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Otolith chemistry indicates recent worsened Baltic cod condition is linked to hypoxia exposure

Limburg, Karin and Casini, Michele (2019). Otolith chemistry indicates recent worsened Baltic cod condition is linked to hypoxia exposure. Biology Letters. 15 :12 , 1-5
[Research article]

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Deoxygenation worldwide is increasing in aquatic systems with implications for organisms' biology, communities and ecosystems. Eastern Baltic cod has experienced a strong decline in mean body condition (i.e. weight at a specific length) over the past 20 years with effects on the fishery relying on this resource. The decrease in cod condition has been tentatively linked in the literature to increased hypoxic areas potentially affecting habitat range, but also to benthic prey and/or cod physiology directly. To date, no studies have been performed to test these mechanisms. Using otolith trace element microchemistry and hypoxia-responding metrics based on manganese (Mn) and magnesium (Mg), we investigated the relationship between fish body condition at capture and exposure to hypoxia. Cod individuals collected after 2000 with low body condition had a higher level of Mn/Mg in the last year of life, indicating higher exposure to hypoxic waters than cod with high body condition. Moreover, lifetime exposure to hypoxia was even more strongly correlated to body condition, suggesting that condition may reflect long-term hypoxia status. These results were irrespective of fish age or sex. This implies that as Baltic cod visit poor-oxygen waters, perhaps searching for benthic food, they compromise their own performance. This study specifically sheds light on the mechanisms leading to the low condition of cod and generally points to the impact of deoxygenation on ecosystems and fisheries.

Authors/Creators:Limburg, Karin and Casini, Michele
Title:Otolith chemistry indicates recent worsened Baltic cod condition is linked to hypoxia exposure
Series Name/Journal:Biology Letters
Year of publishing :2019
Page range:1-5
Number of Pages:5
Publisher:The Royal Society
Associated Programs and Other Stakeholders:SLU - Environmental assessment > Programme Coastal and sea areas
SLU - Environmental assessment > Programme Biodiversity
SLU - Environmental assessment > Programme Climate
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Accepted version
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 405 Other Agricultural Sciences > Fish and Wildlife Management
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Fish and Aquacultural Science
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
Keywords:hypoxia, body condition, Gadus morhua, otoliths, trace element analyses
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Type of IDID
ID Code:16535
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Aquatic Resources
Deposited By: SLUpub Connector
Deposited On:03 Sep 2020 10:02
Metadata Last Modified:03 Sep 2020 10:02

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