Estimation of the annual consumption of food by Cape hake <i>Merluccius capensis</i> and <i>M. paradoxus</i> off the South African west coast

Punt, André E.; Leslie, R. W.; Plessis, S. E. Du

doi:10.2989/02577619209504728

Cited by 28 publications

(24 citation statements)

References 7 publications

(21 reference statements)

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“…epipelagic species, in the diet of hake, which are demersal species that live near the bottom during the day and feed in the water column at night (Pillar andBarange 1995, 1997). The predation of hake by hake (either cannibalism or predation of deep-water hake by shallow-water hake) observed largely in the data occurs between 150 and 400 m depth (Punt et al 1992) where small pelagic fish are not abundant. It is possible that in nature predators of hake spend more time surrounded by hake prey than by small pelagic prey, which is not modelled here and thus induces biases in the diets modelled.…”

Section: Lessons From the Pom Approachmentioning

confidence: 97%

“…Therefore, a similarity in the prey species composition between emergent simulated diets and observed diets would contribute to the structural validation of the model concerning the formulation of the predation process. We compared the diets of all species with the data collated by Shannon et al (2003), where the diet matrix used as input to an Ecopath model came from empirical studies of stomach contents by Pillar and Barange (1993, Punt et al (1992), Pillar and Wilkinson (1995) inter alia, and synthesised the data available for this ecosystem over the 1990s. The model outputs were also compared with detailed observations from Griffiths (2002) on the diet of medium-sized snoek in the western (north of 34.4° S) and southern part (south of 34.4° S) of the system.…”

Section: Validation Via the Pattern-oriented Modelling (Pom) Approachmentioning

confidence: 99%

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An end-to-end coupled model ROMS-N₂P₂Z₂D₂-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation

Travers-Trolet

Shin

Field

2014

African Journal of Marine Science

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In order to better understand ecosystem functioning under simultaneous pressures (e.g. both climate change and fishing pressures), integrated modelling approaches are advocated. We developed an end-to-end model of the southern Benguela ecosystem by coupling the high trophic level model OSMOSE with a biophysical model (ROMS-N 2 P 2 Z 2 D 2 ). OSMOSE is a spatial, multispecies, individual-based model simulating the whole life cycle of fish with fish schools interacting through opportunistic and size-based predation. It is linked to the biogeochemical model through the predation process; plankton groups are food for fish and fish apply a predation mortality on plankton. Here we describe the two-way coupling between the models and follow a pattern-oriented modelling approach to validate the simulations. At the individual level, model outputs are consistent with observed diets for several species from small pelagic fish to top predatory fish, although biases emerge from underestimation of macrozooplankton and lack of vertical structure. At the population level, the seasonality of the size structure is similar between the model and data. At the community level, the modelled trophic structure is consistent with the knowledge available for this ecosystem. The structure of the foodweb is an emergent property of the model, showing trophic links between species, their strength and the strong connectivity observed. We also highlight the capacity of this model for tracking indicators at various hierarchical levels. Online supplementary material:(1) Additional ROMS-N 2 P 2 Z 2 D 2 equations and parameters, (2) maps of the spatial distribution of species modelled in OSMOSE, (3) graphs of the seasonality of fishing pressure and spawning for species modelled in OSMOSE, and (4) literature references of parameter values used for HTL (high trophic level) organisms in OSMOSE, are available as Supplementary Appendices S1-S4 to the online publication at http://dx.

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Section: Lessons From the Pom Approachmentioning

confidence: 97%

Section: Validation Via the Pattern-oriented Modelling (Pom) Approachmentioning

confidence: 99%

An end-to-end coupled model ROMS-N₂P₂Z₂D₂-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation

Travers-Trolet

Shin

Field

2014

African Journal of Marine Science

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“…In the laboratory, prey items were sorted into the lowest possible taxonomic group. Taxa were grouped into the 13 major categories listed by Payne et al (1987), Punt et al (1992) and Pillar and Wilkinson (1995). Each prey item was weighed wet to the nearest 0.01 g and, where possible, its length was determined and it was classified according to a digestive state of between 1 (fresh, intact material) to 4 (unidentifiable digested matter).…”

Section: Methodsmentioning

confidence: 99%

Diel variability in bottom trawl catches and feeding activity of the Cape hakes off the west coast of South Africa

Barangé¹

1997

ICES Journal of Marine Science

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Pillar, S. C., and Barange, M. 1997. Diel variability in bottom trawl catches and feeding activity of the Cape hakes off the west coast of South Africa. -ICES Journal of Marine Science, 54: 485-499.The diel variability in bottom trawl catches and the feeding patterns of the Cape hakes Merluccius capensis and M. paradoxus were investigated during thirteen 28-h experiments in winter and summer between 1984 and 1990 within the same locality off the west coast of South Africa. Considerable variation was found in the diel differences in the catches, but day-time numbers and mass were generally greater than at night. Catch rates of M. capensis were significantly different in nine experiments whereas five experiments yielded significant differences in M. paradoxus. For small hake, especially M. paradoxus, euphausiids were eaten more frequently in summer and mesopelagic fish were of more dietary importance in winter. Hake-on-hake predation was a prominent feature in M. capensis, especially in summer when larger fish were caught at the study site. In the majority of cases, the size composition of M. capensis was not significantly different between the day and night catches. By contrast, diel size differences were generally found in M. paradoxus, but with no consistent pattern. There was little indication of any diel feeding periodicity in either hake species, with up to one-third of the hake examined with food in their stomachs having recently fed, regardless of time of day or night. The diet composition indicated that hake move into midwater at night in response to similar movement of their prey. International Council for the Exploration of the Sea

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“…1987; Punt et al, 1992). There is evidence indicating that cannibalism might be related with the intensity of annual classes of walleye pollock (Livingston and Lang, 1996) producing a population feedback mechanism (Laevastu and Favorite, 1988).…”

Section: Discussionmentioning

confidence: 95%

Incorporating cannibalism into an age-structured model for the Chilean hake

2006

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Estimation of the annual consumption of food by Cape hake Merluccius capensis and M. paradoxus off the South African west coast

Cited by 28 publications

References 7 publications

An end-to-end coupled model ROMS-N₂P₂Z₂D₂-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation

An end-to-end coupled model ROMS-N₂P₂Z₂D₂-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation

Diel variability in bottom trawl catches and feeding activity of the Cape hakes off the west coast of South Africa

Incorporating cannibalism into an age-structured model for the Chilean hake

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Estimation of the annual consumption of food by Cape hake Merluccius capensis and M. paradoxus off the South African west coast

Cited by 28 publications

References 7 publications

An end-to-end coupled model ROMS-N2P2Z2D2-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation

An end-to-end coupled model ROMS-N2P2Z2D2-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation

Diel variability in bottom trawl catches and feeding activity of the Cape hakes off the west coast of South Africa

Incorporating cannibalism into an age-structured model for the Chilean hake

Contact Info

Product

Resources

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An end-to-end coupled model ROMS-N₂P₂Z₂D₂-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation

An end-to-end coupled model ROMS-N₂P₂Z₂D₂-OSMOSE of the southern Benguela foodweb: parameterisation, calibration and pattern-oriented validation