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首页> 外文期刊>Marine biology >Habitat use by dusky dolphin in patagonia: how predictable is their location?
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Habitat use by dusky dolphin in patagonia: how predictable is their location?

机译：巴塔哥尼亚的昏暗海豚栖息地的使用：它们的位置有多可预测？

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Off Patagonian coasts, Argentina, the dusky dolphin is one of the most common small cetaceans. This species is the aim of newly developed watching activities during summer in Golfo Nuevo. However, the real occurrence and movement pattern are unknown. The objectives of this work were to investigate the predictability of dusky dolphin distribution, group structure and behaviour in the western portion of Golfo Nuevo, with respect to environmental features (bottom depth, bottom slope, distance from shore and substrate). Random transects in the bay were searched by small boat during the summer and autumn of 2001-2004. When a group of dolphins was sighted, estimates of group size, composition (mothers with calves, adults and juveniles only, and mixed groups) and the predominant activity (feeding, travelling, socialising, resting and milling) were recorded and thereafter at 2 min intervals. A grid of 1.5 x 1.5 km was constructed and each cell was characterised by environmental features, Area Use Index (percent of total annual search effort) and Activity Index (predominant behaviour of groups observed in that cell). Mothers with calves and smaller groups and resting behaviour occurred in shallowest waters supporting the idea/hypothesis that movement to shallower water is related to increased safety for individuals. Travelling occurred in the deepest areas with other behaviours observed in intermediate depths. Dolphin distribution within the bay differed significantly between years, but this was not related to any of the factors analysed in this study. Although there was considerable variation between years, in general, dolphins were found in deeper waters further from shore (except for mother-calf groups) and over areas with steeper seafloor gradient. The high variability in the distribution of the animals does not allow for the generation of a simple, area-specific management plan.
机译：在阿根廷巴塔哥尼亚海岸附近，灰暗的海豚是最常见的小鲸类动物之一。该物种是夏季在Golfo Nuevo新开发的观赏活动的目标。但是，实际的发生和移动方式是未知的。这项工作的目的是就环境特征（底部深度，底部坡度，距海岸和底物的距离）调查Golfo Nuevo西部西部黄昏海豚分布，群体结构和行为的可预测性。在2001年至2004年夏季和秋季，用小船搜索了海湾中的随机样带。当看到一群海豚时，记录其种群大小，组成（仅有小牛的母亲，成年和少年，以及混合的种群）以及主要活动（进食，旅行，社交，休息和碾磨）的估计值，然后记录2分钟间隔。构造了一个1.5 x 1.5 km的网格，每个单元的特征是环境特征，区域使用指数（年度总搜索量的百分比）和活动指数（在该单元中观察到的组的主要行为）。犊牛和小群体的母亲以及休息行为发生在最浅的水中，这支持了以下想法/假设：向浅水运动会增加个体的安全感。旅行发生在最深的区域，在中等深度观察到其他行为。海湾中海豚的分布在几年之间存在显着差异，但这与本研究中分析的任何因素均无关。尽管几年之间变化很大，但总的来说，海豚发现于离海岸较远的深水域（母小牛群除外）和海底梯度较陡的地区。动物分布的高度可变性无法生成简单的，针对特定区域的管理计划。

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