The brown mussel Perna perna on the Natal coast, South Africa: utilization of available food and energy budget

Abstract

The filtration rate of Perna perna (L.) at the approximate annual mean local water temperature (20 "C) is high, being 2.7 X I O -~ (shell length in mm)'-86 1 h-' or 8.85 (dry flesh weight in 1 h-'. It was found to be able to filter latex particles down to at least 0.46 pm in diameter, these being roughly the mean size of free coccoid bacteria in the study area. Its mean assimilation efficiency, determined by the Conover method, was 61 % on a natural diet of particles < 100 p m in diameter which had a mean organic content of 3.16 mg 1-'. The faeces production rate was also established and an energy budget for P. perna is discussed in the light of available data.

Faecal bacteria in Perna perna (Linnaeus, 1758) (Mollusca: Bivalvia) for biomonitoring coastal waters and seafood quality

“…The parameters of the equation that explains the allometric relation between the clearance rates (CR) and the size of the mussels (L) were rather different from those obtained by Berry and Schleyer (1983). While in this present study the values for a and b were 28 and 1.6, respectively, the authors quoted had obtained values of a = 0.0027 and b = 1.86.…”

Utilization of muddy detritus as organic matter source by the fan mussel Pinna nobilis.

“…Fan mussels were not fed on the day before the experiments to ensure that their guts were mostly empty. We checked that no food rejection occurred at the beginning of the experiments from previous meals, thus confirming our previous observations that the specimens eliminate most of the digested food in less than 24 h. Therefore, despite the fact that typical duration of similar closed-circuit experiments for other bivalves usually last 5 hours ��riffiths, 1980; Berry & Schleyer, 1983;Vincendeau & Robert, 1987), the duration of our experiments was set to 8 hours. Only after this time could we are confident that most excretion had occurred.…”

Measuring reproductive condition in the Greenshell™ musselPerna canaliculus

“…Late winter-spring gametogenesis and summer spawning is typical of other species of mussels including M. edulis (Wilson & Seed 1974;Sprung 1983;Rodhouse et al 1984;King et al 1989), M. galloprovincialis (Villalba 1995), and P. perna (Berry 1978). In New Zealand, Kennedy (1977) reported winter gametogenesis and spring-summer spawning in M. edulis aoteanus and Aulacomya maoriana.…”

“…Spawning may be followed by a resting and storage period before winter gametogenesis begins again. This pattern of reproduction has been reported for the mussels Mytilus edulis (Wilson & Seed 1974;Sprung 1983;Rodhouse et al 1984;King et al 1989), M. galloprovincialis (Villalba 1995), and P. perna (Berry 1978). This study aimed, in part, to verify the general patterns of the annual reproductive cycle through assessment of gonad morphology.…”