Document Detail


Endocrine changes associated with spawning behavior in male kokanee salmon (Oncorhynchus nerka) and the effects of anosmia.
MedLine Citation:
PMID:  8294117     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study examines the relationship between social status, behavioral activity, and hormone levels through the spawning cycle in male kokanee salmon (Oncorhynchus nerka). Shortly after arrival at the spawning grounds, male kokanee undergo dramatic changes in morphological and physiological condition: there is an increase in body depth, a bright silvery appearance is replaced by an intense red coloration, and spermiation commences. Males become associated with nesting females which they defend against other males. The androgens, testosterone and 11-ketotestosterone, decline slowly over the spawning period from high levels observed in the silvery males; gonadotropin (GtH II) and 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one increase as males approach final maturation. Androgen and GtH levels in males placed in pens with females over the spawning bed were higher than those in males penned without females. Among males competing for females, amounts of milt and plasma concentrations of GtH were higher in those males that were successful in gaining access to nesting females. A marked reduction in milt and plasma hormones following cauterization of the olfactory nares indicates that olfactory stimuli play a role in mediating endocrine and spermiation responses to the nesting females. Anosmic males were less vigorous and persistent in their courtship, suggesting that, either a female pheromone and/or high levels of hormone are necessary to maintain full reproductive behavior in male kokanee. The role of socially induced hormone changes in modulating reproductive behavior is discussed.
Authors:
N R Liley; K H Olsén; C J Foote; G J Van der Kraak
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Hormones and behavior     Volume:  27     ISSN:  0018-506X     ISO Abbreviation:  Horm Behav     Publication Date:  1993 Dec 
Date Detail:
Created Date:  1994-03-03     Completed Date:  1994-03-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0217764     Medline TA:  Horm Behav     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  470-87     Citation Subset:  IM    
Affiliation:
Department of Zoology, University of British Columbia, Vancouver, Canada.
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MeSH Terms
Descriptor/Qualifier:
Animals
Female
Gonadal Steroid Hormones / physiology
Male
Oncorhynchus / physiology*
Sex Attractants / physiology
Sexual Behavior, Animal / physiology*
Smell / physiology*
Social Dominance
Social Environment
Spermatogenesis / physiology
Chemical
Reg. No./Substance:
0/Gonadal Steroid Hormones; 0/Sex Attractants

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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