FYI - aging info - be sure to note location

Neal et al. Invalidation of Otolith Ageing Techniques for Tropical Largemouth Bass
Otoliths have been used to determine individual age of many species of fish in different regions of the world (Warburton 1978, Erickson 1983, Summerfelt and Hall 1987, Crawford et al. 1989, Brothers 1990, Fowler 1990). For temperate regions, an nual growth checks (annuli) in otoliths have been validated for many species, and are generally related to seasonal changes in water temperature and corresponding changes in the growth rate of the fish (Williams and Bedford 1974, Bagenal and Tesch 1978, Jearld 1983, Schramm 1989). In sub-tropical regions, such as Florida, accurate ageing of centrarchids using otoliths has been accomplished where scales have been shown to lose their validity (Hoyer et al. 1985, Crawford et al. 1989, Schramm 1989). The same is true for temperate fishes such as walleye (Stizostedion vitreum), for which otoliths are preferable to scales and spines for age determination (Erickson 1983). Ageing of tropical fish using otoliths has not enjoyed the same success as in temperate regions (Pannella 1980, Longhurst and Pauly 1987). This inadequacy is due to a lack of discernible or interpretable patterns on otoliths, possibly resulting from the lack of variation in environmental conditions affecting growth rates (Pan nella 1980). However, fish ages obtained from otolith annuli have been verified in some tropical marine fish families, including Lutjanidae, Serranidae, Lethrinidae, and Sciaenidae (Fowler 1990). Largemouth bass are not native to the tropics or marine environments, but they have been widely introduced into freshwater reservoirs in tropical regions. For age and growth studies of largemouth bass in temperate and sub-tropical regions, annuli from whole and sectioned otoliths have been verified (Miller and Storck 1982, Taubert and Tranquilli 1982, Hoyer et al. 1985, Crawford et al. 1989). Yet, there is no evidence in the literature of validation studies of ageing techniques for tropical large mouth bass. As sport fish management increases in Puerto Rico, so does the use of otoliths as an indicator of fish age without proper validation. This study was under taken to assess the utility of otoliths for age and growth analyses of largemouth bass populations in a Puerto Rican reservoir.

For the entire sample, only 14% (5 of 36) of the otoliths exhibited opaque bands that correctly identified largemouth bass age. Although true age only spanned 3 years, ob served ages from otoliths often missed the true age by 2 years, and average ageing error was 1.25 years.