The distribution of two sympatric crabs of the genus Plychognathus, P. ishii and P. capillidigitatus, occurring estuarine environments in Kochi Prefecture was studied from December 2004 to October 2005. Previously known localities for P. ishii and P. capillidigitatus in Kochi Prefecture were 12 and five, respectively. This study confirmed 18 and 12 new localities for each species. These two crabs were common in estuarine environments from central to western Kochi Prefecture. Their occurrence could not be confirmed in rivers where its mouth frequently closed by wave actions, and in rivers where its bed and banks protected artificially.
The distribution of two camptandriid crabs, Deiratonotus cristatus and D. japonicus, were studied on the basis of 380 specimens collected in 2004 and 2005. from the brackish waters in Kochi Prefecture, Japan. The former species was abundant on intertidal sandy-mud bottoms of the innermost part of Urado Estuary and water pools formed during the ebb tides near the mouth of the Niyodo River. Specimens of D. japonicus were frequently collected from pebby bottoms in the rivers from eastern to western Kochi Prefecture. Although many localities for these species were confirmed than previous studies, their habitats seemed to be easily affected by various human activities.
Crabs inhabiting brackish rivers and estuaries on the southern coast of Tokushima Prefecture were studied on the basis of 169 specimens collected in August and October 2005. The occurrence of 24 species belonging to 19 genera in 5 families were recognized. The following species seemed to be zoogeographically important: Halicarcinus coralicola, Neorhyunchoplax okinawaensis, Ura lactea, Acmaeopleura parvula, Ptychognathus capillidigitatus and P. ishii, Chasmagnathus convexus, Helice sp., Nanosesarma gordoni and Parasesarma acis.
The distribution of Nanosesarma minutum was studied on the basis of 336 specimens collected in 2004 and 2005. This study showed that N. minutum commonly occurred among bivalves and holdfasts of seaweeds attached to the substrata in estuarine enviroments on the coasts of central Kochi Prefecture.
Stomatopod crustaceans of the genus Harpiosqulla in the family Squillidae were studied on the basis of 141 specimens collected by bottom trawlers from Tosa Bay. The following four species were recognized: H. harpax( de Haan, 1844), H. ammamdalei(Kemp, 1911), H. melanoura Manning, 1968, and H. sinensis Liu et Wamg, 1998. In the Japanese fauna, H. melanoura has been represented only by two specimens, the first from Kochi Prefecture and the second from Osaka Bay, but 12 additional specimens were collected during this study. Harpiosquilla sinensis frequently collected at Saga fish market (33°04′18″N，133°06′55″E）is reported for the first time in Japanese waters.
The occurrenc of gobies (Family Gobiidae) in the southern region of Urado Estuary in Kochi City was studied from April 2004 to January 2005. A total of 27 species belonging to 22 genera were recorded. Acanthogobius lactipes (endangered species of Kochi Prefecture), Apocryptodon punctatus (vulnerable species), two near endangered species Drombus sp. and Pseudogobius masago, and Bathygobius hongkongensis were first obtained from Urado Estuary. Specimens of Psammogobius biocellatus and Oxyurichthys ophthalmonema represented the second record for each species in Kochi Prefecture. The occurrences of the following four endangered species of Kochi Prefecture were also confirmed: Callogobius tanegasimae, Eutaeniichthys gilli, Periophthalmus modestus and Taenioides cirratus. These facts strongly suggested that Urado Estuary is one of the important brackish water environments in Kochi Prefecture.
Fishes from the Shinbori River in central Kochi City were studied. Nine specimens confirmed the occurrence of Lates japonicus, one of the critically endangered fishes of Kochi Prefecture. Four specimens of Eleotris oxycephala designated as one of the near endangered fishes of Kochi Prefecture were collected. In addition, a pipefish Hippichthys (Hippichthys) heptagonus was first recorded from Kochi Prefecture, representing the northernmost record of this species. The occurrence of L. japonicus and pipefishes seemed to be closely related with Zostera japonica growing on the riverbed.
A brackish water potamidid snail Cerithidea cingulata was studied in Uranouchi Inlet and Susaki Bay. In 2000, this species was designated as one of the critically endangered species of Kochi Prefecture. Prior to this study, living individuals of C, cingulata were observed in 1981 on the intertidal sandy-mud flats in Uranouchi Inlet, known to be the only locality for living snails in Kochi Prefecture, according to a report in 2002. However, the species seemed to be extinct, because the living snails have not been seen after 1981. This study confirmed the occurrence of C. cingulata at two localities, Shimo-nakayama and Kongauchi, both in Uranouchi Inlet in 2005. In addition, a dead-shell of C. cingulata was obtained from Susaki Bay in 2005, where no living or fossil records of this species have been reported.
Roost usage during the hibernation by cave-dwelling bats was studied in Kochi Prefecture from 2003 to 2005. The following four species were found from the roosts: Rhinolophus ferrumequinum, Rhinolophus cornutus, Myotis macrodactylus and Miniopterus fuliginosus. The number of roosts used by bats was highest in R. ferrumequinum, though R. cornulus was most abundant among the four species. Although the hibernation colony of M. fuliginosus in the Ryugado cave had been reported, the occurrence of this colony was not confirmed in the present study.
Avifauna and vegetation were studied in the Kuroson Natural Observation Forest, Kochi Prefecture. A survey stand was set in the old-growth natural forest in warm-temperate zone where 640-700m above sea level was. A total of 25 bird species, including 19 in the summer and 16 in the winter, were record in the stand. Frequently observed birds were Parus major (great tit), Troglodytes troglodyies (wren), Sphenurus sieboldii (japanese green pigeon) and Cyanoptila cyanomelana (blue-and -white flycather) in the summer, while Fringilla montifringilla (brambling), Hypsipeles amaurotis (brown-eared bulbul). T. troglodyles and Parus ater (coal tit) in the winter. Dominant woody plants with a large basal area were Qurcus salicina, Carpinus laxiflora and Acer mono var. ambiguum.
We investigated the vegetation and flora of Naruyama area, Ino Town, a typical rural mountainous area in Kochi Prefecture. We listed 117 families and 567 species (including subspecies and variety) in the area of 2.2㎢. They consist of 73 spp. belonging to Pteridophyta, 6 spp. Gymnospermae, and 488 spp. Angiospermae which include 13 endangered species and 29 alien species. The alien species rate of this area was very low (5%) as compared with those of other areas. The differences in floristic composition and species diversity among community types were discussed based on 188 vegetation data collected from sample stands of seven forest types and many types of scrubs and herbaceous communities developing on roadside slopes and abandoned terraced paddy fields. The values of species diversity indices of slope stands maintained by frequent mowing around roads and paddy fields were very high, while those of abandoned terraced paddy fields were relatively low. The beta diversity between communities in Naruyama area was high, because various human disturbances such as cutting, mowing, clearing, plowing and burning, provided a variety of habitats for plants. In addition, serpentine areas Which have particular vegetation and flora, contributed to increase the plant species diversity of Naruyama area. However, the increase of abandonment of arable fields and vegetation succession following after that has reduced the plant species diversity of this area.
Two interesting crabs trawled from Tosa Bay and collected at Saga Fishing Port, Shikoku, Japan (33°04′25″N,133°06′55″E) are reported. A single specimen of lecosiid crab Philyra misagoana represents the third record of this rare species, and also the first record from Shikoku Island. A heterosexual pair of Quadrella maculosa is reported for the first time from Shikoku Island. Figures and short descriptions for these two species are given.
The occurrences of the following three brackish water gastropods inhabiting sandy mud flats on the southern coasts of Tokushima Prefecture are reported: Stenomelania rufescens from the Kaifu Riverin Kaifu Town, and Cerithidea cingulata and Batil laria zomalis from Nasa Estuary in Shishi-kui Town. Stenomelania rufescens seems to be a rare species in Japan, and C. cingulata and B. zonalis were designated as the endangered species of Tokushima Prefecture, though recent status of these snails had been unknown in the present district.
In 2004, a specimen of neritid snail Neritlima sp. was collected from the mouth of the Misaki River at Tatsukushi in Tosashimizu City, Kochi Prefecture, southern Japan. Currently, this species has been known only from several rivers in Amami-ohshima Island and Okinawa Island, southernmost district of Japan. A brief description, Figure and comments on habitat of this species are given.
Specimens of syngnathid fish Hippocampus kuda were collected from Kamino-kae Fishing Port in Nakatosa Town and Shimizu Port in Tosa-shimizu City, both on the western coast of Kochi Prefecture. Prior to the present study, the occurence of this fish in KOchi Prefecture had been recorded only from Urado Estuary on the central coast of this district. This study reconfirmed the occurence of this fish in Urado Estuary. Various-sized specimens in the present study strongly suggested that spawing and nurturing of this species widely occurred on the central to western coasts of Kochi Prefecture. Fourteen dorsal and three anal fin rays, and 12 trunk rings found in a single specimen were recognized as new intraspecific variation of this species.