Diel vertical movements and feeding behaviour of blue humphead parrotfish Scarus ovifrons in a temperate reef of Japan

Abstract

The feeding ecology of scarinine parrotfishes on tropical coral reefs has received considerable attention in the past few decades; nonetheless, relatively few studies have been conducted in high-latitude reefs. Among the Indo-Pacific Scarus species, Scarus ovifrons is unique, being largely restricted to the warm temperate waters of Japan.Nonetheless, there is very little information available on the feeding ecology of this species. In this study, the authors used acoustic telemetry to detect the diel vertical movement patterns of S. ovifrons, video survey to detect its feeding depths and substrata and focal follow survey and genetic analysis to identify algae composition on the feeding scars at Kashiwajima Island, southwestern Japan (32 46 0 N, 132 38 0 E).Acoustic telemetry revealed that S. ovifrons spent most of its time in shallow water (<10 m) during the day and slept in deeper water (10-15 m) at night. Video and focal follow surveys revealed that most fishes of various sizes regularly took bites on epilithic algae and detrital materials on rocky substrata at depths of <10 m, but large fishes (>40 cm total length) sometimes took bites directly on live corals (Acropora solitaryensis) at the 5 m depth zone where live tabular corals dominated the benthos.Molecular phylogenetic analyses revealed that epilithic algae collected from feeding scars were mainly composed of Rhodophyta, and coralline algae were less often targeted. Overall, this study revealed that S. ovifrons feeds mostly at depths <10 m, and the feeding algae substrata of the species are similar to those of tropical coral reef parrotfishes.

The health status of coral reef ecosystem in Taka Bonerate, Kepulauan Selayar Biosphere Reserve, Indonesia

“…Among offshore reef edges with high fish diversity, Scaridae was recorded only low at location 3 with the lowest coral cover, gentle slope, and dominated by sand (low habitat complexity). Although location 2 has a more complex benthic structure (16.2% scleractinian live coral) than location 1, this may be due to the vertical movement behavior of Scaridae (Gomi et al 2021), which corresponds with the reef habitat at location 1 (high depth variation).…”

Predicting Future Shifts in the Distribution of Tropicalization Indicator Fish that Affect Coastal Ecosystem Services of Japan

“…For example, S. ovifrons spends most of their time in shallow water lower than 10 m in the daytime. However, S. ovifrons sleeps at 10-15 m during nighttime (Gomi et al, 2021). Biotelemetry attached to K. bigibbus showed that the most time was spent at a depth of 10-15 m near the seafloor with migration to shallow water to search for seaweeds in western Japan (Yamaguchi et al, 2006).…”

“…The presence of seagrass/seaweed was selected as an important factor for S. ovifrons and S. fuscescens, which have different food preferences. Scarus ovifrons is a scraper that feeds on small epiphytic algae on rocky substrata and dead corals (Steneck et al, 2017;Gomi et al, 2021). The contribution of seagrass/seaweed beds to the S. ovifrons model can be attributed to the fact that the macroalgae vegetate on rocky reefs and the rocky reefs form the habitats of S. ovifrons.…”

De Novo Genome Assembly of the Whitespot Parrotfish (Scarus forsteni): A Valuable Scaridae Genomic Resource

“…The Scaridae family is classified into 10 genera, comprising a total of 90 identified species [3]. Within this family, the genus Scarus is the largest one, encompassing about 50 species [4]. Scaridae originated in the late Miocene, around 10 million years ago (Mya), and subsequently underwent a rapid evolutionary split into three major clades [5][6][7].…”