熱波がウニの繁殖に及ぼす影響を解明(Even moderate heat waves depress sea urchin reproduction along the Pacific coast)

2025-11-14 カリフォルニア大学バークレー校(UCB)

太平洋沿岸域に生息するウニ類(例えば紫ウニ Strongylocentrotus purpuratus)の研究で、中程度の海水温上昇(致死温度には達しない程度)でも、繁殖能力が大幅に抑制されることが判明しました。研究チームは30年間にわたる沿岸温度データやウニの幼生・成体個体数の記録を分析し、実験により成体雌ウニの産卵停止が18 °C付近と、従来想定されていた致死温度よりかなり低い温度で起きることを確認しました。これは、海藻林とウニの間の生態バランスに大きな影響を与え、温暖化によってウニの「ブーム&バスト(急増・急減)」のサイクルが予想より頻繁に起き得ることを示唆します。また、比較的「安全」と思われていた温度範囲でも種の回復力が削がれ、他の海洋無脊椎動物(アワビ、サンゴ、貝類など)にも同様の現象が起こる可能性があると研究者は指摘しています。

<関連情報>

配偶子形成の熱抑制はStrongylocentrotus purpuratusの幼生加入の歴史的崩壊を説明できる Thermal suppression of gametogenesis can explain historical collapses in larval recruitment in Strongylocentrotus purpuratus

Daniel K. Okamoto,Nathan B. Spindel,Maya J. Munstermann,Sam Karelitz,Brenna Collicutt,Iria Gimenez,Kate Rolheiser,Evan Cronmiller,Megan Foss,Natalie Mahara,Dan Swezey,Rachele Ferraro,Laura Rogers-Bennett & Stephen C. Schroeter
Communications Biology  Published:03 November 2025
DOI:https://doi.org/10.1038/s42003-025-08829-8

熱波がウニの繁殖に及ぼす影響を解明(Even moderate heat waves depress sea urchin reproduction along the Pacific coast)

Abstract

Projections for population viability under climate change are often made using estimates of thermal lethal thresholds. These estimates vary across life history stages and can be valuable for explaining or forecasting shifts in population viability. However, sublethal temperatures can also depress vital rates and shape fluctuations in the reproductive viability of populations. For example, heatwaves may suppress reproduction, causing recruitment failure before lethal temperatures are reached. Despite a growing awareness of this issue, tying sublethal effects to observed recruitment failure remains a challenge especially in marine environments. For the urchin Strongylocentrotus purpuratus, larval supply is known to decline near the southern edge of the range during marine heatwaves despite temperatures remaining below temperatures thought to limit larval survival. We experimentally show that sublethal suppression of gametogenesis by marine heatwaves can partially explain these historical collapses in recruitment. This response differs by sex: male spermatogenesis is less sensitive to elevated temperatures and marine heatwaves than females who exhibit substantial reductions in production of mature oocytes. Results were similar between animals from warmer and cooler regions of their range. Overall, we show sublethal thermal sensitivities of reproduction can narrow the thermal envelope for population viability compared to predictions from lethal limits.

1404水産水域環境
ad
ad
Follow
ad
タイトルとURLをコピーしました