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

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.

Parasite Fauna of the White-Streaked Grouper (Epinephelus ongus) from the Thousand Islands, Java, Indonesia

Purpose Fish parasites can cause diseases in humans and lead to commercial losses in fisheries and aquaculture. The objectives of this study were to analyze E. ongus’s parasite fauna regarding food safety and parasite transmission risk between Epinephelus species and test whether E.ongus populations can be distinguished by their parasite community. Methods We studied the metazoan parasite fauna of 30 white-streaked groupers Epinephelus ongus from the Thousand Islands, Java Sea, Indonesia, and compared the parasite community with specimens from Karimunjawa archipelago, Java Sea, from a former study. We used common fish parasitological methods for fish examination and parasite calculations. Results We found 12 metazoan parasite species, establishing five new host and five new locality records, increasing the known parasite fauna of E. ongus by 21%. No anisakid worms infected E. ongus. All but one (trematode Gyliauchen cf. nahaensis) species have been previously reported from Epinephelus. Parasite abundance of E. ongus differed significantly between the two regions. Conclusions Due to a certain degree of host specificity to groupers, there is potential risk of parasite transmission from E. ongus into groupers in mariculture or surrounding fishes, which increases (sea) food security related health risks from zoonotic parasites and calls for better monitoring and management plans for E. ongus. The regional separation of the Thousand Islands and Karimunjawa with different food availability and fish ecology causes different parasite abundances, distinguishing two separate E. ongus populations by their parasite fauna.

Barcoding of Fin Clip Samples Revealed High Exploitation of Plectropomus leopardus in Spermonde Archipelago

Spermonde Archipelago in South Sulawesi is among groupers sources in Indonesia for International Marine Live Trade. It was not much known which species are mostly exploited in those areas during the study because only fin clip samples could be obtained. Here we performed DNA forensic analysis to groupers fin clips collected from Spermonde Archipelago using barcode marker to know what species were exploited and which ones was the most exploited species. A total of 110 fin clip samples were obtained during the field trips. Sequencing of the cytochrome c oxidase 1 gene was successful for only 36 samples. Species determination was based on sequences similarity to conspecific sequence available in barcoding of life database (BOLD). BOLD similarity test placed the 36 fin clip samples into four different species, namely Cromileptes altivelis, Epinephelus ongus, Plectropomus leopardus, and Plectropomus maculatus. The K-2P taxonomic tree showed clear separation among species which was supported by high K2P genetic distances among species. Most of fin clips were identified as Plectropomus leopardus indicates that this species was the most exploited in Spermonde Archipelago. This proved that molecular identification not only can be used to biodiversity study in certain area but also in forensic analysis of a threatened wildlife. This study has important contribution for conservation effort of those groupers species, especially P. leopradus and provides new approach for taxonomist and conservation managers to identify samples, especially when only incomplete specimens are available.

Parasite fauna of white-streaked grouper, Epinephelus ongus (Bloch, 1790) (Epinephelidae) from Karimunjawa, Indonesia

SUMMARYThis study provides the first comprehensive information on the parasite fauna of the white-streaked grouperEpinephelus ongus. A total of 35 specimens from the archipelago Karimunjawa, Java Sea, Indonesia were studied for metazoan parasites. For comparison, the documented parasite community of 521E. areolatus,E. coioidesandE. fuscoguttatusfrom previous studies were analysed. A total of 17 different parasite taxa were recognized forE. ongus, including 14 new host and four new locality records. This increases the known parasite taxa ofE. ongusby more than 80%. The ectoparasite fauna was predominated by the monogeneanPseudorhabdosynochus quadratusresulting in a low Shannon index of species diversity of the entire parasite community (0.17). By contrast, the species diversity excluding the ectoparasites reached the highest value recorded for Indonesian epinephelids (1.93). The endoparasite fauna was predominated by generalists, which are already known from Indonesia. This demonstrates the potential risk of parasite transmission throughE. ongusinto mariculture and vice versa. One-way analyses of similarity revealed a significantly different parasite community pattern ofE. onguscompared withE. areolatusandE. fuscoguttatusas well as minor differences withE. coioides. This finding refers to different habitat preferences of these epinephelids within the analysed size range.