ABSTRACT

The Japanese mantis shrimp Oratosquilla oratoria (De Haan, 1844) is a large stomatopod crustacean that was first reported from New Zealand in 2009, and is now present in many upper North Island estuaries, including the Kaipara and Manukau harbours. To assess the sediment traits of harbours potentially vulnerable to invasion by Japanese mantis shrimps, we examined its relationship with the sediments in which it forms burrows. We quantified the grain size distribution of sediments from known O. oratoria habitat in the Kaipara, and ran a choice experiment with four sediment types varying in sand and mud content to determine the preferred sediment type for burrow construction. In the Kaipara, O. oratoria occurred in sediments varying widely in mud content, but the mean grain size distribution of those sediments was similar to the ‘sandy mud’ (44% silt and clay) that individual O. oratoria preferred in the choice experiment. The large amount of apparently suitable habitat around New Zealand’s coast and estuaries, in combination with the broad temperature tolerance of O. oratoria in its native range, suggest this species could inhabit much of mainland New Zealand, with potentially significant ecological consequences.

摘要

日本螳螂虾Oratosquilla oratoria (De Haan, 1844) 是一种大型口足类甲壳动物，于 2009 年首次从新西兰报道，现在出现在北岛上游的许多河口，包括凯帕拉港和曼努考港。为了评估可能易受日本螳螂虾入侵的港口的沉积物特征，我们研究了它与形成洞穴的沉积物的关系。我们量化了来自 Kaipara 已知的 O. oratoria栖息地的沉积物的粒度分布，并进行了四种不同沙泥含量的沉积物类型的选择实验，以确定洞穴建造的首选沉积物类型。在 Kaipara, O. oratoria发生在泥质含量差异很大的沉积物中，但这些沉积物的平均粒度分布与个体O. oratoria在选择实验中偏爱的“砂泥”（44% 的淤泥和粘土）相似。新西兰海岸和河口周围有大量明显适合的栖息地，再加上O. oratoria在其原生范围内的广泛温度耐受性，表明该物种可能栖息在新西兰大陆的大部分地区，并可能产生重大的生态后果。