Geographic distribution and environmental control of vertebral count in Ammodytes spp. along the northern Pacific coast of Japan

Abstract

To examine species composition and population structures in sand lance (Ammodytidae) along the northern Pacific coast of Japan, genetic analysis were carried out for specimens collected in 2014 from Otsuchi Bay, Iwate, Ishinomaki Bay, Miyagi, off Soma, Fukushima and Ise-Mikawa Bays, Aichi. The samples consisted of Ammodytes japonicus and Ammodytes heian, of which the latter is a recently described species. Neither species exhibited significant genetic differences among localities. Only A. japonicus was found in the most southern locality at Aichi, but it decreased northward to <90% in Miyagi and Fukushima and the two species occurred almost evenly in Iwate suggesting a latitudinal cline in their species composition along the northern Pacific coast of Japan, off Tohoku. The vertebral counts differed between A. japonicus and A. heian with modes of 65 and 63, respectively, but this characteristic did not differ significantly within a locality (Iwate). This suggests that the vertebral counts of Ammodytes spp. in Japanese waters are probably strongly determined by the environment than by a species-specific genetic trait.

Species of the genus Ammodytes (Ammodytidae) in the northwestern part of the Sea of Japan

“…Earlier, A. heian (EU200482) which COI sequence we used for comparative purpose, was collected here (Vostok Bay of the Sea of Japan, Table ) in 2006 but at that time being the only sand lance specimen it was identified as A. hexapterus (Kartavtsev et al, ). We approve that the only reliable means for the discrimination of these species and sand lances at all is unique haplotypes of mitochondrial COI sequences of type specimens (Aoyama et al, ; Orr et al, ).…”

“…The studied specimens of sand lances from Peter the Great Bay are very likely to be “pure” A. heian because they were caught in spring, at low water temperatures (2.6°C) and much north of the Subpolar Front. For sand lances around the Japanese Archipelago, it has been shown that the proportion of A. heian increases from south to north, while A. japonicus , on the contrary, decreases the same way (Aoyama et al, ; Tanaka et al, ). Moreover, most of the “pure” A. heian (Kim et al, ) were found in the northernmost point in the Laperouse Strait where, in addition to the species mentioned, the boreal species A. hexapterus was found.…”

“…The studied specimens of sand lances from Peter the Great Bay are very likely to be "pure" A. heian because they were caught in spring, at low water temperatures (2.6°C) and much north of the Subpolar Front. For sand lances around the Japanese Archipelago, it has been shown that the proportion of A. heian increases from south to north, while A. japonicus, on the contrary, decreases the same way (Aoyama et al, 2017;Tanaka et al, 2016).…”

“…The only reliable means for the discrimination of the sand lances is unique haplotypes of mitochondrial COI sequences of type specimens (Aoyama, Yoshinaga, Tanaka, & Ishii, 2017;Orr et al, 2015;Tanaka et al, 2016) although their ranges may be scattered by the unidirectional hybridization as inferred form microsatellites data (Kim et al, 2017). The aim of our study was to ascertain the species composition of the genus Ammodytes in northwestern part of the Sea of Japan.…”

Circadian Rhythm and Endocrinological Control on the Swimming and Sand Burrowing Behaviors of Japanese Sand Lances Ammodytes spp. (Uranoscopiformes, Ammodytidae)

“…The experimental fish were obtained from two localities in Japan: The Sea of Itsuki in the Seto Inland Sea, Ehime Prefecture (33°55′N, 132°44′E) in mid-April between 2018 and 2021, and Otsuchi Bay, Iwate Prefecture (39°20′N, 141°56′E) in late-May 2018. The former was a single species of western sand lance, A. japonicus Duncker and Mohr, 1939, and the latter was a mixed population of A. japonicus and peaceful sand lance, A. heian Orr, Wildes, and Kai, 2015 (Orr et al, 2015; Tanaka et al, 2016; Aoyama et al, 2017). However, it should be noted that the taxonomic validity of A. heian remains controversial (Han et al, 2012; Ren et al, 2015; Kim et al, 2017).…”