Reproductive cycle of the yellow clam Amarilladesma mactroides (Reeve, 1854)

Studies on the reproductive cycle are essential for understanding the reproduction of a species. No studies on the reproductive cycle of Amarilladesma mactroides in Brazil have been conducted. Therefore, the present study sought to analyze, in the wild, the influence of the seasons on the development of the gonadic tissue of the yellow clam in southern Brazil (28 degrees 50'10.4"S, 49 degrees 13'55.7"W) and to evaluate the effect of water temperature on the development of gonadic tissue and its growth in the laboratory. A total of 227 animals were collected monthly between October 2019 and October 2020 to evaluate the reproductive cycle of the species using a condition index (CI) and histological analysis. In addition, the effect of temperature (17 degrees C and 23 degrees C) on the maturation and growth of 270 animals was evaluated in the laboratory. A higher CI was observed in autumn and winter when compared to that observed in spring and summer. The results of the histological analyses corroborated those obtained for the CI, demonstrating that the mature animals had a higher CI than the immature animals. Animals exposed to a temperature of 23 degrees C reached maturation faster than those exposed to a temperature of 17 degrees C. At both temperatures, the animals increased in shell length and total live weight, with no significant differences in these parameters between the temperatures. It was concluded that 23 degrees C is the most suitable temperature for the maturation of A. mactroides in the laboratory and that the best season of the year to collect wild animals for subsequent spawning induction in the laboratory is winter. (c) 2023 Elsevier B.V. All rights reserved.