GROWTH OF BIVALVES BASED ON ALLOMETRIC RELATIONSHIP AND A TIME SERIES OF LENGHT-FREQUENCY DATA

Abstract

The relationship of shell length with wet,dry and shell weight of the bivalve species-Cyclina sinesis, Gafrarium tumidum, Katelysia japonica, Psammotaea elongate, Quidnipagus palatum and Semele carnicolor from Tomigusuku intertidal flat, Okinawa, Japan were measured. In P.elongata and Q.Palatum (predominant species), relationship between shell length and wet weight was examined monthly. There were a significant relationship and strong correlation between shell length and wet, dry and shell weight in all species (p<0.01;r2>0.818). The regression lines were significantly different by species (ANCOVA p<0.01). Allometric growth by wet,dry and shell weight in bivalve species indicates the highest rate in G.tumidum and lowest in P.elongata. The regression lines between shell length and wet weight were significantly different by months in P.elongata (ANACOVA p<0.05) and Q.palatum (ANACOVAp<0.01). Growth of the bivalves in P.elongata and Q.palatum on the tidal flat were measured and compared. The von Bertalanffy growth function (VBGF) was applied on a length-frequency data of the both species. The growth parameters were determined using electronic length frequency analysis (ELEFAN) module in “FiSAT” program. The maximum length recorded during sampling for P.elongata and Q.Palatum were 80.1 and 54.9mm, respectively. However, as indicated by asymptotic length, L∞of VBGF growth constant, K for P.elongata and Q.palatum were 0.65 and 0.58 year -1, respectively. These indicate that on the tidal flat, P.elongata grows faster than Q.palatum.