|A new quantitative analysis of ovarian development in echinoderms: the maturity stage index|Doyle, G.M.; Hamel, J.-F.; Mercier, A. (2012). A new quantitative analysis of ovarian development in echinoderms: the maturity stage index. Mar. Biol. (Berl.) 159(2): 455-465. hdl.handle.net/10.1007/s00227-011-1823-3
In: Marine Biology. Springer: Heidelberg; Berlin. ISSN 0025-3162, more
|Authors|| || Top |
- Doyle, G.M.
- Hamel, J.-F.
- Mercier, A.
This study developed an objective quantitative method for detecting small-scale temporal or spatial differences in gametogenesis in echinoderms. The method was applied to conventional monthly samples of the planktotrophic brittle star, Ophiopholis aculeata, collected at a single site in Newfoundland (eastern Canada) at 10–15 m depth. The samples were analysed to determine gonad index, oocyte size and gonadal stage using histology. The maturity stage index (MSI) was developed to integrate a measure of brittle star size (disc diameter), oocyte size and oocyte density. The MSIs ranged from 0 to 800 and had significantly different means among the four gametogenic stages (early growth, growth, mature and spent). The MSI was more sensitive in revealing significant differences between consecutive stages than any of its individual constituents. The MSI was also applied to gametogenic data from the lecithotrophic holothuroid, Mesothuria lactea, again revealing significant differences between successive oogenic stages. This method is expected to be useful in field and experimental studies of gametogenesis in echinoderms (and possibly other taxa), where it is important to detect not just the timing of annual peaks in reproduction but small differences in reproductive status among individuals or populations (e.g. from different habitats or feeding regimes).