In the aquatic world, one of the topics that has aroused increasing interest in recent years is the impact that noise has on the behavior of fish. Although it has traditionally been thought that fish are animals that depend solely on visual and olfactory stimuli, the reality is that the sense of hearing plays a very important role in fish behavior. crucial role in their survival. Noises generated by human activities not only alter their behavior, but can cause harmful effects long-term health and the ecosystems they live in.
The inner ear of fish: An essential tool
Contrary to what many might think, fish have a developed internal auditory systemThis system includes fluid-filled semicircular canals and structures called otoliths, which are sensitive to vibrations and help fish perceive sounds. In many species, such as carp and fish in the Characidae family, the swim bladder acts as an acoustic resonance chamber, amplifying sounds in the aquatic environment.
Water transmits sound to a five times faster to that of the air, which makes acoustic signals play an essential role in the fish communication, their feeding and the detection of predators. However, this hearing ability makes them extremely vulnerable to artificial noise.
Noise sources in fish habitat
Noise in aquatic habitats can have several sources, both natural and anthropogenic. The former include sound generated by waves, currents and other physical interactions in the water. However, increasing human development has introduced significant levels of man-made noise, such as:
- Vessel traffic, especially in areas with high vessel density.
- Subsea construction, such as the installation of piles and structures for oil platforms.
- Seismic exploration for oil and gas extraction.
- Noise generated by sonars and maritime navigation equipment.
These sounds not only reach harmful frequencies fish, but are often constant and prolonged, amplifying their negative impact. According to recent studies from universities such as Bristol, even short noises can alter their behavioral patterns, such as food.
Effects of noise on fish behavior and physiology
Anthropogenic noise has a direct effect on fish, causing everything from distractions to serious health problems. One of the landmark experiments conducted by scientists at the University of Bristol showed that when aquarium fish were exposed to noise from underwater speakers, they committed feeding errors, confusing waste with food. In the long term, these alterations can lead to:
- Hearing loss: Constant exposure to high-intensity noise can damage sensory cells in the inner ear.
- Effects on communication: Fish rely on low sound frequencies to interact socially. Noise interferes with this communication, making it difficult to form groups or mate.
- Chronic stress: Persistent noise triggers stress responses, releasing cortisol, which affects your immune system and increases your vulnerability to illness.
- Alterations in behavior: In addition to eating erratically, fish may display erratic behaviors such as increased aggression or disorientation.
The impacts of noise are not limited to aquarium fish. In the wild, species on coral reefs or high navigation areas may face similar challenges or even greater due to noise pollution.
Landmark experiments on noise pollution
Several studies have explored how noise affects fish welfare, broadening our understanding of this problem:
- During the COVID-19 pandemic, the reduction in human activities allowed us to observe that fish increased their vocal activity in lower noise conditions, improving your ability to communicate.
- Research on coral reefs has shown that ship noise disrupts symbiotic interactions between cleaner fish and their “clients,” negatively impacting ecosystem biodiversity.
- In Norway, the FHF Research Fund studied the effects of noise on farmed fish, highlighting that it can lead to a fatal outcome under extreme conditions.
Measures to minimize the impact of noise in aquariums
While much of the focus is on mitigating noise in the natural environment, aquarium owners should also take actions to ensure the well-being of your fish. Some recommendations include:
- Avoid placing the aquarium near televisions, speakers or sound equipment.
- Ensure that pumps and filtration systems are operating properly and without generating unnecessary vibrations.
- Use insulating coatings to reduce environmental vibrations.
In addition, keeping fish in a balanced environment favors their adaptation and health. Check out our guide on aquarium filters to ensure good water quality.
Proposing acoustically protected areas, such as "silent corridors" and adopting technologies to reduce the noise emitted by vessels, are some solutions to mitigate this threat to marine fauna.
Understanding the importance of maintaining an adequate sound environment is essential to ensure the balance of these unique and delicate ecosystems. Reducing noise, both in natural spaces and in domestic aquariums, not only benefits the fish, but allows for better environmental harmony.