Temporal Dynamics of Top Predators Interactions in the Barents Sea

Durant, Joël M.; Skern‐Mauritzen, Mette; Krasnov, Yu. V.; Nikolaeva, Natalia; Lindstrøm, Ulf; Dolgov, Andrey V.

doi:10.1371/journal.pone.0110933

Cited by 30 publications

(25 citation statements)

References 48 publications

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“…This stock exhibits huge variation in abundance, with 3 collapses (mid-1980s, early 1990s and early 2000s) due to recruitment failure, and is highly affected by trophic interactions with other Barents Sea species such as herring and cod (Hjermann et al 2010). Reciprocally, the fluctuations in capelin abundance in the Barents Sea affect its predators (Durant et al 2014). The time series can be roughly divided in 2, with a first period prior to 1985 when the population was intensively harvested and a second period when it was not.…”

Section: Discussionmentioning

confidence: 99%

Age-structure, harvesting and climate effects on population growth of Arcto-boreal fish stocks

Durant¹,

Hjermann²

2017

Mar. Ecol. Prog. Ser.

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We used a comparative approach investigating commercially fished species with contrasting life histories and trophic positions in an Arcto-boreal system, the Barents Sea. Our objective was to address the ecological consequences of harvesting on stock properties (stochastic growth rate; a property related to intrinsic growth rate) in relation to different external conditions (fishing pressure and climate). We used age-structured population matrices to calculate the transient elasticity of population growth with respect to recruitment (how much population growth depends on recruitment) over time. Using a generalized additive model (GAM) analysis, we found that the transient elasticity of population growth to recruitment overall depends mostly on age structure (which in turn is affected by fishing) but also on climate (temperature change or winter North Atlantic Oscillation). Our results indicate that under warmer conditions, population growth of high latitude stocks becomes increasingly dependent on recruitment, which makes the stocks more difficult to manage. In general, there was no effect of ongoing fishing pressure on elasticity after age structure had been taken into account, supporting the view that long-term fishing pressure affects the susceptibility of the population to climate indirectly, by changing the age structure of the stock. However, for most of the stocks we have studied here, populations have low elasticity to recruitment due to their life history, meaning that the health of the stock mainly depends on survival after the recruitment stage; i.e. fisheries management is more important than climate.

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Section: Discussionmentioning

confidence: 99%

Age-structure, harvesting and climate effects on population growth of Arcto-boreal fish stocks

Durant¹,

Hjermann²

2017

Mar. Ecol. Prog. Ser.

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“…Given our dietary knowledge of these predators they compete (directly) for krill and capelin in these periods Johannesen et al, 2012). A recent study in which the intra-and interspecific competition among top-predators (cod, minke whale and sea birds) was analyzed concludes that minke whales and cod compete for food and that their diets depend on the abundance of herring and capelin, respectively (Durant et al, 2014). That study further suggests that the diet overlap among these predators generally increase with changes in herring and krill abundances.…”

Section: Discussion Possible Mechanisms In Predation and Competitionmentioning

confidence: 99%

A review of the battle for food in the Barents Sea: cod vs. marine mammals

et al. 2015

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Cod, harp seal and minke whale are the main top predators in the Barents Sea ecosystem. In the last decade, the abundance of cod has increased considerably, and is at a record high level. In spite of this, the growth and condition of cod has remained rather stable, although some decrease is seen in size at age of large, mature cod. During the same period, the abundance of harp seals has declined whereas the minke whale stock has been at a stable level. The body condition (blubber thickness) of these two mammal stocks has, however, decreased, with the strongest decrease observed for harp seals. A possible hypothesis for explaining this is that cod outperform the marine mammal stocks in the competition for food. The main advantages for cod are most likely larger availability of food (mainly capelin) during winter-spring than for marine mammals, as well as a wider range of prey species being available to cod than to marine mammals. Harp seals are more dependent on prey items found close to the ice edge than the other two predator stocks are, which could partly explain why the performance of harp seals is worse than that of the two other main top predators in the area.

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“…Yet, the focus has been on a single species or a few species in relation to their main prey abundance and distribution (Mackinson et al, 2006;Bluhm and Gradinger, 2008;Skern-Mauritzen et al, 2011;Durant et al, 2014) or their habitat use (Moore, 2008). Marine mammals are a diverse phylogenetic group with a variety of diet and habitat requirements, but they may also display some degree of resource overlap in certain regions (Spitz et al, 2006;Bogstad et al, 2015;Haug et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

The role of marine mammals in the Barents Sea foodweb

Blanchet

Primicerio

Frainer

et al. 2019

ICES Journal of Marine Science

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Marine mammals are important players in the Barents Sea ecosystem but their structural role in the foodweb has been little explored. We compare foodweb-related characteristics within and between phylogenetic groups for 19 marine mammals. As a group, they directly connect to the most central species (i.e cod and haddock) in the Barents Sea (i.e. cod and haddock) and consume over half of the available species. Pinnipeds are the most homogenous phylogenetic group with high omnivory and high prey richness. Mysticetes are split between well-connected species with high omnivory like the humpback whale, and peripheral specialists like the blue whale. Based on foodweb-derived indices some species consistently cluster together forming two groups, suggesting topological redundancy within them. One is dominated by Arctic seals and the other includes most of the baleen whales. Marine mammals generally contribute to network modularity as their trophic links are mainly within their own module. However, Atlantic species such as the grey seal act as a module connector decreasing modularity. This might negatively affect ecosystem robustness with perturbation effects spreading further and quicker in the foodweb. In the Arctic reaches of the Barents Sea, climate warming is likely to bring about extensive changes in the foodweb structure through a redistribution of species.

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Temporal Dynamics of Top Predators Interactions in the Barents Sea

Cited by 30 publications

References 48 publications

Age-structure, harvesting and climate effects on population growth of Arcto-boreal fish stocks

Age-structure, harvesting and climate effects on population growth of Arcto-boreal fish stocks

A review of the battle for food in the Barents Sea: cod vs. marine mammals

The role of marine mammals in the Barents Sea foodweb

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