The University of Victoria has confirmed that human disturbance of seagrass meadows results in lower fish diversity.

Coastal seagrass meadows are important nursery grounds for commercial and ecologically significant fish species. Globally, these ecosystems have declined at an average rate of seven percent since 1990.

Photo credit: Emily AdamczykJuvenile rockfish in Barkley Sound

While human activity is known to impact a variety of ecosystems, the effect on coastal biodiversity is relatively unknown.

Research was led by University of Victoria post-doctoral fellow Josie Lacarella and biology professor Julia Baum.

Alongside government and non-government organizations, the researchers examined 89 seagrass meadows across Canada Pacific Coast.

Disturbance was measured by the proportion of overwater structures such as ferry terminals and marinas, amount of shoreline modification and the number of people living in a particular watershed.

Photo credit: University of Victoria

The study found that in areas with high levels of human disturbance, the same few fish thrived.

Species such as threespine stickleback dominated in high-disturbance areas, sensetive rockfish species and slow-swimming egg-guarders such as pipefish, were more likely to be found in areas with less human disturbance.

“We discovered that the number of different fish species that thrive across disturbed areas is reduced,” says Lacarella.

“Understanding how human disturbance affects fish communities will inform our conservation efforts of seagrass meadows.” 

The paper, Anthropogenic disturbance homogenizes seagrass fish communities, has been published online.