Population dynamics and metabolism of Aequipecten opercularis (L.) from the western English Channel (Roscoff, France)

Abstract

Population dynamics of the queen scallop, Aequipecten opercularis, was investigated in the western English Channel off Roscoff. Annual formation of natural growth rings on the shell surface was validated by stable isotope (y 18 O and y 13 C) analysis. A von Bertalanffy growth function (H t = 58.9 mm . (1Àe À 0.604.(t + 0.235) )) was fitted to size-at-age data of 249 individuals. Annual somatic and gonad production amounted to 19.74 kJ m À 2 and 0.98 kJ m À 2 y À 1 , respectively. Total mortality rate Z was estimated to be 1.716 y À 1 . Net growth efficiencies (ranging from 45% in 1-y-old to 11% in 6-y-old individuals) were in the same range as in other short-lived scallops. Individual growth, however, was distinctly slower in this population than in other A. opercularis populations from similar latitudes, most likely due to a more stressful environment. D

Cell turnover in tissues of the long-lived ocean quahog Arctica islandica and the short-lived scallop Aequipecten opercularis

“…In the case of the Icelandic ocean quahog, we could distinguish between age groups, whereas our entire sample of A. opercularis comprised 2-4 years old mature individuals still in the phase of highest growth. Von Bertalanffy growth models for A. opercularis from the English Channel demonstrate highest shell growth rates in conjunction with highest somatic production between 0 and 2 years of age, whereas from the 5th year on growth rates become asymptotic (Heilmayer et al 2004). Rapid growth in young and mature A. opercularis of up to 4 years is in agreement with higher proliferation and cell turnover rates in tissues of the scallops compared to the ocean quahog.…”

“…Cross-sections were ground and polished and annual shell growth bands were counted using a stereomicroscope at 10-to 80-fold magnification. In A. opercularis, individual age was inferred from shell height and a von Bertalanffy growth model (VBGM) established by Heilmayer et al (2004) and based on height-at-age-data of the same scallop population from the English Channel. The von Bertalanffy growth function (VBGF):…”

Plasticity in shell morphology and growth among deep-sea protobranch bivalves of the genus Yoldiella (Yoldiidae) from contrasting Southern Ocean regions

“…Increased shell weights in the Amundsen Sea may also offer extra protection against invasive predators associated with regional warming or ice scouring (Aronson et al, 2007(Aronson et al, , 2011Harper et al, 2012). No ecaudata in the Amundsen Sea over the Scotia and Weddell Seas are also evidence of environmental conditions being more favourable for growth (Heilmayer et al, 2004;Brey et al, 2011). The morphological variations found in this study demonstrate distinct ecotypes within species and although the degree of connectivity between these deep populations is still unknown, showcase the protobranch bivalves as a group for future molecular and ecological studies in the Antarctic, with special regard to likely cryptic speciation processes.…”

“…Size-at-age data were analysed using the von Bertalanffy growth function (vBGF); -e -k(t-t0) where S t is length, S is asymptotic length, K is growth coefficient, t is age and t 0 is age when size equals zero. This method, commonly used for fish growth analysis, has more recently been used for bivalve growth (Brey and Hain, 1992;Brey, 2001;Heilmayer et al, 2004;Brey et al, 2011;Higgs et al, 2009). As individual growth is non-linear, it is difficult to compare the overall growth between individuals.…”

Population dynamics of the tropical bivalve Cardita affinis from Málaga Bay, Colombian Pacific related to La Niña 1999–2000

“…Accordingly, growth performance was higher during LN. Increased growth performances of suspension feeding bivalves could be mainly related to food availability (Peterson 1982;Sastre 1984;Nakaoka 1992;Laudien et al 2003;Heilmayer et al 2004). As ENSO-induced increases in freshwater flow seem to boost estuarine phytoplankton biomass and production in tropical estuarine ecosystems (e.g.…”