Larval and post-larval growth, spat production and off-bottom cultivation of the smooth venus clam Chionista fluctifraga

Abstract

Harvesting practices of the clam Chionista fluctifraga show a decline in commercial size and densities, but no strategies have been developed to maintain clam beds. Aquaculture represents an alternative for preserving this resource. Adult clams from commercial grounds were used as broodstock. Conditioning, induction of spawning, cultivation of larvae, settlement of eyed larvae and nursing of postlarvae were performed in the hatchery for producing spat. Larvae and postlarvae were used to measure increase in shell height and data were fitted to exponential growth models. Spat were placed in floating trays and maintained in off-bottom cultivation for 9 months. Samples of clams and tissues were collected monthly to measure absolute growth, shell height increase and a condition index. Larvae, postlarvae and juveniles showed exponential growth patterns. Mean shell height increased about 0.030 mm day À1 during larval and post-larval stages and 0.049 mm day À1 during field cultivation. Pediveligers (height 215 AE 83 lm) entered metamorphosis at days 9-13 after fertilization, and postlarvae reached 3011.7 AE 325.5 lm (height) at day 60. After field cultivation, survival was about 95%; juvenile shell height was 20.6 AE 2.2 mm, and total weight was 5.3 AE 0.7 g. Growth rates were superior to natural conditions and the condition index was high throughout the study. Our results show that spat of C. fluctifraga can be produced in the hatchery, and that field production can be maintained in off-bottom trays until reaching commercial size.Aquaculture activities for this species need to be established and evaluated.

Spawning induction and embryonic development of the clam Ameghinomya antiqua (King, 1832)

“…Among the methodologies described in the literature to achieve the expulsion of gametes, the most used for clams is the thermal shock with a high percentage of spawning (Bustos & Olavarría 2000, Castagna 2001, Helm et al 2006, Hadley &Whetstone 2007, Da Costa et al 2008, Contreras-Guzmán et al 2014. This methodology has been used with previous conditioning in Mercenaria mercenaria, Ruditapes philippinarum, Chione cancellata, Ameghinomya antiqua, Chionista fluctifraga, and Pholas orientalis with temperature differences between 8-9°C and induction periods of 2 to 3 h (Bustos & Olavarría 2000, Castagna 2001, Ng et al 2009, Rengel et al 2009, Aranda-Burgos et al 2014, Castillo-Durán et al 2015. The gradual temperature increase has been successful for Katelysia rhytiphora and Mulinia edulis (Nell et al 1994, Oliva et al 2013.…”

“…Physical stimuli are the most used, among them temperature variation (thermal shock) and biological stimulation using gonadal extracts (Reverol et al 2004, Helm et al 2006, Barría et al 2021. The thermal shock is the less stressful method and induces a successful gametes expulsion (Bustos & Olavarría 2000, Helm et al 2006, Ng et al 2009, Rengel et al 2009, Aranda-Burgos et al 2014, Castillo-Durán et al 2015.…”

“…Factors affecting bivalve growth in their developmental stages are water column depth, temperature, food, salinity, and culture density (Gosling 2004, 2015, Helm et al 2006, Liu et al 2006, 2010, Huo et al 2017). These issues have been addressed in studies of embryonic, larval, and postlarval development in clams (Reverol et al 1998, 2004, Liu et al 2006, 2010, Mouëza et al 2006, Yan et al 2006, Rengel et al 2009, Jagadis 2011, Aranda-Burgos et al 2014, Contreras-Guzmán et al 2014, Castillo-Durán et al 2015, Huo et al 2017.…”

Growth and survival analysis of early stages in the pen shell Atrina maura during pilot-commercial production

“…The growth of bivalve larvae, including that of A. maura, has been characterized by size (height and length of the shell) and age parametrization. Obtained growth rates are one of the main attributes of selecting a species for breeding purposes in commercial aquaculture (Castillo-Durán et al 2016, Reynaga-Franco et al 2019, Hoyos-Chairez et al 2020. The growth analysis in living organisms requires mathematical models that can be selected according to the Akaike information criterion (AIC) (Aragón-Noriega 2013).…”