Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences

Shaozhi Zuo, Bastian Huwer, Qusay Bahlool, Azmi Al-Jubury, Nanna Daugbjerg Christensen, Rozalia Korbut, Per Kania, Kurt Buchmann

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Abstract

A significant increase in the infection level of Baltic cod Gadus morhua with the anisakid nematode larvae Contracaecum osculatum and Pseudoterranova decipiens has been recorded during recent years due to the expanding local population of grey seals Halichoerus grypus, which act as final hosts for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmothoë sarsi) are preferred food items by small cod, the isopod Saduria entomon is taken by all size classes, and sprat Sprattus sprattus are common prey items for cod larger than 30 cm. Parasitological investigations (microscopic and molecular analyses) of H. sarsi (100 specimens) and S. entomon (40 specimens) did not reveal infection in these invertebrates, but 11.6% of sprat (265 specimens examined) was shown to be infected with 1-8 C. osculatum third stage larvae per fish. Analyses of sprat stomach contents confirmed that copepods and cladocerans are the main food items of sprat. These observations suggest that the C. osculatum life cycle in the Baltic Sea includes grey seals as final hosts, sprat as the first transport host and cod as second transport host. It may be speculated that sprat obtain infection by feeding on copepods and/or cladocerans, which could serve as the first intermediate hosts. One cannot exclude the possibility that the size-dependent C. osculatum infection of cod may contribute (indirectly or directly) to the differential mortality of larger cod (>38 cm) compared to smaller cod (
Original languageEnglish
JournalDiseases of Aquatic Organisms
Volume120
Issue number1
Pages (from-to)69-75
ISSN0177-5103
DOIs
Publication statusPublished - 2016

Keywords

  • Aquatic Science
  • Ecology, Evolution, Behavior and Systematics
  • Contracaecum osculatum
  • Gadus morhua
  • Halichoerus grypus
  • Harmothoë
  • Hysterothylacium aduncum
  • Life cycle
  • Pseudoterranova decipiens
  • Saduria
  • Sprattus sprattus
  • Animalia
  • Anisakidae
  • Copepoda
  • Gadus callarias
  • Invertebrata
  • Polychaeta
  • Saduria entomon

Cite this

Zuo, Shaozhi ; Huwer, Bastian ; Bahlool, Qusay ; Al-Jubury, Azmi ; Christensen, Nanna Daugbjerg ; Korbut, Rozalia ; Kania, Per ; Buchmann, Kurt. / Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences. In: Diseases of Aquatic Organisms. 2016 ; Vol. 120, No. 1. pp. 69-75.
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title = "Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences",
abstract = "A significant increase in the infection level of Baltic cod Gadus morhua with the anisakid nematode larvae Contracaecum osculatum and Pseudoterranova decipiens has been recorded during recent years due to the expanding local population of grey seals Halichoerus grypus, which act as final hosts for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmotho{\"e} sarsi) are preferred food items by small cod, the isopod Saduria entomon is taken by all size classes, and sprat Sprattus sprattus are common prey items for cod larger than 30 cm. Parasitological investigations (microscopic and molecular analyses) of H. sarsi (100 specimens) and S. entomon (40 specimens) did not reveal infection in these invertebrates, but 11.6{\%} of sprat (265 specimens examined) was shown to be infected with 1-8 C. osculatum third stage larvae per fish. Analyses of sprat stomach contents confirmed that copepods and cladocerans are the main food items of sprat. These observations suggest that the C. osculatum life cycle in the Baltic Sea includes grey seals as final hosts, sprat as the first transport host and cod as second transport host. It may be speculated that sprat obtain infection by feeding on copepods and/or cladocerans, which could serve as the first intermediate hosts. One cannot exclude the possibility that the size-dependent C. osculatum infection of cod may contribute (indirectly or directly) to the differential mortality of larger cod (>38 cm) compared to smaller cod (",
keywords = "Aquatic Science, Ecology, Evolution, Behavior and Systematics, Contracaecum osculatum, Gadus morhua, Halichoerus grypus, Harmotho{\"e}, Hysterothylacium aduncum, Life cycle, Pseudoterranova decipiens, Saduria, Sprattus sprattus, Animalia, Anisakidae, Copepoda, Gadus callarias, Invertebrata, Polychaeta, Saduria entomon",
author = "Shaozhi Zuo and Bastian Huwer and Qusay Bahlool and Azmi Al-Jubury and Christensen, {Nanna Daugbjerg} and Rozalia Korbut and Per Kania and Kurt Buchmann",
year = "2016",
doi = "10.3354/dao03002",
language = "English",
volume = "120",
pages = "69--75",
journal = "Diseases of Aquatic Organisms",
issn = "0177-5103",
publisher = "Inter Research",
number = "1",

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Zuo, S, Huwer, B, Bahlool, Q, Al-Jubury, A, Christensen, ND, Korbut, R, Kania, P & Buchmann, K 2016, 'Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences', Diseases of Aquatic Organisms, vol. 120, no. 1, pp. 69-75. https://doi.org/10.3354/dao03002

Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences. / Zuo, Shaozhi; Huwer, Bastian; Bahlool, Qusay; Al-Jubury, Azmi; Christensen, Nanna Daugbjerg; Korbut, Rozalia; Kania, Per; Buchmann, Kurt.

In: Diseases of Aquatic Organisms, Vol. 120, No. 1, 2016, p. 69-75.

Research output: Contribution to journalJournal articleResearchpeer-review

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T1 - Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences

AU - Zuo, Shaozhi

AU - Huwer, Bastian

AU - Bahlool, Qusay

AU - Al-Jubury, Azmi

AU - Christensen, Nanna Daugbjerg

AU - Korbut, Rozalia

AU - Kania, Per

AU - Buchmann, Kurt

PY - 2016

Y1 - 2016

N2 - A significant increase in the infection level of Baltic cod Gadus morhua with the anisakid nematode larvae Contracaecum osculatum and Pseudoterranova decipiens has been recorded during recent years due to the expanding local population of grey seals Halichoerus grypus, which act as final hosts for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmothoë sarsi) are preferred food items by small cod, the isopod Saduria entomon is taken by all size classes, and sprat Sprattus sprattus are common prey items for cod larger than 30 cm. Parasitological investigations (microscopic and molecular analyses) of H. sarsi (100 specimens) and S. entomon (40 specimens) did not reveal infection in these invertebrates, but 11.6% of sprat (265 specimens examined) was shown to be infected with 1-8 C. osculatum third stage larvae per fish. Analyses of sprat stomach contents confirmed that copepods and cladocerans are the main food items of sprat. These observations suggest that the C. osculatum life cycle in the Baltic Sea includes grey seals as final hosts, sprat as the first transport host and cod as second transport host. It may be speculated that sprat obtain infection by feeding on copepods and/or cladocerans, which could serve as the first intermediate hosts. One cannot exclude the possibility that the size-dependent C. osculatum infection of cod may contribute (indirectly or directly) to the differential mortality of larger cod (>38 cm) compared to smaller cod (

AB - A significant increase in the infection level of Baltic cod Gadus morhua with the anisakid nematode larvae Contracaecum osculatum and Pseudoterranova decipiens has been recorded during recent years due to the expanding local population of grey seals Halichoerus grypus, which act as final hosts for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmothoë sarsi) are preferred food items by small cod, the isopod Saduria entomon is taken by all size classes, and sprat Sprattus sprattus are common prey items for cod larger than 30 cm. Parasitological investigations (microscopic and molecular analyses) of H. sarsi (100 specimens) and S. entomon (40 specimens) did not reveal infection in these invertebrates, but 11.6% of sprat (265 specimens examined) was shown to be infected with 1-8 C. osculatum third stage larvae per fish. Analyses of sprat stomach contents confirmed that copepods and cladocerans are the main food items of sprat. These observations suggest that the C. osculatum life cycle in the Baltic Sea includes grey seals as final hosts, sprat as the first transport host and cod as second transport host. It may be speculated that sprat obtain infection by feeding on copepods and/or cladocerans, which could serve as the first intermediate hosts. One cannot exclude the possibility that the size-dependent C. osculatum infection of cod may contribute (indirectly or directly) to the differential mortality of larger cod (>38 cm) compared to smaller cod (

KW - Aquatic Science

KW - Ecology, Evolution, Behavior and Systematics

KW - Contracaecum osculatum

KW - Gadus morhua

KW - Halichoerus grypus

KW - Harmothoë

KW - Hysterothylacium aduncum

KW - Life cycle

KW - Pseudoterranova decipiens

KW - Saduria

KW - Sprattus sprattus

KW - Animalia

KW - Anisakidae

KW - Copepoda

KW - Gadus callarias

KW - Invertebrata

KW - Polychaeta

KW - Saduria entomon

U2 - 10.3354/dao03002

DO - 10.3354/dao03002

M3 - Journal article

VL - 120

SP - 69

EP - 75

JO - Diseases of Aquatic Organisms

JF - Diseases of Aquatic Organisms

SN - 0177-5103

IS - 1

ER -