Age and Growth of Striped Venus Clam Chamelea gallina (Linnaeus, 1758) in the Mid-Western Adriatic Sea: A Comparison of Three Laboratory Techniques

Abstract

Age and growth studies provide critical data for clam fishery management. Three aging techniques, thin sections and acetate peel replicas-which involve shell sectioningand surface growth rings were used to estimate the age and growth of Chamelea gallina populations in the mid-western Adriatic Sea. Their results were compared to identify the most reliable and least time-consuming approach. There were no significant differences between the two shell sectioning techniques (χ 2 = 4.66, df = 3, p = 0.198), which were described by the same von Bertalanffy (VBF) growth curve parameters (L 8 = 43.9, k = 0.26, t 0 = −0.84), whereas significantly different L 8 and k values were found between the two shell sectioning techniques and surface growth rings (L 8 : χ 2 = 13.62, df = 1, p < 0.001; k: χ 2 = 9.18, df = 1, p < 0.002; these statistics refer to the comparison between acetate peels and surface growth rings). The latter approach proved unreliable and error-prone, as it underestimated age and overestimated the growth rate (L 8 = 26.4, k = 1.91, t 0 = −0.11). Although the thin sections and acetate peel techniques both provide reliable age and growth estimates, the former approach was less time-consuming. Our analyses demonstrated that shell growth is slower in the cold season and in older specimens and that it has slowed down over the past few decades.

Chamelea gallina reproductive biology and Minimum Conservation Reference Size: implications for fishery management in the Adriatic Sea

“…Both sexes of the striped venus clam reach sexual maturity at about 11.2 mm TL, in the first year of life; indeed, the first year specimens grow to about 15 mm TL [ 61 ]. Clams longer than 15 mm TL were all found sexually mature.…”

Reburial potential and survivability of the striped venus clam (Chamelea gallina) in hydraulic dredge fisheries

“…Altogether, previous findings and the present data—documenting that a very large proportion of clams survive harvesting and sorting and that they show a high reburial ability and survival rate after reburying—demonstrate the high survival potential of C. gallina and support the claim that undersized specimens of this bivalve can be returned to the sea as per Regulation (EU) 2020/2237 17 . The present data suggests that a very high proportion of discarded C. gallina survive and grow to the commercial size (MCRS), which is reached on around 2 years of age 47 . The common observation of clams with repaired shells further testifies to their survival ability.…”

Oxygen and carbon isotope variations in Chamelea gallina shells: Environmental influences and vital effects

“…The biology of the clam C. gallina in the Adriatic Sea was already studied in terms of growth rate (Bargione et al, 2020;Keller et al, 2002;Mancuso et al, 2019), physiology (Matozzo et al, 2007;, and shell properties (Cheli et al, 2021;Gizzi et al, 2016; Mancuso time (Keller et al, 2002). However, this confined area is not representative of the wide shifts in C. gallina habitat from North to South of the Adriatic basin that influence shell growth (Mancuso et al, 2019).…”

“…The biology of the clam C. gallina in the Adriatic Sea was already studied in terms of growth rate (Bargione et al, 2020 ; Keller et al, 2002 ; Mancuso et al, 2019 ), physiology (Matozzo et al, 2007 ; Monari, Matozzo, et al, 2007 ; Monari, Serrazanetti, et al, 2007 ), and shell properties (Cheli et al, 2021 ; Gizzi et al, 2016 ; Mancuso et al, 2019 ). A previous study conducted in the Bay of Trieste in the North of the Adriatic Sea investigated the shell isotopic composition of C. gallina in relation to its growth rates and settlement time (Keller et al, 2002 ).…”