Gulf menhaden are characterized by large scales, a series of
smaller spots on the body behind the scapular spot, and radiating striations on the upper part of
the opercle. Yellowfin and finescale menhaden have smaller scales and do not have the smaller
spots and strong opercular striations (Hildebrand 1948). Gulf menhaden range from the Yucatan
in Mexico to Tampa Bay, Florida. The finescale menhaden occurs from Mississippi Sound to the
Gulf of Compeche in Mexico; yellowfin menhaden range from Chandeleur Sound, Louisiana,
southward to the Caloosahatchee River, Florida (presumably around the Florida peninsula), to
Cape Lookout, North Carolina (Hildbrand 1948; Christmas and Gunter 1960). The only other
Atlantic coast menhaden species is Atlantic menhaden (B. tyrannus), which occurs from Nova
Scotia to Jupiter Inlet, Florida. Atlantic menhaden, which lack a bright yellow caudal fin, can be
distinguished from yellowfin menhaden in several ways; Atlantic menhaden have larger coarser
scales in regular rows, pointed (vs rounded) scale pectintation, and a row of lateral spots behind
the humeral spot (Dahlberg 1970). Among menhaden species, B. patronus is the most abundant
species on the gulf coast, and B. tyrannus is the most abundant species on the Atlantic coast.
Menhaden are estuarine-dependent species. Spawning occurs offshore, and young move
into estuarine nursery areas where they spend the early part of their lives. Maturing adults return
to offshore waters to spawn (Lewis and Roithmayer 1981). The gulf menhaden form large
surface schools, appearing in nearshore gulf waters from about April to November. Tagging
information shows that gulf menhaden do not undergo extensive coastwide migration. Spawning
peaks during December and January in offshore waters (Lewis and Roithmayer 1981). Eggs
hatch at sea, and currents carry larvae into estuaries where larvae develop into juveniles
(Christmas and Gunter 1960). Juveniles migrate offshore during winter and move back to coastal
waters the following spring as age-1 adults. Initial growth is rapid, and adults reach a size of
approximately 4.9 inches fork length (FL) by age 1. Significant growth continues through age 3.
Individuals reach approximately 6.7 inches FL at age 2, about 7.9 inches FL at age 4, and about
9.2 inches FL at age 5 (Table 1). Gulf menhaden may reach a maximum age of five to six years
(Ahrenholtz 1991). Lewis and Roithmayer (1981) concluded that spawning occurs for the first
time at age 1 as the fish approach their second birthday.
Atlantic menhaden spawn primarily from January to March in the South Atlantic Bight.
Most females are sexually mature at age 3 (Judy and Lewis 1983). Eggs hatch in 36–48 hours.
The larvae are passive drifters and are transported inshore by currents. During the following
spring, they enter the fishery at age 1. They may ultimately reach a length of 14 inches FL at
their maximum age of 8 or 9 years (Schaaf 1979). Atlantic menhaden make extensive coastwise
migrations. In mid-winter, nearly all menhaden are concentrated in offshore waters south of
Cape Hatteras, North Carolina. They begin a slow inshore and northward movement in late
February and March. By about mid-June they are stratified by age and size along the coast from
northern Florida to the Gulf of Maine. In late summer, a southward movement begins (Schaaf
Menhaden are selective feeders throughout most of the larval stage. Juveniles and adults
are omnivorous filter feeders (Ahrenholtz 1991). Deegan (1985) demonstrated that gulf
menhaden have two mechanisms (microbial cellulase activity and a gizzard-like stomach) that
allow digestion of detritus. Because of their high abundance and schooling behavior, menhaden
are prey for a large number of piscivorous fish and birds (Overstreet and Heard 1982).
In Florida, menhaden are primarily used for bait in the commercial and recreational
fisheries. The annual statewide total landings of menhaden during 2005 were 364,453 pounds.
The commercial fishery made 32% of the statewide landings. Total landings were greater on the
Atlantic coast where about 79% of the statewide landings were made in 2005. Commercial
landings in 2005 were greatest in Duval, St. Johns, Volusia, and Brevard Counties on the
Atlantic coast and in Franklin and Wakulla Counties on the gulf coast (Fig. 1). Recreational
landings were greatest in the northeast and east-central regions of the Atlantic coast and all
counties on the gulf coast except Monroe county (Fig. 2).
The commercial fishery, formerly centered along the Panhandle region of the gulf coast,
has been severely limited by Florida’s constitutional amendment restricting the use of purse
seine nets in Florida waters. For instance, the average annual Florida gulf coast commercial
landings were only 145,042 pounds during 1997–2001 compared to the annual average of 12.3
million pounds during 1986–1994 (Fig. 3). The annual Florida gulf coast recreational landings of
menhaden have averaged about 152,000 pounds during 1997–2001. The Atlantic coast
commercial landings have declined from an annual average of 2.3 million pounds during 1990–
1994 to about 369,867 pounds during 1997–2001 due to net limitations (Fig. 3). The recreational
fishery on the east coast landed about 170,000 pounds of menhaden in 2001. Atlantic and gulf
coast landings for both recreational and commercial fisheries have continued to decline since
Catch rates for the commercial fisheries on the Atlantic coast decreased between 1992
and 1996, catch rate increased through 2000 following the 1995 net limitations, declined from
2004 and showed a sharp increase in 2005 (Fig. 4). Commercial catch rates on the gulf coast
decreased after the 1995 net limitations and have fluctuated without apparent trend since (Fig. 5).
Young-of-the-year (YOY) indices of abundance for menhaden showed strong year
classes in 1996, 1997, 1998, 1999, and 2004 and have varied without trend on the gulf coast with
a strong year class in 1998 (Figs. 6, 7). Abundances of post-YOY menhaden have also declined
on the Atlantic coast, whereas abundances have varied without trend on the gulf coast (Figs. 9,
10). Occurrence of gross external abnormalities in menhaden on the Atlantic coast has varied
without trend with the highest level in 2004, while on the gulf coast the incidence of
abnormalities was highest from 2001-2004 (Figs. 10,11). On both coasts the rate of
abnormalities was low in 2005 and most menhaden that did exhibit gross external abnormalities
in recent years were suffering from parasites (Figs. 12,13). Note that incidences of abnormalities
for 2001 are probably higher relative to other years because many menhaden were examined for
oral parasitic infestation in that year, a practice that was not continued in subsequent years (M.
Bakenhaster, FWRI Aquatic Health, personal communication).
No formal stock assessment for Florida menhaden is available at this time, however, the
Gulf-wide stock assessment of the gulf menhaden (Vaughan et al. 2004, Vaughan et al. 2006)
and Atlantic-wide stock assessment of the Atlantic menhaden (Vaughan 1998; Vaughan et al.
2002, Vaughan et al. 2006) show that both stocks appear to be reasonably stable.
|Download complete report
|Status and Trends 2007 Report
Florida’s Inshore and Nearshore Species
by Florida Fish and Wildlife Research Institute