Diel and tidal studies are critical to understanding many aspects of fish behavior and habitat use. In this study, diel and tidal abundance, size composition and food habits of four common juvenile fish ( Anchoa mitchilli, Cynoscion regalis, Leiostomus xanthurus, Micropogonias undulatus ) present in Delaware Bay (USA) marsh creeks was assessed. Fish were collected with otter trawls near daytime and nighttime high tides and with seines near daytime and nighttime low tides at two mesohaline sites. Anchoa mitchilli and C. regalis were both significantly more abundant and significantly smaller in nighttime samples. Micropogonius undulatus was the most abundant species, while A. mitchilli was entirely absent, in low tide collections. An index of stomach fullness for A. mitchilli and L. xanthurus indicated feeding during periods of maximum flooding. Trophic interactions among the four species were also apparent. Both C. regalis and M. undulatus commonly consumed A. mitchilli only during nighttime high tides. Cynoscion regalis and M. undulatus both consumed large quantities of Fundulus heteroclitus (mummichog) during low tides during both the day and night. This important interaction demonstrates the trophic transfer of production in the marsh ( F. heteroclitus ) to the open ocean via the fall migration of piscivorous M. undulatus . These findings demonstrate the need for diel and tidal sampling programs if we are to adequately understand the dynamics of marsh ecosystems.

中文翻译：

---

干旱和潮汐对美国特拉华湾沼泽溪中四种年幼鱼的丰度和食物习性的影响

饮食和潮汐研究对于了解鱼类行为和栖息地利用的许多方面至关重要。在这项研究中，评估了存在于特拉华湾（美国）沼泽小溪中的四种常见幼鱼（Anchoa mitchilli、Cynoscion regalis、Leiostomus xanthurus、Micropogonias undulatus）的昼夜和潮汐丰度、大小组成和食物习性。在白天和夜间高潮附近使用水獭拖网以及在白天和夜间低潮附近使用围网在两个中盐碱地收集鱼。Anchoa mitchilli 和 C. regalis 在夜间样本中都显着更丰富，但显着更小。Micropogonius undulatus 是最丰富的物种，而 A. mitchilli 在低潮集合中完全不存在。A. mitchilli 和 L. xanthurus 的胃饱胀指数表明在最大洪水期间进食。四个物种之间的营养相互作用也很明显。C. regalis 和 M. undulatus 通常只在夜间涨潮时食用 A. mitchilli。Cynoscion regalis 和 M. undulatus 都在白天和晚上的低潮期间消耗了大量的 Fundulus heteroclitus (mummichog)。这种重要的相互作用证明了沼泽（F.heteroclitus）中的生产通过鱼食性波状鱼的秋季迁移向公海的营养转移。这些发现表明，如果我们要充分了解沼泽生态系统的动态，就需要进行昼夜和潮汐采样计划。undulatus 在白天和晚上的退潮期间都消耗了大量的 Fundulus heteroclitus (mummichog)。这种重要的相互作用证明了沼泽（F.heteroclitus）中的生产通过鱼食性波状鱼的秋季迁徙向公海的营养转移。这些发现表明，如果我们要充分了解沼泽生态系统的动态，就需要进行昼夜和潮汐采样计划。undulatus 在白天和晚上的退潮期间都消耗了大量的 Fundulus heteroclitus (mummichog)。这种重要的相互作用证明了沼泽（F.heteroclitus）中的生产通过鱼食性波状鱼的秋季迁移向公海的营养转移。这些发现表明，如果我们要充分了解沼泽生态系统的动态，就需要进行昼夜和潮汐采样计划。