Comparative genomics highlights the virulence and evolutionary trajectory of white spot syndrome virus.

White spot syndrome virus (WSSV) poses a significant threat to shrimp aquaculture, leading to substantial economic losses. This study aims to evaluate the virulence and evolution of recent WSSV outbreaks in Japan. Shrimp infected with WSSV were collected from Okinawa, Miyakojima and Miyazaki prefectures, yielding a total of seven isolates.

Age, growth and reproductive biology of a widespread coral reef fish, yellowfin goatfish Mulloidichthys vanicolensis (Valenciennes, 1831).

Yellowfin goatfish Mulloidichthys vanicolensis (Valenciennes, 1831) is a widely distributed commercial fish in the Indo-Pacific. The authors examined the age, growth, sexual maturity and spawning season of M. vanicolensis around Okinawa Island, southwestern Japan, based on sectioned otolith and gonadal histology.

Comparative genomics of four strains of the edible brown alga, Cladosiphon okamuranus.

Background: The brown alga, Cladosiphon okamuranus (Okinawa mozuku), is one of the most important edible seaweeds, and it is cultivated for market primarily in Okinawa, Japan. Four strains, denominated S, K, O, and C, with distinctively different morphologies, have been cultivated commercially since the early 2000s. We previously reported a draft genome of the S-strain.

Comparative age-specific demography of four commercially important deep-water snappers: implication for fishery management of a long-lived lutjanid.

Lutjanid snappers belonging to the subfamilies Apsilinae and Etelinae are commercially valuable components of tropical deep-water fisheries throughout much of the Indo-Pacific region. Based on age assessment using sagittal otoliths, the age-specific demographic characteristics of four deep-water snappers, Etelis coruscans, Paracaesio caerulea, Pristipomoides filamentosus and Pristipomoides sieboldii, in the Okinawa Islands, southwestern Japan, were examined, and the results were discussed for fishery management. Age validation using edge-type analysis demonstrated that opaque zones in all species were formed once per year and were considered valid annual growth increments.

Study on expelled but viable zooxanthellae from giant clams, with an emphasis on their potential as subsequent symbiont sources.

Unlike most bivalve shellfishes, giant clams (tridacnines) harbor symbiotic microalgae (zooxanthellae) in their fleshy bodies. Zooxanthellae are not maternally inherited by tridacnine offspring, hence, the larvae must acquire zooxanthellae from external sources, although such algal populations or sources in the environment are currently unknown. It is well known that giant clams expel fecal pellets that contain viable zooxanthellae cells, but whether these cells are infectious or just an expelled overpopulation from the giant clams has not been investigated.

Molecular Phylogeny Demonstrates the Need for Taxonomic Reconsideration of Species Diversity of the Hydrocoral Genus Millepora (Cnidaria: Hydrozoa) in the Pacific.

Millepora (Cnidaria: Hydrozoa: Milleporidae) spp. are distributed throughout shallow subtropical and tropical marine environments in the Indo-Pacific and Caribbean-Atlantic, and have traditionally been identified using pore characteristics and colony form. Until now, representatives of Millepora spp.

Zooxanthellal genetic varieties in giant clams are partially determined by species-intrinsic and growth-related characteristics.

Giant clams (tridacnine shellfishes) are large bivalves that inhabit tropical and subtropical waters and harbor the symbiotic microalgae zooxanthellae, which consist of diverse phylotypes (clades). Each clade exhibits unique physiological characteristics, and the cladal composition may influence the host's survival and its ability to tolerate environmental changes. Using quantitative PCR (qPCR) assays, we investigated the zooxanthellal genetic clades in Tridacna crocea (n = 93) and Tridacna squamosa (n = 93).

A draft genome of the brown alga, Cladosiphon okamuranus, S-strain: a platform for future studies of 'mozuku' biology.

The brown alga, Cladosiphon okamuranus (Okinawa mozuku), is economically one of the most important edible seaweeds, and is cultivated for market primarily in Okinawa, Japan. C. okamuranus constitutes a significant source of fucoidan, which has various physiological and biological activities.

Transient sex change in the immature Malabar grouper, Epinephelus malabaricus, androgen treatment.

To clarify the cause of sex change recovery after the withdrawal of androgen treatment, immature female Malabar grouper were fed a diet containing 17alpha-methyltestosterone (MT) at 50 μg/g for 7 mo and then a normal diet for 6 mo. The MT brought about precocious sex change from immature ovaries to mature testes with active spermatogenesis, including the development of spermatozoa, and sex change reversed soon after MT treatment withdrawal. This result indicates that precocious sex change in immature Malabar grouper with oral MT treatment is impermanent.