Suspended culture evaluation of Pacific oysterCrassostrea gigasin a tropical estuary

Abstract

The growth and survival of Crassostrea gigas were evaluated in hanging culture in the Chone River estuary (Bahía de Caráquez), Manabí province, Ecuador. Oyster seeds (~10 mm) were confined in lantern nets at a density equal to the occupation of half the surface of the basket base, until reaching commercial size (80 mm). A sample for oyster biometric, parasitic and bacterial analysis was obtained monthly. Temperature, salinity, oxygen concentration, seston and phytoplankton biomass were determined. At the end of the study, the oysters were analysed for heavy metal concentration. The commercial oyster production was extrapolated to estimate the possible economic performance of a family production module (a 7 × 7 m bamboo raft). The results show a great biological feasibility of culture of C. gigas with harvests of commercial size oysters in only 5 months and acceptable survivals (accumulated >70%, after 3 weeks of crop seed selection). The heavy metal concentrations and the parasitological and bacteriological analyses did not indicate levels of contamination. The economic projections suggest that, even with a profitability of 57%, the initially invested capital could be recovered within the first harvest.

Socioecological factors related to aquaculture introductions and production of Pacific oysters (Crassostrea gigas) worldwide

“…Reduced establishment at lower latitude suggests that reproductive and/or larval settlement barriers, associated with high temperature and other variables, are likely to exist for the Pacific oyster in the tropics, or high temperatures may generate a poor energy balance for adults under oligotrophic conditions 102,103 . Low establishment risk is an advantage to obtain permits to introduce and cultivate Pacific oysters in tropical regions considering that the culture of the species shows high feasibility and profitability in these areas 16,104 …”

“…102,103 Low establishment risk is an advantage to obtain permits to introduce and cultivate Pacific oysters in tropical regions considering that the culture of the species shows high feasibility and profitability in these areas. 16,104 While establishment could be less risky for C. gigas in the tropics, another oyster species (or strain) with warmer temperature tolerances might have less risk of mortality in culture. In all cases, the activities must be carried out with high precaution.…”

Producing young, single and meaty oyster Crassostrea iredalei (Faustino, 1932) in grow‐out culture using pouches suspended from rafts

“…Survival remained high at harvest, both for oysters reared in pouches and trays, at more than 90%. These were higher than the 70% considered as adequate survival for cultivation (Treviño et al, 2020). Although insignificant, oyster survival in pouches was higher than in trays.…”

Growth of Crassostrea gigas (Thunberg, 1793) cultivated in different cultivation devices deployed in sheltered and non‐sheltered sites of central Chile

“…The potential for commercial development of C. gigas aquaculture requires studies of growth and knowing which environmental and technological factors influence its growth, to select cultivation devices and cultivation sites with the best production index. It is known that the growth and development of C. gigas depends on environmental factors such as water quality (Gangnery et al, 2004; Chávez‐Villalba et al, 2010; Cardoso et al, 2013; Dauphin et al, 2013; Treviño et al, 2020), water temperature (Chávez‐Villalba et al, 2007; Flores‐Vergara et al, 2004; Sicard et al, 2006; Li et al, 2009; Malham et al, 2009; Kheder et al, 2010; Bernard et al, 2011) and also other operational factors such as cultivation density (Honkoop & Bayne, 2002; Marshall & Dunham, 2013), cultivation equipment (Brundu et al, 2020), cultivation depth (Ngo et al, 2006; Zrnčić et al, 2007), site features (Buck et al, 2017; Pogoda et al, 2011, 2013), characteristics of the phytoplankton (Barillé et al, 2003; Barrilé et al, 2011; Bayne, 2009; Evans & Langdon, 2006; Powell et al, 2002; Rico‐Villa et al, 2006) and the seasonal factors of the cultivation zone (Dégremont et al, 2010; Luna‐González et al, 2008; Mao et al, 2006; Mizuta et al, 2012; Royer et al, 2007; Soletchnik et al, 2005, 2006). However, few studies have evaluated the growth of C. gigas farmed in different cultivation devices and cultivation zones.…”