Methodical aspects of rearing decapod larvae,Pagurus bernhardus (Paguridae) andCarcinus maenas (Portunidae)

Improved methods for experimental rearing ofPagurus bernhardus andCarcinus maenas larvae are presented. Isolated maintenance was found essential for reliable statistical evaluation of results obtained from stages older than zoea-1. Only by isolated rearing is it possible to calculate mean values ±95% confidence intervals of stage duration. Mean values (without confidence intervals) can only be given for group-reared larvae if mortality is zero. Compared to group rearing, isolated rearing led to better survival, shorter periods of development and stimulated growth. Due to different swimming behaviorP. bernhardus zoeae needed larger water volumes thanCarcinus maenas larvae.P. bernhardus zoeae were reared with best results when isolated in Petri dishes (ca. 50 ml). They fed on newly hatched brine shrimp nauplii (Artemia spp.).P. bernhardus megalopa did not require any gastropod shell or substratum; it developed best in glass vials without any food.C. maenas larvae could be reared most sucessfully in glass vials (ca 20 ml) under a simulated day-night regime (LD 16:8); constant darkness had a detrimental effect on development, leading to prolonged stage-duration times.C. maenas larvae were fed a mixture of newly hatched brine shrimp naupli and rotifers (Brachionus plicatilis).