Heterogeneous genetic basis of age at maturity in salmonid fishes

Proliferative Kidney Disease in Salmonid Fishes

Salmonid fishes undergoing the process of smoltification

have elevated levels of thyroid hormones (Barron, 1986; Hoar, 1988; Datta et al., 1999; Eales, 1990). Thyroid hormones play a central role in controlling many of the alterations in physiology, morphology and behavior noted during this metamorphic transition in juvenile salmon (Hoar, 1988). Thyroid hormones have also been identified in altering the visual system during smoltification. During mig...

Genetic basis of differential opsin gene expression in cichlid fishes.

Visual sensitivity can be tuned by differential expression of opsin genes. Among African cichlid fishes, seven cone opsin genes are expressed in different combinations to produce diverse visual sensitivities. To determine the genetic architecture controlling these adaptive differences, we analysed genetic crosses between species expressing different complements of opsin genes. Quantitative gene...

Inheritance of Age at Sexual Maturity

Dr. RAYMOND PEARL (1912) was the first worker to suggest that sexlinked factors were involved in the inheritance of fecundity. PEARL used as a measure of fecundity the eggs produced during the winter period. He proposed that two major dominant factors were responsible for high egg production, one of which resided in the sex chromosome. GOODALE (1919) and HURST (1921) each failed to confirm the ...

The evolutionary ecology of alternative migratory tactics in salmonid fishes.

Extensive individual variation in spatial behaviour is a common feature among species that exhibit migratory life cycles. Nowhere is this more evident than in salmonid fishes; individual fish may complete their entire life cycle in freshwater streams, others may migrate variable distances at sea and yet others limit their migrations to larger rivers or lakes before returning to freshwater strea...