Reproduction and growth in captivity of the polychaete Nereis diversicolor O

The polychaetes used as bait for sport and commercial fishing are a natural resource exploit-ed in a large number of estuaries. One of the most common species captured is the ragworm Nereis diversicolor O. F. Müller (1776). This species is also used in aquaculture, mainly because of its easy availability to local dealers, and plays an important role as a nutrient stimulating gonad maturation and spawning in hatcheries. The high economic value of these worms, and the size of their catch in the main Portuguese estuaries, have led to their intense exploitation as commercial bait. Accordingly, a small-scale reproduction study of this species was carried out under controlled conditions (temperature, salinity and luminosity) in two different sediments (sand and mud), following its development from the larval to the adult stages. Such elucidation of certain aspects of its life cycle is instrumental for the species’s future culture in artificial systems. The present study represents the starting point of large-scale production that will reduce the anthropogenic disturbance to biological estuary communities. The main objective of this study was to obtain preliminary results that would enable us to understand the period of growth necessary to reach a commercially valuable size. Such growth was rapid in both types of sediment, taking only a few months