Habitat suitability of eight threatened gobies inhabiting tidal flats in temperate estuaries: model developments in the estuary of the Kuma River in Kyushu Island, Japan

A slender symbiotic goby hiding in burrows of mud shrimp Austinogebia edulis in western Taiwan

“…Biological and ecological investigations need more follow-up support. Proven habitat need to consider the interspecific differences in environmental factor preference and tolerance of gobies inhabiting tidal flats [67]. The protection of suitable habitats will be an important biodiversity conservation measure.…”

Revising the distribution of a threatened goby, Apocryptodon punctatus (Perciformes, Oxudercidae), in Japan with the discovery of an isolated population

“…This mudflat has a recorded salinity of 2.1–2.9 at low tide, maintaining a higher salinity level than an adjacent stream (zero salinity), and is composed of a maximum of more than 45% silt and clay (on average more than 35% and 31% in spring and autumn respectively). The occurrence rate of Apocryptodon punctatus reaches its maximum at a silt and clay level of around 60%, in the estuary of Kuma-gawa River, western Kyushu ( Koyama et al 2016 , Akihiko Koyama, pers. comm.).…”

“…In order to elucidate the condition of the environment, salinity and water temperature in tidal pools on the mudflat where the specimens of Apocryptodon punctatus were captured were measured at the time of fish sampling using YK-31SA (Sato Shouji Inc., Kawasaki) and TT-508 (Tanita, Tokyo). In addition, the percentages of silt and clay were calculated following Koyama et al (2016 a) using a sediment core of 2.5 cm depth and 5 cm diameter. These water environment and sediment samplings were repeated five times and 20 times on each collection date (27 September 2015 and 8 April 2016) respectively.…”

“…This species inhabits silty mudflat environments utilizing the burrows of alpheid shrimps ( Dôtu 1961 ; Koyama et al 2017 ). It is an ecological indicator for natural tidal flat environments ( Suzuki 2003 ) and recent ecological studies have shown habitat preferences and symbiotic partner specificity for the species ( Koyama et al 2016 , 2017 ). Although the species is considered threatened because of the vulnerability of its habitat ( Iwata 1997 , Suzuki 2003 ), recent increases in field sampling efforts have resulted in the discovery of several new locality records ( Inui 2015 ).…”

Classification of River Esturies Using Physical Environment and Benthic Fauna Basesd on Ecoregion Concept

“…(1) 生物データ 本研究では，カニ類相及び貝類相を解析対象とした． これまで，汽水性魚類に着目し河口域の生息環境を評価 した研究 14), 15) はみられるが，汽水性魚類は偶発的に河川 に侵入する種も多く，当該地点のハビタットの状況を直 接反映する生物として充分でない．一方，貝類やカニ類 は、水質や底質などに影響されやすく，自力での移動能 力が低い種や特殊な環境条件下でのみ出現する種も多く， その場所の環境の現状を直接反映しており 16) ，環境の良 否を判断する適切な生物と考えられる． 生物データは国土交通省が実施した水辺の国勢調査 (1993 年～2012 年)の対象種の有無データを用いた． 各河川 4～5 回の調査が実施されているが，一度でも生 息が確認された場合は，当該河川に生息するものとした．…”