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Adipose tissue fatty acids suggest spatial and temporal dietary differences in great cormorants of the Baltic Sea area

Tverin, Malin and Granroth, Janne and Abrahamsson, Alexander and Tang, Patrik and Pihlstrom, Henry and Lundström, Karl and Kakela, Reijo (2021). Adipose tissue fatty acids suggest spatial and temporal dietary differences in great cormorants of the Baltic Sea area. Journal of the Marine Biological Association of the United Kingdom. 101 , PII S0025315420001320 , 199-213
[Research article]

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Abstract

Increased numbers of great cormorants (Phalacrocorax carbo) in the Baltic Sea may have local impacts on fisheries and salmonid hatcheries. We studied spatial and temporal variability in cormorant diet, and potential consumption of hatchery salmonids, by analysing knee subcutaneous adipose tissue fatty acids (FA) of specimens (N = 77) collected along Swedish and Finnish coasts in different seasons during 2013-2017. The FA profiles of the subspecies sinensis and carbo were similar, with large individual variation. The proportion of C18 polyunsaturated FAs (PUFAs) was the largest in the north, whereas the proportion of C20-22 monounsaturated FAs (MUFAs) increased towards the south, reflecting diminishing freshwater and increasing marine food web characteristics towards the south. As an exception, the C20-22 MUFA percentage was high in sinensis collected in June 2017 from the northern Baltic Sea. The source of C20-22 MUFAs was probably hatchery salmonids, raised on ocean fish hatchery feed and released 10 days before, near the cormorant capture site. The FA profiles of northern and southern cormorants differed from each other both in early and late summer samples, suggesting spatially different diets. The largest individual variation was found in 22:1n-11, characteristic of ocean zooplanktivorous fish, and likely originating from Atlantic wild or Baltic Sea hatchery-reared fish. This study shows that adipose tissue FA profiles can be used as proxies for seabird diet monitoring and indicators of predation on hatchery-reared fish. Obtaining quantitative estimates on the proportions of dietary fish species requires future feeding experiments, allowing calibration between the FA compositions and diet.

Authors/Creators:Tverin, Malin and Granroth, Janne and Abrahamsson, Alexander and Tang, Patrik and Pihlstrom, Henry and Lundström, Karl and Kakela, Reijo
Title:Adipose tissue fatty acids suggest spatial and temporal dietary differences in great cormorants of the Baltic Sea area
Series Name/Journal:Journal of the Marine Biological Association of the United Kingdom
Year of publishing :2021
Volume:101
Article number:PII S0025315420001320
Number of Pages:15
Publisher:CAMBRIDGE UNIV PRESS
ISSN:0025-3154
Language:English
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Fish and Aquacultural Science
Keywords:Diet analysis, fatty acid, Phalacrocorax carbo, population management, seabird–fishery conflict
URN:NBN:urn:nbn:se:slu:epsilon-p-112161
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-p-112161
Additional ID:
Type of IDID
DOI10.1017/S0025315420001320
Web of Science (WoS)000641485600019
ID Code:24515
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Aquatic Resources
Deposited By: SLUpub Connector
Deposited On:11 Jun 2021 11:03
Metadata Last Modified:11 Jun 2021 11:11

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