Satoshi Tomano

• Fellow at The University of Tokyo

In some squids, such as those in the family Loliginidae, upon copulation, females receive and store male-delivered sperm capsules, spermatangia, at two different body locations: the buccal membrane and the distal end of the oviduct. This insemination site dimorphism is associated with alternative reproductive strategies. However, in Loliolus sumatr...

Sperm morphology is generally uniform within a species due to selective pressures that act to achieve better fertilization outcomes under postcopulatory competitive circumstances. Therefore, polyandry that intensifies post-mating sperm competition should constrain intraspecific sperm polymorphism. Contrary to this paradigm, we previously found that...

Deep-ocean biology has been the least explored—although rapidly growing—area of research. In particular, behavior, reproduction and ecology of deeper-living squids remain poorly documented due to the extreme difficulties of encountering and capturing them. Here we report on a mature/maturing female giant squid, Architeuthis dux, caught as by-catch...

The black sea bream Acanthopagrus schlegelii (Bleeker, 1854) is a commercially important species in Japanese waters. Assessing its population structure is essential to ensure its sustainability. In the Northwestern Pacific, historical glacial and interglacial periods during the Pleistocene have shaped the population structure of many coastal marine...

In Hiroshima Bay, parasitic isopods of the genus Mothocya infest the black sea bream Acanthopagrus schlegelii (Bleeker, 1854) and the Japanese halfbeak Hyporhamphus sajori (Temminck and Schlegel, 1846), two fish species that are abundant and commercially important in the Seto Inland Sea of Japan. Immature and mature Mothocya individuals can infect...

Male animals are not given equal mating opportunities under competitive circumstances. Small males often exhibit alternative mating behaviours and produce spermatozoa of higher quality to compensate for their lower chances of winning physical contests against larger competitors [1]. Because the reproductive benefits of these phenotypes depend on so...

Identification of the population structure of harvested species is the first step in the management of wild fisheries. Although the marbled rockfish Sebastiscus marmoratus is a commercially important species in Japan, information on the population structure of this species is limited. We analyzed 646 individuals of S. marmoratus from 13 sampling lo...

Ten novel microsatellite markers were developed for the western sand lance, Ammodytes japonicus, which has decreased significantly in many fishing grounds because of overexploitation and deterioration of its habitat. The 10 markers were successfully amplified in two sets of multiplex polymerase chain reactions (PCR). A total of 63 individuals colle...

The relative contribution of Sepioteuthis sp. 1 and Sepioteuthis sp. 2 to oval squid fishery stocks in western Japan was examined using microsatellite DNA and partial sequences of mitochondrial cytochrome oxidase subunit I. A total of 1718 Sepioteuthis spp. individuals from 19 populations were identified to determine the proportion of each species...

The present study seeks to incorporate a highly variable DNA barcode marker, additional to the standard regions of the cytochrome oxidase I gene and the 3′ end of the 16S large ribosomal subunit (16S rRNA), for a more effective species-level identification among cephalopods. Thus, we evaluated whether the 5′ end region of the 16S rRNA gene can be s...

The level of genetic diversity and population differentiation of oval squid Shiro-ika Sepioteuthis sp. 2 around mainland Japan were examined using highly polymorphic DNA markers. Ten microsatellite loci showed relatively low genetic diversity (average observed heterozygosity H O = 0.68, overall mean number of alleles N A = 10.0) as compared with ot...

Yellowfin black seabream Acanthopagrus latus is an important fish species found in the coastal waters along the Pacific coast of Japan. The genetic variability of A. latus was estimated by analyzing seven populations in western Japan, using highly variable microsatellite loci (n=312) and the sequence variability in the mitochondrial DNA (mtDNA) (n=...

Stock identification of oval squid Sepioteuthis spp. in the coastal waters of Tanega-shima Island were examined using ten polymorphic microsatellite loci and partial nucleotide sequences of cytochrome oxidase subunit I (COI) in the mtDNA. Also, we suggested spawning depth through eggs identification collected from artificial reefs from 20-50 m in d...

Stable isotopes can provide useful knowledge about sources and processes within an ecosystem. The stable isotopes of carbon (δ13 C) and nitrogen (δ15 N) were used to investigate trophic relationships of relatively commercially important 21 finfish species, cephalopods in Hiroshima Bay. Among 21 finfish species, the lowest mean δ15 N of 14.4‰ was re...

The oval squid Sepioteuthis lessoniana is one of the most economically important squid species in Japan; however, its population structure is poorly understood due to the lack of hypervariable markers. Such information is critical for managing sustainable fisheries, as well as for ensuring the existence of wild S. lessoniana stocks. Eleven candidat...