Department of Primary Industries and Regional Development, Port Stephens Fisheries Institute, Taylors Beach, NSW, 2316, Australia.
The Nature Conservancy, 100 Harris Street, Pyrmont, NSW, 2009, Australia.
BMC Ecol Evol. 2024 Aug 23;24(1):114. doi: 10.1186/s12862-024-02296-1.
Shellfish reef restoration is relatively new in Australia, particularly to intertidal estuarine environments. In late 2019/early 2020 the first large-scale shellfish reef restoration project of the Sydney rock oyster, Saccostrea glomerata was undertaken in the Myall and Karuah Rivers, Port Stephens, on the mid north coast of New South Wales (NSW), Australia. The present study aimed to determine whether locally sourced clean conspecific oyster shells, and/or locally quarried rocks were better for natural recruitment of natural S. glomerata for large-scale oyster reef restoration, and subsequent recruitment of fishes and invertebrates. Over two years, recruitment of S. glomerata spat, and associated fishes and invertebrates were assessed on reefs made of: (1) rock, and (2) rock and shell.
The mean (± SE) density of oyster spat on rock reefs (Myall River: 1790 ± 48, Karuah River: 1928 ± 68) was significantly greater (Myall River: ANOVA Si: MS = 31080167, F = 96.05, P < 0.001, Karuah River: ANOVA Si x Ti: MS = 2965449, F = 5.99, P < 0.001) than on rock and shell reefs (Myall River: 840 ± 40, Karuah River: 1505 ± 75). Rock reefs had significantly greater densities (Myall River: ANOVA Si x Ti: MS 18, 270 = 15657, F = 2.71, P < 0.001, Karuah River: ANOVA Si x Ti: MS 18, 270 = 20322, F = 5.25, P < 0.001) of the most abundant invertebrate, Bembicium auratum (Myall River: 85 ± 9, Karuah River: 100 ± 8) than reefs of rock and shell (Myall River: 59 ± 8, Karuah River: 44 ± 5), but there was no significant difference in the diversity and relative abundance of the most abundant species of fish, Acanthopagrus australis.
This study demonstrates that using locally sourced rock is better for S. glomerata recruitment than shells. Although shell might have benefits that were not investigated in the present study, such as elicit greater social licence for oyster reef restoration projects, but as shown here, it may not be beneficial from an ecological perspective. With the global expansion of the range of different native species of reef oysters for restoration, the appropriate material used for reef bases needs to be chosen for a specific species and purpose.
贝类珊瑚礁恢复在澳大利亚相对较新，特别是在潮间带河口环境中。2019 年末/2020 年初，在新南威尔士州（新州）中北部海岸的斯蒂芬斯港的迈尔和卡鲁阿河，进行了第一个大规模的悉尼石蚝（Saccostrea glomerata）贝类珊瑚礁恢复项目。本研究旨在确定当地来源的清洁同种蚝壳和/或当地开采的岩石，对于大规模牡蛎礁恢复的天然 S. glomerata 的自然繁殖以及随后鱼类和无脊椎动物的繁殖，哪种更好。在两年的时间里，评估了由以下两种方法制成的珊瑚礁上的 S. glomerata 幼体以及相关鱼类和无脊椎动物的繁殖情况：（1）岩石，和（2）岩石和贝壳。
岩石礁上牡蛎幼体的平均（± SE）密度（迈尔河：1790±48，卡鲁阿河：1928±68）明显更高（迈尔河：ANOVA Si：MS=31080167，F=96.05，P<0.001，卡鲁阿河：ANOVA Si x Ti：MS=2965449，F=5.99，P<0.001）比岩石和贝壳礁上的密度（迈尔河：840±40，卡鲁阿河：1505±75）更高。岩石礁上最丰富的无脊椎动物 Bembicium auratum 的密度（迈尔河：ANOVA Si x Ti：MS 18，270=15657，F=2.71，P<0.001，卡鲁阿河：ANOVA Si x Ti：MS 18，270=20322，F=5.25，P<0.001）明显更高（迈尔河：85±9，卡鲁阿河：100±8），比岩石和贝壳礁上的密度（迈尔河：59±8，卡鲁阿河：44±5）更高，但最丰富的鱼类 Acanthopagrus australis 的多样性和相对丰度没有差异。
本研究表明，与壳相比，使用当地来源的岩石更有利于 S. glomerata 的繁殖。尽管壳可能具有本研究未调查到的好处，例如为牡蛎礁恢复项目赢得更大的社会许可，但正如这里所示，从生态角度来看，这可能并不有益。随着不同本地种贝类珊瑚礁的范围在全球范围内扩大，用于珊瑚礁基地的适当材料需要根据特定物种和目的进行选择。
