Myxobolus nagaraensis (Myxozoa: Myxosporea) was first reported in 2007 in
freshwater gobies (Rhinogobius sp.) from Nagara River in the Gifu Prefecture, Japan.
Although freshwater gobies are common fish species found in rivers of the Kanagawa
Prefecture, infection of these fishes with M. nagaraensis has not been reported. Therefore,
this study surveyed for M. nagaraensis infection in freshwater gobies from Sakai River,
which runs through the Kanagawa Prefecture. Freshwater gobies were captured using hand
nets at different locations along the Sakai River in November 2017 and February 2018.
Diseased fish displaying enlarged abdomens and nodules in the caudal peduncle were caught
from 2 locations which were 20 km apart. Cysts excised from these diseased fish contained
parasitic spores resembling the morphology of M. nagaraensis. DNA was extracted from
the cysts and the small subunit ribosomal RNA gene was amplified (SSU rDNA). Based on
homology search, the amplified partial product was 99.6% identical with M. nagaraensis
SSU rDNA (Accession no. AB274267). This is the first report of M. nagaraensis infection
in freshwater gobies from a river in Kanagawa. Since prevalence of the parasite and its
pathogenicity to the goby populations are still unclear, continued examination of other rivers
in the prefecture is crucial.
Algal floras of intertidal and infralittoral zones that were located on the rocky
shore and the artificial coast in Enoshima Island in Sagami Bay of central Japan, were
carried out from May in 2016 to April in 2018. In this study, totally 105 species of algae in
which contained 10 species of green algae (Chlorophyceae sensu lato), 25 species of brown
algae (Phaeophyceae) and 70 species of red algae (Rhodophyceae sensu lato) were recorded.
Numbers of species (from 21 to 46) at each stations in Enoshima Island were quite variable.
Seedlings of three tropical/subtropical coastal plants (Scaevola taccada, Ipomoea
pes-caprae, and Canavalia lineata) were found on Jogashima Island, located on the southern
tip of the Miura Peninsula in Kanagawa Prefecture, Japan. This was the first recorded
occurrence of S. taccada from an area north of Kyushu in Japan. The S. taccada seedling
observed remained on the island over the winter of 2016, but disappeared in October 2017,
which may have been due to the storm surge or high waves caused by Typhoons no. 21 and
22 in 2017. Despite the study site being situated within the distribution of C. lineata, the
seedlings of this species were also absent after these typhoons hit the island. The seedling
of I. pes-caprae observed did not survive the winter of 2016, which may have been owing to
human activity. These results show that disturbances to germination sites directly impact
the establishment of coastal plants.
An sub-adult male of Plagusia immaculata (CL: 20.1 mm, CW: 20.8 mm) was
collected from Sagami Bay (around Enoshima Island), Kanagawa Prefecture, central Japan
in July 2018. This is the first record of P. immaculata from Sagami Bay. This should be the
northernmost record for this species.
Two individuals of Catoptometra rubroflava (A. H. Clark, 1907) (Arm Length:200–220 mm) were collected from the mouth of the Koajiro Inlet, Misaki, Miura Peninsula, Kanagawa Prefecture, central Japan, in 22 May 2018. This is the second record of this species from Sagami Bay since the first discovery in 104 years.
We have studied fish fauna of the southwestern coast of the Miura Peninsula since
1988. Previous to this current study, 484 species of fishes were recorded. Sixty two species
are newly added in the present study undertaken from September 2012 to August 2018.
Oncorhynchus kisutch, Lampanyctus alatus, Pseudamia gelatinosa, Scorpaenodes varipinnis,
Scorpaenopsis venosa, Stegaster fasciolatus, Kochichthys flavofasciatus, Acanthurus
leucopareius, Acanthurus maculiceps, and Acanthurus nigricauda are the first record on the
basis of specimens from Sagami Bay.
Morphological changes accompanying the growth of the shortspine spurdog,
Squalus mitsukurii (Squaliformes: Squalidae) were examined in ten specimens of 304.1 to
952.6 mm in total length (TL), collected from Sagami and Suruga bays, Japan. The caudal
fin of specimens less than 330 mm TL has a broad white margin on the upper lobe, and the
lower lobe is overall white. The upper lobe changes from having a rounded tip to a pointed
tip at total lengths between about 450 to 500 mm, and the white posterior margin of the
caudal fin also narrows in specimens of this size. The dermal denticles on the anterior part of
the first dorsal fin in smaller specimen are arranged with a space between each one, bearing
a tricuspid leaf-like portion and a stalk at the base. On the other hand, the dermal denticles
change to a rhomboidal shape and become arranged in a muriform pattern without spaces
between them in larger specimens. In comparison with Squalus sp. 2 specimens less than
324.1 mm TL, it is suggested that S. mitsukurii specimens of the same size are distinguished
in having the second dorsal spine less covered with dermal denticles.
We investigated the habitat of the endangered Japanese eight-barbel loach, Lefua
echigonia (Cypriniformes: Cobitidae). This fish inhabits a stream that adjoins a construction
site on the university farm. The aim of this study was to document their occurrence and
growth during and after construction. During construction, an accident occurred that led
to the death of all the Japanese eight-barbel loaches due to the drainage of the stream. The
results of the study confirm that there was no significant change in the population density
of several investigated sections of the stream, even at the site of the accident. Moreover,
the growth of the recaptured individuals was assessed using the mark-recapture method，
and the effect of the accident was considered to be small. Despite the deterioration of water
quality in the stream during construction, the fish were still expected to swim upstream
from the river into the stream, because the habitat structure and continuity of the stream
with the Misawa River were not lost. Therefore, it was possible for the stream to re-emerge
as a habitat for the re-establishment of the Japanese eight-barbel loach.
Two Risso's Dolphins (Grampus griseus; Cetacea: Delphinidae) were recorded in
the Sagami Bay in the first half of 2018. The first individual was a young male, with a body
length of 2550 mm, stranded on the Katase Nishihama Coast of Fujisawa City on January
28, 2018. The second individual was a male calf with a body length of 1840 mm, found
drifting along the Tsujido Higashi Kaigan Coast of Fujisawa City on June 2, 2018. There
have been 54 reports of this species from the coasts of Sagami Bay and Tokyo Bay, recorded
over 60 years between 1958 and 2018. This study reports on the sighting of the two stray
individuals in 2018, as well as presents an overview of the observational records from the
past 60 years.