Quantification of coral sperm collected during a synchronous spawning event

Area of Science:

• Marine Biology
• Reproductive Biology
• Coral Ecology

Background:

• Most coral reproductive studies focus on eggs, neglecting sperm counts.
• Sperm enumeration data are vital for understanding fertilization success.
• Previous sperm quantification was limited to ex situ studies.

Purpose of the Study:

• To quantify sperm and egg numbers per gamete bundle for six coral species.
• To introduce and validate a novel, cost-effective in situ method for collecting coral gametes.
• To provide data critical for coral fertilization models.

Main Methods:

• In situ collection of egg-sperm bundles using a simple suction device during synchronous spawning.
• Quantification of sperm and eggs within collected bundles from six coral species (Echinophyllia aspera, Favites abdita, F. chinensis, Merulina ampliata, M. scabricula, Platygyra pini).
• Comparison of the novel collection technique's advantages over traditional methods.

Main Results:

• Mean sperm numbers per bundle ranged from 2.04 × 10^6 to 1.93 × 10^7.
• Mean egg numbers per bundle ranged from 26.67 to 85.33.
• The developed suction method proved effective, low-cost, and user-friendly for in situ collection.

Conclusions:

• The study provides essential quantitative data on sperm and eggs in coral gamete bundles.
• The novel in situ collection technique is a valuable tool for coral reproductive research.
• Findings support the development of more accurate coral fertilization success models.