Long-term and large-scale variability in productivity of the tellinid bivalve Macoma balthica on Wadden Sea tidal flats

Abstract

A series of 27 successive annual estimates of production of soft parts of the bivalve Macoma balthica (L.) populating the tidal flats of Balgzand (western Wadden Sea, The Netherlands) was obtained using multi-station (15 sites) and long-term (27 yr: 1978 to 2004, inclusive) monitoring data on numerical densities and ash-free dry mass (AFDM). Annual production values were estimated from seasonal growth increments, which were positive in spring and early summer and (in adults) negative in the remainder of the year, when up to 70% of individual weight gain of the preceding growing season was lost. Annual estimates based on twice-annual sampling were checked and refined on the basis of a detailed 2 yr study. Weight loss proportions increased with age of animals and with water temperature in winter. Net annual somatic production of the entire population varied from 1 to 9 (27 yr mean: 2.9 ± 0.3) g AFDM m -2 yr -1. Lifetime production per individual averaged 0.007 g AFDM for recruits of ~3 mo old and 0.032 g AFDM for ~10 mo olds. Numerical densities of ~10 mo old recruits predicted, within narrow limits, subsequent cohort production by way of a positive linear relationship. However, production of 3 mo old recruits was on average higher at low than at high densities, owing to better juvenile survival at low densities. Local (between-station) variation in mean annual production was primarily related to local variation in recruitment. However, production per recruit was significantly higher at low than at high intertidal levels, in accordance with higher growth and lower mortality rates at lower levels. Strong temporal and local variation was also found in annual production/biomass (P/ -B) ratio values, which reflected the variable age composition of the population: P/ -B ratio values were augmented whenever mean age was low. Consistently higher mean P/ -B ratio values (~0.6 vs. ~0.4 yr -1) were found at high near-coast compared with low off-shore tidal flats, in accordance with higher mortality rates on high flats. Environmental factors affecting variation in annual production included between-year variability in recruitment (which was related to winter temperature and shrimp predation pressure) and growth (which was related to diatom abundance).

Some like it cold: populations of the tellinid bivalve Macoma balthica (L.) suffer in various ways from a warming climate

“…These stations cover the entire tidal range (mean range from 60 to -80 cm relative to mean-tide level) and almost all sediment types. Sampling procedures are explained in Dekker & Beukema (2007). In short, the samples were sieved in the field over 1 mm sieves and sorted alive in the laboratory.…”

“…Its relatively high sensitivity to elevated ambient temperatures is the main reason why it was chosen for the present study: it may be one of the first to suffer and disappear from a substantial part of its present range as a consequence of a warming climate. Over nearly all of the Dutch Wadden Sea, M. balthica abundance has seriously declined for the past 1 or 2 decades (Dekker & Beukema 2007, Dekker & Waasdorp 2008, J. M. Jansen pers. obs., see Fig.…”

Modeling marine protected areas for threatened eiders in a climatically changing Bering Sea

“…Climate change may in fact be manifested as changes in the frequency and duration of cyclic events, such as less frequent or less sustained recruitment. Consequently, for delineating critical habitat that will be adequate into the future, a more useful focus than assuming directional trend may be to identify processes related to periodic recruitment and decline of major prey, and long-term patterns of conditions that drive those processes (e.g., Mo¨ller 1986, Dekker andBeukema 2007). Such factors may include changes in organic FIG.…”

Spillover but no spillback of two invasive parasitic copepods from invasive Pacific oysters (Crassostrea gigas) to native bivalve hosts

“…comm. ), two additional sample batches of this host species were taken in summer 2012, one from a tidal flat near an oyster bed in the south of Texel (Mokbaai; Online Resource 3) and one from extensive tidal flats southeast of Texel (Balgzand), the latter being aggregated samples from five transects of 1 km length each (Dekker and Beukema 2007;Online Resource 4). Host samples were stored in plastic bags for up to 1 week at 4°C (known to prevent cross-infections of Mytilicola; Dethlefsen 1972).…”