Original Article
Population status and lunar periodicity of spawning of Tripneustes gratilla (Echinodermata: Echinoidea), in Jose Abad Santos, Davao Occidental, Philippines
Authors:
Jhun Rheil H. Molina1,2,
, Marcelo Jr. G. Sumondong1, Jenelyn M. Tigaldao1, Hanna Grace Ann Melindo1, Shellamae Padayag1 and Michael Jeriel I. Bersaldo1
1Institute of Fisheries and Marine Sciences, Department of Environmental Science, Southern Philippines Agri-business and Marine and Aquatic School of Technology (SPAMAST), 8012 Malita, Philippines
2Mindanao State University – Iligan Institute of Technology Department of Marine Science, College of Science and Mathematics Tibanga, Lanao del Norte, Philippines
ABSTRACT
The population structure and lunar periodicity of spawning were investigated from January to February 2024 across three sites in Jose Abad Santos, Davao Occidental, Philippines. Monthly field surveys were conducted using the belt transect method to assess population structure, while laboratory analyses were performed to examine the lunar periodicity of spawning across different lunar phases. A total of 160 individuals of Tripneustes gratilla (Linnaeus 1758) were recorded with an estimated mean density of 645.83 ± 171.50 ind ha-1 and mainly dominated by adult size classes having a test diameter (TD) of 61 – 65 mm followed by pre-adults of 51 – 55 mm TD and only very few recruits 33 – 40 mm TD. The relationship between the TD and weight of T. gratilla displayed a high positive correlation. It exhibited a negative allometric growth with a b value of less than 3 in three sites. The result of the gonad index (GI) and fecundity showed that the highest GI and total number of eggs occurred during the full moon while the lowest occurred during the new moon with notes on sexual maturity at 54 mm TD. While the findings of this study provide valuable insights, they are not conclusive regarding the population structure and lunar spawning periodicity, as the study was conducted over only two months. Long-term monitoring is needed for a more accurate understanding of the status of T. gratilla at these sites.
Keywords: fecundity, gonad index, lunar phase, size structure, test diameter-weight relationship
Available Online: 09 May 2025
How to Cite:
Molina JR, Sumondong Jr. MG, Tigaldao JM, Melindo HGA, Padayag S and Bersaldo MJI. 2025. Population status and lunar periodicity of spawning of Tripneustes gratilla (Echinodermata: Echinoidea), in Jose Abad Santos, Davao Occidental, Philippines. The Palawan Scientist, 17(2): 1-12. https://doi.org/10.69721/TPS.J.2025.17.2.01
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License
