| head-shape polymorphism in japanese eels anguilla japonica in relation to differences of somatic growth in freshwater and brackish habitats. | the age, total length (l(t)), head shape and skull shape were investigated for 379 japanese eels anguilla japonica sampled in freshwater and brackish areas of the kojima bay-asahi river system, okayama, japan, to learn about the differentiation process of head-shape polymorphism. the relative mouth width (ratio of mouth width to l(t)) of a. japonica > 400 mm l(t) collected in fresh water was significantly greater than that of fish collected in brackish water. growth rates of mouth width and the ... | 2013 | 23557308 |