Morphometric analysis of Icelandic charr in lake Þingvallavatn

• Main Author: Baldur Kristjánsson 1989-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2012
• Subjects: Líffræði; Bleikja; Þingvallavatn; Arctic; Arctic charr; Iceland; Salvelinus alpinus
• Online Access: http://hdl.handle.net/1946/11570

Morphometric geometric analyses are a useful tool in developmental evolutionary biology and studying shape can help us to better understand evolutionary processes. In Iceland four morphs of arctic charr (Salvelinus alpinus) can be found and extensive research has been done on their biology, habitats and evolutionary processes. In this study I wanted to examine the effects of morph and sex on shape in charr from Lake Þingvallavatn. I applied landmarks on photos of 256 charr of three morphs. My main focus was on the small benthic and small pelagic morphs. For analysis I used ANOVA tests evaluating the effect of several variables, morph, sex and weight as a covariate, Pearson’s correlation tests and polynomial linear regression done in R. The data suggests that there is a significant shape difference between morph and sex in at least two warps. I also checked the effects of bending of specimens and how unbending procedures affect the data. My conclusion was that unbending the data set is not crucial but makes data analysis easier. I also checked the correlation between of size and weight between morphs and sex. A strong correlation was seen between size and weight and the large benthic morph had the largest weight distribution and contained the biggest and heaviest individuals. An interesting result was seen for the weight distribution of small benthic females. It was by far greater than for the small benthic males suggesting that some individuals might have been wrongly classified.