Reproductive Isolation? Interannual Variability in the Timing of Reproduction in Sympatric Sea Urchins, Genus Pseudechinus

Relative importance of parental diet versus larval nutrition on development and phenotypic plasticity of Pseudechinus huttoni larvae (Echinodermata: Echinoidea)

“…When the oocyte diameters were approaching 100 mm (the size of a mature ovum; McClary & Barker 1998), and neither the germinal vesicle nor the nucleolus were visible, a number of individuals (20Á 25) were selected randomly from each diet treatment and induced to spawn by intracoelomic injection of 1.5Á2 ml 0.5 M KCl per animal. After KCl injection, if sperm was released, the male specimen was discarded.…”

“…The species typically lives on coarse-grained sediments (McClary & Sewell 2003), but can also be found attached to rocky substrates in fjords. There is a distinct annual reproductive cycle with mature ova being around 70Á100 mm (McClary & Barker 1998). The larvae are pluteus-type planktotrophs (McEdward & Miner 2001).…”

“…The genus Pseudechinus has 11 species all restricted to the southern hemisphere (Kirby et al 2006), of which six are endemic to New Zealand waters (McClary & Barker 1998). Pseudechinus huttoni Benham, 1908 inhabits New Zealand's continental shelf in waters deeper than 30 m, and fjordic habitats in depths as shallow as 9 m (Kirby et al 2006).…”

Effects of nutrition on somatic growth and reproductive strategy of the sea urchin Pseudechinus huttoni

“…Scheibling & Lawrence (1982) pointed out that the method of study may critically affect the results. Furthermore, the gonad index is not a true indicator of reproductive maturation (McClary & Barker 1998) and thus does not show if gamete production is influenced by the nutritional status of animals, since fluctuations in the amount of gonadal tissues may not be proportional to fluctuations in the amount of gametogenic tissues. For example, found that food type had a significant effect on the gonad index but no effect on the ovum size, the relative abundance of spermatocytes or nutritive phagocytes in testes.…”

“…The sea urchin genus Pseudechinus (Family: Temnopleuridae) consists of 11 species, of which 6 are endemic to New Zealand waters (McClary & Barker 1998). Pseudechinus huttoni Benham, 1908 is mainly an inhabitant of the continental shelf at depths from 30 to 550 m, but can also be found in New Zealand's southern fjords in depths as shallow as 9 m (Kirby et al 2006).…”