Yen-Ting Lin

A new cryptic species of Rhinogobius within the R. similis species complex, Rhinogobius feitsuiensis sp. nov., is described based on 12 specimens collected from the Feitsui Reservoir, northern Taiwan. Although R. feitsuiensis shares the unique transverse cheek papillae pattern typical of the R. similis complex, it differs from the three other species in this complex by having three longitudinal rows of papillae, with three to four transverse rows between the eye and the upper longitudinal row and none between the upper and lower longitudinal rows. Rhinogobius feitsuiensis differs from R. similis by having a shorter second dorsal‐fin base (11.9–14.1% SL vs. 17.4–20.6% SL in topotypic R. similis ) and body depth at pelvic‐fin origin (12.1–14.7% SL vs. 18.3–19.3% SL in topotypic R. similis ). Further, R. feitsuiensis also has more pre‐dorsal ctenoid scales (12–13 vs. 8–12 in topotypic R. similis ). Phylogenetic analysis based on mitochondrial COI gene sequences supports R. feitsuiensis as a well‐defined monophyletic lineage. The recognition of R. feitsuiensis increases the number of nominal species within the R. similis complex to four and unravels the cryptic diversity among the Rhinogobius similis complex in East Asia.

The jaguar cichlid ( Parachromis managuensis ), an invasive species native to Central America, was first recorded in Feitsui Reservoir, Taiwan, in 2014. From 2014 to 2024, 846 individuals were captured, with abundance increasing notably from 2018. Stomach content analysis revealed predation on native crustaceans ( Caridina , Macrobrachium ) and native fish ( Sinibrama macrops ), suggesting potential ecological impacts. Growth analysis indicated negative allometric growth and signs of growth retardation in larger individuals. The decline of S. macrops may be linked to increasing predation. This study marks the northernmost record of this species in East Asia and raises concerns about its ecological impact.

In this study, a single specimen of Pacific black scabbardfish Aphanopus arigato Parin, 1994 was collected at a depth of ~500 m near Dongsha Island in southwestern Taiwan (18°49′ to 20°45′N and 112°46′ to 116°15′E), on 14 March 2023. This is the southernmost record of A. arigato, with a significantly wide range extension from northern Japan, and southern Kuril Islands to the South China Sea. We also provide comparisons of the morphological measurements, first description of sagittae otoliths, and a partial sequence of the cytochrome oxidase subunit I gene for the specimen studied in this study.

Dongsha Island, situated in the northern part of the South China Sea, is surrounded by coral reefs and deep-sea habitats. The coastal areas of the atoll, a marine protected area, serve as important nursery habitats for many reef fish species. At the same time, the offshore deep-sea continental slopes are historically important fishing grounds. Although previous inventories primarily focused on coral reef fishes within the atoll listing 652 species from 73 families, comprehensive surveys of fishes from deeper waters have been incomplete. In this study, the species composition of the fish fauna around Dongsha was updated by analyzing large volumes of frozen bycatch from commercial deep-sea trawlers operating in the area for the past four years and reviewing the existing literature. The species list increased to 1087 species belonging to 167 families, including several documented as new records and potentially undescribed species. This updated checklist also includes images of each species and most of their sagittal otoliths. This will assist further taxonomic work and significantly enhance understanding of marine biodiversity in the South China Sea.

Indoor recirculating aquaculture systems make light control possible and enable the usage of specific coloured lights to promote the growth and immunity of aquaculture species. Five different LED wavelengths (white light [460 nm], red light [622 nm], green light [517 nm], blue light [467 nm], and the dark) were used in this study to evaluate growth and immunity in the glass eel stage of two high-valued anguillid species, Japanese eel (Anguilla japonica) and giant mottled eel (A. marmorata). There were no significant differences in growth of the Japanese eel among the groups after 12 weeks of feeding (p > 0.05); the survival rate of each group was over 95%. The giant mottled eel showed better growth in total length and body weight in the red light and dark groups (p < 0.05). Expression levels of immune-related genes were not significantly different between each group of the Japanese eel and the giant mottled eel (p > 0.05). The growth of the Japanese glass eel was not significantly sensitive to different LED wavelengths, while the giant mottled glass eel showed better growth under red light and dark environments. Neither eel species showed significant differences in innate immunity under different LED wavelengths.