Seasonal variation in the occurrence of planktic bivalve larvae in the Schleswig-Holstein Wadden Sea

Abstract

In the late 1980s, recruitment failures of the mussel Mytilus edulis led to economic problems in the mussel fishing and cultivation industries of northwestern Europe. As part of a collaborative study to gain a better understanding of the mechanisms affecting recruitment processes of mussels, plankton samples were collected regularly over a four-year period (t990-I993) from three stations in the Schleswig-Holstein Wadden Sea. The bivalve component of the plankton was dominated by the Solenidae, which was almost exclusively represented by Ensis americanus [= directus). NI. eduhs was the second most abundant species. Abundances of mussel larvae peaked 2 to 4 weeks after spawning maxima in the adult populations. Although variations in timing and amplitude of the tota~ [arvaL densities occurred, annua[ abuadances o[M. edulis larvae remained stable during the study period, and regional abundance differences were insignificant. A close relaUonsh~p was found between peaks in larval abundance and phytoplankton blooms. Differences in larval concentrations in the ebb and the flow currents were insignificant. Planktic mussel larvae measured between 200 }am and 300 ~tm, and successive cohorts were recognizable in the majority of samples. Most larvae were found to originate from local stocks, although imports from outside the area do occur.

Colonization of an artificial hard substrate byMytilus edulisin the German Bight

“…In the southern North Sea populations of M. edulis exhibit a major spawning peak in spring (Pulfrich 1997). During their planktonic stage mussel larvae can be distributed over large distances by currents (Pulfrich 1997;de Vooys 1999).…”

“…During their planktonic stage mussel larvae can be distributed over large distances by currents (Pulfrich 1997;de Vooys 1999). In the absence of suitable substrates, pediveliger potentially delay metamorphosis for several weeks (up to 40 days at 108C) (Bayne 1965(Bayne , 1976 allowing for the colonization of distant substrates.…”

Feeding selectivity of bivalve larvae on natural plankton assemblages in the Western English Channel

“…In September 2010 (experiments 6 and 7), the peak of bivalve abundance showed the greatest diversity with 5 OTUs being represented in experiment 6 alone; these were annotated to be P. pellucidus, the families Mytilidae, Hiatellidae and Pectinidae, and the order Veneroida. Considering that bivalve larvae are often spawned in response to elevated SST (Highfield et al 2010) or to take advantage of increased prey during a phytoplankton bloom (Pulfrich 1997;Highfield et al 2010), it was unusual to see a peak of bivalve larvae in winter 2010 (experiments 3, 4 and 5). Indeed, peaks in bivalve larvae abundance in winter are only seen on occasional years (our unpublished L4 data).…”

“…Bivalve larvae may be released into the plankton to take advantage of a phytoplankton bloom (Pulfrich 1997;Highfield et al 2010); however, availability and quality of food may be patchy, both spatially and temporally (Haury et al 1978), thereby possibly creating a mismatch in the distribution of the bivalve larvae and their preferred diet. Despite studies suggesting that bivalve larvae have a high tolerance to food deprivation (Moran and Manahan 2004;Ben Kheder et al 2010;Matias et al 2011), food quality and quantity have a notable influence on the duration of larval phases (Ben Kheder et al 2010) with insufficient food resulting in delayed development.…”

Meeting the quest for spatial efficiency: progress and prospects of extensive aquaculture within offshore wind farms

“…Moreover, the prospect of cultivating mussels for direct consumption has to be considered in the future. The idea of having two production cycles in a single year is not possible due to the main spat fall event of blue mussels being between April and May (Pulfrich 1997).…”