Age determination and growth of picarel (Spicara smaris) from the Cretan continental shelf (Greece)

Publication Type:Journal Article
Year of Publication:1996
Authors:Vidalis, K., Tsimenidis, N.
Journal:Fisheries ResearchFisheries Research
Date Published:1996///
Keywords:Age determination, Age validation, growth, hermaphroditism, Periodicity, Pisces, Spicara smaris (Centracanthidae)

Picarel (Spicara smaris), a protogynous species, was studied in order to obtain information on its life history off the coasts of Crete during 1988- 1990. Marginal increment analysis together with length-frequency distribution analysis (LFDA) and comparison of age readings between two anatomical structures (otoliths and scales) were used to validate age determination. The validation revealed that annuli were formed once a year between March and July. The relationship between scale radius (Rs) or otolith radius (Ro) and the fish length (FL) was linear. For the first 2 years of its life, S. smaris showed a relatively rapid growth, followed by a low growth rate after that. The maximum life span was 5 years for females and 7 years for males. The von Bertalanffy growth formula was estimated for males (L(x) = 192.3, k = 0.154, t(o) = -3.522); females (L(á) = 128.4, k = .921, t(o) = -0.215); and the sexes combined (L(á) = 137.8, k = 0.393, t(o) = -0.678). A modified model for hermaphrodite fishes was also tested for estimation of the theoretical growth in length at each age. The modified model was best fitted to observed lengths at age. Length-weight relationship was calculated for male, female and the sexes combined. This relationship showed allometric growth in weight (slope b = 3.17 - 3.25 > 3.00).

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith