ABSTRACT

Endangered Australian southern right whales, Eubalaena australis, are vulnerable to threats from human activities, particularly at calving aggregation areas. As the population increases, new calving areas are being established, which are important to monitor. In the Encounter Bay/Lacepede Bay region, South Australia, distribution, relative abundance, residency and site fidelity were studied using historical sightings (n = 1071, 1970–2013) and photo-identified individuals (n = 191, 2006–2019). Whales were observed throughout the study area and concentrated in Encounter Bay during April to November where an inshore core calving area was identified between Port Elliot and the River Murray Mouth. Annual maximum daily sightings increased from 2 to 8 ($\bar{X}$ = 2.9) whales during 1983–1997 to 1–25 ($\bar{X}$ = 8.6) after 2002. Numbers of identified female-calf pairs (CC) increased from 10 (2006–2012) to 31 (2013–2019). During 2013–2019, when survey effort increased, a mean of 4.4 (1–9 pairs/year) CC and 18.0 (7–40/year) unaccompanied animals (UA) visited Encounter Bay each season. Mean residency was greater for CC (51.3, 13–126 days) than UA (13.4, 2–40 days). Calving females that arrived pregnant had more than twice the residency time than those first sighted with a calf. A quarter of calving females returned in two or three subsequent seasons. Encounter Bay is an important calving area and requires re-classification by the Commonwealth from “emerging aggregation area” to “small, established aggregation area”. Ongoing research is needed to document southern right whale population dynamics at Encounter Bay in the context of the broader Australian population.

摘要

濒临灭绝的澳大利亚南露脊鲸（Eubalaena australis）很容易受到人类活动的威胁，尤其是在产犊聚集区。随着人口的增加，正在建立新的产犊区，这对监测很重要。在南澳大利亚的 Encounter Bay/Lacepede Bay 地区，使用历史目击 ( n = 1071, 1970-2013) 和照片识别的个体 ( n  = 191, 2006-2019) 研究了分布、相对丰度、居住地和场地保真度。在整个研究区域都观察到了鲸鱼，并在 4 月至 11 月期间集中在遭遇湾，在埃利奥特港和墨累河口之间确定了一个近岸核心产犊区。年度最大每日目击次数从 2 次增加到 8 次（$\bar{X}$= 2.9) 鲸鱼在 1983-1997 到 1-25 ($\bar{X}$= 8.6) 2002 年之后。确定的母牛对 (CC) 的数量从 10 (2006-2012) 增加到 31 (2013-2019)。在 2013-2019 年期间，随着调查工作量的增加，每个季节平均有 4.4 只（1-9 对/年）CC 和 18.0 只（7-40 对/年）无人陪伴的动物 (UA) 访问了邂逅湾。CC（51.3, 13-126 天）的平均居住时间高于 UA（13.4, 2-40 天）。怀孕的产犊雌性的居住时间是第一次看到产犊的雌性的两倍多。四分之一的产犊雌性在随后的两三个季节返回。Encounter Bay 是一个重要的产犊区，联邦要求将其从“新兴聚集区”重新分类为“小型、成熟聚集区”. 需要进行持续的研究，以在更广泛的澳大利亚人口背景下记录遭遇湾的南露脊鲸种群动态。