Ben-Tzvi Ofer, Kiflawi Moshe, Polak Omer, Abelson Avigdor
The Interuniversity Institute for Marine Sciences of Eilat, Eilat, Israel.
PLoS One. 2009;4(5):e5511. doi: 10.1371/journal.pone.0005511. Epub 2009 May 13.
Coral-reef fishes experience a major challenge when facing settlement in a multi-threat environment, within which, using settlement cues, they need to select a suitable site. Studies in laboratories and artificial setups have shown that the presence of conspecific adults often serves as a positive settlement cue, whose value is explained by the increased survival of juveniles in an already proven fit environment. However, settlement in already inhabited corals may expose the recruits to adult aggression. Daily observations and manipulation experiments were used in the present study, which was conducted in the natural reef. We revealed differential strategies of settlers, which do not necessarily join conspecific adults. Dascyllus aruanus prefer to settle near (not with) their aggressive adults, and to join them only after gaining in size; whereas Dascyllus marginatus settlers in densely populated reefs settle independently of their adult distribution. Our results present different solutions to the challenges faced by fish recruits while selecting their microhabitat, and emphasize the complexity of habitat selection by the naïve settlers. Although laboratory experiments are important to the understanding of fish habitat selection, further studies in natural habitats are essential in order to elucidate the actual patterns of settlement and habitat selection, which are crucial for the survival of coral-reef fish populations.
珊瑚礁鱼类在多威胁环境中面临定居挑战，在这种环境下，它们需要利用定居线索选择合适的地点。实验室和人工环境中的研究表明，同种成年个体的存在通常是一种积极的定居线索，其价值在于幼鱼在已被证明适宜的环境中存活率提高。然而，在已有人居住的珊瑚礁中定居可能会使幼鱼遭受成年个体的攻击。本研究在自然珊瑚礁中进行，采用了每日观察和操纵实验。我们揭示了定居者的不同策略，它们不一定会与同种成年个体聚集在一起。双带宅泥鱼更喜欢在其具有攻击性的成年个体附近（而非与之在一起）定居，并且只有在体型增大后才会加入它们；而在人口密集的珊瑚礁中定居的缘边宅泥鱼幼鱼则独立于成年个体的分布进行定居。我们的研究结果展示了幼鱼在选择微生境时应对挑战的不同解决方案，并强调了初来乍到的定居者在栖息地选择上的复杂性。虽然实验室实验对于理解鱼类栖息地选择很重要，但在自然栖息地进行进一步研究对于阐明实际的定居模式和栖息地选择模式至关重要，而这些模式对于珊瑚礁鱼类种群的生存至关重要。
