Dalian Ocean University, Key Laboratory of Mariculture & Stock Enhancement in North China's Sea, Ministry of Agriculture and Rural Affairs, Dalian, Liaoning, China.
Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China.
PeerJ. 2022 Jan 19;10:e12820. doi: 10.7717/peerj.12820. eCollection 2022.
Sea urchin aggregation is a common phenomenon in coastlines. However, it remains controversial whether sea urchins form resource aggregations or behavioral aggregations in a non-spawning season. To clarify, we studied the aggregative responses to food and predators in the sea urchin when high fitness areas (HFAs) were scarce versus sufficient. By taking the occupied area of each sea urchin (test diameter + spines = 4.5 cm) as a square (4.5 cm × 4.5 cm), we set scarce HFAs for the sea urchins in Experiment 1 (the squares of HFAs: the area occupied by experimental sea urchins = 1:1) and sufficient HFAs for the sea urchins in Experiment 2 (the squares of HFAs: the area occupied by experimental sea urchins = 2:1). If form resource aggregations, they would aggregate passively under the scarce HFAs conditions, but not in the sufficient HFAs conditions. Conversely, if form behavioral aggregation, aggregation would occur in both scarce and sufficient HFAs. The present results showed that in the scarce HFAs, in the food and predator groups were significantly closer to the food and further from predators, and had significantly more aggregated numbers in HFAs than those in the control group. Sea urchins did not aggregate in response to food or predators under the sufficient HFAs, although significantly more sea urchins of the experimental group was found in HFAs than that of the control group. Sea urchins (at least ) form resource aggregations that are driven by the scarce HFAs. This provides valuable information into the mechanisms of the aggregation of sea urchins.
海胆聚集是海岸线上常见的现象。然而，海胆在非繁殖季节是形成资源聚集还是行为聚集，这仍然存在争议。为了阐明这一点，我们研究了在高适合度区域（HFA）稀缺与充足的情况下，海胆对食物和捕食者的聚集反应。通过将每个海胆的占据区域（测试直径+刺= 4.5 厘米）视为一个正方形（4.5 厘米×4.5 厘米），我们在实验 1 中为海胆设置了稀缺的 HFA（HFA 的正方形：实验海胆占据的区域= 1：1），在实验 2 中为海胆设置了充足的 HFA（HFA 的正方形：实验海胆占据的区域= 2：1）。如果形成资源聚集，它们将在稀缺 HFA 条件下被动聚集，但在充足 HFA 条件下不会聚集。相反，如果形成行为聚集，那么聚集将在稀缺和充足的 HFA 中发生。本研究结果表明，在稀缺的 HFA 中，食物和捕食者组的海胆明显更接近食物，远离捕食者，并且在 HFA 中的聚集数量明显多于对照组。尽管实验组的海胆明显多于对照组，但在充足的 HFA 下，海胆不会对食物或捕食者做出聚集反应。海胆（至少）形成了由稀缺 HFA 驱动的资源聚集。这为海胆聚集的机制提供了有价值的信息。
