Ecosystem relevance of variable jellyfish biomass in the Irish Sea between years, regions and water types

Bastian, Thomas; Lilley, Martin K. S.; Beggs, Steven E.; Hays, Graeme C.; Doyle, Thomas K.

doi:10.1016/j.ecss.2014.08.018

Cited by 18 publications

(11 citation statements)

References 73 publications

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“…McLaren 1969, Bottrell and Robins 1984, Hay et al 1991Uye 1991, Pond et al 1996 Uye 1988, 1991, Liaing et al 1996Other copepod copepodites McLaren (1969, Uye (1991) Chaeotognaths McLaren 1969, Uye 1982, Little and Copley 2003 Kiørboe and Titleman 1998 Appendicularians Gorsky et al 1988, Sato et al 2001Cladocerans McLaren 1969, Uye 1982 McConville et al 2017 Cirripede larvae Uye 1982, Berggeen et al 1988, Sabatini and Kiørboe 1994, Hygum et al 2000 Uye 1982, Munk and Nielsen 1994Ctenophores and Cnidarians McLaren 1969, Larson 1986, Mizdalski 1988, Daan1989, Clarke et al 1992, Mutlu and Bingel 1999, Gibson and Paffenhöfer 2000, Båmstedt et al 2001, Persad et al 2003, Bastian et al 2014 Other rarer, non-copepod taxa Little andCopley 2003, McConville et al 2017…”

Section: Taxonmentioning

confidence: 99%

High prey-predator size ratios and unselective feeding in copepods: A seasonal comparison of five species with contrasting feeding modes

Djeghri¹,

Atkinson²,

Fileman³

et al. 2018

Progress in Oceanography

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There has been an upsurge of interest in trait-based approaches to zooplankton, modelling the seasonal changes in the feeding modes of zooplankton in relation to phytoplankton traits such as size or motility. We examined this link at two English Channel plankton monitoring sites south of Plymouth (L4 and E1). At L4 there was a general transition from diatoms in spring to motile microplankton in summer and autumn, but this was not mirrored in the succession of copepod feeding traits; for example the ambushing Oithona similis dominated during the spring diatom bloom. At nearby E1 we measured seasonality of food and grazers, finding strong variation between 2014 and 2015 but overall low mesozooplankton biomass (median 4.5 mg C m-3). We also made a seasonal grazing study of five copepods with contrasting feeding modes (Calanus helgolandicus, Centropages typicus, Acartia clausi, Pseudocalanus elongatus and Oithona similis), counting the larger prey items from the natural seston. All species of copepod fed on all food types and differences between their diets were only subtle; the overriding driver of diet was the composition of the prey field. Even the smaller copepods fed on copepod nauplii at significant rates, supporting previous suggestions of the importance of intra-guild predation. All copepods, including O. similis, were capable of tackling extremely long (>500 µm) diatom chains at clearance rates comparable to those on ciliates. Maximum observed prey:predator length ratios ranged from 0.12 (C. helgolandicus) up to 0.52 (O. similis). Unselective feeding behaviour and the ability to remove highly elongated cells have implications for how copepod feeding is represented in ecological and biogeochemical models.

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Section: Taxonmentioning

confidence: 99%

High prey-predator size ratios and unselective feeding in copepods: A seasonal comparison of five species with contrasting feeding modes

Djeghri¹,

Atkinson²,

Fileman³

et al. 2018

Progress in Oceanography

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“…Nevertheless, others have reported different morphometric relationships for the same species in different locations. For example, Bastian et al (2014) showed that the allometric relationship for three jellyfish species in the Irish Sea was different when compared to other studies; they also found significantly different average mass per individual between the western and the eastern regions of the Irish Sea, presumably due to the different food environments. Recent studies found that the different R. octopus populations around the United Kingdom and France were genetically distinct (Lee et al, 2013;Glynn et al, 2015).…”

Section: Discussionmentioning

confidence: 78%

“…Morphometric and weight characteristics of R. octopus Jellyfish population size can vary considerably in time and in space (Kingsford et al, 2000;Pitt and Kingsford, 2003;Bastian et al, 2014). To aid more effective monitoring of jellyfish population, simple morphometric measurements can be used to estimate individual biomass (Lucas, 2009;Bastian et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Balancing fishery and conservation: a case study of the barrel jellyfish Rhizostoma octopus in South Wales

Elliott

Hobson

Tang

2016

ICES Journal of Marine Science

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In Wales, the barrel jellyfish Rhizostoma octopus is commercially harvested to produce high-value medical grade collagen. Although the fishery is presently not regulated, there are concerns how it may affect the leatherback turtle (Dermochelys coriacea), which preys on R. octopus in local waters. We combined monitoring data and morphometric and weight measurements in models to estimate the potential impact of R. octopus fishery on foraging turtles. We found a significant quadratic relationship between bell diameter and wet weight of R. octopus, with bell diameter explaining 88% of the variability in wet weight. R. octopus biomass in the Carmarthen Bay varied inter-annually between 38.9 and 594.2 tonnes y−1. The amount of R. octopus needed to satisfy a leatherback turtle’s daily energetic requirements was estimated at 85.1–319.1 kg. Using leatherback turtle sighting data, our models show that during a jellyfish ‘low year”, the R. octopus population could be completely depleted by an average of two foraging turtles along with the current level of commercial harvesting (4.3 tonnes). During a jellyfish “high year”, the current level of commercial harvesting is predicted to have relatively little impact on food supply for even the maximum number of foraging leatherback turtle reported in the area. However, uncertainties related to the jellyfish’s life cycle in the local waters need to be resolved for proper management of this emerging fishery.

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“…The jelly-fish surveys showed a trend of increase in jellies from 1994 to 2009 (Lynam et al, 2011;Bastian et al, 2014).…”

Section: Observations Of Zooplanktonic Predatorsmentioning

confidence: 99%

“…Scyphome-dusan jellies Pelagic predator, sexually reproducing stage of strobilating benthic polyp and so linked to shallow seas where the polyp can grow: Aurelia Lynam et al, 2011;Bastian et al, 2014 Mero-plankton Larvae of benthic invertebrates including molluscs, echinoderms and annelids Scrope-Howe and Young of nekton Fish larvae, Nephrops larvae-feeding type, seasonality Conway et al, 1997 Nutrients, Oxygen, Chlorophyll, and Production…”

Section: Ecohydrodynamicsmentioning

confidence: 99%

Assessing the State of the Pelagic Habitat: A Case Study of Plankton and Its Environment in the Western Irish Sea

2016

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Much work had been undertaken on tracking change in the condition of marine pelagic ecosystems and on identifying regime shifts. However, it is also necessary to relate change to states of good ecosystem health or what the European Marine Strategy Framework Directive (MSFD) calls "Good Environmental Status" (GES). Drawing on existing scientific and legislative principles, including those of OSPAR's "Strategy to Combat Eutrophication," we propose a framework for assessing the status of what the MSFD calls the "pelagic habitat" in temperate coastal seas. The framework uses knowledge of local ecohydrodynamic conditions, especially those relating to the stratification and optical environment, to guide expectations of what would be recognized as healthy in terms of ecosystem "organization" and "vigor." We apply this framework to the seasonally stratified regime of the Western Irish Sea, drawing on published and new work on stratification, nutrient, and phytoplankton seasonal cycles, zooplankton, and the implications of plankton community structure and production for higher trophic levels. We conclude that, despite human pressures including nutrient enrichment, and the food-web effects of fisheries, the pelagic ecosystem here is in GES, and hence may be used as a reference for the "Plankton Index" method of tracking change in state space in seasonally stratified waters.

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Ecosystem relevance of variable jellyfish biomass in the Irish Sea between years, regions and water types

Cited by 18 publications

References 73 publications

High prey-predator size ratios and unselective feeding in copepods: A seasonal comparison of five species with contrasting feeding modes

High prey-predator size ratios and unselective feeding in copepods: A seasonal comparison of five species with contrasting feeding modes

Balancing fishery and conservation: a case study of the barrel jellyfish Rhizostoma octopus in South Wales

Assessing the State of the Pelagic Habitat: A Case Study of Plankton and Its Environment in the Western Irish Sea

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