TY - JOUR
T1 - Reproduction of the long-spined sea urchin Diadema setosum in the Gulf of Aqaba - Implications for the use of gonad-indexes
AU - Bronstein, Omri
AU - Kroh, Andreas
AU - Loya, Yossi
N1 - Funding Information:
We gratefully acknowledge A. Rankov and J. Larsson for their assistance in the field and laboratory. We are in debt to Dr. I. Brikner for assistance with the histological analysis and for fruitful discussions. We thank the Inter University Institute (IUI) at Eilat for providing laboratory and logistical support throughout this study. This research was supported by the Israel Science Foundation (ISF) to Y.L., O.B. was partially supported by a postdoctoral fellowship of the Israeli Council For Higher Education and the Steinhardt Museum of Natural History, Israel National Center for Biodiversity Studies, Tel Aviv University, Israel. Finally we thank the editor and three anonymous reviewers for their constructive comments that helped improve the manuscript.
PY - 2016/7/12
Y1 - 2016/7/12
N2 - As global warming and climate-change proceeds ever more rapidly, organisms depending on seasonal cues to synchronize reproduction face an unclear future. Reproduction in Diadema setosum in the Gulf of Aqaba (Red Sea) is seasonal, with mature individuals occurring from July to October. Gonad indexes (GI), in contrast, indicate that spawning occurs from August through December and suggests two main spawning events. Histological analysis, however, indicate that the second peak of GI values cannot be related to spawning, but rather correspond to recovering individuals. In Diadema, examination of GI values alone may thus lead to erroneous conclusions. GI was moderately-strong positively correlated with sea-surface temperatures, but not with chlorophyll-a concentrations or photoperiod. Spawning coincides with the onset of the annual chlorophyll-a increase, however, which might be advantageous for nutrition of the developing larvae. First significant GI increase coincides with the shortening of day-length, which may act as a cue for D. setosum gametogenesis. Gametogenesis is highly synchronised between sexes, although the mature phase of females exceeds that of males. The non-complete overlap may represent sampling bias or represent an adaptive strategy for enhancing fertilisation success. Skewed sex ratios (♀: ♂, 1:0.59, n = 360) in the Gulf of Aqaba may be related to pollution.
AB - As global warming and climate-change proceeds ever more rapidly, organisms depending on seasonal cues to synchronize reproduction face an unclear future. Reproduction in Diadema setosum in the Gulf of Aqaba (Red Sea) is seasonal, with mature individuals occurring from July to October. Gonad indexes (GI), in contrast, indicate that spawning occurs from August through December and suggests two main spawning events. Histological analysis, however, indicate that the second peak of GI values cannot be related to spawning, but rather correspond to recovering individuals. In Diadema, examination of GI values alone may thus lead to erroneous conclusions. GI was moderately-strong positively correlated with sea-surface temperatures, but not with chlorophyll-a concentrations or photoperiod. Spawning coincides with the onset of the annual chlorophyll-a increase, however, which might be advantageous for nutrition of the developing larvae. First significant GI increase coincides with the shortening of day-length, which may act as a cue for D. setosum gametogenesis. Gametogenesis is highly synchronised between sexes, although the mature phase of females exceeds that of males. The non-complete overlap may represent sampling bias or represent an adaptive strategy for enhancing fertilisation success. Skewed sex ratios (♀: ♂, 1:0.59, n = 360) in the Gulf of Aqaba may be related to pollution.
UR - http://www.scopus.com/inward/record.url?scp=84978370166&partnerID=8YFLogxK
U2 - 10.1038/srep29569
DO - 10.1038/srep29569
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AN - SCOPUS:84978370166
SN - 2045-2322
VL - 6
JO - Scientific Reports
JF - Scientific Reports
M1 - 29569
ER -