Balanus balanoides (L.) in the Firth of Clyde: The Development and Annual Variation of the Larval Population, and the Causative Factors

Abstract

Normal sequence is liberation of nauplius I in Mar., development through several nauplial stages to cyprids and settlement in early Apr. In some seasons liberation and development of early stage nauplii is followed by a reduction in numbers of cyprids. Failures during such yrs. are associated with abnormalities in spring diatom outburst, which may be important controlling factor through its nutrient value to developing larvae. Winds also appear correlated with failure yrs; this could be sampling effect or could be primary cause of diatom variations. Failure in spatfall of Balanus may permit its competitor Chthamalus stellatus to expand its population.