Reproduction, condition and mortality of the Pacific oysterCrassostrea gigas(Thunberg) in Sonora, México

Abstract

Starting in 1997, mortality outbreaks in cultured oysters Crassostrea gigas have been reported in northwestern México. Previous studies have shown that massive die‐offs result from multi‐factor processes related to reproduction of the species. We studied the reproductive cycle and the condition index of cultured oysters in the coastal lagoon of El Soldado, Sonora, as well as the relationship of the life cycle with environmental parameters. We used oocyte diameter to determine reproductive stages and the condition index to describe the physiological state of oysters. Additionally, the temperature, salinity, seston and chlorophyll a were recorded at the study site. The results showed that C. gigas began accelerated reproductive activity in March under the influence of high temperature and increased concentrations of food. No spawning events were recorded and gametes were reabsorbed within the gonad in September and October. The results showed a period of nutrient storage during autumn–winter and another period of gamete production in spring–summer. A mortality event occurred at the end of winter, tied to significant increases in temperature and availability of food and in accelerated reproductive activity and high condition index. These conditions were very similar to those reported in other countries during summer die‐offs of C. gigas.

Growth and economic performance of diploid and triploid Pacific oysters Crassostrea gigas cultivated in three lagoons of the Gulf of California

“…GD: Guasave/diploid, GT: Guasave/triploid, ND: Navolato/diploid, NT: Navolato/triploid, AD: Ahome/diploid, AT: Ahome/triploid. ) was similar to that reported by Chávez-Villalba et al (2007) culturing oysters in the Gulf of California, but POM concentration was lower. As mentioned by Brown (1988) and Lodeiros & Himmelman (1999), the Chl-a concentration is one of the main factors that influence Table 5.…”

“…Except for average final size, growth rate, survival and fuel, all production characteristics for culturing diploid and triploid oysters were the same. The longline cultivation method used in the present study has been proven along the Pacific coast of Mexico (GalloGarcía et al, 2001;Chávez-Villalba et al, 2007;Góngora-Gómez et al, 2012). For cleaning the longlines and animals, paddle transport ships was used in Guasave and Ahome meanwhile an outboard motor boat in Navolato.…”

Seasonal variation in reproductive activity and biochemical composition of flat oyster (<em>Ostrea edulis</em>) in the Homa Lagoon, Izmir Bay, Turkey

“…According to Okumus et al (1998), fluctuations in the CI and MY have important implications for cultivation and harvesting strategy. Meat quality and biochemical composition in bivalves primarily depends on food, environmental parameters (mainly temperature) (Brown and Hartwick 1988, Austin et al 1993, Fabioux et al 2005 and reproductive activities (Chávez-Villalba et al 2007). In this study, MY and CI ranged from 2.69% to 12.29% and from 5.21% to 20.42%, respectively.…”

Relación del crecimiento, condición y supervivencia del ostión del Pacífico Crassostrea gigas y las variables ambientales, cultivado en suspensión en el sistema lagunar Navachiste-Macapule, Sinaloa, México

“…Algunas teorías basadas en la combinación e interacción de factores extrínsecos (bióticos y abióticos) e intrínsecos (genéticos, inmunológicos y fisiológicos), son usadas frecuentemente para explicar la drástica reducción de bivalvos en cultivo (Royer et al 2007, Enríquez-Espinoza et al 2010. Derivado de esfuerzos coordinados del gobierno con los productores y centros de investigación para tratar de conocer las causas de mortalidad en C. gigas, se ha concluido que la presencia de patógenos (Enríquez-Espinoza et al 2010, Vázquez-Yeomans et al 2010, Enríquez-Espinoza et al 2015 y/o la combinación de parámetros ambientales (Chávez-Villalba et al 2007, Castillo-Durán et al 2010 pueden estar asociados a la reducción del cultivo. No obstante, la erradicación de los patógenos y el control de las condiciones del medio ambiente son tareas imposibles, por lo que la única opción para los productores parece ser el seguimiento de buenas prácticas de cultivo para minimizar el impacto de las mortalidades (Enríquez-Espinoza et al 2010).…”