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Fish

Our fish are also paying a tremendous price due to the pollution in the Chesapeake Bay.  Fish use their gills to extract the oxygen from the water of the Bay in order to survive.  As the level of oxygen in the water rises, their gills work more effectively.  Conversely, as the level of dissolved oxygen in the water decreased, fish become stressed.   And if it falls far enough, of course, the fish die.

Massive fish kills tend to occur in creeks or other shallow-water areas with poor circulation.  After a large algae bloom, oxygen can be rapidly depleted from the water as the algae decompose.

There were 45 separate fish kills in 2007 in Maryland alone, each affecting between 50 and 20,000 fish.   As just one example, a “brown tide” killed 7,000 fish in Baltimore’s Inner Harbor in June 5, 2007.   Even more horrifying was the death of 296,000 menhaden, white perch and croakers in Virginia’s Mattox Creek on July 11, 2007. 


Nor was 2007 an exceptional year.  A high rate of fish kills continued in 2008.  It is estimated that 100,000 fish died in Aberdeen Creek, Maryland over Labor Day weekend.  As shown on the left, the dead fish were so numerous, it looked like they were leaves on the surface of the water.

 

Photo courtesy of John Surrick, Chesapeake Bay Foundation, www.cbf.org. 

 
Periodic fish kills are only one of many threats to the fish who call the Chesapeake Bay home:

The population of shad, which used to be one of the most commercially-important fish in the Bay, has declined so much that shad fishing has been banned. The shad were hurt not only by pollution, but also by the damming of the rivers shad needed to traverse to get to their fresh water spawning grounds.  In 1992, the last year shad fishing was legal in Virginia, about 0.5 million pounds of shad were caught, down dramatically from the average estimated annual harvest of 17.5 million pounds at the turn of the century.

As many as many as 60% of the Bay’s rockfish are suffering from chronic wasting disease as a result of being infected with mycobacteria.

In the Potomac River and some of its tributaries, almost all of the male smallmouth bass recently studied are growing eggs!  It is not known what type of pollution is responsible for this abhorrent finding.