Functional descriptions of feeding and energetics of the Pacific oyster Crassostrea gigas in New Zealand

Abstract

Pacific oysters Crassostrea gigas were fed a mixed diet of algae and silt over a range of concentrations from 0.8 to 637 mg l -1 , and an organic content ranging from 0.7 to 72%. These data were used to parameterise a set of functions describing the physiological response of oysters to varying environmental conditions. All parameters were standardised to body length. There was greater variation of size-specific clearance rate (CR) standardised to dry tissue weight than to length. CR increased hyperbolically with temperature with a maximum rate (0.24 l h -1 cm -1 ) at 20.7°C. Most feeding experiments were carried out at 10 to 13°C, except for the measurements of temperature effect. CR increased rapidly with increasing seston concentration, peaked at about 10 mg l -1 , above which it consistently decreased. It was modelled as a function of pumping rate of water and extraction efficiency of particles from water. The filtration rate was found to be a Type 2 hyperbolic function of seston concentration within the range tested. Ingestion rate was described as a function of food quantity, quality and selective ingestion of organic particles. A positive effect of organic content on absorption efficiency was found only at a very low organic content of less than 5%, while above this level, absorption efficiency was constant at 86%. Oxygen consumption rate had an allometric relationship to body size and increased over the range of experimental temperatures.

Influence of Monsoon on Macrobenthic Assemblage in Outer Channel Area of Chilika Lagoon, East Coast of India

“…Stations located in the mouth region are dominated by the filter feeders such as bivalve Crassostrea cuttackensis, Meretrix, Modiolus, Perna viridis were also reported elsewhere (Pati et al, 2008). These are the filter feeders which have a role to accumulate the different pollutants, metals and other elements in their tissues due to this filter feeding mechanism (Ren et al, 2000). Sediment Grain size had also great influence on macrobenthic abundance distribution.…”

Ocorrência de larvas Pedivéliger de ostras do genero Crassostrea Sacco, 1897 no setor euhalino do Complexo Estuarino de Paranaguá – PR.

“…Porém, fatores como salinidade e turbidez podem inibir o crescimento, causar mortalidade das larvas, retardar o crescimento ou interferir na dispersão das mesmas na natureza (LIANG et al, 2000;REN et al, 2003).…”

Reproductive periods of Lucina pectinata (BIVALVE; LUCINIDAE) in the Paranaguá Estuarine Complex, Paraná - Brazil

“…The average shell height and length of L. pectinata collected monthly from the Peças River Individuals' gross weight was within an interval found in other studies in the Northeast region of Brazil (Nogueira and Freitas, 2002;Poggio, 2002;Delfino, 2005;Santana, 2010;Rondinelli and Barros, 2010). Since the animals' body weight is closely related with the gonad developmental stage, fluctuation of this variable can be interpreted through the association of weight with the individual's physiological condition (Kang et al, 2000;Ren et al, 2003).…”

“…Food availability can also contribute to regulate reproductive processes (Bayne, 2004). In environments where temperatures rise in the beginning of spring and during summer, there is a trend towards the continuous reproduction of organisms, however with periods of more expressive gamete elimination during higher temperature months (Kreeger et al, 2003;Ren et al, 2003).The objectives of the present study is to describe the size of exploitation and gonadal maturation during two periods of the year of L. pectinata in Peças Island in Paraná coast, Brazil.…”