Effets de la ration alimentaire, de la densité intraspécifique et des relations entre individus sur la croissance des juvéniles de l'espèce Nereis diversicolor (Annelida: Polychaeta)

Abstract

Requ le 2 1 janvier 1992 Accept6 le 17 septembre 1992 SCAPS, P., RETICRE, C., DESROSIERS, G., et MIRON, G. 1993. Effets de la ration alimentaire, de la densitk intraspkcifique et des relations entre individus sur la croissance des juvkniles de l'espkce Nereis diversicolor (Annelida : Polychaeta). Can. J. Zool. 71 : 424-430.L'klevage, en laboratoire, de juvkniles du Nereis diversicolor sur alimentation a base de Tetramin a permis de quantifier les effets des variations de la quantitk de nourriture, de la densitk intraspkcifique et des relations entre individus sur la croissance. Une ration alimentaire de 3,33 mg d-' de Tetramin par individu assure une croissance optimale de la masse moyenne. Un effet marquk de dkpendance face h la densitk se manifeste non seulement par un ralentissement de la vitesse de croissance mais aussi par une diminution de la biomasse et des taux de survie, pour des valeurs supkrieures h 3000 individus/m2. Le stress provoquk par une manipulation trop frkquente des individus et par le choc thermodiffkrentiel qui en rksulte engendre les memes effets nkgatifs. La variabilitk de la rkponse h l'effet de groupement ou d'isolement est grande puisque des lots de juvkniles prklevks en pkriodes hivernale et printannikre rkagissent diffkremment : alors que la croissance de la masse chez les premiers n'est pas affectke par les conditions d'klevage, celle des seconds est plus importante dans le cas ou les individus sont maintenus isolkment. SCAPS, P., RETICRE, C., DESROSIERS, G., and MIRON, G. 1993. Effets de la ration alimentaire, de la densitk intraspkcifique et des relations entre individus sur la croissance des juvkniles de l'espkce Nereis diversicolor (Annelida : Polychaeta). Can. J. Zool. 71: 424-430. We studied the effects of food intake, intraspecific density, and interactions between individuals on the growth of laboratory-raised juveniles of Nereis diversicolor fed different quantities of Tetramin. A daily intake of 3.33 mg of Tetramin per individual resulted in an optimal mean mass gain. At densities above 3000 individuals/m2, not only was the growth rate reduced, but biomass and survival rates were also diminished. Frequent handling and the thermodifferential shock that ensured created a stress that had the same negative effects. Variations in responses to aggregation or isolation were high, as revealed by groups of juveniles captured in winter or in spring reacting differently: growth was not affected by the breeding conditions in the winter-caught worms but was faster in spring-caught individuals kept in isolation.[Journal translation]

Density-dependent growth of the polychaete <i>Diopatra aciculata</i>

“…Studies undertaken by Esnault et al (1990) and Scaps et al (1993) ture were also found to induce negative effects on growth (Scaps et al, 1993). This study provides the first known account of the growth rates of juvenile D. aciculata and demonstrates the effect of density on growth rates, posterior segment condition and mortality when food is not limiting.…”

“…Competition for space has also been shown for Neanthes arenaceodentata, which exhibit aggressive behaviour at high density, as demonstrated by an increase in the frequency of polychaetes regenerating posterior segments (Bridges et al, 1996). Scaps et al (1993) recorded a reduction in growth and survival of lab-reared juveniles of Hediste diversicolor at high densities (3000/m 2 ), even in the presence of abundant food.…”

Effects of diet and density on growth, survival and gametogenesis of Hediste diversicolor (O.F. Müller, 1776) (Nereididae, Polychaeta)

“…m −2 (high). The highest value was chosen as the maximum limit reported in literature for this species, above which not only growth rates but also survival capacity decrease (Scaps et al, 1993). The two lower values, similar to those recorded in natural populations of the Venice Lagoon (Maggiore and Keppel, 2007) might be both appropriate for a commercial farm system.…”

Evaluation of different procedures for fertilization and larvae production inHediste diversicolor(O.F. Müller, 1776) (Nereididae, Polychaeta)

“…In addition, it may also take the typical alimentary filter‐feeder behaviour, being able to select the particles trapped in the mucus which are subsequently passively conveyed to U‐ or Y‐shaped burrows by the water circulation (Harley, ; Vedel, Andersen & Riisgård, ). Various studies had already suggested that H. diversicolor might be a suitable species for aquaculture purpose, proving to be easy to breed in indoor systems and to exhibit several favourable physiological traits, such as high tolerance to a wide range of environmental parameters (salinity, temperature, substrate grain size) and rapid growth rates, at least when fed with commercial fish foods (Fidalgo e Costa, ; Fidalgo e Costa, Narciso & Cancela da Fonseca, ; Nesto, Simonini, Prevedelli & Da Ros, ; Scaps, Retiére, Desrosiers & Miron, ). Moreover, H. diversicolor may be a potentially high‐quality fatty acids source for reared fish and shrimp as it has been demonstrated that fat assimilation by ragworms reflects fat content of their diet (Santos et al., ).…”