Investigation of the marine communities of Midway Harbor and adjacent lagoon, Midway Atoll, Northwest Hawaiian Islands in 1998 (NODC Accession 0001098)

A survey of the marine communities of Midway Atoll harbor and surrounding lagoon was conducted at 12 sites from September 5 to 9, 1998. The primary focus of these surveys was the invertebrates of the fouling communities present on artificial substrates. Occurrence of reef fishes at each site was also recorded, and algae was collected and identified from four stations. A total of 444 taxa were identified (47 algae, 316 invertebrates, and 81 fishes) from all stations. Approximately 250 invertebrate and 35 algae species are considered new records for Midway Atoll. All fishes observed were previously record form the atoll. Only three invertebrates identified in this survey are considered to be nonindigenous species in the Hawaiian Islands. One introduced bryozoan, Amathia distans, dominated the fouling communities atmost stations where artificial substrates were available. Another introduced bryozoan, Schizoporella errata, was also common at the same stations. A non indigenous barnacle, Chthamalus proteus, recently introduced from the Caribbean, was common on pier pilings inside Midway harbor. No introduced invertebrates were present in natural habitats. The introduced snapper, Lutjanus kasmira, was also present along the reef outside the lagoon. The threat to the native reef community by established non-indigenous species is considered minimal. The presence of these introduced species at Midway, especially Chthamalus proteus, suggests that vectors of future, potentially more deleterious introductions exist. Transport of these introductions was most likely as fouling on ship bottoms, but other sources of introductions, such as ballast water carried in ships, should be guarded against to protect the relatively pristine reefs of Midway Atoll.

1998年9月5日至9日，研究团队于中途岛环礁港口及周边潟湖的12个采样点位开展了海洋群落调查。本次调查的核心研究目标为人工基质上附着的污损生物群落中的无脊椎动物；同时记录了各采样点位的礁栖鱼类出现情况，并在4个站位采集并鉴定了藻类样品。所有采样点位共鉴定出444个分类单元（其中藻类47种、无脊椎动物316种、鱼类81种）。约有250种无脊椎动物与35种藻类被认定为中途岛环礁的新记录物种。本次调查观测到的所有鱼类均为该环礁此前已有记录的物种。本次鉴定出的无脊椎动物中，仅有3种被视为夏威夷群岛的非本土物种。一种外来苔藓虫（bryozoan）Amathia distans在存在人工基质的多数采样点位的污损生物群落中占据优势地位；另一种外来苔藓虫（bryozoan）Schizoporella errata在上述点位也较为常见。一种源自加勒比海的外来藤壶（Chthamalus proteus）在中途岛港口内部的码头桩柱上十分常见。自然生境中未发现外来无脊椎动物。外来笛鲷（Lutjanus kasmira）同样在潟湖外侧的珊瑚礁区域被观测到。已定殖的非本土物种对本地珊瑚礁群落造成的威胁被认为极低。中途岛环礁存在这些外来物种的事实，尤其是Chthamalus proteus的出现，表明未来存在传入潜在危害性更强的外来物种的传播途径。上述外来物种的传入途径极有可能为船舶底部附着的污损生物，但为保护中途岛环礁相对原始的珊瑚礁生态系统，仍需防范船舶压载水等其他外来物种传入途径。