Chaetoceros

Chaetoceros is a genus of planktonic diatoms that significantly influences aquatic environments. While it is not a traditional terrestrial plant pathogen, in the context of aquaculture, it is regarded as a major biological hazard that can cause severe physiological stress and mortality among farmed aquatic species.

The causative agent consists of unicellular organisms that often form long, chain-like colonies. These diatoms are characterized by rigid, sharp, siliceous bristles or setae. These structural elements are the primary cause of damage when these organisms come into contact with sensitive animal tissues.

This organism primarily affects finfish aquaculture, especially salmonids. The sharp bristles physically penetrate the gill filaments, causing severe inflammation, tissue necrosis, and impairment of respiratory function. This leads to reduced growth, stress, and high mortality rates in aquaculture systems.

Environmental conditions that favor the development of Chaetoceros blooms include high levels of nutrient enrichment (nitrogen and phosphorus) and stable water columns with adequate light exposure. These conditions trigger rapid population explosions, often referred to as harmful algal blooms, which drastically change the surrounding water quality.

Protective measures are focused on prevention and early detection. Effective management strategies include:

• Regular monitoring of water quality and phytoplankton density.
• Implementation of high-performance water filtration systems.
• Optimizing feed management to reduce nutrient loading in the water.
• Using aeration and water circulation to disrupt bloom formation.