![]() Often the circuli/annuli run transverse across the scale. The circuli/annuli are concentric with the scale margin, but are not always concentric around the focus. False rings are not related to growth slowdowns in winter, and should not be counted when reading age. The scales lack radii, but fracture cracks are common and often run parallel and across circuli. Such occassional disturbances manifest themselves, among others, by an additional mark on the scale. These (often partial) rings are the result of unusual conditions encountered by the bass such as food shortage or climate ‘accidents’ as sudden colds. When counting annual rings, don’t be fooled by so called ‘false’ rings that you might encounter. The white arrows point out the annual rings, the red arrows indicate the false rings. They correspond to the little calcified area between two circuli, which appears clear and rather thick. Annuli are formed when a new growing season begins. They are often discontinuous and their frequency can vary from one scale to another on the same fish. The circuli are fine, dark streaks that are usually very close to each other. The front field has two types of stripes that are arranged concentrically around the nucleus: the circuli and annuli. months after hatching, or annuli in older fish can be obsclred by compression of the circuli as growth slows wit11 age. The four fields are in contact at the starting point of development of the scale, which is called the nucleus. Only the last field is visible, the others being embedded in the skin and covered by the adjacent scales. There is the front field – the one with the most prominent annual rings (annuli) on it – two lateral fields and a rear field. The annual rings thus also disclose the speed of growth.Ī bass scale is roughly quadrangular shaped and made up of four fields. ![]() This can be somewhat more difficult with bass of ten years and older: their scales are thicker and the annual rings are located closer to each other due to a slowdown in growth. These marks of growth originate each year during the winter months and are generally clearly visible, thus making it fairly easy to determine the age of the fish. Each of these growth rings equals one year.īass scales have annual rings on them. To determine how old a fish exactly is, scientists usually count the number of annual rings on the scales with a microscope. Seabass is a long-lived species and can reach up to 30 years of age. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |