Philippine Journal of Science
150 (3): 729-736, June 2021
ISSN 0031 – 7683
Date Received: 28 Sep 2020

In Vitro Egg Release and Fertilization
of Sargassum polycystum C.Agardh, 1824
in Response to Different Environmental Conditions

Maria Lyn M. Magcanta¹*, Lovella R. Calala², Frederick B. Cabactulan²,
Venus E. Leopardas², Hernando P. Bacosa^3,4, and Wilfredo H. Uy^1,2*

¹Seagrass Ecosystems Laboratory, Institute of Fisheries Research and Development
Mindanao State University, Naawan, Misamis Oriental 9023 Philippines
²College of Science and Environment
Mindanao State University, Naawan, Misamis Oriental 9023 Philippines
³College of Science and Engineering, Texas A&M University
Corpus Christi, Texas 78412 Unites States
⁴Department of Biological Sciences
Mindanao State University–Iligan Institute of Technology
Tibanga, Iligan 9200 Philippines

*Corresponding authors:
marialyneuterpe21@gmail.com; wilfredo.uy@gmail.com

ABSTRACT

The brown seaweed Sargassum spp., locally known as “samò,” is subject to increasing overexploitation in the natural environment; thus, culturing the species for mass production is necessary. Understanding the required environmental factors is essential in the successful culture and mass production of this species. This study aims to determine the egg release and fertilization of Sargassum polycystum in response to the different environmental conditions that may influence its reproduction. Fertile thallus of S. polycystum was collected at Naawan, Misamis Oriental, Philippines in March 2018. Reproductive receptacles were excised and placed in Petri dishes and were exposed to varying environmental conditions under laboratory conditions. The experiments were conducted in triplicate Petri dishes per treatment. Percent (%) egg release and percent fertilization were observed for about 2 wk. Results showed that percent egg release and percent fertilization did not differ significantly across temperature ranges (20–30°C) and desiccation time (5–60 min). Receptacles treated with nutrients resulted in only ~ 45% egg release with a daily decrease of 10% towards the addition of AGP fertilizer. The highest % egg release (80%) was observed in the control treatment (no fertilizer). Percent egg release in receptacles subjected to 20–45 PSU showed no significant difference. This study suggests that the optimum condition for the release of eggs and subsequent fertilization can be achieved under ambient temperature, with no direct exposure to sunlight, no addition of fertilizer, and within the ambient salinity of 30–32 PSU.