The question of whether period blood attracts fish is a common concern, particularly for those who enjoy aquatic activities. While the idea might seem plausible, scientific understanding provides a clear answer regarding this common myth.
The Makeup of Menstrual Blood
Menstrual blood is not solely blood; it is a complex biological fluid. It consists of arterial blood, some venous blood, uterine tissue, mucus, and vaginal secretions. This fluid also contains proteins, lipids, stem cells, hormones, and enzymes. The average volume of menstrual fluid released during a period is typically between 30 to 80 milliliters, which is equivalent to about two to five tablespoons.
How Fish Sense Their Environment
Fish possess highly developed chemosensory systems, primarily olfaction (smell) and gustation (taste). Their nostrils contain sensory cells that detect minute amounts of chemicals. Fish use these senses for various behaviors, including finding food, avoiding predators, navigating, and communicating. Fish are particularly sensitive to specific chemical cues that signal the presence of food, such as amino acids and bile acids. Amino acids are released when prey items are present or decaying, acting as feeding stimulants.
Scientific Look at Fish Attraction
Based on the composition of menstrual blood and the specific chemical sensitivities of fish, menstrual blood is not a significant attractant for most fish. While fish can detect extremely small amounts of chemicals, the components of menstrual fluid are generally not the types of chemical signals that trigger a feeding response. Fish are attuned to detect chemical profiles that indicate typical food sources. The volume of menstrual fluid released is relatively small and quickly dilutes in a large body of water, significantly reducing the concentration of any detectable compounds. The chemical makeup of menstrual blood does not mimic the amino acid profiles fish associate with their natural prey.
The Shark Question
Sharks have a keen sense of smell, capable of detecting very small concentrations of blood and other organic materials in the water. However, there is no scientific evidence linking menstrual bleeding to an increased risk of shark attacks. The amount of blood released during menstruation is minimal and disperses rapidly in water. Sharks are primarily attracted to the amino acids found in the blood and guts of marine animals, which are characteristic of injured prey. Studies have shown that human blood does not elicit a feeding frenzy.