ABSTRACT

Larvae (glochidia) of Unionida mussels form obligate symbiotic associations with host fish to complete their life-cycle. To identify previously unknown host fish associations for the threatened New Zealand Echyridella aucklandica, glochidia infestation on fish by two mussel species was quantified in four Waikato streams. A host for E. aucklandica was identified for the first time, with glochidia found to attach and encyst on the common smelt Retropinna retropinna but not on other fish species caught. In contrast, E. menziesii was found on a range of fish species but not on the two R. retropinna caught. Encysted E. aucklandica glochidia showed evidence of growth on the gills of host fish. These preliminary results provide critical knowledge of host–glochidia interactions in sympatric New Zealand unionid species to support integrated conservation management targeting both unionid communities and host fish populations.

摘要

Unionida 贻贝的幼虫 (glochidia) 与宿主鱼形成专性共生关系以完成其生命周期。为了确定受威胁的新西兰Echyridella aucklandica以前未知的寄主鱼类协会，在四个怀卡托溪流中量化了两种贻贝物种对鱼类的 glochidia 感染。首次确定了E. aucklandica的宿主，发现 glochidia 附着并包囊在普通胡瓜鱼Retropinna retropinna上，但不附着在其他捕获的鱼类上。相比之下，E. menziesii在一系列鱼类身上被发现，但在捕获的两种R. retropinna身上却没有。包囊奥克兰glochidia 显示在寄主鱼的鳃上生长的证据。这些初步结果提供了新西兰 unionid 同域物种中寄主 - glochidia 相互作用的关键知识，以支持针对 unionid 群落和寄主鱼类种群的综合保护管理。