Alternatives to Sectioned Otoliths: The use of other Structures and Chemical Techniques to Estimate Age and Growth for Marine Vertebrates and Invertebrates

Age determination in echinoderms: first evidence of annual growth rings in holothuroids

“…the dark section grows over the margin of the plate from the previous year, and the light zone extends outward). While it is still unclear why the plates add one layer each year and how they are connected, it is obvious that the dual ring pattern in P. fabricii is not the result of differences between rapid and slow growth periods reported in other echinoderms [2].…”

“…Among them, echinoids are the most calcified and the most widely studied. Two techniques are currently used to estimate their age: mark -recapture and sclerochronology [2]. In the mark -recapture method, the diameter of the calcareous test is measured, and the skeletal elements (ossicles or plates) are tagged using baths or injections of chemicals such as tetracycline and calcein.…”

Evaluating the effectiveness of teeth and dorsal fin spines for non‐lethal age estimation of a tropical reef fish, coral trout Plectropomus leopardus

“…Additional comparisons between spines and otoliths outside this age range are required to determine if spines are suitable for estimating all ages. This is particularly important for fish >9 years old because it is difficult to distinguish annuli on the outer edge of spines in older fish (Debicella, ; Moltschaniwskyj & Cappo, ; Murie et al , ). The potential for spines to underestimate the age of older fish (due to the above limitation) is critically important for managing vulnerable and fisheries species because biased estimates of growth and mortality rates can result in overexploitation and population collapses (Campana, ).…”

“…Scales, fin rays and fin spines have been proposed as useful structures for non‐lethal age estimation of fish. Although scales have been used to age many fishes, scale loss can significantly limit the success of this approach (Moltschaniwskyj & Cappo, ). Fin rays and spines have been successfully used to age many freshwater and marine species ( Debicella, ; Moltschaniwskyj & Cappo, ); however, in some species, it can be difficult to determine the first annulus (due to occlusion and resorption) and to distinguish annuli on the outer edge of spines of older fish (Beamish & Chilton, ; Graynoth, ; Debicella, ).…”

“…Although scales have been used to age many fishes, scale loss can significantly limit the success of this approach (Moltschaniwskyj & Cappo, ). Fin rays and spines have been successfully used to age many freshwater and marine species ( Debicella, ; Moltschaniwskyj & Cappo, ); however, in some species, it can be difficult to determine the first annulus (due to occlusion and resorption) and to distinguish annuli on the outer edge of spines of older fish (Beamish & Chilton, ; Graynoth, ; Debicella, ). In the marine environment, fin spines have been used to successfully age pelagic species (Franks et al , ; Kopf et al , ), as well as temperate (Metcalf & Swearer, ) and subtropical reef fishes (Debicella, ; Brusher & Schull, ).…”