Effects of copepod size on fish growth: a model based on data for North Sea sandeel

Deurs, Mikael van; Jørgensen, Christian; Fiksen, Øyvind

doi:10.3354/meps11092

Cited by 29 publications

(30 citation statements)

References 42 publications

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“…The substantial downward shift in key elements of the plankton (McQuatters-Gollop et al, 2007;Pitois & Fox, 2006) and stock production across a range of zooplanktivorous species (results presented here), seem to indicate a declining primary production (Ware & Thompson, 2005). However, other studies point to changes in zooplankton species composition as the cause of reduced fish growth (Beaugrand et al, 2003;Van Deurs, Jørgensen, & Fiksen, 2015). Factors such as spawning site diversity or the frequency of unlikely events governing extreme recruitment outburst (Lowerre-Barbieri et al, 2016;Pepin, 2015) have also been proposed as drivers of variation in fish stock production.…”

Section: Discussionmentioning

confidence: 99%

Shifts in North Sea forage fish productivity and potential fisheries yield

Clausen

Rindorf

Deurs

et al. 2017

Journal of Applied Ecology

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Forage fish populations support large scale fisheries and are key components of marine ecosystems across the world, linking secondary production to higher trophic levels. While climate‐induced changes in the North Sea zooplankton community are described and documented in literature, the associated bottom‐up effects and consequences for fisheries remain largely unidentified. We investigated the temporal development in forage fish productivity and the associated influence on fisheries yield of herring, sprat, Norway pout and sandeel in the North Sea. Using principal component analysis, we analysed 40 years of recruitment success and growth proxies to reveal changes in productivity and patterns of synchroneity across stocks (i.e. functional complementarity). The relationship between forage fish production and Calanus finmarchicus (an indicator of climate change) was also analysed. We used a population model to demonstrate how observed shifts in productivity affected total forage fish biomass and fisheries yield. The productivity of North Sea forage fish changed around 1993 from a higher average productivity to lower average productivity. During the higher productivity period, stocks displayed a covariance structure indicative of functional complementarity. Calanus finmarchicus was positively correlated to forage fish recruitment, however, for growth, the direction of the response differed between species and time periods. Maximum sustainable yield (MSY) and the associated fishing mortality (Fmsy) decreased by 33%–68% and 26%–64%, respectively, between the higher and lower productivity periods. Synthesis and applications. The results demonstrate that fisheries reference points for short‐lived planktivorous species are highly dynamic and respond rapidly to changes in system productivity. Furthermore, from an ecosystem‐based fisheries management perspective, a link between functional complementarity and productivity, indicates that ecosystem resilience may decline with productivity. Based on this, we advise that system productivity, perhaps monitored as forage fish growth, becomes an integral part of management reference points; in both single species and ecosystem contexts. However, to retain social license of biological advice when fish catch opportunities are reduced, it is crucial that shifts in productivity are thoroughly documented and made apparent to managers and stakeholders.

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Section: Discussionmentioning

confidence: 99%

Shifts in North Sea forage fish productivity and potential fisheries yield

Clausen

Rindorf

Deurs

et al. 2017

Journal of Applied Ecology

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“…Adult anchovies of the Bay of Biscay feed primarily in offshore habitats (Chouvelon et al, 2014) but Pasquaud et al (2008) observed that small anchovies can also feed along with sprats in estuarine habitats of the Gironde. If competition between the three species occurs in the Gulf of Lions, sprats should have an advantage considering their larger niche width, the feeding on slightly larger, and thus, more energetic prey (Gerking, 1994;van Deurs et al, 2015) than anchovies and sardines, their lowest predator/prey size ratios and because they seem to recover well after the spawning period (Pethybridge et al, 2014).…”

Section: Interaction Between Planktivorous Teleost Speciesmentioning

confidence: 98%

Trophic niche overlap of sprat and commercial small pelagic teleosts in the Gulf of Lions (NW Mediterranean Sea)

Bourg

Bănaru

Saraux

et al. 2015

Journal of Sea Research

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This study was funded by the programmes PERSEUS FP7 EU project, EMIBIOS FRB, IPP WP2-MERMEX and EcoPelGol FFP.Increasing abundance of non-commercial sprats and decreasing biomass and landings of commercial anchovies and sardines justify the need to study the feeding ecology and trophic niche overlap of these planktivorous species in the Gulf of Lions. Their diet has been investigated on the basis of stomach content and stable isotope analyses in 2011 and 2012 according to different depths and regions in the study area. The main prey were Corycaeidae copepods, Clauso/Paracalanus, Euterpina acutifrons and Microsetella, for sprats and small copepods, such as Microsetella, Oncaea and Corycaeidae, for anchovies and sardines. This is the first time that the diet of sprats is described in the Gulf of Lions. Sprats fed on a larger size spectrum of prey and seem to be more generalist feeders compared to anchovies and sardines. Ontogenetic changes as well as spatial and temporal variations of the diet occurred in the three species. Stable isotope analysis revealed mobility of sardines and sprats among feeding areas while anchovies exhibited preferred feeding areas. Sprats showed a higher relative condition assessed by C/N ratios than sardines and anchovies. Our results showed an overlap of the trophic niches for the three species, indicating a potential trophic competition in the Gulf of Lions. (C) 2015 Elsevier B.V. All rights reserved

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“…Here, higher SSTs did not affect recruitment, but were associated with lower SSB and TSB. Sandeels face greater metabolic costs at higher temperatures and under these conditions their prey may be less abundant (van Deurs, Koski, & Rindorf, 2014;van Deurs et al, 2011), leading to slower growth, reduced maturation, reduced reproductive investment, increased overwintering weight loss, and reduced survival (Heath et al, 2012;van Deurs, Jørgensen, & Fiksen, 2015;van Deurs et al, 2009;Wright, Orpwood, & Scott, 2017). However, whilst expected impacts of high temperatures on sandeels were observed, impacts on kittiwakes appeared more complex.…”

Section: Environmental Effectsmentioning

confidence: 99%

Kittiwake breeding success in the southern North Sea correlates with prior sandeel fishing mortality

Carroll

Bolton

Owen

et al. 2017

Aquatic Conservation

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In the North Sea, sandeels provide a vital food source for breeding seabirds, but are also the target of an industrial fishery. GPS tracking suggests that the most productive fishing grounds overlap with foraging areas of black‐legged kittiwakes from eastern England, raising the prospect that the fishery could affect the birds. Rising sea temperatures also threaten sandeels, so kittiwake food supplies could be affected by local and larger‐scale processes. Drivers of kittiwake breeding success at Flamborough Head and Bempton Cliffs Special Protection Area, the UK's largest colony, and one of the closest to the sandeel fishing grounds, were examined. Relationships between sandeel stocks, sea surface temperature and kittiwake breeding success were analysed with generalized linear mixed models and generalized linear models, with model performance assessed using the Akaike Information Criterion and R2. Higher kittiwake breeding success was associated with higher sandeel spawning stock biomass (SSB; biomass of sexually mature fish) the preceding winter (R2 = 21.5%) and lower sandeel fishing mortality two years previously (R2 = 22.3%). After temporal trends were removed, only the fishing mortality effect remained. Models with multiple predictors supported the importance of fishing mortality. Higher sandeel SSB was associated with lower temperatures (R2 = 15.2–38.6%) and lower sandeel fishing mortality (R2 = 24.2–26.1%). Hence, lower temperatures and fishing mortality were positively associated with sandeel biomass, and higher sandeel biomass and lower fishing mortality were positively associated with kittiwake productivity. In light of worsening environmental conditions and declining sandeel and kittiwake populations, careful consideration should be given to the requirements of sandeel‐dependent predators when making fishery management decisions.

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Effects of copepod size on fish growth: a model based on data for North Sea sandeel

Cited by 29 publications

References 42 publications

Shifts in North Sea forage fish productivity and potential fisheries yield

Shifts in North Sea forage fish productivity and potential fisheries yield

Trophic niche overlap of sprat and commercial small pelagic teleosts in the Gulf of Lions (NW Mediterranean Sea)

Kittiwake breeding success in the southern North Sea correlates with prior sandeel fishing mortality

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