Larvae, Juveniles, and Young of the Gobiid Fish, Astrabe lactisella

Abstract

The gobiid fish, Astrabe lactisella Jordan and Snyder, attaining to 50 mm in total length in adulthood, has seldom been collected from rocky tide pools of the middle and western Japan.
The planktonic larvae and juveniles of A. lactisella, measuring from 6.7 to 12.0 mm in total length, were collected with boat seine of minnow net, working to catch mainly the larvae of the anchovy at the coastal water of Suzaki, Kochi Pref. (33°22.7'N, 133°17.4'E), in 1954 and 1955.
The planktonic larvae and juveniles, ranging from 4.9 to 15.4 mm, were also collected with fish lamp in Nomo Bay near Nagasaki (32°35.3'N, 129°45.5'E) during 1969 to 1971.One of the juveniles, about 12 mm in total length, was fed with copepods and reared for seven days in a 40-liter plastic aquarium and grew up to a 13.8 mm young entering into the early bottom life, while the late planktonic juveniles, ranging from 12.0 to 15.4 mm in total length, came around fish lamp in the bay.
The characters of the planktonic larvae of the fish, being about 5 mm, are as follows.The body is compressed moderately and rather stocky in appearance.The head is rather compressed with large eyes.The anus opens in the posterior part of body.The rudiment of the swim bladder begins to appear.The myomeres are 29 (14+15) or 30 (14+16) in each individual.Melanophores appear on the side of body except the posterior part of the tail.The body color is blackish.
The number of the spines and rays of each fin is nearly complete in a 11.1mm planktonic juvenile as shown in the following fin formula: D.III-11;A.10;P₁ 25;P₂ 5.
The planktonic larvae and juveniles were collected in both coastal waters of Suzaki and Nomo during early February to early May.The spawning season of the present species is probably from late winter to early spring in these districts.