ABSTRACT Whitebait comprise a culturally, commercially and recreationally important fishery in New Zealand, where post-larvae are netted while returning from their marine phase. In this study, we expanded an historical (1964) sampling programme to gain a contemporary understanding of the species composition of the whitebait fishery; 87 rivers were sampled over six months in 2015. Over the entire country, >12 species were found in samples and 87.6% of these were īnanga (Galaxias maculatus). Kōaro (G. brevipinnis) and banded kōkopu (G. fasciatus) were abundant in some rivers and regions at particular times of the year. Buller was the most variable region, spatially and temporally, for species composition; Canterbury was the least variable. Banded kōkopu whitebait migrated one month earlier north of Cook Strait than in the south. There was a positive association between the abundance of kōaro and banded kōkopu in samples and the level of indigenous forest cover in catchments. Compared to samples from 50 years ago, there was a greater proportion of kōaro and banded kōkopu whitebait throughout the country. This spatio-temporal variability requires fishery regulations to be more tailored and flexible if they are to conserve the diversity of life-histories present in the catch and sustain the whitebait fishery.

中文翻译：

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新西兰银鱼渔业物种组成的时空变化

摘要银鱼是新西兰重要的文化、商业和娱乐渔业，幼鱼从海洋阶段返回时被网捕。在这项研究中，我们扩展了一个历史（1964 年）的抽样计划，以获得对银鱼渔业物种组成的当代理解；2015 年六个月内对 87 条河流进行了采样。在整个国家，样本中发现了 12 种以上的物种，其中 87.6% 是 īnanga（Galaxias maculatus）。Kōaro (G. brevipinnis) 和带状 kōkopu (G. fasciatus) 在一年中的特定时间在一些河流和地区很丰富。布勒是物种组成在空间和时间上变化最大的区域；坎特伯雷的变化最小。带状 kōkopu 银鱼在库克海峡以北的迁徙时间比在南部提前一个月。样本中 kōaro 和带状 kōkopu 的丰度与集水区的土著森林覆盖水平之间存在正相关。与 50 年前的样本相比，全国各地的 kōaro 和带状 kōkopu 银鱼的比例更高。这种时空可变性要求渔业法规更加有针对性和灵活性，如果它们要保护渔获物中存在的生活史的多样性并维持银鱼渔业。