Length–Weight Relationship, Condition Factor, Gonadosomatic Index and Gut-Content Analysis of Planiliza planiceps (Valenciennes 1836) (Actinopterygii, Mugiliformes, Mugilidae) from the Four Major Estuaries of Gujarat, India

Planiliza planiceps (Valenciennes 1836) commonly known as tade-grey mullet is having non-carnivorous feeding habit, high-quality flesh, wide environmental resilience power and high fecundity make it a good candidate for poly-culture. A study was conducted on P. planiceps in the four major estuaries of Gujarat between June 2017 to March 2018. The significant results of the length–weight relationship were measured. The male populations were showing negative allometric (b < 3) growth in all the study sites i.e. , Sabarmati, Mahi, Narmada and Tapi estuaries. The female populations from Sabarmati and Mahi were showing isometric growth while from Narmada and Tapi were showing positive (b > 3) and negative (b < 3) allometric growth respectively. The Fulton’s condition factor of males and females was measured and the average condition factor in males were reported as 0.81 ± 0.08, 0.71 ± 0.11, 0.91 ± 0.18, 0.86 ± 0.15 and in females were reported as 0.90 ± 0.10, 0.82 ± 0.08, 0.87 ± 0.12, 0.97 ± 0.21 from the Sabarmati, Mahi, Narmada and Tapi estuaries respectively. The mean gonadosomatic index ( I G ) was observed 16.92 ± 2.46 from Sabarmati, 8.73 ± 1.39 from Mahi, 7.87 ± 1.56 from Narmada and 7.60 ± 1.34 from Tapi. Gut content analysis confirmed that P. planiceps consumes rotifers, copepods, phytoplankton such as Bacillariophyceae, Cyanophyceae, Ulvophyceae, Zygnematophyceae and Chlorophyceae; zooplanktons and fish eggs. The present study findings will be useful in the context of scientific management of tade-grey mullet fishery as well as to find out its aquaculture potential.