Vessel movements are considered the main anthropogenic pathway for secondary spread of marine non-indigenous species. Recent studies have highlighted the potential for viable organisms to be transported within bilge water of small vessels. In this study, a survey was conducted to (1) describe the bilge water operational profiles of a range of domestic vessels operating in New Zealand and (2) identify factors driving the level of biosecurity risk. The proportion of vessels with pre-discharge treatments was low (13.7%), confirming the potential for organisms to be viable at discharge. Significant differences in risk scores among vessel types were shown; risk scores were highest for yachts, followed by launches, trailer boats and commercial vessels. Yachts were characterised by a high frequency of use, visits to multiple regions and a high likelihood of bilge water on board when leaving port (i.e. high-risk source regions). Almost all yachts operated automatic bilge systems, suggesting that discharge occurs primarily when the volume is sufficient to trigger the pump mechanism and that associated bilge water could be carried significant distances. Validation of vessel risk profiles through targeted sampling is recommended, along with research to identify potential practical and cost-effective mitigation measures such as public awareness campaigns.

中文翻译：

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与小型船舶舱底水相关的生物安全风险：对系统和操作员行为的评估

船舶移动被认为是海洋非本土物种二次传播的主要人为途径。最近的研究强调了在小型船舶的舱底水中运输活生物体的潜力。在这项研究中，进行了一项调查，以 (1) 描述在新西兰运营的一系列国内船舶的舱底水操作概况，以及 (2) 确定推动生物安全风险水平的因素。进行排放前处理的船舶比例较低（13.7%），证实了排放时生物体可能存活的可能性。显示了血管类型之间风险评分的显着差异；游艇的风险评分最高，其次是下水、拖船和商船。游艇的特点是使用频率高，访问多个地区，离开港口时船上很可能有舱底水（即高风险源区）。几乎所有游艇都运行自动舱底系统，这表明排放主要发生在体积足以触发泵机构并且相关的舱底水可以携带很远的距离时。建议通过有针对性的抽样来验证船舶风险状况，并进行研究以确定潜在的实用且具有成本效益的缓解措施，例如公众意识运动。