. Living Resour.

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-Capelin in the Barents Sea are primarily harvested in a terminal fishery that targets maturing individuals. Theory predicts that, in a semelparous population (i.e., one in which reproduction is seasonal, synchronous, and followed by parental mortality), an unselective, terminal fishery (i.e., one in which most of the fish that are not caught will not have a new spawning opportunity) does not generate strong selection for changed age and size at maturation. The probabilistic maturation reaction norm (PMRN) method was applied to test this prediction and to detect possible temporal changes in length at maturation of Barents Sea capelin between 1978 and 2008. Maturation reaction norms suggest that maturation is age-independent in capelin, but that males require a larger size to attain the same maturation probability as females. No temporal trends in length at maturation could be detected, thus confirming the theoretical prediction. Furthermore, none of the candidate environmental variables tested to explain the temporal variability in length at maturation (water temperature and capelin biomass) consistently showed a significant correlation with the PMRN midpoints.

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

Cited by 42 publications

References 47 publications

Change in Fish Community Structure in the Barents Sea

Change in Fish Community Structure in the Barents Sea

The recruitment process of the Barents Sea capelin (Mallotus villosus) stock, 2001–2003

Temporal stability of the maturation schedule of capelinMallotus villosusin the Barents Sea

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