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Effects of laboratory salmon louse infection on Arctic char osmoregulation, growth and survival.

https://arctichealth.org/en/permalink/ahliterature308180
Source
Conserv Physiol. 2019; 7(1):coz072
Publication Type
Journal Article
Date
2019
Author
P G Fjelldal
T J Hansen
Ø Karlsen
D W Wright
Author Affiliation
Institute of Marine Research (IMR), Matre Aquaculture Research Station, 5984 Matredal, Norway.
Source
Conserv Physiol. 2019; 7(1):coz072
Date
2019
Language
English
Publication Type
Journal Article
Abstract
High salmon lice (Lepeophtheirus salmonis) infestation levels resulting from intensive salmonid sea-cage aquaculture can threaten populations of wild salmonid hosts. This includes anadromous Arctic char (Salvelinus alpinus), which rely on short migrations into more productive seawater environments to build energy stores for maturation, spawning and over-wintering in freshwater. Elevated salmon lice burdens may limit the benefits of migration by constraining osmoregulation, growth, survival and reproduction. To test for these effects, we simulated anadromous migration in tanks by transferring individually tagged Arctic char smolts (n?=?352, averaging 133 g) to seawater where they were infected with salmon lice or left as uninfected controls for 1 month, and then transferring them back to freshwater for 2 months. After the seawater phase, infected post-smolts had a mean of 0.33 (range of 0.09-0.91) mobile lice g-1 fish weight. At this point, specific growth rates (SGRs) dropped in infected compared to control fish (0.1% vs. 1.6% day-1). Higher plasma Na+ and osmolality in infected fish also indicate osmoregulatory impairment. Throughout the study, mortality was 18.2% and 1.7% in infected and control groups, but sexual maturation was low and comparable between groups. Infection intensity correlated positively with mortality rate and plasma Cl-, and correlated negatively with SGR and condition factor (CF). CF dropped (?CF?0.09 lice g-1 fish weight, and intensities of >0.3 causing zero or negative SGRs and increased mortality were particularly concerning. If infection intensities reach these levels in the wild, char could be impacted by growth restrictions and increased mortality rates, which potentially cause shorter migration durations, lowered reproductive success and possibly also selection against anadromy. This study provides vital information for conservation practitioners wanting to understand the physiologically derived burden salmon lice can have on Arctic char populations, and can be used to define thresholds in the monitoring and conservation of Arctic char populations affected by aquaculture-driven salmon lice infestations.
PubMed ID
31723431 View in PubMed
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[Osteomalacia among the elderly in Norway].

https://arctichealth.org/en/permalink/ahliterature206803
Source
Tidsskr Nor Laegeforen. 1997 Nov 30;117(29):4288
Publication Type
Article
Date
Nov-30-1997
Author
I. Abbasi
T J Hansen
Source
Tidsskr Nor Laegeforen. 1997 Nov 30;117(29):4288
Date
Nov-30-1997
Language
Norwegian
Publication Type
Article
Keywords
Age Factors
Aged
Female
Humans
Male
Norway - epidemiology
Osteomalacia - diagnosis - epidemiology - prevention & control
PubMed ID
9441478 View in PubMed
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