Gasterosteus aculeatus (Threespine Stickleback)
Credit: Thor Veen
about the species
Threespine stickleback fish fall into three (eco)types: ‘marine’ populations, which complete their entire life cycle in saline habitats, ‘anadromous’ populations that breed in freshwater after spending most of their life cycle in the ocean, and freshwater populations that spend their entire life cycle in creeks, ponds, streams or lakes. All three types are native to coastal regions throughout California, with additional freshwater populations found further inland. In California there are also two recognized stickleback subspecies (the unarmored and Shay Creek stickleback), which exhibit considerable morphological differentiation from other freshwater forms.
why species was selected
Threespine stickleback have a Holarctic distribution; however, populations in southern California represent the southern extent of the species distribution. A survey of these populations has the potential to yield insight into factors that determine thermal tolerance. Within California, stickleback inhabit a variety of habitat types and span a large geographic region that varies in many climatic and ecological parameters; this study will help identify factors that limit range and help identify genomic regions associated with local adaptation. Additionally, the unarmored stickleback is a federally listed endangered species, so this study can yield insight into the biology of this threatened species.
