Scientists who study ichthyology, the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). (Adapted from Wikipedia, 2024. Ichthyology https://en.wikipedia.org/wiki/Ichthyology)
Adjustment of a population to changes in environment over generations, associated (at least in part) with genetic changes resulting from selection imposed by the changed environment. Not acclimatization. (FAO, 2001 Glossary of Biotechnology for Food and Agriculture - A Revised and Augmented Edition of the Glossary of Biotechnology and Genetic Engineering https://www.fao.org/3/Y2775E/Y2775E00.htm)
Note
Adjustment of a living organism to environmental conditions