FWRI's Freshwater Resource Assessment and Marine Fisheries
Biology sections are assessing the current status of adult American
shad in the St. Johns River.
(top) and blueback herring (bottom).
The American shad (Alosa sapidissima) is a member of
the herring family. American shad ascend rivers from the ocean in
order to spawn. Juveniles spend their first growing season in the
river of their birth and then swim to the ocean in the fall to grow
and mature. They remain in the ocean for two to six years before
they mature and return to spawn in the river in which they
American shad range along the Atlantic coast, from Florida to
Canada. The St. Johns River harbors the southern-most spawning
population. Shad that spawn in rivers south of Cape Hatteras, North
Carolina die after spawning. However, those spawning in rivers
north of Cape Hatteras often survive to spawn in subsequent years.
Populations from all rivers mix in the ocean and migrate between
the coastal Atlantic and adjacent bays of Canada in the summer and
the Atlantic off the southeast coast of the U.S. in the winter. As
the offshore stock reaches the southern end of its migration, it
enters the St. Johns River beginning in December. Spawning activity
peaks in February and March in the St. Johns River between Deland
Historically, shad had been an important food source in North
America since the colonial era. Shad have been important to
recreational anglers in the modern era; however, recreational
angling peaked in the St. Johns River during the 1950s and 1960s.
Atlantic coast commercial landings peaked at the turn of the
twentieth century but have declined dramatically along with most of
the shad's range. Obstruction of spawning runs, pollution, and high
harvest rates have all taken a toll on abundance, prompting the
Atlantic States Marine Fisheries Commission (ASMFC) to mandate
protective measures that include a directive to monitor existing
populations and rebuild stocks where necessary.
Commercial landings in the St. Johns River also peaked in the
early 1900s and declined significantly throughout the century.
Recreational effort and landings have also decreased markedly in
recent years. The net ban in 1995 eliminated most of what remained
of Florida's commercial American shad fishery. Later in 2005, a
commercial fishery off the coast of the mid-Atlantic states was
terminated, so directed fisheries, other than a small in-river
recreational fishery, should no longer be impacting the stock.
There is hope that as commercial harvest is eliminated, the
stock will rebuild and this will be reflected in improved
recreational catch rates and renewed recreational interest in the
species. So far, the resurgence in the recreational fishery has not
been observed. Angler catch rates have fluctuated annually with no
apparent trend, and the number of recreational anglers continues to
decline as of the last angler survey in 2005. Are there too few
fish making the run to interest anglers? Will increased angling be
detrimental to the recovery of American shad on the St. Johns
River? This study should provide information to help answer these
Since 2002, researchers have sampled American shad at three
sites on the St. Johns River to monitor the abundance and
distribution of spawning individuals. Scientists from the DeLeon
Springs Freshwater Fisheries Field Lab collect adult shad by
electrofishing every other week from January to May of each year.
Shad are counted, sexed (or have the sex of the fish recorded),
measured, and released. Samples are collected between Lake Monroe
and Iron Bend including an area known as "Shad Alley." This area is
generally considered the heart of the shad spawning grounds, and
most of the recreational fishing effort for this species has
historically occurred there.
Two additional sites upstream of "Shad Alley" in the vicinity of
Puzzle Lake and State Road 50 are also sampled. No trend in average
electrofishing catch rate has been observed over the six years of
monitoring. Low water conditions of 2006 and 2007 reduced available
spawning habitat to small sections of the river upstream of Lake
Harney. Dense concentrations of spawning shad were found in these
locations, but the overall survey catch rates did not increase
because shad were scarcer in other locations than in years with
higher flows. These findings indicate that the population has
remained unchanged, neither increasing nor declining. Without
substantial fishing pressure, there may be other factors hindering
the population from rebounding as expected. An annual survey of
abundance of juvenile American shad was initiated in 2006 to
monitor the success of spawning from year to year and determine
whether poor recruitment is slowing the recovery of the stock.