Vertical distribution and mortality of Calanus finmarchicus during overwintering in oceanic waters southwest of Iceland

Gíslason, Ástþór; Eiane, Ketil; Reynisson, Páll

doi:10.1007/s00227-006-0400-7

Cited by 26 publications

(18 citation statements)

References 37 publications

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“…We used the function relating mortality in these early stages to adult female abundance given by Ohman et al (2002). The mortality rate in C5d was 10% of daily mortality in non-diapausing C5 (McLaren et al 2001, Gislason et al 2007). The mortality rate in C6m was twice the mortality rate of C6f (Kiørboe 2006).…”

Section: Equations Of the Parametersmentioning

confidence: 98%

Control of dormancy by lipid metabolism in Calanus finmarchicus: a population model test

Maps¹,

Plourde²,

Zakardjian³

2010

Mar. Ecol. Prog. Ser.

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The life cycle of Calanus finmarchicus includes a prolonged dormancy phase that allows it to avoid the unfavourable environmental conditions typical of the upper ocean from late summer to early spring in the subarctic North Atlantic. Recent demographic, physiological and genetic evidence supports the hypothesis of a crucial role for lipid accumulation and metabolism in the control of dormancy. We present a stage-resolving biomass model of C. finmarchicus, implementing a mechanistic approach of the control of dormancy based on this lipid hypothesis. The dormancy process obeys 2 rules: (1) active copepodite stage Vs (C5s) enter dormancy when the ratio of lipid to total body carbon exceeds some threshold, and (2) diapausing C5s exit dormancy when their lipid storage approaches a lower threshold. We implemented the model into a 1-dimensional water column framework and compared our results to 2 consecutive years of observations of stage-specific copepodite abundances and lipid content of C5 from the Northwest Gulf of St. Lawrence, Canada. The model produced realistic phenology and temporal patterns in lipid content of C. finmarchicus in response to the observed environmental forcing. Interannual variations in the timing of entry and contributions of different generations to the overwintering stock were shown. Our results are consistent with the hypothesis of a lipid-mediated control of entrance and exit from dormancy in C. finmarchicus.

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Section: Equations Of the Parametersmentioning

confidence: 98%

Control of dormancy by lipid metabolism in Calanus finmarchicus: a population model test

Maps¹,

Plourde²,

Zakardjian³

2010

Mar. Ecol. Prog. Ser.

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“…The literature commonly advocates use of vertical vs. horizontal methods whenever transport processes influence abundances, with the proviso that advection equally influences different stages Elliott and Tang, 2011;Gislason et al, 2007;Hirst et al, 2007;Mollman and Koster, 2002;Plourde et al, 2009b), which has generally been interpreted to mean advective effects are minimal when subsequent stages have similar depth distributions (e.g. Hirst et al, 2007;Plourde et al, 2009b).…”

Section: Clarification Of Assumptionsmentioning

confidence: 99%

“…(4) and (5)) Calanus finmarchicus N3- C6 Ohman et al (2004) Ratio (Eqs. (4) and (5)) Calanus finmarchicus C4-C6 Gislason et al (2007) (their Eqs. (1) and (2)) Ratio (Eqs.…”

Section: Alternativementioning

confidence: 99%

“…Vertical methods are relatively robust to moderate noise, and the literature advocates their use over horizontal methods when transport influences abundance, provided different development stages are equally influenced by advection (e.g. Aksnes and Ohman, 1996;Gislason et al, 2007;Hirst et al, 2007;Skarohamar et al, 2011). Their main limitation is cited as being sensitivity to temporal trends in recruitment Aksnes et al, 1997).…”

Section: Introductionmentioning

confidence: 98%

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Estimating mortality: Clarifying assumptions and sources of uncertainty in vertical methods

Gentleman

Pepin

Doucette

2012

Journal of Marine Systems

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“…developmental stage, availability of food and predation (e.g. Eiane et al 2002, Eiane & Ohman 2004, Gislason et al 2007). Our VLT-estimated mortality rates for C. finmarchicus (3.3 and 4.8% d -1 ) during summer are much higher than the rates currently used in the model (0.75% d -1 ).…”

Section: Field-derived Mortality Rates Versus Model Ratesmentioning

confidence: 99%

Effects of mortality changes on biomass and production in Calanus spp. populations

Skarðhamar

Reigstad²,

Carroll³

et al. 2011

Aquat. Biol.

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Calanus species are the main link between primary producers and higher trophic-level organisms in the Barents Sea. The natural mortality rate is an essential parameter for determining the standing stock of Calanus, but it is also one of the most uncertain parameters in present knowledge. The level of human activity, and the associated risk of pollution, is increasing in the Barents Sea, and knowledge of the Calanus population response to increased mortality is crucial for management of the ecosystem. In the present study, we estimated natural mortality rates of Calanus, based on available field data from the Barents Sea, and performed numerical simulation experiments with a coupled physical-biological model, testing the response of Calanus populations to changes in mortality rates, and other related ecological parameters. The field-based estimates of natural mortality showed high variability. The model simulations showed that the 2 Calanus species modelled, C. glacialis and C. finmarchicus, respond differently to increased mortality, and that in creased mortality alters both the timing of peak Calanus production and biomass relative to peak primary production. These simulations illustrate the potential for a mismatch between peak food availability and Calanus population dynamics in the Barents Sea as a consequence of natural or human-induced perturbations. We suggest that the observed differences in the 2 Calanus species' responses to perturbations relates to each species' life cycle and habitat characteristics. The present study illustrates how models can be used to assess key parameters affecting species' population dynamics and some potential consequence of external forcing factors affecting mortality. KEY WORDS: Zooplankton · Calanus finmarchicus · Calanus glacialis · Numerical modelling · Ecological modelling · Arctic · North Atlantic · Barent Sea · SimulationResale or republication not permitted without written consent of the publisher Aquat Biol 12: 129-145, 2011 130 Ohman 1996). Mortality may be the result of natural events driven by, for example, limited food availability or the presence of abundant predatory species, or by human activities, such as pollution. In the Arctic, industrial activities are on the rise. For example in the Barents Sea, petroleum transport from Russia along the Norwegian coastline increased from insignificant volumes in 2002 to an estimated 20 million tons in 2009 (Bambulyak & Frantzen 2009). Parts of the Barents Sea have already been opened for oil and gas exploration, and the Lofoten and Vesterålen shelves, at the 'entrance' to the Barents Sea, are currently being considered for oil and gas exploration by the Norwegian government. In creasing petro leum transport, oil and gas exploration, and other industrial activities increase the risk of accidents and the potential for negative impacts on individual organisms and ecosystems (Chap man & Riddle 2003). Understanding Calanus population re sponses to increased mortality is crucial for management of the Barents Sea ...

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Vertical distribution and mortality of Calanus finmarchicus during overwintering in oceanic waters southwest of Iceland

Cited by 26 publications

References 37 publications

Control of dormancy by lipid metabolism in Calanus finmarchicus: a population model test

Control of dormancy by lipid metabolism in Calanus finmarchicus: a population model test

Estimating mortality: Clarifying assumptions and sources of uncertainty in vertical methods

Effects of mortality changes on biomass and production in Calanus spp. populations

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