Experimental rearing of Polychaetes - Nereis diversicolor

European Network for the Dissemination of Aquaculture RTD Information (Q5CA-2000-30105) and previously FAIR-3837, Aquaflow ref. : TL2003-177

The aquaculture of polychaetes in Europe began in the United Kingdom and in the Netherlands, and it has been developed in the last few years. Its implementation in different countries aims to prevent the intense dilapidation of the natural stocks. Commercial importance of polychaetes (Annelida) is increasing due to their use as bait for sport and professional fishing, and also as a nutritional resource used for fish (Soleidae) and crustacean (Penaeidae) aquaculture. Several families of polychaetes are gaining very rapidly in popularity within another niche, the marine aquarium trade. Those worms are used as ornamental, favoured by the hobbyist, or as scavenger given an appropriate substratum, and with a bit of care, controlling the physical and chemical conditions.

There are several species used currently as fresh bait, caught manually in many coastal environments throughout Europe. Bait digging is done without any environmental consideration, causing severe disturbance in these areas. One of these species frequently found in estuaries and lagoons is the polychaete Nereis diversicolor. This species is known because it tolerates a large range of salinities, temperature, and dissolved oxygen and it is found living and breeding in different sediment types.

N. diversicolor has some traits that ease its growth, such as a totally benthic life cycle (live on the sea bottom), an easy artificial fertilisation and lecithotrophic larvae (larvae with food reserves). This last trait results on the delaying of the beginning of feeding, which allows the larvae to be fed early on with the same food given to adults. Under laboratory conditions, which is an important step for beginning of its culture, this species demonstrate ability to utilise a variety of food items as, extruded soy, Artemia cysts and pollen.

Reproduction and growth of N. diversicolor in captivity was attempted successfully at Guia Marine Laboratory. Densities of larvae between 36000 and 49000 individuals per m² were obtained by reproducing in captivity wild mature adults bought in the market. Reproduction was carried out in aquariums with constant aeration, with a 5cm sediment layer, salinity between 15 and 20‰ and photoperiod adjusted to a long photoperiod (LD 16:8). Since sex determination, even in adults, is very difficult, 30 mature adults were introduced in each aquarium. Development from larvae to adult has been performed and commercial size, according to observation at local market, could be obtained on laboratory scale in six months. TetraMenü, a commonly used diet for ornamental fish and polychaetes in laboratory, was used in the experiments and high survival rates (more then 90%) were obtained when juveniles were reared at densities of 100, 250, 500, 750 and 1000 individuals per m².

For more information, contact:

Ana Passos
Faculdade de Ciências da Universidade de Lisboa. Departamento de Biologia Animal.
Laboratório Marítimo da Guia
Estrada do Guincho
2750-642 Cascais - Portugal
Tel.: 351-214869211
Fax: 351-214869720

E-mail: ampassos@fc.ul.pt

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