Annual reproductive cycles of the commercial sea urchinParacentrotus lividus from an exposed intertidal and a sheltered subtidal habitat on the west coast of Ireland

Abstract

Reproduction of the commercial sea urchin Paracentrotus lividus (Lamarck) from contrasting habitats on the west coast of Ireland was examined from May 1986 through August 1988. Urchins were collected intertidally from an exposed rocky shore and subtidally from a protected bay. Monthly measurements of the gonad index and histological examination of the gonads demonstrated that P. lividus has an annual reproductive cycle. Although the two populations exhibited similar reproductive patterns over three breeding seasons, there were inter-annual and inter-population differences in the amplitude of gonadal growth and in the time when spawning started. The subtidal urchins had significantly larger gonads and exhibited a longer period of reproductive maturity compared with the intertidal urchins. This difference was also evident in the histology of the ovaries at the beginning of breeding, when most of the subtidal females contained mature ovaries, whereas most of the intertidal females contained premature ovaries. An inter-annual difference in the onset of spawning was observed, with the start of gamete release differing by as much as four weeks between years. It appears that inter-annual differences in sea temperature influence the temporal variation in spawning by P. lividus and that increasing temperature may serve as an exogenous cue for gamete release. The inter-annual variability in the onset of spawning suggests that photoperiod does not cue gamete release. Gonadal growth, on the other hand, occurs during the coldest months of the year and during the period of shortest days, suggesting that temperature and photoperiod may both influence gonadal growth during the winter. Oogenesis and spermatogenesis of P. lividus were examined histologically. During the post-spawning recovery and growth stages, the gonads gained weight through growth of the nutritive phagocytes and the accumulation of periodic acid Schiff (PAS)+ droplets by these cells. The * Present address: School of Biological Sciences, Zoology AO8, University of Sydney, Sydney, New South Wales 2006, Australia PAS + material appears to play a nutritive role in gametogenesis. For the females, the frequencies of six ovarian maturity stages was assessed at approximately monthly intervals. Small oocytes were present throughout the year and clusters of early oocytes were most apparent during the spent and recovery stages. With the onset of vitellogenesis and subsequent accumulation of ova, the nutritive phagocytes and their PAS + droplets became depleted. The ovarian condition at the onset of breeding was variable, due to differences in the number of vitellogenic oocytes, differences in the number of ova in storage, and differences in the amount of PAS + material. In general, the nutritive phagocyte tissue is reduced by the onset of spawning and is exhausted by the termination of breeding. A similar series of events occurs during spermatogenesis. The relevance of this study for the use of P. lividus as a brood-stock organism for mariculture is discussed.

Sex-specific biochemical and histological differences in gonads of sea urchins (Psammechinus miliaris) and their response to phenanthrene exposure

“…Reproductive stage of each animal was determined according to the classification for sea urchins by Byrne (1990) and Kelly (2000). Lipofuscin was quantified as areal density [%] in cross-sections of gonadal tissue with the aid of computerassisted image analysis at 100Â magnification (Schäfer and Köhler, 2009).…”

“…Premature sea urchins are characterized by the presence of gametes in all stages of development. Mature gametes, eggs and spermatozoa, accumulate in the lumen of the gonadal acini, whereas the nutritive phagocytes are displaced to the acinal periphery (e.g., Byrne, 1990;Kelly, 2000). One female was partially spawned evident from large areas of vacant space between relict oocytes.…”

Population Dynamics of Edible Sea Urchins Associated with Variability of Seaweed Beds in Northern Japan

“…(Byrne 1990;Laegdsgaard et al 1991;King et al 1994;Byrne et al 1998;Meidel and Scheibling 1998b;Brewin et al 2000). A prolonged recovering I stage was first observed.…”

Molluscs and echinoderms aquaculture: biological aspects, current status, technical progress and future perspectives for the most promising species in Italy

“…In general, Paracentrotus lividus biology has been well studied, and much research has been carried out to determine all the phases of the reproductive cycle from many European countries (Byrne, 1990;Lozano et al, 1995;Spirlet et al, 1998b;Sanchez-Espana et al, 2004;Pais et al, 2006a). This Echinoid has external fertilisation and gametes are released in the water.…”

“…This sea urchin lives on rocky substrates and in seagrass meadows, from shallow waters down to about 20 m depth. It is a species of commercial importance, with a high market demand for its roe, particularly in the Mediterranean basin (Régis et al, 1986) and more recently in other European non-Mediterranean areas (Byrne, 1990;Barnes and Crook, 2001). In the last decades, its populations have shown a wide scale decline in many European countries due to overfishing (Boudouresque and Verlaque, 2001).…”