Fish and species that reside in the ocean, are considered expert migrators. Where do they migrate to? Well, that’s a story for a completely different day, but the reasons why they migrate, however, are several by itself.
Since water is considered the only habitat for fish to live in, with rivers providing water supply, irrigation, fishing, hydropower, and the possibility to navigate, it is essential for humans specifically.
However, humans have caused many problems to rivers, which all connect to the ocean, including water quality deterioration, flow regime modification, river fragmentation, and finally habitat destruction/ modification. This has all lead to a declination ins fish stocks, which has had a major negative impact on food supply, especially for regions who rely on fishing as a primary food source.
Of course, this also affects the fish themselves, which is one of the reasons they choose to migrate, humans.
The migration struggle of fish
- Free migration
Sometimes, fish migrate just because. Fish species, such as salmon, catfishes, Dorado, and shad, migrate merely to complete the cycle of life, while others again, choose to migrate from rivers to more critical habitats. Free migration routes are important for their survival, as they cannot survive in an environment that is outside of their breeding ground. Migrating freely, outside of their habitats, have already caused many fish species to become extinct.
Many barriers, like dams, sluices, and weirs, have been built for water management, land drainage, and hydropower, but these barriers have prevented fish to migrate for reproduction and feeding purposes. This has caused freshwater ecosystems to perish and have also affected the fish market in a negative manner.
- A primary food source
Fish serve as one of the biggest food sources for villages, small towns, and even countries, all over the world. Not only does a collapse in fish stocks affect it as a food source for people, but it also affects the jobs of fisherman and those who are involved in the fish market.