The role of social rank in the development, physiology and reproductive strategies in salmonids

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The role of social rank in the development, physiology and reproductive strategies in salmonids

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dc.contributor.author Murua, Jefferson en_GB
dc.date.accessioned 2010-06-10T09:42:49Z en_GB
dc.date.accessioned 2011-01-25T17:02:09Z en_US
dc.date.accessioned 2013-03-21T10:58:20Z
dc.date.issued 2009-11-13 en_GB
dc.description.abstract Salmonids naturally organise into social hierarchies both in the wild and aquaculture. This thesis investigates how social rank influences the physiology and development of salmonids with different life strategies using Atlantic salmon (Salmo salar) as a model. In broad terms two types of studies were conducted. Firstly osmoregulatory traits of freshwater parr prior to smolting, maturing or remaining immature where investigated using Na+ gill uptake kinetics. Highly distinct patterns emerged, especially for Na+ uptake affinity, between future alternative phenotypes, which could potentially be used as an identification tool in otherwise visually identical fish. Examination of Na+ uptake kinetics from a social status perspective revealed that first and intermediate ranked fish, which received less aggression and had lower cortisol, were better prepared for sea water entry. In the second batch of studies brain serotonergic activity (5-HIAA/5-HT), a key regulator of agonistic behaviour in vertebrates, was examined in a range of social conditions. First, the stability of social ranks was tested by food manipulation. The most dominant fish were able to retain their high status even after being kept in nutrient poor conditions. High status was associated with a high standard metabolic rate (SMR) and low brain 5-HIAA/5-HT. Secondly, studies on hierarchies with marked bimodal size asymmetries showed that upper modal group fish (UMG) became dominant. Despite being subordinate lower modal group (LMG) individuals showed similar growth rates, serotonin turnover and cortisol to UMG fish, possibly due to high aggression and fin injury sustained by high rank fish fighting for dominance. Thirdly, the association between social dominance and developmental pathway was examined in size-matched groups of immature parr and precocious parr, with the latter obtaining higher social positions and showing higher aggression. Brain serotonin turnover revealed higher 5-HIAA/5-HT in immature parr, a phenotypic distinction that was also identified in immature salmonids in aquaculture. Plasma samples from alternative life histories (immature parr, precocious parr and smolts) were also used for a preliminary investigation of potential metabolite signatures utilising metabolomic techniques. en_GB
dc.description.sponsorship BBSRC, West Country Rivers Trust, University of Exeter en_GB
dc.identifier.grantnumber BBS/S/L/2005/12124 en_GB
dc.identifier.uri http://hdl.handle.net/10036/104585 en_GB
dc.language.iso en en_GB
dc.publisher University of Exeter en_GB
dc.rights.embargoreason To allow publication en_GB
dc.subject Aalmonid en_GB
dc.subject Physiology en_GB
dc.subject Behaviour en_GB
dc.subject Serotonin en_GB
dc.title The role of social rank in the development, physiology and reproductive strategies in salmonids en_GB
dc.type Thesis or dissertation en_GB
dc.date.available 2011-12-10T05:00:03Z en_US
dc.date.available 2013-03-21T10:58:20Z
dc.contributor.advisor Wilson, Roderic William en_GB
dc.publisher.department School of Biosciences en_GB
dc.type.degreetitle PhD in Biological Sciences en_GB
dc.type.qualificationlevel Doctoral en_GB
dc.type.qualificationname PhD en_GB


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