The Bronx: A Thriving River
Runs Through It
Dr. Joseph W. Rachlin,
Professor of Biological Sciences and director of the Laboratory
for Marine and Estuarine Research (LaMER) at Lehman College, reports
on a study of the Bronx Rivers surprising state of health.
|Professors Joseph Rachlin and Barbara Warkentine
with Doctoral student Linda Lalicata (center).
warm summer day this June, I carefully picked my way through the
rubble littering the shore at the mouth of the Bronx River, watching
the incoming tide push its way past the Krasdale food plant. In
spite of the industrial wasteland all around, I knew new life
was being born.
On that afternoon I watched several pairs of horseshoe crabs come
ashore to mate in the pebbly sand. The larger female, with the
male attached to her abdomen, buried herself and deposited her
instantly fertilized eggs. Then they glided back past abandoned
tires and rusting truck chassis and into the depths. The eggs
would hatch at the next new moon.
How many city residents have witnessed this event, or are even
aware of its cyclical occurrence? How much of the beauty and mystery
of this river is missed because of the abandoned debris that blights
its shoreline? The quality and diversity of life in this estuarine
portion of the Bronx River are treasures about to be rediscovered
once the long-awaited process of restoration and reclamation begins.
For two years, I have led a small scientific team that includes
Dr. Barbara Warkentine of SUNY Maritime (a Lehman College alumna)
and several CUNY students. The conclusions we have reached in
our study of the rivers estuary may surprise: despite appearances,
the river is thriving and serves as a breeding ground and nursery
for more than a dozen species of fish and other aquatic organisms,
including shrimp, horseshoe crabs and blue crabs. Fish species
include striped bass, mossbunker, bluefish, gizzard shad, killifish,
silversides, and flounder. And this summer we discovered the presence
of two new fish species in the river, the naked goby and the seaboard
Bronx Rivers original source, in Westchester County, is
now part of the Kensico Reservoir system. With completion of the
Kensico Dam in 1915, its flow was reduced by about a quarter,
and its main tributary below the dam, Davis Brook, became its
new source. The Bronx River travels south for approximately 23
miles to the East River, between Hunts Point and Clasons Points.
The course of the river at the dams base starts at an elevation
of 238 feet above sea level and gently drops to a level of seven
feet at its mouth.
The Bronx River Parkway, a 15-mile, four-lane roadway, was built
between 1916 and 1925. This limited-access parkway is protected
on both sides by broad bands of parkland and follows the course
of the river. The road was designed to cause minimum disturbance
to the landscape, but during construction the rivers original
course was significantly straightened to reduce local flooding.
The old Delancy Dam and waterfall in River Park at the southern
boundary of the Bronx Zoo is the northern-most incursion of marine
and estuarine fauna. For its entire length above the falls the
river is completely freshwater, with appropriate freshwater flora
and fauna. Below this point, as it flows through the south Bronx,
the river becomes increasingly more saline and tidally influenced.
Over the years, neglect and abandonment of commercial establishments
have led to marked degradation along the estuarine shoreline.
Worse, this industrialization effectively cut the riverbanks off
from local residents. Only in the last few years has awareness
of the value of the river emerged, along with growing desire for
Congressman José Serrano, whose district includes the Bronx
River estuary, worked with Governor Pataki to secure federal funds
both for restoration and educational studies. Admini-stered by
the National Oceanic and Atmospheric Administration (NOAA) as
part of its estuary restoration program, these funds are supporting
projects designed to improve the shoreline, increase the habitat
and educate the community about this valuable natural resource.
Jointly sponsored by NOAA, the City Parks Foundation and Partnership
for Parks, our team (which included Lehmans Dr. Antonios
Pappantoniou) has focused on characterizing estuarine fauna and
flora, especially on the population dynamics and resource partitioning
of fish species.
Most notably, our findings reveal the presence of sensitive indicator
species, like sea anemones and oysters, as well as a high diversity
of organisms. This points to good water quality despite years
of neglect and dumping. Local fishermen regularly catch fish and
blue crab in the river and report consuming them without ill effects.
This August, the team took samplings from the 46-foot SUNY Maritime
research vessel Privateer during a bloom of dinoflagellates in
the vicinity of Lafayette Avenue. The heavy concentration of this
microorganismas high as 17,000 cells per milliliterturned
the river the color of red wine, a condition sometimes called
the red tide when it occurs off the Jersey Shore.
Dinoflagellate blooms temporarily lower the waters dissolved
oxygen, which causes stress for fish and other aquatic organisms.
|Mating horseshoe crabs
than a week later, the dinoflagellate cell count in this section
had already dropped to 5,000 cells per milliliter, indicating
that the condition was abating. Five days after that, it was virtually
Despite these occasional occurrences, the river is a prime candidate
for restoration. It is home not only to aquatic life but also
to a variety of shore birds such as egrets, cormorants, blue herons,
swans, mallard ducks, ibis, plovers, sandpipers, and a variety
Unfortunately, community residents are unacquainted with this
rich fauna because access to the shore is severely restricted,
especially on the estuarys west bank.
A goal of the restoration efforts is to provide increased access
to this marvelous opportunity for community enjoyment. With restoration
efforts and cleanup, the river can become a place to find both
quality boating and a strong recreational fishery. It can also
serve as a living resource for the development of school curricula
on aquatic biology and environmental stewardship.
Our CUNY/SUNY collaboration will continue. We are currently awaiting
approval of our request for additional NOAA and Wildlife Conservation
Society funding that will allow us to extend our study to the
freshwater Bronx River. The data and species collected by the
team will be housed at Lehman Colleges new LaMER facility
as a repository for future research and educational applications.
Prime among these applications will be the creation of a Comprehensive
Faunal and Floral Field Guide to the Bronx River for teachers,
students, and community organizations in the borough.