Jellyfish overtake fish in a heavily fished ecosystem

Lynam, Christopher P.; Gibbons, Mark J.; Axelsen, Bjørn Erik; Sparks, Conrad; Coetzee, Janet C.; Heywood, Benjamin G.; Brierley, Andrew S.

doi:10.1016/j.cub.2006.06.018

Cited by 309 publications

(159 citation statements)

References 13 publications

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“…In particular, the energy contained in gelatinous bodies can rapidly attract large numbers of scavengers, and be rapidly incorporated into deep-sea food webs, lessening expected impacts of enhanced jellyfish production on deepwater fisheries and pelagic-benthic coupling [8]. Thus, changes to biological communities and biogeochemical cycling in the deep ocean resulting from overlying jellyfish blooms, and the resulting societal and economic consequences, could be lower than those currently being forecasted [8,36,37].…”

Section: Resultsmentioning

confidence: 99%

Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs

et al. 2014

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Jellyfish blooms are common in many oceans, and anthropogenic changes appear to have increased their magnitude in some regions. Although mass falls of jellyfish carcasses have been observed recently at the deep seafloor, the dense necrophage aggregations and rapid consumption rates typical for vertebrate carrion have not been documented. This has led to a paradigm of limited energy transfer to higher trophic levels at jelly falls relative to vertebrate organic falls. We show from baited camera deployments in the Norwegian deep sea that dense aggregations of deep-sea scavengers (more than 1000 animals at peak densities) can rapidly form at jellyfish baits and consume entire jellyfish carcasses in 2.5 h. We also show that scavenging rates on jellyfish are not significantly different from fish carrion of similar mass, and reveal that scavenging communities typical for the NE Atlantic bathyal zone, including the Atlantic hagfish, galatheid crabs, decapod shrimp and lyssianasid amphipods, consume both types of carcasses. These rapid jellyfish carrion consumption rates suggest that the contribution of gelatinous material to organic fluxes may be seriously underestimated in some regions, because jelly falls may disappear much more rapidly than previously thought. Our results also demonstrate that the energy contained in gelatinous carrion can be efficiently incorporated into large numbers of deep-sea scavengers and food webs, lessening the expected impacts (e.g. smothering of the seafloor) of enhanced jellyfish production on deep-sea ecosystems and pelagic-benthic coupling.

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Section: Resultsmentioning

confidence: 99%

Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs

et al. 2014

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“…Jellyfish are now recognized as critical indicators and drivers of ecosystem performance and change (Molinero et al 2005;Hay 2006;Lynam et al 2006). Jellyfish mass developments in several coastal areas may allow ecosystem shifts from fish dominance to dominance of gelatinous carnivores, which have been found generally irreversible, as jellyfish may control fish eggs and larvae and compete with fish for food (Lynam et al 2006).…”

Section: Consequences For the Ecosystem Functionmentioning

confidence: 99%

“…Jellyfish mass developments in several coastal areas may allow ecosystem shifts from fish dominance to dominance of gelatinous carnivores, which have been found generally irreversible, as jellyfish may control fish eggs and larvae and compete with fish for food (Lynam et al 2006). Since these voracious predators may channel flows of energy and matter away from the economically important food chain algae-copepods-fish (Sommer et al 2002;Stibor and Tokle 2003), the integration of jellyfish understanding and data becomes a critical component of an ecosystem approach to fishery management increasingly critical (Lynam et al 2005).…”

Section: Consequences For the Ecosystem Functionmentioning

confidence: 99%

Seasonal changes and population dynamics of the ctenophore Mnemiopsis leidyi after its first year of invasion in the Kiel Fjord, Western Baltic Sea

et al. 2008

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We analyzed the seasonal variations of the ctenophore Mnemiopsis leidyi weekly collected since its first record in the western Baltic Sea in October 2006. The distribution pattern together with the seasonal dynamics and population outbreaks in late summer 2007 indicate recent successfully establishment of M. leidyi in this area. Seasonal changes showed two periods of high reproductive activity characterized by a population structure dominated by small size classes, followed by an increase of larger ones. These results further revealed that the bulk of the population remains in deep layers during the periods of low population density, whereas it appeared situated in upper layers during the proliferation of the species. We further emphasized the strength of the population outbreaks, which can reach abundances [10-fold higher in time periods shorter than a week. The predatory impact this species may have in pelagic ecosystems warns on the importance of its recent range of expansion.

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“…A number of life-history features of jellyfish help them to increase in perturbed systems, including their short generation times, high reproductive output, lack of predators, broad prey spectrum and, owing to their tactile rather than visual feeding, an ability to feed efficiently in turbid water and during both night and day [2,3]. Once this switch to a jellyfish-dominated system has occurred, there is concern that by consuming large amounts of plankton prey, including fish eggs and larvae, high densities of jellyfish may impede the recovery of fish stocks even if fishing pressure is then reduced [4,5]. Certainly, it is widely recognized that the plankton feeding phase for developing fish plays a key role in fisheries recruitment, with high feeding success leading to good recruitment [6].…”

Section: Introductionmentioning

confidence: 99%

High activity and Lévy searches: jellyfish can search the water column like fish

et al. 2011

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Over-fishing may lead to a decrease in fish abundance and a proliferation of jellyfish. Active movements and prey search might be thought to provide a competitive advantage for fish, but here we use data-loggers to show that the frequently occurring coastal jellyfish (Rhizostoma octopus) does not simply passively drift to encounter prey. Jellyfish (327 days of data from 25 jellyfish with depth collected every 1 min) showed very dynamic vertical movements, with their integrated vertical movement averaging 619.2 m d 21 , more than 60 times the water depth where they were tagged. The majority of movement patterns were best approximated by exponential models describing normal random walks. However, jellyfish also showed switching behaviour from exponential patterns to patterns best fitted by a truncated Lévy distribution with exponents (mean m ¼ 1.96, range 1.2 -2.9) close to the theoretical optimum for searching for sparse prey (m opt % 2.0). Complex movements in these 'simple' animals may help jellyfish to compete effectively with fish for plankton prey, which may enhance their ability to increase in dominance in perturbed ocean systems.

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Jellyfish overtake fish in a heavily fished ecosystem

Cited by 309 publications

References 13 publications

Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs

Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs

Seasonal changes and population dynamics of the ctenophore Mnemiopsis leidyi after its first year of invasion in the Kiel Fjord, Western Baltic Sea

High activity and Lévy searches: jellyfish can search the water column like fish

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