Feeding Behaviour of the Mussel,Mytilus edulis: New Observations, with a Minireview of Current Knowledge

Abstract

Under optimal conditions, bivalves tend to filter the ambient water at a maximum rate but under suboptimal environmental conditions, including low or very high algal concentrations, the filtration rate is reduced. The upper algal concentration at which the blue mussel, Mytilus edulis, exploits its filtration capacity over an extended period of time was identified by stepwise raising the algal (Rhodomonas salina) concentration in steady-state experiments above the threshold for continuous high filtration rate. The duration time before incipient saturation reduction decreased with increasing algal concentration, and the threshold concentration for incipient saturation reduction of filtration activity was found to be between about 5,000 and 8,000 cells mL −1 , equivalent to 6.3 and 10.0 µg chl a L −1 , respectively. Reduced filtration rate was related to total number of algal cells ingested previous to incipient saturation and found to be 11.4 ± 1.7 × 10 6 cells. Video-microscope recordings of pseudofaeces production revealed that the trigger threshold concentration for formation of pseudofaeces was about 12,000 cells mL −1 . Faeces produced by saturated mussels consisted of closely packed undigested algal cells, indicating severe overloading of the digestive system caused by high algal concentrations which mussels are not evolutionary adapted to cope with.

Effect of Salinity on Growth of Mussels, <i>Mytilus edulis</i>, with Special Reference to Great Belt (Denmark)

“…The growth experiments were carried out as 3 series, each performed at a well-defined algal concentration, adjusted by means of the dosing pump within the concentration interval where the mussels exploit their filtration capacity (i.e. above lower trigger concentration leading to closure of the valves, and below the satiation concentration where the mussels shut down [23][24][25][26] thus ensuring a steady-state between the addition and removal (feeding by mussels, wash out with through flow) of algal cells [27]. The algal concentration was measured by means of an electronic particle counter (Elzone 5380) several times a day during the experimental period to ensure that the concentration of Rhodomonas salina in the stock solution flask could be adjusted to be near constant.…”

Modelling the effects of recreational boating on self-purification activity provided by bivalve mollusks in a lowland river

“…However, we did not observe such a pattern, possibly because an upstream lake provided a consistent supply of seston or because DO concentrations were low during the study period (Vero and Salanki 1969, Morton 1970, Lorenz and Pusch 2012. Shell-closing responses also can be caused by changes in particle size and concentration (Riisgard et al 2011) and rapid large changes in water temperature (Salanki et al 1974). Particle concentration was relatively constant during our study period, and water temperature changed only slightly between measurement days.…”

Individual Variability of Rate of Physiological Processes in Bivalve Mussels

“…[6,7] были получены похожие степенные зависимости коэффициентов вари-ации от среднего значения функциональной характеристики (рис.2). В то же время данные по скорости фильтрации, приведенные в [8], не указывают на наличие степенной зависимости коэффициента вариации от средней скорости в выборке. Здесь необходимо обратить внимание на то, что средние скорости в экспериментах, обсуждаемых в [8], были относительно близки друг другу, т.е.…”

“…В то же время данные по скорости фильтрации, приведенные в [8], не указывают на наличие степенной зависимости коэффициента вариации от средней скорости в выборке. Здесь необходимо обратить внимание на то, что средние скорости в экспериментах, обсуждаемых в [8], были относительно близки друг другу, т.е. эксперименты проводились при схожих внешних условиях, тогда как наблюдения, приведенные в [6], выполнялись в существенно различающихся условиях по солености воды.…”

“…эксперименты проводились при схожих внешних условиях, тогда как наблюдения, приведенные в [6], выполнялись в существенно различающихся условиях по солености воды. Соответственно, диапазон средних скоростей фильтрации в данных [8] ). По нашему мнению, этим и объясняется кажущееся противоречие.…”