Blackfly larvae are known as hosts of fungi classified in Harpellales (Kickxellomycotina). To investigate the ecological aspects of these fungi, we collected larvae of Simulium (Simulium) japonicum monthly from a small stream in Iryuda, Odawara City, Japan from April 2016 to March 2017. We dissected the collected larvae and examined the harpellalean fungi inhabiting the larval midguts and hindguts. Harpella melusinae was observed in the midgut of every larva. Simuliomyces microsporus was collected from hindguts in the spring and autumn–winter seasons, whereas Pennella angustispora was collected from hindguts in the summer and winter seasons. A specimen Smittium sp. inhabiting the hindgut of the Simuliidae larvae was obtained. This genus is new to Kanagawa Prefecture, however, additional isolates need to be obtained for species-level identification. In addition, simultaneous infection of three species, (i. e., Harpella melusinae in midgut, and P. angustispora and Si. microsporus in hindgut), was observed in some individuals in February and November.

An adult male Macrophthalmus banzai (SL: 15.0 mm, SW: 23.4 mm) was collected with 28 individuals of M. japonicus from Ena Cove in Miura Peninsula, Kanagawa Prefecture, central Japan, in September 2016. This is the first record of M. banzai from Sagami Bay. This is probably the easternmost and northernmost record of this species in Japan.

The fish fauna of the Sekine River, a small river system in the Miura Peninsula, Kanagawa Prefecture, was investigated in May and November, 2016. A total of 10 species belonging to 4 families (Anguillidae, Plecoglossidae, Mugilidae and Gobiidae) were recorded. Rhinogobius brunneus, a near threatened species according to The Red Data Species in Kanagawa Prefecture 2006, was distributed along the entire river and its tributaries. These facts emphasize the ecological and conservational importance of the Sekine River.

Eight species were recorded for the first time in the Shimoyama River system. The survey was conducted between September and October 2016 in the lower reaches of the Shimoyama River and in one of its tributaries, the Yokote stream. Five tropical/subtropical species (Lutjanus argentimaculatus, Eleotris melanosoma, E. fusca, Redigobius bikolanus, and Scatophagus argus) were collected in its lower reaches of the Shimoyama River. Rhinogobius mizunoi and E. oxycephala, listed as near threatened (NT) and endangered (EN) species in The Red Data Species in Kanagawa Prefecture 2006, respectively, were also obtained in the Shimoyama River system. In addition, the photographic record of E.acanthopoma from the lower reaches of the Shimoyama River in September 2013 was also described.

Two specimens of Taractes rubescens (Jordan & Evermann, 1887) (Perciformes: Bramidae) were recorded from Sagami Bay, Japan. The first specimen (205.8 mm SL) was collected at Umezawa Beach and the second specimen (610.0 mm SL) at Fukuura. Both specimens were caught by set net and represent the first records of the species from the bay. The species is characterized by the following combination of characters: origin of dorsal fin behind posterior end of opercle; origin of anal fin distinctly behind pectoral-fin base; dorsal and anal fins covered with small scales, not depressible; dorsal contour of head almost straight; large keeled scales along lateral mid-line of caudal peduncle. Morphometric and meristic data are provided.

Two specimens of Trichiurus sp. 2 sensu Nakabo, 2000 were collected from eastern Sagami Bay, southern Japan, in November 2012 and January 2017. These specimens represent the first records from Sagami Bay, and the northernmost records for the species. The occurrence of T. sp. 2 from Sagami Bay in winter is attributed to transportation by the warm Kuroshio Current in summer or autumn, and suggests that survivability is affected by the development of a body of warm water.

The endemic species Rhacophorus arboreus (Anura: Rhacophoridae) is widely distributed through main island of Japan, but it has always been considered as rare in Kanagawa Prefecture. The first records of this species of Kanagawa Prefecture, in a limited area, date from 1983. This study is the first report of Rhacophorus arboreus from Hakonetown, in the western part of the Prefecture. In Hakone-town this species was first recognized from the Kojiri area, Shirayuri-dai-enchi, near Lake Ashinoko in 2005, and it has expanded its distribution toward the Northwest, Sengoku-hara, from 2009 onwards. There are three possible centres of origin for the Hakone-town population: Nagao, Gotenba-city, Shizuoka Prefecture; Mt. Kintoki, Minamiashigara-city; and Yugawara-town. Of these three, Nagao, Gotenba-city is closest to Hakone-town and the species may have extended its range from Nagao to the Kojiri area of Hakone-town.