Growth of the purple dye murex, Bolinus brandaris (Gastropoda: Muricidae), marked and released in a semi-intensive fish culture earthen pond

The present study reports the growth rate of the purple dye murex, Bolinus brandaris (Gastropoda: Muricidae), estimated from mark-recapture experiments. A total of 1067 specimens (shell length = 43.4±8.1 mm, range = 14.6−78.4 mm) were marked with Dymo® tape tags and released in a semi-intensive fish culture earthen pond. After a period at liberty ranging from almost two months to around two years, 288 individuals were recaptured (shell length = 67.4±6.2 mm, range = 45.3−88.6 mm), which corresponded to a recapture rate of 27.0%. At recapture, only one specimen had lost the tag (tag loss rate < 0.1%) and all remaining tags were intact and legible. Mean monthly growth rates were 0.9±1.0 mm in shell length, 0.4±0.5 mm in shell width and 0.7±0.7 g in total weight. Growth rates showed high inter-individual variability and an evident decreasing trend with specimen size. Comparison of growth rates with similar information available for other muricids confirmed that B. brandaris is a relatively slow-growing species. This provides valuable information for both fisheries management and for assessing the potential of B. brandaris as a candidate species for molluscan aquaculture.