Biological assessment of world's rivers presents incomplete but bleak picture

February 21, 2021

An international team of scientists, including two from Oregon State University, conducted a biological assessment of the world's rivers and the limited data they found presents a fairly bleak picture.

"For the places that we have data, the situations are not really that good. There are many species that are declining, threatened or endangered," said Bob Hughes, co-author of the paper and a courtesy associate professor in Oregon State's Department of Fisheries and Wildlife. "But for most of the globe, there just is little rigorous data."

The work by Hughes and the team, which included scientists from 16 countries and six continents, was recently published in the journal Water.

The biological assessment of rivers is essential to evaluate the condition of the ecosystems and to establish ways for them to recover. Such assessments occurred in some countries beginning in the 1990s but have not occurred on a global scale.

Data from biological assessments the research team located showed: The paper also outlines river rehabilitation efforts, with the greatest implementation occurring in North America, Australia, Western Europe, Japan, Singapore and South Korea. Most rehabilitation measures have focused on improving water quality, river connectivity for fish, or riparian vegetation.

Yet, rehabilitation efforts are usually limited to a river segment, which often constrains the overall improvement of the waterway. Rehabilitation projects also often lack before and after monitoring of ecological conditions. Economic roadblocks are the most cited reason for not implementing monitoring programs and rehabilitation actions.

The authors of the paper offer several recommendations for rehabilitation projects, including establishing rehabilitation needs, defining clear goals, tracking progress towards achieving them and involving local residents and stakeholders.

They also say that long-term monitoring programs are essential to providing a realistic overview of the condition of rivers worldwide. Finally, they propose developing transcontinental teams to develop and improve guidelines for implementing biological monitoring programs and river rehabilitation efforts in collaboration with scientists of nations lacking such expertise.

"If we can correct these problems before they get dreadful, like they are in some places, it will cost a lot less than trying to recover those rivers," Hughes said. "If they get too bad then they become really, really dangerous for human health."

In addition to Hughes, Philip Kaufmann, also a courtesy associate professor in the Oregon State's Department of Fisheries and Wildlife in the College of Agricultural Sciences, and a scientist with the Environmental Protection Agency, is a co-author of the paper. Maria João Feio of the University of Coimbra in Portugal is the lead author.

"Scientists at the EPA and OSU have been collaborating on implementing biomonitoring programs with Brazilian, Chinese and European scientists since 1990," Kaufmann said.

Oregon State University

Related Fish Articles from Brightsurf:

Fish banks
Society will require more food in the coming years to feed a growing population, and seafood will likely make up a significant portion of it.

More than 'just a fish' story
For recreational fishing enthusiasts, the thrill of snagging their next catch comes with discovering what's hooked on the end of the line.

Fish evolution in action: Land fish forced to adapt after leap out of water
Many blennies - a remarkable family of fishes - evolved from an aquatic 'jack of all trades' to a 'master of one' upon the invasion of land, a new study led by UNSW scientists has shown.

How fish got onto land, and stayed there
Research on blennies, a family of fish that have repeatedly left the sea for land, suggests that being a 'jack of all trades' allows species to make the dramatic transition onto land but adapting into a 'master of one' allows them to stay there.

Fish feed foresight
As the world increasingly turns to aqua farming to feed its growing population, there's no better time than now to design an aquaculture system that is sustainable and efficient.

Robo-turtles in fish farms reduce fish stress
Robotic turtles used for salmon farm surveillance could help prevent fish escapes.

Heatwaves risky for fish
A world-first study using sophisticated genetic analysis techniques have found that some fish are better than others at coping with heatwaves.

A new use for museum fish specimens
This paper suggests using museum specimens to estimate the length-weight relationships of fish that are hard to find alive in their natural environment.

Reef fish caring for their young are taken advantage of by other fish
Among birds, the practice of laying eggs in other birds' nests is surprisingly common.

Anemones are friends to fish
Any port in a storm, any anemone for a small fish trying to avoid being a predator's dinner.

Read More: Fish News and Fish Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to