Ocean warming is increasingly recognized as a leading environmental risk to marine organisms. This phenomenon has led to poleward range extension of the sea urchin Heliocidaris crassispina to Toga Bay along the Oga Peninsula in Japan since 2014. Observations of H. crassispina gonads in maturation–spawning stages suggested delayed spermatogenesis in the new habitats. To determine the effects of ocean warming on H. crassispina, particularly to verify the delay in spermatogenesis and identify its specific cause, we investigated the seasonal changes in gonad development in relation to temperature and the associated carbon and nitrogen contents of the gonad and gut tissues and the gut contents to evaluate the nutritional status of the newly range-extended sea urchins by sex. Heliocidaris crassispina showed a defined gametogenic cycle with a single spawning per sex. The sex ratio was skewed to females (1.27:1). Males exhibited growing gonads during February–May, while females exhibited recovering gonads during February–April. Spermatogenesis was delayed one month compared to oogenesis. Spawning was partially synchronized between the sexes from August to September. A long-term warming trend in annual average and May–August in Toga Bay indicates that H. crassispina is subjected to the low temperature, particularly during winter in new habitat. The carbon/nitrogen (C/N) ratios were lower in the testes than in the ovaries regardless of no sexual differences in the gut from February to October. Although higher total protein content in testes than that of ovaries is required from the recovery to growing stages, N content of gonad showed no significantly sexual difference, suggesting that insufficient protein accumulation in testes suppress spermatogenesis that would be the possible factor of delayed spermatogenesis and partially synchronized spawning between sexes. Female-skewed sex ratio and delayed spermatogenesis suggest the lower possibility of self-reproduction in the newly extended population.

人们日益认识到海洋变暖是海洋生物面临的主要环境风险。自2014年以来，这种现象已导致海胆Heliocidaris crassispina沿极地延伸至日本的Oga半岛的Toga湾。在成熟-产卵期对H. crassispina生殖腺的观察表明，新栖息地的精子发生延迟。确定海洋变暖对H. crassispina的影响特别是为了验证精子发生的延迟并确定其具体原因，我们调查了性腺发育的季节性变化，该变化与温度以及性腺和肠道组织的相关碳和氮含量以及肠道含量有关，以评估精子的营养状况。按性别划分的新范围海胆。鸡血吸虫显示出确定的配子发生周期，每性别一次产卵。性别比例偏向女性（1.27：1）。在2月至5月期间，雄性生殖腺生长旺盛，而在2月至4月，雌性生殖腺发育旺盛。与卵子发生相比，精子发生被推迟了一个月。从八月到九月，两性之间的产卵部分同步。多加湾的年平均和5-8月的长期变暖趋势表明H. crassispina处于低温下，特别是在冬天在新的栖息地。睾丸中的碳/氮（C / N）比在卵巢中低，无论从二月到十月肠道中的性别没有差异。尽管从恢复到生长期，睾丸中的总蛋白质含量要高于卵巢，但性腺中的N含量并未显示出明显的性别差异，这表明睾丸中蛋白质积累不足会抑制精子发生，这可能是精子发生延迟和部分原因的可能因素。性别之间的同步产卵。女性性别比例偏高和精子发生延迟表明在新扩展的人群中自我繁殖的可能性较低。