The Oogenic Cycle of Nereis Diversicolor Under Natural Conditions

Abstract

Until recently, the most detailed and widely quoted account of the life cycle and reproductive biology of Nereis diversicolor O. F. Müller was that of Dales (1950; 1951) for a population in the Thames Estuary followed for a single season. The study combined a periodic analysis of the population structure with assessment of reproductive maturity, by gamete analysis of individual worms, and a record of larval recruitment. The conclusions reached were that worms grew to maturity in one year, spawning in February, but that some survived up to a maximum life span of 18 months.

Induction of swarming ofNereis succinea

“…Kristensen (1984) described temperature control in the spawning of N. diversicolor, leading to geographical differences in spawning seasons. At Norsminde Fjord, Denmark, (Kristensen 1984) N. diversicolor spawn in February and April; in the Severn Estuary, Britain, in May (Mettam et al 1982);and at Cherbourg, France, (Herpin 1925) throughout the year. In the Danish Isefjord spawning of eight polychaete species is attributed to specific minimum temperatures (Rasmussen 1956).…”

Spatio-temporal population and reproductive responses inPerinereis gualpensis(Polychaeta: Nereididae) from estuaries under different anthropogenic influences

“…[33] The bioenergetics approach related to energetic cost of tolerance to contaminants could also be a reasonable explanation. [19,22] The reallocation of energy results in individual responses such as changes in time to reproduction, or reproductive success. [34] However, Hg, as other pollutants from oil industry (crude oil derivatives and phenol-based compounds), acts as endocrine disruptor chemicals (EDCs) in invertebrates.…”

“…[35] Thus, further studies should focus on a new sediment characterisation based on some EDCs compounds in order to assess the contribution of other oil industry chemicals in pollution problems from Lenga. Also, the development of Vitellogenin (Vg) and Energy Metabolism biomarkers is an endpoint that should be assessed in the future, [22,35] helping to determine which mechanisms are involved in reproductive differences observed in Lenga ragworms.…”

“…[38,39] Differences in spawning periods in some nereid species between geographically distant populations were reported and related to differences in temperature and photoperiod. [3,22] The proximity among these coastal type basin estuaries dismisses the influence of the above-mentioned factors. Nevertheless, the complexity of establishing pollutionrelated responses by the currently used responses, differential exposure and damaged pollution biomarkers observed in P. gualpensis from Lenga sediments [2] represent lines of evidence for related population deployment by high levels of concerning pollutants.…”

“…[20] The study of oocytes' sexual maturity stages throughout the year is a valuable tool for monitoring studies since sex ratio in some estuarine nereid polychaetes greatly favoured females and indicates the time and prevalence of spawning periods during the year. [21,22] Biometric measurements, such as L3, which summarise the length of prostomium, peristomium and first segment, are recommended in animals, which can easily lose part of their body. [23,24] L3 size frequency histograms are a valuable tool to determine the number of cohorts and recruitment patterns in polychaetes.…”