Differential Occupation of Available Coral Hosts by Coral-Dwelling Damselfish (Pomacentridae) on Australia’s Great Barrier Reef

Abstract

Associations between habitat-forming, branching scleractinian corals and damselfish have critical implications for the function and trophic dynamics of coral reef ecosystems. This study quantifies how different characteristics of reef habitat, and of coral morphology, determine whether fish occupy a coral colony. In situ surveys of aggregative damselfish–coral associations were conducted at 51 different sites distributed among 22 reefs spread along >1700 km of the Great Barrier Reef, to quantify interaction frequency over a large spatial scale. The prevalence of fish–coral associations between five damselfish (Chromis viridis, Dascyllus aruanus, Dascyllus reticulatus, Pomacentrus amboinensis and Pomacentrus moluccensis) and five coral species (Acropora spathulata, Acropora intermedia, Pocillopora damicornis, Seriatopora hystrix, and Stylophora pistillata) averaged ~30% across all corals, but ranged from <1% to 93% of small branching corals occupied at each site, depending on reef exposure levels and habitat. Surprisingly, coral cover was not correlated with coral occupancy, or total biomass of damselfish. Instead, the biomass of damselfish was two-fold greater on sheltered sites compared with exposed sites. Reef habitat type strongly governed these interactions with reef slope/base (25%) and shallow sand-patch habitats (38%) hosting a majority of aggregative damselfish-branching coral associations compared to reef flat (10%), crest (16%), and wall habitats (11%). Among the focal coral species, Seriatopora hystrix hosted the highest damselfish biomass (12.45 g per occupied colony) and Acropora intermedia the least (6.87 g per occupied colony). Analyses of local coral colony traits indicated that multiple factors governed colony usage, including spacing between colonies on the benthos, colony position, and colony branching patterns. Nevertheless, the morphological and habitat characteristics that determine whether or not a colony is occupied by fish varied among coral species. These findings illuminate the realized niche of one of the most important and abundant reef fish families and provide a context for understanding how fish–coral interactions influence coral population and community level processes.

Struktur Komunitas Ikan Karang dan Tutupan Karang pada Terumbu Buatan Artificial Patch Reef (APR)

“…Hal ini menunjukkan bahwa kelimpahan ikan karang yang berasosiasi dengan terumbu buatan APR hampir sama dengan kelimpahan ikan karang di terumbu karang alami. Hal ini kemungkinan terkait lokasi terumbu buatan yang berdekatan dengan terumbu karang alami, serta lama waktu pemasangan terumbu buatan (Chase & Hoogenboom, 2019). Struktur komunitas ikan karang pada terumbu buatan akan lebih menyatu dengan terumbu karang alami seiring dengan waktu (Komyakova et al, 2019).…”

“…Awal pengamatan kelimpahan dan keragaman jenis ikan karang pada terumbu buatan APR sangat rendah, 15-20 individu dari 5 jenis ikan karang (Munasik et al, 2018) setelah empat tahun pemasangan, kelimpahan dan komposisi jenis ikan karang pada terumbu buatan APR telah meningkat signifikan. Pemasangan terumbu buatan dan transplantasi karang di beberapa perairan di Indonesia dapat meningkatkan kelimpahan dan komposisi jenis ikan karang (Fadli et al, 2012;Manembu et al, 2014 (Chase & Hoogenboom, 2019). Struktur komunitas ikan karang yang berasosiasi dengan terumbu buatan sangat ditentukan oleh desain, bentuk dan lokasi terumbu buatan (Paxton, et al, 2020a(Paxton, et al, , 2020bMujianto & Sugiyanti, 2008…”