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However, toward the end of the larval period,
flatfishes settle to the benthos and take up a cryptic, somewhat sedentary
lifestyle, lying on one side of the body, and swimming laterally to the
substratum. Metamorphosis to the juvenile stage involves complex
modification of the skeletal structure of the head, and rearrangement of
the nervous system and muscle tissues. Additionally, the eye on the side
which faces the substratum (termed the blind-side eye) begins to migrate
to the upper side of the body. P. albigutta is a left-eye flounder,
thus it lies on its right side, and at metamorphosis, the right eye
migrates to the left side of the head. Lefteye flounders sometimes exhibit
sexual dimorphism, with females having eyes that are closer together than
in males, and males having somewhat longer pectoral fins (Rogers and Van
Den Avyle 1983).
Body color in this species is brown overall, and
can vary in shade depending on the color of the substratum. There are
numerous splotches and spots on the upper surface of the body, with 3
ocellated (eye-like) spots prominent: 2 are posterior to the pectoral
fin, and 1 is located inside the base of the tail. Together, these form a triangle on
the body surface. Teeth are strong and canine-like. The blindside is white
or dusky.
Synonymy:
None
Other Taxonomic Groupings:
Subphylum: Vertebrata
Superclass: Osteichthyes
Subclass: Neopterygii
Infraclass: Teleostei
Superorder: Acanthopterygii
Suborder: Pleuronectoidei
Potentially Misidentified Species:
This species can be confused with the
southern flounder, P. lethostigma. However, P. lethostigma
is significantly larger in size and lacks P. albigutta's 3 distinct
ocellated spots.
II. HABITAT AND DISTRIBUTION
Regional Occurrence:
The summer flounder, Paralichthys albigutta, occurs from North
Carolina south through Florida and the Gulf of Mexico to Texas. Its range
is sympatric with that of the southern flounder, P. lethostigma.
IRL Distribution:
P. albigutta is found inshore throughout the Indian River Lagoon.
It is sometimes found in nearshore reef areas.
III. LIFE HISTORY AND
POPULATION BIOLOGY
Age, Size, Lifespan:
P. albigutta typically grows to 15 inches (38 cm), and is
common to 2 pounds.
Embryology:
Eggs of P. albigutta are spherical and
measure approximately 0.85 - 0.90 mm in diameter (Powell and Henley 1995),
with a single oil globule. Yolk is homogeneous, and the chorion smooth.
Pigmentation in eggs is most apparent in the caudal area. Young larvae
have well developed melanophores around the dorsal and anal finfolds.
During metamorphosis to the juvenile stage, pigmentation in P.
albigutta becomes more intense. Data from Powell and Henley (1995)
show that P. albigutta begins metamorphosis at a smaller size than
do other flounders, especially its close relative P. lethostigma,
the southern flounder. In P. albigutta, the migrating eye reaches
the dorsal midline of the body when larvae attain approximately 7.8 mm SL.
In P. lethostigma, the migrating eye does not settle in place until
larvae are 8.7 mm SL.
Powell and Henley (1995) examined egg and larval
development in both P. albigutta and P. lethostigma. Results
from their study show that fins begin to develop when larvae reach
approximately 5.2 mm notochord length (NL). The dorsal fin is generally
the first to begin development, followed by the caudal, anal, pelvic, and
pectoral fins (Powell and Henley 1995). Dorsal fins begin to develop when
larvae are approximately 5.5 mm NL, and are first observed in the head
region. Development of this fin proceeds posteriorly, and is most rapid
during the postflexion stage. By the time larvae reach 6.9 mm NL, the
adult complement of caudal fin rays (10 upper, 8 lower) is reached.
Following postflexion, when larvae reach approximately 6.1 mm standard
length (SL), anal fin rays begin to develop, with the full adult
complement of fin rays developed by the time larvae reach 7.7 mm SL.
Pelvic fins are first observed on larvae at approximately 7.0 mm SL, and
are fully developed by the time larvae attain 8.5 mm SL. Pectoral fins
first begin formation when larvae are approximately 7.1 mm SL, and are
fully formed when larvae reach 8.5 mm SL.
VI. SPECIAL STATUS
Special Status:
Fisheries.
Fisheries
Importance:
COMMERCIAL FISHERY:
Sixty percent of Florida's commercial catch of
flounders is harvested from Atlantic coast waters, both inland and coastal, with
flounders of all species captured in and around the Indian River Lagoon. However, the commercial
flounder fishery is not of particularly high
value and accounts for only 30 - 35% of the annual catch, with the recreational
fishery being of far more importance. For the years 1987 - 2001, 1.7 million pounds of mixed flounder
species were
harvested commercially, with a dollar value of over 3.1 million reported in the 5 county area
encompassing the IRL (Volusia, Brevard, Indian River, St. Lucie and Martin
Counties). This ranks flounders nineteenth in commercial value
within the IRL, and twenty-ninth in pounds harvested.
Figure 1 below shows the dollar value of the commercial flounder
fishery to IRL counties by year. Note that all species of flounders were
combined in the data presented. As shown, commercial catch ranged from a low of $77,149 in
1987 to a high of over $350,927 in 1999. Volusia County annually accounts
for the largest percentage of the flounder catch with 83% in total (Figure 2),
followed distantly by Brevard County, which accounts for 8% of the total.
Indian River, St. Lucie and Martin Counties account for 3%, 4% and 2% of the
total respectively. Note that the fishery's value brings in $125,000 -
$300,000 annually to Volusia County businesses, while in all other IRL counties,
the dollar value is typically less than $25,000.
Figure 1. Annual dollar value of
the commercial catch of flounders to the 5-county area
of the Indian River
Lagoon.
Figure 2. Breakdown of total
flounder
dollar value by county for the years 1987 - 2001.
|
|
Volusia |
Brevard |
Indian River |
St. Lucie |
Martin |
Total |
| |
Value |
Value |
Value |
Value |
Value |
Value |
|
YEAR |
($) |
($) |
($) |
($) |
($) |
to IRL |
|
1987 |
$52,332 |
$16,478 |
$462 |
$4,740 |
$3,137 |
$77,149 |
|
1988 |
$125,679 |
$24,502 |
$773 |
$4,896 |
$6,499 |
$162,349 |
|
1989 |
$159,271 |
$0 |
$0 |
$5,312 |
$0 |
$164,583 |
|
1990 |
$135,210 |
$20,461 |
$1,113 |
$10,947 |
$5,396 |
$173,127 |
|
1991 |
$168,724 |
$20,692 |
$2,446 |
$22,654 |
$6,410 |
$220,926 |
|
1992 |
$117,085 |
$16,988 |
$2,813 |
$15,816 |
$4,620 |
$157,322 |
|
1993 |
$182,403 |
$20,647 |
$1,574 |
$11,826 |
$7,469 |
$223,919 |
|
1994 |
$202,828 |
$15,739 |
$6,091 |
$5,041 |
$5,984 |
$235,683 |
|
1995 |
$238,435 |
$14,654 |
$6,773 |
$5,227 |
$4,412 |
$269,501 |
|
1996 |
$137,805 |
$7,207 |
$7,347 |
$638 |
$2,625 |
$155,622 |
|
1997 |
$194,655 |
$20,528 |
$19,640 |
$7,254 |
$2,787 |
$244,864 |
|
1998 |
$145,311 |
$16,449 |
$13,133 |
$14,215 |
$5,855 |
$194,963 |
|
1999 |
$306,281 |
$25,090 |
$9,182 |
$8,772 |
$1,602 |
$350,927 |
|
2000 |
$265,389 |
$19,629 |
$3,097 |
$13,248 |
$3,244 |
$304,607 |
|
2001 |
$148,233 |
$14,655 |
$9,103 |
$4,789 |
$1,256 |
$178,036 |
|
Cumulative
Totals: |
$2,579,641 |
$253,719 |
$83,547 |
$135,375 |
$61,296 |
$3,113,578 |
Table 1. Total dollar value of
flounders to IRL counties between
1987 -2001.
|
|
Volusia |
Brevard |
Indian River |
St.
Lucie |
Martin |
| |
% |
% |
% |
% |
% |
|
YEAR |
Total |
Total |
Total |
Total |
Total |
|
1987 |
67.8% |
21.4% |
0.6% |
6.1% |
4.1% |
|
1988 |
77.4% |
15.1% |
0.5% |
3.0% |
4.0% |
|
1989 |
96.8% |
0.0% |
0.0% |
3.2% |
0.0% |
|
1990 |
78.1% |
11.8% |
0.6% |
6.3% |
3.1% |
|
1991 |
76.4% |
9.4% |
1.1% |
10.3% |
2.9% |
|
1992 |
74.4% |
10.8% |
1.8% |
10.1% |
2.9% |
|
1993 |
81.5% |
9.2% |
0.7% |
5.3% |
3.3% |
|
1994 |
86.1% |
6.7% |
2.6% |
2.1% |
2.5% |
|
1995 |
88.5% |
5.4% |
2.5% |
1.9% |
1.6% |
|
1996 |
88.6% |
4.6% |
4.7% |
0.4% |
1.7% |
|
1997 |
79.5% |
8.4% |
8.0% |
3.0% |
1.1% |
|
1998 |
74.5% |
8.4% |
6.7% |
7.3% |
3.0% |
|
1999 |
87.3% |
7.1% |
2.6% |
2.5% |
0.5% |
|
2000 |
87.1% |
6.4% |
1.0% |
4.3% |
1.1% |
|
2001 |
83.3% |
8.2% |
5.1% |
2.7% |
0.7% |
Table 2.
By-county annual and cumulative percentages of the flounder harvest for the years
1987-2001.
|
|
Volusia |
Brevard |
Indian River |
St. Lucie |
Martin |
|
Dollars |
$2,579,641 |
$253,719 |
$83,547 |
$135,375 |
$61,296 |
|
% |
82.9% |
8.1% |
2.7% |
4.3% |
|
