engleski

Growth and reproduction of the limpet Patella rustica Linnaeus, 1758 and heat stress physiology of the Mediterranean patellid limpets

First investigation of age, growth and reproduction cycle of the limpet Patella rustica on the south eastern Adriatic coast was performed. Marginal increment analysis showed annual periodicity of growth line formation, with annual growth line being deposited in May. Population structure was described and the von Bertalanffy growth curves were fitted for: asymptotic length L∞=40.86 mm, asymptotic width W∞=33.02 mm and asymptotic height H∞=14.07 mm, with corresponding values of growth constant (K) of 0.23, 0.24 and 0.21 year-1, respectively. Shells were found to grow allometrically (α=1.66). The maximum, mathematically defined longevity was 12.7 years, but only 2 individuals were observed to be more than 6 years old (6.75 and 7.75 years). Males and females were found to differ in size, with females becoming more prevalent from ~28 mm onwards, suggesting P. rustica is a protandrous hermaphrodite. Patella rustica has only one reproductive cycle per year with longer breeding period. The spawning occurred synchronously in November. The biggest oocytes were measured in ripe stage with the mean value of 115.6±44.1 µm for diameter and 329.0±125.4 µm for perimeter, while the smallest oocytes were recorded in early developmental stage, 21.3±9.7 µm for diameter and 60.2±30.5 µm for perimeter. Performed experimental research demonstrated that congeneric limpets P. rustica, P. caerulea and P. ulyssiponensis have different physiological responses to thermal stress related to their vertical zonation on the shore. Arrhenius breakpoint temperature for P. rustica was 37.9°C, for P. caerulea 35.9°C and for P. ulyssiponensis 32.2°C. Levels of hsp70 increased at 34°C and kept increasing with temperature in P. rustica, while in P. caerulea reached a maximum at 36°C. This suggests that the high shore P. rustica is able to tolerate higher temperatures than the lower shore counterparts. Temperature influenced stability of haemocytes in both P. rustica and P. caerulea, with both species showing inability to recover damaged lysosomes after stress. The results showed that Patella congeners already live at the edges of their thermal window and further temperature changes may have large-scale consequences for these species.

cardiac activity; growth; heat shock proteins expression (hsp70); lysosomal stability; Patella rustica; P. caerulea; P. ulyssiponensis; reproduction

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