The recovery of the Barents Sea capelin (Mallotus villosus) from a larval point of view

Fossum, Petter

doi:10.1093/icesjms/49.2.237

Cited by 15 publications

(9 citation statements)

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“…Capelin larvae are subjected to mortality by predation by herring during the offshelf transport (Fossum, 1992; Hamre, 1994), and it is likely to assume that there should be reduced level of larvae reaching the offshelf area. However, to what extent the herring juveniles overlapped spatially with capelin larvae, is presently being analysed.…”

Section: Offshore Transport Of Capelin Larvae – Comparsion Between Momentioning

confidence: 99%

Hydrodynamic model forecasts as a guide for process studies on plankton and larval fish

Pedersen

Slagstad

Tande

2003

Fisheries Oceanography

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The interaction between hydrography, zooplankton and capelin larvae was studied during a 15‐day survey in May 2001 in the southern part of the Barents Sea within the strategic programme Capelin and Herring in the Barents Sea Coexistence or Exclusion (BASECOEX). The spawning ground of capelin is found on shallow grounds close to the coast and after hatching the fish larvae are being transported offshelf towards the central part of the Barents Sea. The objective of the field study was to provide estimates of mortality and growth during the duration of the survey. Estimating vital rates requires sampling upon the same population over time. Areas feasible for studying these processes for capelin larvae would have to fulfil several conditions, such as moderate advection, high population numbers of larvae together with appropriate sampling techniques. This paper describes how a model approach may be used as a guideline for planning and executing a survey which has to meet the above conditions. Initially, the biological field was nowcasted with an Individual Based Model (IBM) at the start of the survey. The hydrodynamic model used in conjunction with the IBM required realistic weather forcing. Because of collecting and processing of the data, they are always lagging 1–2 days behind the current date. In order to solve the problem of nowcasting and forecasting we applied real data as far as we could and continued with forecasted weather for the next 5 days. This map was then utilized at sea as part of the information needed to decide where to place the sampling grid, and in the design of the layout of the grid. The model approach further enabled us to estimate the retention of water masses and consequently the capelin larvae and zooplankton populations within the region of study. The retention analysis shows that the advection in the selected area is significant, and after 2 weeks only a small fraction of the initial population is present in the original grid.

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Section: Offshore Transport Of Capelin Larvae – Comparsion Between Momentioning

confidence: 99%

Hydrodynamic model forecasts as a guide for process studies on plankton and larval fish

Pedersen

Slagstad

Tande

2003

Fisheries Oceanography

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“…While variable or high juvenile mortality generally favours iteroparity (Murphy 1968;Orzack and Tuljapurkar 1989), high adult mortality may force the optimal life history strategy towards semelparity. In the Barents Sea, juvenile mortality (defined here as mortality until spawning) of capelin is usually excessive for year-classes produced when immature Atlantic herring (Clupea harengus) are abundant, due to herring predation on the larvae (Hamre 1988;Fossum 1992;Huse and Toresen 1995). Such recruitment failure occurs at irregular intervals.…”

Section: Introductionmentioning

confidence: 99%

Sex-specific life history strategies in capelin (Mallotus villosus)?

Huse¹

1998

Can. J. Fish. Aquat. Sci.

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The life history of capelin (Mallotus villosus) is presently suggested to be sex specific: while males follow a semelparous batch-spawning strategy, females are iteroparous. This hypothesis is based on predictions from a life history simulation model of Barents Sea capelin that shows that iteroparity is more profitable than semelparity for females, but for males, semelparity with several matings with females may be as profitable as iteroparity. These predictions are supported by (i) reports of males mating with several females during a spawning season, (ii) males having a lower gonadosomatic index than females and instead spending their energy on mating and somatic growth, and (iii) an observed higher mortality for males after spawning. The Darwinian fitness of female capelin is limited by the amount of eggs they can carry, and offspring production may only be increased by undertaking several spawning seasons with yearly intervals. Added together, these indices suggest that male and female capelin follow different life history strategies.Résumé : À l'heure actuelle, il semble que le cycle biologique du capelan (Mallotus villosus) soit différent selon le sexe : les mâles sont sémelpares avec reproduction en lots, tandis que les femelles seraient itéropares. Cette hypothèse repose sur les prévisions d'un modèle de simulation du cycle biologique du capelan de la mer de Barents qui montre que l'itéroparité est plus avantageuse que la sémelparité chez les femelles; mais, chez les mâles, la sémelparité associée à plusieurs accouplements avec des femelles peut être aussi avantageuse que l'itéroparité. Ces prévisions sont appuyées par (i) des mentions d'accouplements de mâles avec plusieurs femelles pendant une saison de ponte, (ii) l'existence chez les mâles d'un indice gonadosomatique plus faible que celui des femelles et l'utilisation, chez les mâles, de l'énergie pour l'accouplement et la croissance somatique et (iii) une mortalité observée plus élevée chez les mâles après la reproduction. La valeur adaptative darwinienne des femelles est limitée par le nombre d'oeufs qu'elles peuvent porter, et plusieurs saisons de ponte à intervalles annuels sont nécessaires pour augmenter le nombre de descendants. Tous ces indices combinés portent à croire que les capelans mâle et femelle ont un cycle biologique différent. [Traduit par la Rédaction]

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“…Fortunately, capelin stocks usually recover at nearly the same rate as they were previously reduced. Fossum (1992) explained this recovery efficiency of capelin stocks by the short generation times and the ability of the stocks to produce spawning products at the expense of biomass. Another reason for fast capelin stock recoveries might have been that the herring migrated out of the Barents Sea as maturation was reached, reducing predation pressure on the capelin (Tjelmeland and Bogstad, 1998).…”

Section: Discussionmentioning

confidence: 99%

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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The recovery of the Barents Sea capelin (Mallotus villosus) from a larval point of view

Cited by 15 publications

References 50 publications

Hydrodynamic model forecasts as a guide for process studies on plankton and larval fish

Hydrodynamic model forecasts as a guide for process studies on plankton and larval fish

Sex-specific life history strategies in capelin (Mallotus villosus)?

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

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