Length/Width-Weight Relationship of Giuris laglaizei Sauvage, 1880 and Evaluation of the Morphometric Variations among its Colormorphs in Lake Mainit, Northeastern Mindanao, the Philippines

Giuris laglaizei – a commercially valuable freshwater eleotrid fish found in Lake Mainit, the Philippines – has seen its population decline due to overharvesting and various anthropogenic activities affecting its habitat. The study evaluated the relationship between length/width- weight, the condition factor (CF) of G. laglaizei, and the morphometric variations among its colormorphs. The study reports the occurrence of new colormorph (light pink) in the lake. A total of 255 individuals were measured and revealed that most samples are categorized as small (71–96 mm) to medium (97–120 mm) marketable sizes. Exploratory analysis of TL-BW, SL- BW, MAXH-BW, and MINH-BW best fits the power equation. The length-weight (TL-BW and SL-BW) relationships depicted a positive allometric growth pattern (b = 3.88 and b = 3.65; p < 0.01). Computed Fulton’s CFs were higher (> 1) among colormorphs and combined samples. In addition, multivariate analysis of morphometric traits of the colormorphs indicated high variability (p < 0.001). Data ordination implied variability in the morphological traits of G. laglaizei among colormorphs (light pink, light yellow, and dark yellow) supported by principal coordinate analysis and analysis of variance. The morphological variations were more prominent in the head, ventral, and dorsal parts of G. laglaizei (F-value; p < 0.001). The morphological variability detected can be attributed to their niches, wherein colormorphs have been reported to have different environmental preferences and feeding habits. Overall, the study provided a computational analysis of its marketable size structure, CF, and morphological variations, which is crucial for sustainable utilization and conservation management of the species.