Age and growth of the mudskipper Boleophthalmus pectinirostris in Ariake Bay, Kyushu, Japan

By measuring the growth rings of the second pectoral radial bone, we estimated the age and growth of blue spotted mudskipper, Boleophthalmus pectinirostris, collected from mudflats at the mouth of the Tojin River running into Ariake Bay in Kyushu, Japan, between April 2001 and March 2002. We examined a total of 999 individuals ranging from 48 to 138 mm in standard length (SL). An additional opaque margin of radial bone was produced once a year, between September and November. The pattern of this increment was consistent with that in a previous study of a population in Ariake Bay, but differed from those of other studies in terms of the number of annual increments and/or the seasonal timing of the increment. The von Bertalanffy growth parameters derived from back-calculated and observed SL were as follows: back-calculated SL, L∞ = 116.3 mm, K = 0.799 year−1, and t0 = 0.70 year for males and L∞ = 109.5 mm, K = 1.097 year−1, and t0 = 0.55 year for females; observed SL, L∞ = 117.5 mm, K = 0.672 year−1, and t0 = 1.70 year for males and L∞ = 114.1 mm, K = 0.702 year−1, and t0 = 1.67 year for females. The maximum age was estimated at 7 years for males and 6 years for females. Compared with previous studies, the fish in our study had the slowest growth, smallest maximum size, and oldest maximum age in both sexes.