Histological observation of spermatogenesis of the scleractinian coral, Porites cylindrica in Misong, Pola Bay, Oriental Mindoro

Abstract

Currently there are no histological studies regarding spermatogenesis of Porites cylindrica in the shallow waters of Pola Bay. This study was conducted in Misong, Pola, Oriental Mindoro (13° 13' 33.6" N, 121° 26' 0.9" E) to describe the histological description of the spermatogenesis of P. cynlindrica within one lunar month. Specifically this study aimed to categorize the developmental stages of spermatocytes based on histological characteristics (tissue lining/layer, shape, presence of zooxanthellae and staining properties) and relative size of gametes and to estimate the different sizes and relative abundance of spermatocytes for each specific reproductive stage and lunar day. Ten colonies were tagged, with two fragments were collected randomly every weekend from December 2015 to January 2016. Sample fragments were fixed with Zenker’s solution, decalcified with buffered HCl solution, preserved in 10% formalin, and histologically processed by the Philippine Kidney Dialysis Foundation (PKDF). Samples were then categorized. Results showed that all samples were containing spermaries with geometric mean diameter (GMD) of 73.24µm, 90.69µm and 77.74µm for Stage II, Stage III and Stage IV, respectively. Stage II exhibits the highest percentage relative abundance followed by Stage III and Stage IV and all stages were consistently present throughout the sampling dates. This may indicate that spermatogenesis can be occurring monthly and simultaneously. This study reveals that P. cylindrica in Pola Bay have male colonies with exclusively male gonads.