2022 Volume 59 Issue 3-4 Pages 113-129
The occurrence patterns of the larval and juvenile gluttonous goby, Chaenogobius gulosus in Omori Furusato-no-Hamabe Park in the innermost portion of Tokyo Bay were investigated by monthly sampling. Four types of gear were used: a small seine net towed off the sandy beach and over the tidal flat between January 2015 and December 2018; basket nets placed at a wharf with a vertical seawall between January 2016 and December 2018; a hand net used at the wharf between January 2016 and December 2016; and a set net placed on the tidal flat and in the waterway from the tidal flat to a tidepool between January 2016 and December 2018. Ontogenetic intervals were determined from the morphometric characters of 274 specimens（3.93–41.7 mm body length［BL］）and the osteological characters of 92 cleared and stained specimens（3.93–25. 5 mm BL）. In total, 124 individuals（3.78–30.3 mm BL）were collected from the sandy beach, 447 （3.98–72.9 mm BL）from the tidal flat, 239（22.8–107 mm BL）from the wharf using basket nets, 221（6.30–45.2 mm BL）from the wharf using a hand net, two（17.3 and 30.4 mm BL）from the tidal flat using a set net, and one（4.50 mm BL）from the waterway. Based on morphological development, the developmental stages of the larvae and juveniles were divided into four phases each of swimming and feeding functions and five phases of relative growth. The occurrence patterns and ontogenetic intervals imply that hatched larvae are transferred to the sandy beach or tidal flat by flow, occupy these habitats while their swimming and feeding functions develop, then begin migrating to the wharf at 8–9 mm BL. Subsequently, juveniles settle on the seafloor; they then migrate and settle at the wharf until ~35 mm BL. C. gulosus utilizes different habitats in this artificially established seaside zone depending on the developmental phase from hatching to immature individuals, although the distribution of mature individuals remains unclear.
https://ror.org/048nxq511 