Spatial distribution of parrotfishes and groupers in an Okinawan coral reef: size-related associations in relation to habitat characteristics

Abstract

Parrotfishes (Labridae: Scarini) and groupers (Epinephelidae) are important fish groups that are regarded as the fisheries targets of primary importance in coral reefs. In order to establish ecosystem-based management of these two fish groups, clarifying the spatial distribution relative to habitat characteristics is of central importance. The present study investigated the spatial distributions of 12 parrotfishes species and seven groupers species in relation to environmental characteristics in an Okinawan coral reef. Ten out of the 12 parrotfish species and all seven grouper species showed species-specific spatial distributions. Four substrate types in the inner reefs (branching Acropora, bottlebrush Acropora, dead branching Acropora, and dead bottlebrush Acropora), three substrate types in the exposed reefs (massive coral, other coral, and calcium carbonate substratum), and water depth showed significant associations with the spatial distribution of fishes. Among the 12 parrotfish species, two species (Scarus spinus and S. forsteni) and four species (S. psittacus, S. hypselopterus, S. dimidiatus and S. ghobban) were primarily found in exposed reefs and inner reefs, respectively. Among the seven grouper species, two species (Cephalopholis argus and C. urodeta) and two other species (C. miniata and Epinephelus ongus) were primarily found in exposed reefs and inner reefs, respectively. Size-related spatial distribution was also found for three parrotfish species (Chlorurus microrhinos, Scarus rivulatus and S. hypselopterus), indicating that smaller-sized and larger-sized individuals were respectively found at sites with greater coverage of substrates with fine structure (live bottlebrush Acropora and dead bottlebrush Acropora) and coarse structure (live branching Acropora, dead branching Acropora and calcium carbonate substratum). The present study suggested that the spatial distribution of parrotfishes and groupers is not necessarily associated with the higher coverage of living corals, but positively associated with high substrate complexity. Thus, actual spatial distributional patterns of species should be considered to select candidate sites for protection and conservation for the two fish groups.

Environmental DNA metabarcoding reveals biodiversity marine fish diversity of a small island at Manokwari District, West Papua, Indonesia

“…Juvenile young fish will use coral reefs as a feeding ground and nursery group that provides a place of protection and resting place because the structure of coral reefs is quite diverse from massive, foliose and branching forms. For example, the fish Cephalopholis cyanostigma hunts in coral areas (Nanami 2021). This fish is included in Serranidae (grouper species), which is an economically important fish species (Rimmer and Glamuzina 2019).…”

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

“…Research suggests that this unique reproductive trait may be linked to the coral reefs in which parrotfishes live. They often form small groups in coral reef areas, and some species exhibit territorial behaviors [17,18]. An expanding corpus of research indicates that habitats exert a substantial influence on speciation patterns via sexual selection.…”

“…Additionally, their waste, rich in nutrients, helps sustain the healthy development of corals [11]. The well-being of live corals, serving as a haven for marine fish, is crucial for preserving biodiversity and ensuring ecosystem stability [18,20].…”

“…Parrotfish populations are currently facing significant threats due to overfishing and coral reef degradation, which could also lead to a decline in the genetic diversity of some parrotfish [21,22]. The conservation of these fish and their habitats is imperative for the preservation of the equilibrium and biodiversity within coral reef ecosystems [18,23]. Owing to their distinct biological characteristics and vital roles in ecological processes, parrotfish have emerged as critical subjects in marine biology and environmental protection research [24].…”

Diversity of the Tabuhan Island coral reef fish revealed by DNA barcoding and implication on conservation strategy in Banyuwangi, Indonesia

“…Furthermore, reef fish are important biota as an indicator of the health of coral reef ecosystems by identifying certain types of fish such as Chaetodontidae (Hamuna et al 2019). In addition, the number of reef fish is also a target for traditional fishermen because they have a fairly high price, such as snapper (Arai et al 2015) and grouper (Nanami 2021). In addition, the number of endemic fish and protected fish (Hobbs et al 2013;Cowman et al 2017) also makes coral reefs an important area for breeding, foraging, and raising children.…”