Migratory fish saw their populations decline on average by 76% between 1970 and 2016. This is indicated in a report from WWF, IUCN and the World fish migration foundation published on Tuesday. At issue: habitat degradation and overfishing.
The report examines 247 species of fish around the world, living in both fresh and salt water. It shows that their populations have declined on average by 3% per year, with a particularly marked drop over the period in Europe (- 93%), Central America and the Caribbean (- 84%). It is less marked in North America (- 28%). Data for Africa, Asia, Oceania and South America are insufficient, the report points out.
Freshwater #Migratoryfish are ecologically, culturally, economically, and recreationally important! DYK that their populations have declined by # 76percent on average? Time to change this! Get involved today - join #worldfishmigrationday #LPImigratoryfishhttps: //t.co/x8FeVuNlYy pic.twitter.com/huRa4EPLs0
- Fish Migration (@fishmigration) July 28, 2020Large fish particularly threatened
"Habitat degradation, modification and loss account for about half of the threats to migrating fish, while overexploitation accounts for about a third," the report calculates. Nearly one in three species of freshwater fish is threatened with extinction, but migratory fish are in even greater proportions, the document points out. Among them, large fish such as the beluga (a species of the sturgeon family) or the giant Mekong catfish are particularly vulnerable.
Dams, weirs and other obstacles that they encounter during their migration, necessary for their feeding and reproduction, are one of the main problems for these species.
A "lack of free waterways"
In addition, climate change will continue to exacerbate the alteration of their habitats, warns the report. Added to this are other difficulties such as the proliferation of invasive species, not to mention new threats such as pollution by microplastics and the salinization of freshwater systems. “In addition, since migrations are cyclical and predictable, migratory fish can easily be exploited” by fishing.
In the case of Europe, one of the main threats weighing on these animals is "the lack of open waterways", with a very important presence of dams or other types of barrier, underlines the report, which speaks of 1.2 million obstacles across the continent. The European Union, in its strategy for biodiversity by 2030, aims, however, "to restore at least 25,000 kilometers of free-flowing rivers".
Planet
"Worrisome" decline in shark populations, say researchers
Planet
Mediterranean: "They continue to kill fish for nothing", an association tracks down the nets abandoned at sea
- Animals
- Environment
- Threatened species
- Report
- Planet
- Fish