Shell Dimension-Weight Relationship and Condition Index of the Invasive Mussel Mytella strigata in Sasmuan, Pampanga, Philippines

Abstract

A total of 300 Mytella strigata were collected at three sampling points in the mussel coastal demonstration farm in Sasmuan, Pampanga, and subjected to morphometric and gravimetric measurements for the evaluation of its growth pattern and condition index. Designated sampling sites were based on the distances to the river mouth (200 m, 400 m, and 600 m) with varying water quality parameters (temperature, salinity, pH, water velocity, and chlorophyll-a). Mussels in Site 2 had significantly larger shell dimensions (SL = 2.862 cm, SW = 1.458 cm, SH = 0.926 cm), shell weight (0.640 g), and total live weight (1.150 g). Significantly higher (p < 0.05) soft-tissue dry weight (0.083 g), however, was obtained in Site 3, while comparable (p >0.05) soft tissue weight was observed in Site 2 (0.364 g) and Site 3 (0.413 g). Nevertheless, mussels in all sites demonstrated negative allometric growth (b < 3). The length-weight relationship revealed a weak to moderate, positive correlation. A significantly higher (p < 0.05) condition index was obtained in Site 3, which could have been influenced by higher chlorophyll-a and substantially lower water velocity. As such, this signifies its potential to have a well-established population in this spatial distance (600 m) from the river mouth. Hence, regular harvest and product development is recommended as strategic options to control its proliferation.

Length – Weight Relationship of Bivalves and Gastropods from Mangrove Forest of Brgy. Nabago, Surigao City, Philippines

“…According to Zuschin and Stanton (2001), marine gastropods need strong shells strength to have a high capacity to live in unfavorable environmental conditions and as an adaptation to environmental stresses. The energy shell growth allocation is higher than the soft organ that shifts growth into a negative allometric pattern (Mendoza et al, 2019). As observed, cutting of mangrove stands and overharvesting of shellfishes are still practiced despite restrictions from the government agencies and local government units.…”