For decades, the fish were literally up against the wall.
Through much of this century, dams designed to harness power and develop water reserves were constructed along Maryland's rivers. The dams did their work beautifully for the human population. But they also kept salt-water (or "anadromous") species such as striped bass, shad, herring and perch from doing what comes naturally -- swimming upstream to their fresh-water spawning grounds.
Many species consequently dwindled in the Patapsco, the Patuxent and other rivers, to the dismay of environmentalists and commercial and recreational fishermen.
Increasing levels of water pollution only worsened the situation. Even if the fish could have reached the spawning areas, they probably wouldn't have survived the oxygen-poor muck they'd find there.
The past decade, however, has brought dramatic improvements and hopes of a major fish comeback in regional rivers.
First came successful efforts to make local waters cleaner than they'd been in years. Then the state's Department of Natural Resources (DNR) saw its way clear to direct fish to fresh-water areas.
Since 1990, DNR has installed 14 "fish passages" at dams that had prevented the anadromous species from spawning. Another four passages are due for completion by the end of this year.
The types of passages in this commendable program include a staircase-like device that allows fish a gradual path up and over a dam; an elevator to carry them up; and a breach, or hole, in the dam that lets fish swim through to the other side.
Most of the passages have been installed at dams between Baltimore and Washington, though DNR has spread the projects among counties throughout the state, as far north as Harford and Cecil, as far west as Montgomery and as far east as Queen Anne's.
DNR fisheries official Howard King says a key goal of the program is to make better use of the "vast pool of energy" contained in local waters.
"With an increase in certain fish like the herring," Mr. King explains, "a lot of oxygen-depleting algae gets eaten. Those fish then get eaten by striped bass, bluefish and other species that are prized by fishermen. What you get in the long run is healthier water and greater numbers of valuable fish."