For dealers and their customers on the Great Lakes and elsewhere, a recent court ruling is reason to cheer. And, with the growing algae bloom problems still plaguing parts of many lakes, some good news is more than welcome.

The U.S. Court of Appeals, in a unanimous 3-0 ruling, slammed the U.S. Environmental Protection Agency for failing in its responsibility under the Clean Water Act to protect U.S. waters from aquatic invasive species introduced by ship’s ballast water discharge. In essence, the court ordered the EPA to rewrite its rules governing the release of ballast water into the Great Lakes and other U.S. waterways.

The decision is a major victory for environmental groups that argued that the EPA’s 2013 permit governing the discharge and treatment of ballast water was insufficient to curb the spread of aquatic invasive species such as zebra mussels and the spiny water flea. The court said EPA wrongly allowed higher limits on live organisms in ballast water when, in fact, there was technology available to meet tougher standards.

“Invasive species cause severe economic and ecological harm, including by destroying native fish species and shellfish industries, creating algae blooms and devastating tourism,” the court wrote. “Zebra mussels are a particularly destructive example.”

They were first introduced to Lake Erie in the 1980s by a freighter from Europe (the Caspian Sea). The vessel entered the Great Lakes through the St. Lawrence Seaway and discharged ballast water containing the mussels. These mussels have caused havoc, infesting lakes throughout the Midwest, and even some Western states, disrupting aquatic habitats.

“More than 21 billion gallons of ballast water are released into waterways each year by ships,” the court continued. “The released water has the potential to release organisms, their eggs and larvae into non-native environments. Invasive species are estimated to cause $137 billion in damages annually. The Great Lakes Region has been disproportionately impacted.”

Accordingly, the court also ruled that so-called “lakers,” (ships that only ply the Great Lakes and don’t travel to the Atlantic Ocean through the St. Lawrence Seaway) should be subject to some of the same ballast requirements as oceangoing vessels. The EPA’s 2013 permit exempted “lakers” built before 2009 from meeting certain effluent limits.

But along with the good news about ballast water comes a dash of disappointment. It’s notable that this ruling really doesn’t address the widespread and growing algae problems in the Great Lakes and many other bodies of water. Summertime algae blooms now occur in many bodies of water from Lake Erie to the Gulf of Mexico. The blooms don’t just turn the waters a murky, smelly brown; they contain bacteria that can make people sick.

Finally, the court noted, if only in passing, that invasive species can contribute to algae problems. But that raises this interesting point: If the biggest contributor to the rampant and often toxic algae blooms is already known to be runoff of fertilizers and manures from big factory farms, shouldn’t the EPA also be issuing pollution regulations under the Clean Water Act that would govern permitting requirements for farming.

Right now, permitting includes a host of exemptions and exclusions enjoyed by agriculture. But the Clean Water Act is supposed to address the pollution and destruction of waterways and to ensure clean and safe water. Runoff from farming is polluting our waters. The EPA needs to address the algae debacle, too.

In the meantime, dealers and boaters can celebrate the idea that better efforts will be undertaken to guard against more invasive species finding their way into our waterways.