Male vs. Female Jellyfish: Reproductive Differences & Identification

Jellyfish belong to the phylum Cnidaria, a structurally simple group of marine animals. Easily identified by a layer of mesoglea or "middle jelly," jellyfish reproduce sexually and are distinguished as either male or female.

Location of Sex Organs

• The reproductive organs, or gonads, develop in the lining of the gut, also known as the gastrodermis.

Identification

• Mature gonads are brightly colored and will vary in color depending on the state of the animal's maturity and sometimes sex.

Male Reproductive Role

• Male jellyfish release sperm from their mouth, a method of reproduction known as mass spawning. Some of the sperm will reach the mouth of a female, where fertilization occurs.

Female Reproductive Role

• Fertilization occurs once the sperm reach the eggs in the female's mouth. Depending on the species, the fertilized eggs are either stored in the female's mouth or in brood pouches on her oral arms.

Physical Differences

• Male gonads may be a different color from female gonads. Adult female jellyfish can be identified by the eggs she holds in her mouth or by brood pouches in the oral arms.