Seahorses in Ria Formosa, endangered?

In 2002, the Ria Formosa was one of the places in the world with the highest density of seahorses, with an estimated population of two million. In 2008, only 300,000 were left.

What happened to the Ria Formosa system in such a short time?
Developed by the Research Group on Fisheries and Biology (CCMAR, the Algarve University) in partnership with Project Seahorse (University of British Columbia and Zoological Society London), is a project that aimed to determine the causes of the population’s decline and contribute to the preparation of a recovery plan and conservation of two seahorse’s species (Hippocampus hippocampus e Hippocampus guttulatus) in Ria Formosa.

The results point to a cause-effect relationship between the boats traffic and the density of sehorses.
This relationship does not exclude other factors, anthropogenic or not, related to density variations of seahorses.