Reproductive cycle of the mangrove oyster, Crassostrea rhizophorae (Bivalvia: Ostreidae) cultured in a macrotidal high-salinity zone on the Amazon mangrove coast of Brazil

Abstract

This study aimed to establish the reproductive cycle of the mangrove oyster, Crassostrea rhizophorae cultured in the macrotidal estuary of the Paciência River, Maranhão state, on the northeastern coast of Brazil, and its relationship with environmental factors. Oysters were collected monthly throughout 2013 for histological analysis of sex ratio, gonadal development and condition index. The sex ratio was 1:1.39 (M:F) and only 5 specimens presented hermaphroditism. The breeding process was continuous throughout the year and mature (IIIA stage) and spawning oysters (IIIB stage) were present in practically all months. Low variation in temperature seemed to be the main factor for the continuity of the reproductive cycle. Besides temperature, the relationship between rainfall, salinity and primary productivity affected the stimulus and timing of reproductive events. The rainy season, with low values of salinity and high values of chlorophyll a and particulate organic matter, appeared to be the main reproductive period, with release of gametes and production and maturation of new gamete cohorts in the short term. In the tropics, where gamete maturation and release seem to be continuous and concomitant, the condition index does not appear to be the best method to assess reserve accumulation peaks and gonadal repletion.

Reproductive Biology and Spawning Pattern of Oyster Magallana bilineata in Mengkabong Bay, Sabah, Malaysia

“…Throughout the sampling period, M. bilineata was observed to spawn in most months in Mengkabong Bay. This finding is consistent with previous studies suggesting that spawning may occur year-round in tropical regions (Castilho-Westphal et al, 2015;Antonio et al, 2021). The relatively constant temperature and salinity conditions in Mengkabong Bay (from 26.58 to 29.14 psu and from 29.56 to 30.14 °C, respectively) appear to be the primary drivers of continuous M. bilineata reproduction (Tan and Ransangan, 2014; Cárdenas and Aranda, 2000).…”

“…The Magallana bilineata population in Mengkabong Bay was found to be female-biased at a ratio of 1:2.36. These findings are consistent with those of several other Crassostrea species, including Crassostrea (M.) saidii, C. brasilliana, C. cortezieensis, C. gigas, and C. rhizophorae (Castilho-Westphal et al, 2015;Ezgeta-Balić et al, 2020;Antonio et al, 2021;Barman et al, 2022). Conversely, several Crassostrea species have been reported to be malebiased (Rodríguez-Jaramillo et al, 2008) or have similar or almost equal sex ratios (Castaños et al, 2009;Vaschenko et al, 2013;Dridi et al, 2014).…”

“…Of the 210 specimens examined in this study, 1.90% were hermaphrodites. This is higher than the recorded hermaphroditism rates for C. (M.) saidii (Barman et al, 2022), C. rhizhophore (Castilho-Westphal et al, 2015), and C. gigas (Ezgeta-Balić et al, 2020), but lower than those reported for C. angulata (Vaschenko et al, 2013) and C. rhizhophore (Antonio et al, 2021). There was no significant difference in shell height between hermaphrodite and non-hermaphrodite specimens in this study, suggesting that the presence of hermaphroditism could represent a transitional stage between sexes (Barman et al, 2022) with a strong predisposition to become female (Bayne, 2017).…”

Reproductive Cycle of the Edible Oyster <i>Crassostrea belcheri</i> in the Myeik Coastal Area of Southern Myanmar

“…Spawning in oysters in the tropics may occur through most of the year, with peaks usually before and after the rainy season (Quayle 1980). Antonio et al (2021) stated that low variation in temperature might be the main factor in continuous spawning in tropical regions. There were variations in the spawning season and spawning peaks between and within the tropical oyster species depending on habitat localities (Table 1).…”

Spat efficiency of the smooth scallop Flexopecten glaber in the Aegean Sea, Türkiye

“…Yigitkurt et al (2020) reported that the most important environmental parameters triggering reproduction in bivalves are temperature and chlorophyll-a and that the amount of chlorophyll-a increases in parallel with the increase in temperature. Antonio et al (2021) reported that environmental parameters such as food availability and TPM can affect the reproductive cycle of oysters. However, in this study, no correlation was found between the number of newly attached individuals, chlorophyll-a, and TPM (p > 0.05).…”