Environmental Conditions Affect ZebrafishGrowth and Behavioral Development
Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
Animals kept in captivity grow in significantly different environment than their wildconspecifics. Differences in factors like complexity of habitat structure, amounts and type offood, predation, competition for mates, levels of disturbance, temperature, and density arelikely to stimulate growth and development of behavior in different ways in captive andnatural environments. This in turn may affect establishment success of individuals introducedto natural environment, either intentionally or accidentally. By using a laboratory strain ofzebrafish (Danio rerio) as a model organism, the present study investigated how temperature,feeding ratios and structural complexity of the habitat affect animal development. A series offour experiments was conducted to explore relationship between experimental conditions,growth rate, survival, and development of boldness and aggressiveness, factors that can havea substantial effect on animal fitness during a post-release period. The most importantfindings of the present study indicate that low structural simplicity and access to abundantfood resources promoted growth and survival while high structural complexity and hightemperature promoted boldness. High structural complexity promoted also aggression andsmaller fish were more aggressive than larger fish. Structural complexity did not affectgrowth of individuals subjected to treatment later in life - after six weeks post hatching andmost mortality occurred at the early life stage. Some of these effects are thought to be causedby food limitations mediated by high temperature and limited food access in habitats withhigh structure complexity. Increased structure complexity and food limitation leading todevelopment of active, bold and aggressive individuals may affect post-release fitness bothnegatively and positively. Such fish may be better at defending territories, monopolizing foodresources and exploring new prey items while at the same time risking high predationpressure.
Place, publisher, year, edition, pages
2015. , 36 p.
phenotypic plasticity, zebrafish, growth, behavior
IdentifiersURN: urn:nbn:se:uu:diva-247077OAI: oai:DiVA.org:uu-247077DiVA: diva2:794788
Master Programme in Biology
Sundstrom, Fredrik, Dr.