Life Cycle and Production of Hydrobia ventrosa and H. neglecta (Mollusca: Prosobranchia)

Abstract

Life cycle, growth, and production of the mud snails Hydrobia ventrosa (Montagu) and H. neglecta Muus were studied in the Kysing Fjord estuary, Denmark. Recruitment of Age class 0 in summer revealed 2 maxima: July-August and September. The first recruited group reached a length of 2.3 mm in H. neglecta and 2.5 mm in H. ventrosa in November. After September, no growth was found in the last recruited group of both species; their mean length remained 1.3 mm. Both species have a life span of approximately 18 months. The annual production of H. ventrosa and H, neglecta was 8.40 and 5.86 g ash-free dry weight m-2, respectively.