Interannual variability in the Northern California Current food web structure: Changes in energy flow pathways and the role of forage fish, euphausiids, and jellyfish

Ruzicka, James J.; Brodeur, Richard D.; Emmett, Robert L.; Steele, John H.; Zamon, Jeannette E.; Morgan, Cheryl A.; Thomas, Andrew C.; Wainwright, Thomas C.

doi:10.1016/j.pocean.2012.02.002

Cited by 105 publications

(144 citation statements)

References 66 publications

Supporting

Mentioning

140

Contrasting

Order By: Relevance

“…Gelatinous micronekton taxa are not dominant in the diets of apex predators, but can consume large amounts of zooplankton and ultimately reduce available resources for other micronekton that are preyed upon more heavily by intermediate and apex predators. The role of gelatinous taxa as trophic 'dead ends' has also been reported from the Northern California Current (Brodeur et al 2008, Ruzicka et al 2012. However, it is possible that their direct importance as prey based on stomach content analyses may be underestimated due to rapid digestion (Choy et al 2013).…”

Section: Discussionmentioning

confidence: 89%

“…The application of the ecological modeling software suite Ecopath with Ecosim to gain greater under standing of the importance of mid-trophic micronekton groups to top predator production is appealing and practical, as demonstrated by a number of previous studies (Field et al 2010, Griffiths et al 2010, Ruzicka et al 2012, Kaplan et al 2013b). However, some of the approach's limitations and assumptions warrant studies focusing on ways to comprehensively evaluate and improve current findings.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Finding the way to the top: how the composition of oceanic mid-trophic micronekton groups determines apex predator biomass in the central North Pacific

Choy

Wabnitz²,

Weijerman³

et al. 2016

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

We updated and expanded a model of the pelagic ecosystem for the area of the central North Pacific occupied by the Hawaii-based longline fishery. Specifically, results from the most recent diet studies were used to expand the representation of the lesser-known non-target fish species (e.g. lancetfish, opah, snake mackerel) and 9 mid-trophic micronekton functional groups. The model framework Ecopath with Ecosim was used to construct an ecosystem energy budget and to examine how changes in the various micronekton groups impact apex predator biomass. Model results indicate that while micronekton fishes represented approximately 54% of micronekton biomass, they accounted for only 28% of the micronekton production. By contrast, crustaceans represented 24% of the biomass and accounted for 44% of production. Simulated ecosystem changes resulting from changes to micronekton groups demonstrated that crustaceans and mollusks are the most important direct trophic pathways to the top of the food web. Other groups appear to comprise relatively inefficient pathways or 'trophic dead-ends' that are loosely coupled to the top of the food web (e.g. gelatinous animals), such that biomass declines in these functional groups resulted in increased biomass at the highest trophic levels by increasing energy flow through more efficient pathways. Overall, simulated declines in the micronekton groups resulted in small changes in biomass at the very top of the food web, suggesting that this ecosystem is relatively ecologically resilient with diverse food web pathways. However, further understanding of how sensitive micronekton are to changes in ocean chemistry and temperature resulting from climate change is needed to fully evaluate and predict potential ecosystem changes.

show abstract

Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Finding the way to the top: how the composition of oceanic mid-trophic micronekton groups determines apex predator biomass in the central North Pacific

Choy

Wabnitz²,

Weijerman³

et al. 2016

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…Studies of trophic interaction between jellyfishes and pelagic fishes in the northern California Current ecosystem have documented the dietary overlap between jellyfishes and fishes, including sardines, anchovies, saury, and herring (Brodeur et al 2002(Brodeur et al , 2008, as well as the ecological consequences of the competition between those two groups (Ruzicka et al 2007, Brodeur et al 2011. Modeling studies of that system highlighted that an increase of flows to jellyfishes most negatively affected the planktivorous fishes and the seabirds, and to a lesser extent other predators such as piscivorous fishes, marine mammals, and fisheries (Brodeur et al 2011), and that jellyfishes constituted an alternate energy pathway (Ruzicka et al 2012) resulting in loss of production, a pattern that has been observed in the NB. Until the late 1960s, the sardine must have represented a formidable competitor for zooplanktonic prey even in a system as productive as the NB.…”

Section: The Role Of Small Pelagic Fishes and What Canmentioning

confidence: 98%

Jellyfication of Marine Ecosystems as a Likely Consequence of Overfishing Small Pelagic Fishes: Lessons from the Benguela

Roux¹,

Lingen²,

Gibbons³

et al. 2013

BMS

128

View full text Add to dashboard Cite

Changes in two contrasting ecosystems of the Benguela upwelling region, one dominated at mid-trophic level by jellyfishes (Namibia, northern Benguela ecosystem, where small pelagic fish abundance has been severely depleted) and one still dominated by small pelagic fishes (South Africa, southern Benguela) were compared in an effort to determine ecosystem trajectories under different exploitation regimes. The role of small pelagic fishes (clupeoids) was highlighted in the context of their importance in maintaining interactions in marine ecosystems. In particular, we examined trophic cascades and possible irreversible changes that promote the proliferation of jellyfishes in marine systems. We found that the presence of large populations of small pelagic fishes has a fundamental role in preserving beneficial trophic interactions in these marine ecosystems. The implications of trophic cascades, such as those observed in the northern Benguela, for ecosystem-based management were apparent. In addition, this comparison provides contrasting case studies to inform the development of management scenarios that avoid ecosystem shifts that affect predators and reduce the value of fisheries production.

show abstract

“…The Mediterranean Sea has been fished heavily, and equilibrium models provide insight into the importance of top-down effects on the ecosystems, including on anchovy (Halouani et al 2015, Piroddi et al 2015. The northern California Current System was modeled in detail using both fisheries-dependent and fisheries-independent data and including both climate (sea-surface temperature) and fishing, showing the overriding importance of bottomup processes (climate) (Field et al 2006) and jellyfish (Ruzicka et al 2012). Ecopath-type models are particularly useful for comparing systems (Shannon et al 2009).…”

Section: Modelsmentioning

confidence: 99%

Climate, Anchovy, and Sardine

Checkley

Asch

Rykaczewski

2017

Annu. Rev. Mar. Sci.

177

129

View full text Add to dashboard Cite

Anchovy and sardine populated productive ocean regions over hundreds of thousands of years under a naturally varying climate, and are now subject to climate change of equal or greater magnitude occurring over decades to centuries. We hypothesize that anchovy and sardine populations are limited in size by the supply of nitrogen from outside their habitats originating from upwelling, mixing, and rivers. Projections of the responses of anchovy and sardine to climate change rely on a range of model types and consideration of the effects of climate on lower trophic levels, the effects of fishing on higher trophic levels, and the traits of these two types of fish. Distribution, phenology, nutrient supply, plankton composition and production, habitat compression, fishing, and acclimation and adaptation may be affected by ocean warming, acidification, deoxygenation, and altered hydrology. Observations of populations and evaluation of model skill are essential to resolve the effects of climate change on these fish.

show abstract

Interannual variability in the Northern California Current food web structure: Changes in energy flow pathways and the role of forage fish, euphausiids, and jellyfish

Cited by 105 publications

References 66 publications

Finding the way to the top: how the composition of oceanic mid-trophic micronekton groups determines apex predator biomass in the central North Pacific

Finding the way to the top: how the composition of oceanic mid-trophic micronekton groups determines apex predator biomass in the central North Pacific

Jellyfication of Marine Ecosystems as a Likely Consequence of Overfishing Small Pelagic Fishes: Lessons from the Benguela

Climate, Anchovy, and Sardine

Contact Info

Product

Resources

About