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Article: Monsoons and habitat influence trophic pathways and the importance of terrestrial-marine linkages for estuary sharks

TitleMonsoons and habitat influence trophic pathways and the importance of terrestrial-marine linkages for estuary sharks
Authors
KeywordsChiloscyllium plagiosum
Compound-specific stable isotopes
Detritus
Fatty acids
Food webs
Marine predators
Mixing model
Monsoonal climate
Pearl River Estuary
Scoliodon laticaudus
Trophic subsidy
Zooplankton
Issue Date2012
PublisherEcological Society of America. The Journal's web site is located at http://www.esajournals.org
Citation
Ecosphere (Washington, DC), 2012, v. 3 n. 1, article no. 8 How to Cite?
AbstractTropical estuaries often receive enhanced fluxes of terrestrial derived organic matter and phytoplankton during the wet season, and such monsoonal events may significantly influence the trophic dynamics of these systems. This study examined spatio-temporal terrestrial-marine linkages in a tropical estuary, the Pearl River Estuary (PRE), southern China, by investigating trophic pathways leading to estuary sharks. We investigated spatial (inshore vs. offshore) and seasonal (wet vs. dry season) variation in the relative importance of terrestrial- and marine-derived carbon, so as to assess the contribution of detrital pathways to the pelagic spadenose shark, Scoliodon laticaudus; ontogentic changes in shark diets were also documented. Stable isotope analyses (SIA) and fatty acid (FA) profiling indicated that spadenose sharks assimilated both marine and terrestrial carbon via consumption of zooplantivorous fish and shrimps. Detrital carbon sources were more important to juvenile and pre-mature sharks at inshore locations, especially during the wet season when river discharge increased and terrestrial detritus was more abundant. Ontogenetic dietary shifts were evident: juvenile and pre-mature sharks had significantly higher levels of bacterial (detrital) FA than adults which contained more animal-derived FA. Inshore sharks, with more depleted δ13C signatures, relied more on terrestrial carbon than sharks offshore. Comparison of spadenose shark FA profiles with those of the sympatric, white-spotted bamboo shark (Chiloscyllium plagiosum)—a benthic predator that acquires detrital carbon via consumption of polychaetes and crustaceans—revealed that they made greater use of detrital carbon sources. However, spadenose sharks in the inner estuary assimilated higher proportions of terrestrial detritus (44–56%) than bamboo sharks (31–45%). The importance of terrestrial detritus for both shark species demonstrated the important contribution of terrestrial detritus to both pelagic and benthic food webs in the PRE. Terrestrial-marine linkages are therefore of great significance, particularly during the wet season, in this estuarine system, which serves as feeding and nursery grounds for both shark species, and trophic subsidies from land are likely to be important for marine predators in other tropical estuaries. Read More: http://www.esajournals.org/doi/abs/10.1890/ES11-00276.1
Persistent Identifierhttp://hdl.handle.net/10722/147034
ISSN
2015 Impact Factor: 2.287
2015 SCImago Journal Rankings: 1.452
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorWai, TCen_US
dc.contributor.authorYeung, JWYen_US
dc.contributor.authorLam, VYYen_US
dc.contributor.authorLeung, KMYen_US
dc.contributor.authorDudgeon, Den_US
dc.contributor.authorWilliams, GAen_US
dc.date.accessioned2012-05-23T05:54:13Z-
dc.date.available2012-05-23T05:54:13Z-
dc.date.issued2012en_US
dc.identifier.citationEcosphere (Washington, DC), 2012, v. 3 n. 1, article no. 8en_US
dc.identifier.issn2150-8925-
dc.identifier.urihttp://hdl.handle.net/10722/147034-
dc.description.abstractTropical estuaries often receive enhanced fluxes of terrestrial derived organic matter and phytoplankton during the wet season, and such monsoonal events may significantly influence the trophic dynamics of these systems. This study examined spatio-temporal terrestrial-marine linkages in a tropical estuary, the Pearl River Estuary (PRE), southern China, by investigating trophic pathways leading to estuary sharks. We investigated spatial (inshore vs. offshore) and seasonal (wet vs. dry season) variation in the relative importance of terrestrial- and marine-derived carbon, so as to assess the contribution of detrital pathways to the pelagic spadenose shark, Scoliodon laticaudus; ontogentic changes in shark diets were also documented. Stable isotope analyses (SIA) and fatty acid (FA) profiling indicated that spadenose sharks assimilated both marine and terrestrial carbon via consumption of zooplantivorous fish and shrimps. Detrital carbon sources were more important to juvenile and pre-mature sharks at inshore locations, especially during the wet season when river discharge increased and terrestrial detritus was more abundant. Ontogenetic dietary shifts were evident: juvenile and pre-mature sharks had significantly higher levels of bacterial (detrital) FA than adults which contained more animal-derived FA. Inshore sharks, with more depleted δ13C signatures, relied more on terrestrial carbon than sharks offshore. Comparison of spadenose shark FA profiles with those of the sympatric, white-spotted bamboo shark (Chiloscyllium plagiosum)—a benthic predator that acquires detrital carbon via consumption of polychaetes and crustaceans—revealed that they made greater use of detrital carbon sources. However, spadenose sharks in the inner estuary assimilated higher proportions of terrestrial detritus (44–56%) than bamboo sharks (31–45%). The importance of terrestrial detritus for both shark species demonstrated the important contribution of terrestrial detritus to both pelagic and benthic food webs in the PRE. Terrestrial-marine linkages are therefore of great significance, particularly during the wet season, in this estuarine system, which serves as feeding and nursery grounds for both shark species, and trophic subsidies from land are likely to be important for marine predators in other tropical estuaries. Read More: http://www.esajournals.org/doi/abs/10.1890/ES11-00276.1-
dc.languageengen_US
dc.publisherEcological Society of America. The Journal's web site is located at http://www.esajournals.org-
dc.relation.ispartofEcosphere (Washington, DC)en_US
dc.rightsEcosphere (Washington, DC). Copyright © Ecological Society of America.-
dc.rightsCopyright by the Ecological Society of America, along with the full citation-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.subjectChiloscyllium plagiosum-
dc.subjectCompound-specific stable isotopes-
dc.subjectDetritus-
dc.subjectFatty acids-
dc.subjectFood webs-
dc.subjectMarine predators-
dc.subjectMixing model-
dc.subjectMonsoonal climate-
dc.subjectPearl River Estuary-
dc.subjectScoliodon laticaudus-
dc.subjectTrophic subsidy-
dc.subjectZooplankton-
dc.titleMonsoons and habitat influence trophic pathways and the importance of terrestrial-marine linkages for estuary sharksen_US
dc.typeArticleen_US
dc.identifier.emailWai, TC: waitakcheung@hotmail.comen_US
dc.identifier.emailLeung, KMY: kmyleung@hku.hken_US
dc.identifier.emailDudgeon, D: ddudgeon@hku.hken_US
dc.identifier.emailWilliams, GA: hrsbwga@hkucc.hku.hken_US
dc.identifier.authorityWai, TC=rp00797en_US
dc.identifier.authorityLeung, KMY=rp00733en_US
dc.identifier.authorityDudgeon, D=rp00691en_US
dc.identifier.authorityWilliams, GA=rp00804-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1890/ES11-00276.1-
dc.identifier.hkuros199541en_US
dc.identifier.volume3en_US
dc.identifier.issue1en_US
dc.identifier.isiWOS:000327298400008-
dc.publisher.placeUnited States-

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