Quacks snack on smacks: mallard ducks (&lt;i&gt;Anas platyrhynchos&lt;/i&gt;) observed feeding on hydrozoans (&lt;i&gt;Velella velella&lt;/i&gt;)

Phillips, Natasha D.; Eagling, Lawrence E.; Harrod, Christopher; Reid, Neil; Cappanera, Valentina; Houghton, Jonathan D. R.

doi:10.3800/pbr.12.143

Cited by 17 publications

(8 citation statements)

References 15 publications

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“…Direct observation and filming by divers have also been reported showing a range of species consuming jellyfish, including fish and turtles, and as with other camera observation allow ingestion rates of jellyfish to be estimated [31,32]. Even more opportunistically, mallard ducks (Anas platyrhynchos) have been photographed at the surface feeding on extensive blooms of the hydrozoan Velella velella which illustrates that the trophic pathways of jellyfish can even extend beyond the marine environment [33]. Recent work is also shedding new light on how pelagic invertebrates, many themselves jellyfish, will routinely feed on jellyfish [34][35][36], supporting a recent review of benthic scavengers and predators of jellyfish which collated many historical and some recent records of invertebrates feeding on jellyfish, mostly anemones, decapod crustaceans and echinoderms [37].…”

Section: Old Question New Methodologies: Recent Evidence For Jellyfimentioning

confidence: 98%

A Paradigm Shift in the Trophic Importance of Jellyfish?

Hays

Doyle

Houghton

2018

Trends in Ecology & Evolution

172

120

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The last 30 years have seen several paradigm shifts in our understanding of how ocean ecosystems function. Now recent technological advances add to an overwhelming body of evidence for another paradigm shift in terms of the role of gelatinous plankton ("jellyfish") in marine food webs. Traditionally viewed as trophic dead ends, stable isotope analysis of predator tissues, animal-borne cameras and DNA analysis of faecal and gut samples (metabarcoding) are all indicating that many taxa routinely consume jellyfish. Despite their low energy density, the contribution of jellyfish to the energy budgets of predators may be much greater than assumed because of rapid digestion, low capture costs, availability and selective feeding on the more energy rich components. Jellyfish as trophic dead ends: a "belly-full-of-jelly" ? Gelatinous zooplankton, loosely termed "jellyfish", are a taxonomically diverse group including many cnidarians, such as scyphozoan jellyfish and siphonophores, ctenophores and also chordates such as salps, pyrosomes and appendicularians (Box 1, Figure 1). Jellyfish are ubiquitous in the World's oceans and can occur in very high densities in large blooms [1, 2]. For example, distinct coastal jellyfish hotspots can occur in coastal waters, such as large aggregations of the barrel jellyfish Rhizostoma octopus extending over tens of square kilometers, with individuals weighing as much as 30 kg [3]. Likewise, in oceanic waters, swarms of salps, each a few cm in size, have been recorded with densities as high as 700 individuals per m-3 over 1000s km 2 [4,5]. While it is well known that jellyfish can be voracious predators and so play important roles as consumers, they have historically often been viewed as trophic dead ends [6]. Underpinning this view is the generally low nutritional content of jellyfish (or at least the gelatinous 'bell'), meaning that large volumes need to be

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Section: Old Question New Methodologies: Recent Evidence For Jellyfimentioning

confidence: 98%

A Paradigm Shift in the Trophic Importance of Jellyfish?

Hays

Doyle

Houghton

2018

Trends in Ecology & Evolution

172

120

View full text Add to dashboard Cite

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“…Despite their low energy density (Doyle et al, 2007;Cardona et al, 2012), true sea-jellies (Class: Scyphozoa), hydrozoans or salps are included in the diets of many marine and coastal birds and some mammals (Childerhouse et al, 2001;Arai, 2005;Cardona et al, 2012;Phillips et al, 2017). These endotherms generally show wide diet composition concordant with a generalist foraging strategy, including jellies in small amounts, seasonally, in accordance with local abundance (Harrison, 1984;Jarman et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Molecular Analysis of Predator Scats Reveals Role of Salps in Temperate Inshore Food Webs

et al. 2018

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High precision, high coverage DNA-based diet analysis tools allow great insight into the food web interactions of cryptic taxa. We used DNA fecal-metabarcoding to look for unrecorded taxa within the diet of a generalist central-placed predator, the little penguin Eudyptula minor. We examined 208 scats from 106 breeding pairs throughout August-February in a large colony at Phillip Island, Australia. While we confirmed a largely piscivorous diet, we also recovered DNA sequences from gelatinous and crustaceous plankton groups that have not previously been detected in the little penguin diet using other diet analysis methods. Gelatinous plankton, including salps, appendicularians, scyphozoans, and hydrozoans were present in 76% of samples and represented 25% of all sequences. DNA recovered from minute copepods and appendicularians may indicate links between trophic levels through secondary predation. Percentage frequency of occurrence (%FOO) demonstrated that little penguin diet composition changed over months and stages (incubation, guard, and post-guard) of the breeding season (month: χ 2 = 201.91, df = NA, p < 0.01; stage: χ 2 = 33.221, df = NA, p = 0.015). Relative read abundance (RRA) uncovered variations in the relative abundance of taxa in the diet over months and stages (month: F = 53.18, df = 59, p < 0.001; stage: F = 66.56, df = 29, p < 0.001). The diet became progressively fish-focused over months of the season and stages, while salps were only present in 4 out of 6 months, with a peak in September. Based on their prevalence in this dataset, in this year of very high breeding success (2.15 chicks per pair), salps may constitute a food source for this largely piscivorous generalist. Our work highlights how DNA metabarcoding can improve our understanding of the trophic role of gelatinous plankton and other cryptic taxa.

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“…Within the last years, growing evidence has shed light on the importance of gelatinous zooplankton within food webs and organisms are more often shown to be Gelativore feeders ( Diaz Briz et al ., 2017 ), may it be occasionally or by rule. Sometimes, even the most unthinkable cases of predation are reported, like the recent observed mallard ducks feeding on the anthomedusae Velella velella (Linnaeus 1758) ( Phillips et al ., 2017 ). Thus, whether jellyfish populations are increasing globally, they appear to provide a constant supply of biomass within many (perturbed) ecosystems and, at least in the case of A. aurita, allow for easy access to valuable FAs ( Gibbons and Richardson, 2013 ).…”

Section: Discussionmentioning

confidence: 98%

Seasonal variability of the fatty acid composition in Aurelia aurita (Cnidaria: Scyphozoa): implications for gelativore food web studies

Stenvers

Chi

Javidpour

2020

Journal of Plankton Research

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Abstract Jellyfish population play an important role in aquatic food chains, and many animals predate on this ‘mostly water containing’ organisms. However, what gelativores predators could gain from their prey is still poorly understood. This study provides insight into the nutritional value of the moon jelly (Aurelia aurita) by means of its fatty acid (FA) composition, while investigating seasonal variability and differences between its free-swimming life stages. A biweekly sampling was carried out in a temperate coastal ecosystem, the Kiel Fjord, Germany and during two consecutive years. FA profile of A. aurita showed significant seasonal variability, while mature medusae (due to reproductive tissues) possessed highest FA content. In addition, moon jelly contained several essential FAs (i.e. arachidonic acid, 20:4ω6; eicosapentaenoic acid, 20:5ω3; docosahexaenoic acid, 22:6ω3), which likely support predator’s vital physiological functions. Even though total FA contents proved to be low (7 × 10−3–34 × 10−3% per g dry weight), evidence supporting A. aurita’s capability to meet the dietary requirements of predators such as fish and crustaceans is provided. Finally, implications for gelativore and future food web configurations are discussed, while proposing that jellyfish are likely to be, and become, more than an opportunistic prey to many organisms.

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Quacks snack on smacks: mallard ducks (<i>Anas platyrhynchos</i>) observed feeding on hydrozoans (<i>Velella velella</i>)

Abstract: This study presents new evidence of the extensive trophic role of gelatinous zooplankton by documenting typically nonmarine predators, mallard ducks, feeding on hydrozoans in shallow, coastal environments.

Cited by 17 publications

References 15 publications

A Paradigm Shift in the Trophic Importance of Jellyfish?

A Paradigm Shift in the Trophic Importance of Jellyfish?

Molecular Analysis of Predator Scats Reveals Role of Salps in Temperate Inshore Food Webs

Seasonal variability of the fatty acid composition in Aurelia aurita (Cnidaria: Scyphozoa): implications for gelativore food web studies

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