Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem
There has been a dramatic increase in jellyfish biomass over the eastern Bering Sea shelf since the early 1990s, which was previously hypothesized to have been triggered by changing climate and ocean conditions. We examine the hypothesis that the presence of these large carnivores has affected fishe...
Published in: | Marine Ecology Progress Series |
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2002
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Online Access: | https://escholarship.org/uc/item/1kv3z59f https://escholarship.org/content/qt1kv3z59f/qt1kv3z59f.pdf https://doi.org/10.3354/meps233089 |
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ftcdlib:oai:escholarship.org:ark:/13030/qt1kv3z59f 2024-09-15T17:59:27+00:00 Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem Brodeur, RD Sugisaki, H Hunt, GL 2002-01-01 application/pdf https://escholarship.org/uc/item/1kv3z59f https://escholarship.org/content/qt1kv3z59f/qt1kv3z59f.pdf https://doi.org/10.3354/meps233089 unknown eScholarship, University of California qt1kv3z59f https://escholarship.org/uc/item/1kv3z59f https://escholarship.org/content/qt1kv3z59f/qt1kv3z59f.pdf doi:10.3354/meps233089 CC-BY jellyfish distribution food consumption ecosystem changes Bering Sea Oceanography Ecology Zoology Marine Biology & Hydrobiology article 2002 ftcdlib https://doi.org/10.3354/meps233089 2024-06-28T06:28:20Z There has been a dramatic increase in jellyfish biomass over the eastern Bering Sea shelf since the early 1990s, which was previously hypothesized to have been triggered by changing climate and ocean conditions. We examine the hypothesis that the presence of these large carnivores has affected fisheries resources, either through direct predation on larval stages, or through competition for zooplankton prey. In this paper, we explore the impact of this jellyfish increase on zooplankton and fish communities based on field data on the composition of the jellyfish community, and the abundance, size, stable isotopic signatures, and feeding habits of the principal scyphomedusae in the region. These data, together with those on zooplankton biomass, are used to estimate the ecosystem impacts of this increase. The center of jellyfish biomass has shifted from the SE Middle Shelf Domain in the early 1980s to the NW in the late 1990s. In recent years, the species composition of large medusae caught in trawls was dominated (>80% by number and >95% by weight) by the scyphozoan Chrysaora melanaster. Dense aggregations of this species occupied the water column in daytime between 10 and 40 m. Their food habits consisted mainly of pelagic crustaceans (euphausiids, copepods, amphipods), although other jellyfish and juvenile pollock were also consumed. Based on stable isotope ratios, the trophic level of this scyphozoan is equivalent to, or higher than, that of Age 0 pollock. Preliminary estimates showed that medusae have a moderate grazing impact on zooplankton in the area around the Pribilof Islands; C. melanaster was estimated on average to consume seasonally about one-third of the standing stock and 4.7% of the annual production of zooplankton in this region. Daily consumption of Age 0 pollock was estimated to be 2.8% of the standing stock around the Pribilof Islands during 1999. A hypothesis for the increase in jellyfishes observed in the eastern Bering Sea, based on release from competition from planktivorous forage ... Article in Journal/Newspaper Bering Sea Copepods University of California: eScholarship Marine Ecology Progress Series 233 89 103 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
jellyfish distribution food consumption ecosystem changes Bering Sea Oceanography Ecology Zoology Marine Biology & Hydrobiology |
spellingShingle |
jellyfish distribution food consumption ecosystem changes Bering Sea Oceanography Ecology Zoology Marine Biology & Hydrobiology Brodeur, RD Sugisaki, H Hunt, GL Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem |
topic_facet |
jellyfish distribution food consumption ecosystem changes Bering Sea Oceanography Ecology Zoology Marine Biology & Hydrobiology |
description |
There has been a dramatic increase in jellyfish biomass over the eastern Bering Sea shelf since the early 1990s, which was previously hypothesized to have been triggered by changing climate and ocean conditions. We examine the hypothesis that the presence of these large carnivores has affected fisheries resources, either through direct predation on larval stages, or through competition for zooplankton prey. In this paper, we explore the impact of this jellyfish increase on zooplankton and fish communities based on field data on the composition of the jellyfish community, and the abundance, size, stable isotopic signatures, and feeding habits of the principal scyphomedusae in the region. These data, together with those on zooplankton biomass, are used to estimate the ecosystem impacts of this increase. The center of jellyfish biomass has shifted from the SE Middle Shelf Domain in the early 1980s to the NW in the late 1990s. In recent years, the species composition of large medusae caught in trawls was dominated (>80% by number and >95% by weight) by the scyphozoan Chrysaora melanaster. Dense aggregations of this species occupied the water column in daytime between 10 and 40 m. Their food habits consisted mainly of pelagic crustaceans (euphausiids, copepods, amphipods), although other jellyfish and juvenile pollock were also consumed. Based on stable isotope ratios, the trophic level of this scyphozoan is equivalent to, or higher than, that of Age 0 pollock. Preliminary estimates showed that medusae have a moderate grazing impact on zooplankton in the area around the Pribilof Islands; C. melanaster was estimated on average to consume seasonally about one-third of the standing stock and 4.7% of the annual production of zooplankton in this region. Daily consumption of Age 0 pollock was estimated to be 2.8% of the standing stock around the Pribilof Islands during 1999. A hypothesis for the increase in jellyfishes observed in the eastern Bering Sea, based on release from competition from planktivorous forage ... |
format |
Article in Journal/Newspaper |
author |
Brodeur, RD Sugisaki, H Hunt, GL |
author_facet |
Brodeur, RD Sugisaki, H Hunt, GL |
author_sort |
Brodeur, RD |
title |
Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem |
title_short |
Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem |
title_full |
Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem |
title_fullStr |
Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem |
title_full_unstemmed |
Increases in jellyfish biomass in the Bering Sea: implications for the ecosystem |
title_sort |
increases in jellyfish biomass in the bering sea: implications for the ecosystem |
publisher |
eScholarship, University of California |
publishDate |
2002 |
url |
https://escholarship.org/uc/item/1kv3z59f https://escholarship.org/content/qt1kv3z59f/qt1kv3z59f.pdf https://doi.org/10.3354/meps233089 |
genre |
Bering Sea Copepods |
genre_facet |
Bering Sea Copepods |
op_relation |
qt1kv3z59f https://escholarship.org/uc/item/1kv3z59f https://escholarship.org/content/qt1kv3z59f/qt1kv3z59f.pdf doi:10.3354/meps233089 |
op_rights |
CC-BY |
op_doi |
https://doi.org/10.3354/meps233089 |
container_title |
Marine Ecology Progress Series |
container_volume |
233 |
container_start_page |
89 |
op_container_end_page |
103 |
_version_ |
1810436547781066752 |