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The age and shell growth patterns in populations of Patella rustica in the Adriatic Sea were determined by analyzing the inner growth lines visible in shell sections. Marginal increment analysis showed annual periodicity with the annual growth line being deposited in May. The growth analysis of 120 individual shells showed that 90.8 % of collected shells were less than 4 years of age and only two shells (1.6 %) were older than 6 years. Population structure was described and generalized von Bertalanffy growth parameters were calculated: asymptotic length (L ∞ ) was 38.22 mm and the growth constant (K) was 0.30 year -1 . Growth performance index value of P. rustica (Ø') was 2.64, among the lowest ranges reported for limpet species. Patella rustica shells were degraded to different degrees by microbial bioerosion. The damage was most often restricted to the oldest parts of the shell, i.e. apex of the shell, posing difficulties in determining the exact position of the first growth line. The microboring organisms identified were pseudofilamentous and filamentous cyanobacteria Hormathonema (Solentia) paulocellulare, Hyella caespitosa, Mastigocoleus testarum and Leptolyngbya sp. The overall intensity of infestation was relatively low, but increased in severity with shell age and length. The present study is first to introduce the use of inner growth lines in Patella rustica shell sections as a reliable method for age determination. It provides the first insight into the growth patterns of this keystone species, while taking the interference by microbial shell bioerosion in consideration.

The reproductive cycle of the high shore limpet Patella rustica is described based on histological analysis as the primary method of staging gonad development. Sex-ratios, shell length at sexual maturity, gonad developmental stages, mean gonad index and oocyte size were investigated. Males and females were found to differ in size distribution, with females becoming more prevalent from ~28 mm onwards. The estimated shell length at which 50% of males were sexually mature was 13.1 mm. Patella rustica has only one reproductive cycle per year with a spawning peak between November and December for both sexes, and gonad redevelopment from January. First data on the size–frequency analysis of oocytes for this species are also presented, concurring with the qualitative analysis of the gonad developmental stages. This study presents updated information on the reproductive cycle of this keystone species and provides the first account of the reproductive biology of P. rustica in the Adriatic Sea.

The growth pattern of the endemic Neretvan roach, Rutilus basak from the Hutovo Blato wetlands was analyzed. A total of 441 specimens ranging from 6.0 to 21.7 cm TL were obtained by electro fishing between December 2007 and November 2008. The male:female ratio for all fish combined was 0.34 : 1.00 but changed across length classes. The spawning period extended from February to April, with a peak in the first half of March. Maximum observed age was 10 years. Predominance of age classes 1-5 in the catch (77.0% of individuals) was noted. The length-weight relationship showed a positive allometric growth (b = 3.321; R 2 = 0.957). Parameters of the von Bertalanffy equation were: L ¥ = 20.201 cm; K = 0.257 per year; t 0 = )1.554 year; R 2 = 0.977. This study revealed that R. basak invests energy in reproduction rather than in body size and thus has a relatively fast growth, short life span and precocious maturity. Moreover, elementary biological population parameters are provided that can be used for conservation purposes.

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