Petromyzontiformes – Lampreys

They are parasitic, attaching to host fishes in order to feed on their blood

Lampreys are easily identifiable by their slender, eel-like bodies and distinctive mouths, which lack jaws but instead feature a circular, toothed structure. This unique adaptation allows them to attach to other fish or marine organisms, adopting parasitic behavior during specific life stages. These parasitic lampreys use their specialized mouthparts to feed on the bodily fluids of their host organisms, a strategy that sets them apart from many other aquatic species. However, it’s important to note that not all lamprey species are parasitic; some are non-parasitic, opting for detritus and small invertebrates as their primary food source within freshwater environments.

One of the most intriguing aspects of lampreys is their anadromous nature, signifying their migratory journeys between freshwater and the ocean. They typically spawn in freshwater habitats, where their larvae, referred to as ammocoetes, engage in filter-feeding activities. As they mature, ammocoetes undergo a remarkable metamorphosis, transforming into the adult lamprey form. While many lamprey species adopt a parasitic lifestyle during adulthood, attaching themselves to hosts in marine or freshwater environments, others remain non-parasitic throughout their entire life cycle, dwelling exclusively in freshwater habitats.

This diversity in feeding strategies and migration patterns showcases the remarkable adaptability of lampreys, making them a unique and intriguing group of aquatic organisms in the world of marine biology.