Species Profiles: Life Histories and 

Environmental Requirements (Gulf of Mexico) 

SPOTTED SEATROUT 

Waterways Experiment Station 

Fish and Wildlife Service Coastal Engineering Research Center 

U.S. Department of the Interior U.S. Army Corps of Engineers 
FWS/OBS-82/11.4 

TR EL-82-4 

February 1983 

Species Profiles: Life Histories and 

Environmental Requirements (Gulf of Mexico) 

SPOTTED SEATROWT 

Dennis R. Lassuy 

U.S. Fish and Wildlife Service 

National Coastal Ecosystems Team 

1010 Gause Boulevard 

Slidell, LA 70458 

Project Manager 

Larry Shanks 

Project Officer 

Norman Benson 

National Coastal Ecosystems Team 

U.S. Fish and Wildlife Service 

1010 Gause Boulevard 

Sl idel 1 , LA 70458 

This study was conducted 

in cooperation with 

U.S. Army Corps of Engineers 

Waterways Experiment Station and 

Coastal Engineering Research Center 

Performed for 

National Coastal Ecosys tems Team 

Division of Biological Services 

Fish and Wildlife Service 

U.S. Department of the Interior 

Washington, DC 20240 
PREFACE 

This series of profiles about coastal aquatic species of commercial, 

sport, and/or ecological significance is heing ,jointly developed and funded by 

the U.S. Army Corps of Engineers and the 1J.S. Fish and Wildlife Service. It 

i s designed to provide coastal managers, engineers , and fi el d bi 01 ogi sts wi th 

an introduction to the subject species and a synopsis of the information 

necessary to re1 ate expected changes (associ ated wi th coastal devel opment) i n 

the physicochemical characteri stics of estuaries to changes in these selected 

biological populations. Each profile includes brief sections on taxonomy and 

identi fication fol lowed by a narrative of 1 i fe hi story, environmental requirements, ecological role, and (where applicable) the fishery of the subject 

species. A three-ring binder is used for this series to facilitate additions 

as new prof.\ 1 es are prepared. 

Suggestions or questions regarding thi s report should be directed to: 

Informati on Transfer Speci ali st 

National Coastal Ecosys tems Team 

U.S. Fish and Wildlife Service 

NASA-Sl idel 1 Computer Complex 

1010 Gause Boulevard 

Sl idel 1, LA 70458 

U. S. Army Engi neer Waterways Experiment Station 

Atten ti on : W ESES 

Post Office Box 631 

Vicksburg, MS 39180 

U. S. Army Coastal Engineering Research Center 

Ki ngman Bui 1 di ng 

Fort Belvoir, VA 22060 

This series should be referenced as follows: 

U.S. Fish and Wildlife Service. 1983. Species profiles: life histories and 

envi ronmental requirements. U .S. Fi sh and Wildli fe Service, Division of 

Bi 01 ogical Services, WS/OBS-82/11. U.S. Army Corps of Engineers, TR 

EL-82-4. 

This profile should be cited as follows: 

Lass~~y, D. R. 1983. Species profiles: 1 i fe h i s t o r i e s and envi ronmental 

requirements (Gulf of Mexico) -- spotted seatrout. U.S. Fish and Wild1i fe Service, Division of Biological Services. FWS/OBS-82111.4. U.S. 

Army Corps of Engineers, TR EL-82-4. 14 pp. 
Figure 1. Spotted seatr,out. 

SPOTTED SEATROUT 

Scientific name. . .Cynoscion nebulosus 

(Cuvier) 

preferred-common name ..... Spotted 

seatrout (Figure 1) 

Other common names ...... .Spotted 

weakfish, spotted squeteague, spotted 

trout, speckles, speckled trout, 

salmon trout, simon trout (Hildebrand 

and Schroeder 1972) 

Class .......... .Ostei chthyes 

Order ........... Perci formes 

Family. .......... Sciaenidae 

Geographic range: Coastal waters from 

Cape Cod, Massachusetts, to the 

Bay of Campeche, Mexico. Common 

along the entire Gulf of Mexico 

coast, but most abundant off eastern Louisiana, south Texas, Mississippi, and Alabama (Figure 2). 

D. X(rare1y XI) + I, 24-26; A. 11, 

10-11; Sc. 90-102; Gr. 4 + 7-9; head 

2.95-3.25; depth 3.4-4.35. Body elongate, somewhat compressed; back 1 i ttle 

elevated; head long and low; snout 

pointed, 3.75 to 4.2 in head; eye 4.45 

to 5.35; interorbital 4.5 to 5.9; mouth 

1 Largely extracted from Pearson (1929), 

Hi ldebrand and Schroeder (1972), and 

Hoese and Moore (1977). See these 

references for explanations of abbreviations and measurements. 

to 5.35; interorbital 4.5 to 5.9; mouth 

large, obl ique; lower jaw projecting; 

maxi 1 lary reaching nearly or quite 

opposite posterior margin of eye, 2.2 

to 2.3 in head; teeth in jaws pointed, 

in two series anteriorly, becoming 

single posteriorly, at least in lower 

jaw, two enlarged, recurved teeth usually present in anterior part of upper 

jaw; gill rakers rather short and thick 

(longest about as long as width of 

pupil ); scales small, thin, ctenoid, 

extending forward on head, cheeks, and 

opercles, not present on fins, 11 or 12 

between origin of anal and lateral 

line; dorsal fins contiguous or separate, spines of the first weak, flexible, the longest spines scarcely 

longer than the longest soft rays; 

caudal fin lanceolate in very young, 

becoming truncate to somewhat concave 

in adults; anal fin small, the spines 

very weak, base of fin ending about an 

eye's diameter in advance of end of 

base of dorsal; ventral fins rather 

small, inserted a little behind base of 

pectorals, 1.85 to 2.25 in head. 

Color in life: dark gray above 

with bluish to greenish reflections; 

silvery below; upper part of side with 

numerous round, black spots, which 

extend on to dorsal and caudal fjns. 

Young above 80 mm total length (TL) are 

similarly spotted. Larval and young 

stages are described by Pearson (1929), 

Hildebrand and Cable (1934), and Fable 

et al. (1978). 

Spotted seatrout support valuable 

commercial and sport fisheries throughout the coastal Gulf of Mexico. Estuaries are considered essential to the 

species as spotted seatrout depend upon 

the estuarine environment for feeding, 

spawning, and nursery grounds. Spotted 

seatrout have been identified as top 

carnivores and may play a significant 

role in the structure and function of 

estuarine communi ties. 

2 25.4 mm = 1 inch. 

LIFE HISTORY 

Spawning 

The only published account of an 

actual observation of spotted seatrout 

spawning found in the literature was 

that of Tabb (1966). He gave a brief 

account of spawning behavior and commented that spawning takes place at 

night "in deeper holes and scourchannels in the grass flats." This 

agrees with the findings of Pearson 

(1529) who reported capturing "many 

ripe and spending adults" along grassy 

shore1 ines. Pearson a1 so be1 ieved that 

spawning actually occurred somewhat 

offshore of these areas in waters up to 

3 to 4.6 m (10 to 15 ft) deep. Both 

authors reported that spawning often 

occurs we1 1 within the estuaries. 

Pearson, in fact, reported spawning as 

much as 81 to 97 km (50 to 60 mi) from 

the open gulf waters in the bayous and 

tidal streams entering Copano Bay, 

Texas. Spawning may also occur in 

lower regions of the estuary (Tabb 

1966), near the passes between barrier 

islands (Tabb and Kanning 1961; Etzold 

and Christmas 1479), or even entirely 

outside the estuaries (Jannke 1971; 

King 1971). , Perret et al. (1980) suggested that the site of spawning "may 

be more related to sal inity and temperature than to other physical parameters" (see Temperature and Sal ini ty 

sections). 

Spotted seatrout have a protracted 

spawning season throughout the Gulf of 

Mexico. Jannke (1971) reported spawning in southern Florida in all months 

with a first peak in May and a lesser 

peak in fall. Perret et al. (1980) 

suggested that the inception of spawning in the gulf is variable and may 

start as early as February, but that it 

has generally ceased by October. Peak 

spawning of the spotted seatrout in the 

Gulf of Mexico is usually cited as late 

as April to July (Pearson 1929; Tabb 

1966) and has been suggested to be 
closely 1 inked with water temperature 

(see Temperature section). Both sexes 

have been reported to mature and spawn 

as early as the end of their first year 

of 1 ife (Sundararaj and Suttkus 1962), 

but most researchers suggest spawning 

at the end of the second or third year 

(Pearson 1929; Etzold and Christmas 

1979). All are apparently mature and 

spawn by age IV (Kl ima and Tabb 1959). 

Several authors have reported that 

males mature at a lesser size and age 

than females (Moody 1950; Tabb 1961; 

Etzold and Christmas 1979). Sundararaj 

and Suttkus (1962) found that age I11 

("three winters1') fish had the greatest 

"spawning power," contributing an estimated 40.6% of all eggs spawned. 

Fecundity and Eggs 

A fecundity estimate of 1.1 million eggs was reported by Pearson 

(1929), Tabb (1961), and Sundararaj and 

Suttkus (1962) for spotted seatrout of 

534, 625, and 433 mm standard lengths 

(SL), respectively. It is uncertain 

whether the differences among these 

studies are real or are due to differences in estimation techniques. 

Pearson's estimate for a fish of 411 mm 

SL, however, was 427,819 eggs, or less 

than half that of the similarly sized 

specimen of Sundararaj and Suttkus mentioned above. Such disparate estimates 

suggest that the differences are real , but may indicate either wide individual 

variation or estuary-to-estuary (stockto-stock) variation. Estimates of 

fecundity among small er females include 

those of Tabb (1961) of 15,000 eggs for 

a 32'5-mm SL fish and Sundararai and 

Suttkus (1962) of 14,000 eggs for a 

238-mm SL fish. No regression equation 

for fish size versus fecundity, or 

estimate of the variation about such a 

curve, was found in the literature. 

The eggs of spotted seatrout are 

spherical and hatch as 1.30- to 1.35-mm 

SL larvae (Fable et al. 1978). Hatching occurs in 40 hours at 25°C or 77°F 

(Smith 1907, cited by Pearson 1929). 

Fab'le et al. (1978) also reported that 

eggs are pelagic, yet Taniguchi (pers. 

comm., cited by 'Perret et al. 1980) 

stated that eggs are buoyant at a salinity of 30 ppt, but sink at 25 ppt. 

At preferred spawning sal ini ties (see 

Salinity section) in the estuary, 

therefore, eggs may either be buoyant . - 

or demersal, as suggested by Tabh 

(1966). 

Larvae 

Little is known about the distribution of larvae less than 10 mm long. 

Jannke (1971) and King (1371) reported 

finding larvae 5 to 6 mm long being 

transported on flood tides through 

passes connecting the Gulf of Mexico 

and inside waters. Pearson (1929) 

reported capturing a 7.8-mm larval 

spotted seatrout near Corpus Christi 

Bay at the edge of a deep channel. 

Taniguchi (pers. comm., cited hy Perret 

et al. 1980) observed that upon hatching, 1 arvae swam upward into the water 

column, but moved toward the bottom 

after 4 to 7 days. 

Post1 arvae through Adults 

Numerous authors have cited an 

apparent preference of post1 arval and 

juvenile spotted seatrout for shall ow, 

vegetated estuarine areas (Pearson 

1929; Miles 1950; Perret et a1 . 1980). 

Tabb (1966) reported school ing at 25 

to 50 mm (6 to 8 weeks). Juveniles of 

75- to 100-mm lengths have formed 

schools of 5 to 50 members (Perret 

et al. 1980) and continue this schooling behavior to age V or VI (Tabb 

1966). By age VI, apparently most 

males have died and the remaining 

fernal es "adopt a semi-sol i tary existence" (Tabb 1966). Juveniles remain 

in the estuarine nursery areas at least 

through the warmer months. Pearson 

(1929) suggested that the young seldom 

move into the gulf until mature, but 

that "many adults 1 inger around the 
entrances to the passes at all times of 

the year." Fall emigration of spotted 

seatrout to the deeper, warmer waters 

of the bays or gulf is apparent, but 

1 ess pronounced than in many other 9ulf 

fishes (Moffett 1961; Tabb 1966). 

Tagged fish have rare1 been found to 

move more than 48 kn (30 mi) from the 

site of tagging (Perret et al. 1980). 

Seasonal movement patterns are apparently in response to changes in water 

temperature and are more pronounced in 

northern waters (Pearson 1329; Tabb 

1966). Movement back into the estuaries 

to feed and, for some, to spawn is usually completed by Hay (Pearson 1929). 

GROWTH CHARACTERISTICS 

Pearson (1929) discussed the use 

of scales in age and growth studies of 

spotted scatrout. He found that there 

"appeared to be little increment in 

size from November to March, but in 

early spring growth was resumed" and 

that annuli were thus formed. He preferred back-cal culation of growth rate 

instead of 1 ength-frequency di stri bution because the latter was difficult 

to interpret due to overlap in lengths 

between age classes, a common problem 

among species with a protracted spawning season. This overlap is a1 so mentioned by Perret et a1 . (1980), who 

summarized the results of several 

growth studies (Table 1). Females 

apparently have a higher growth rate 

than males (Pearson 1929; Etzold and 

Christmas 1979), but separate growth 

equations for a single population were 

not found in the 1 iterature. Data 

presented in Table 1 are representative 

of both sexes combined. A1 though there 

seens to be an indication from the data 

presented in Table 1 of estuary-toestuary variation in growth rate, yearto-year variation cannot be ruled out 

as the primary source of these differences. Of the four studies reported in 

1961, all except the clearly aberrant 

Indian River, Florida, population show 

similar results. Weinstein and Yerger 

(1976) have, however, presented evi - 

dence of electrophoretic differences 

between spotted seatrout stocks from 

different estuaries and of the divergent nature of the Indian River stock. 

Several studies have reported a 

preponderance of ma1 es among younger 

year classes, a near 1:l ratio at age 

I1 to 111, and all or nearly all females by age V to VI or older (Kl ima 

and Tabb 1959; Moffett 1961; Tabb 

1961). This pattern is similar to 

species that exhibit protandrous hermaphroditism, but this has not been suggested for the spotted seatrout. Instead, the shift in older fish is most 

often attributed to greater longevity 

in females. No mention of sexual differences in susceptibil i ty to capture, 

distributional segregation among juveniles or of other than a 1:l sex ratio 

at birth has been found in the literature. Evidence toward an acceptabl e 

explanation for the observed sex ratio 

in the earlier year classes therefore 

remains wanting. 

Harrington et al. (1979, cited by 

Perret et al. 1980) reported the following length-weight relationships for 

spotted seatrout from the coast of 

Texas : 

1 og W(g) = -5.192 + 3.062 log TL(mm) (44-902 mm TL range) 

TL(mm) = 11.804 + 1.138 SL(mm) (36-744 mm SL range) 

W(g) = -33.338 + 1.151 DW(g) (305-4595 g DbJ range) 

where: W = whole wet weight 

TL = total length 

SL = standard length DW = dressed wet weight 
Table 1. Lengths (mn SL) at age for several populations of spotted seatrout. 

Standard lengths for central Texas and Punta Gorda were converted from total 

lengths by the forraula given in the text (Perret et al. 1980). 

Central Apalachicola & Cedar Punta Florida Indian 

Age exa as^ ApalacheeBaysb KeyC Ft. ~yers~ ~orda~ ~a~~ ~iver~ 

apearson 1929. 'Moffett 1961. 

'Klima & Tabb 1959. d~offett 1961. 

COMF.?ERCIAL/SPORT FISHERY 

A useful review of the harvest, 

economic and management history of the 

spotted seatrout fishery in the Gulf of 

Mexico is provided by Perret et al. 

(1980). Based on their report, the 

commercial catch (lb) was converted to 

retric tons (mt) and is presented in 

Tab'le 2. Most who fish for spotted 

seatrout com~ercially also fish for red 

drum and a variety of other inshore 

species. Landings occur throughout 

the year along the gulf coast (Perret 

et al. 1980). Commercial catches of 

spotted seatrout from 1950 through 1377 

fluctuated between 1,572 mt in 1954 and 

3,374 mt in 1973, but no trends in 

abundance were discernable. Most of 

the coml~~ercial catch is sold fresh in 

local markets. The estimated sport 

catch of spotted seatrout for the gulf 

as a whole is substantially greater 

than the commercial catch (see footnote b, Table 2). Fish taken in the 

sport fishery average about 1.25 1b 

(0.6 kg) with the highest estimated 

e fWelsh & Breder 1924. g~abb 1961. 

Stewart 1961. 

catch per unit effort recorded from 

Louisiana during the summer (Perret 

et al. 1980). 

No estimates of maximum and optimum sustainable yield were found and 

very little has been published relating 

to population or community dynamic 

model ing parameters. The only published quantitative comparison of the 

effects of fishing and natural mortali ty on spotted seatrout dynamics found 

in the literature was that of Iversen 

and t4offett (1962). For fish ranging 

fror 280 to 700 mm TL, they estimated a 

coefficient of instantaneous fishing 

mortal i ty of 1.4 and instantaneous 

natural mortality of 5.8. The resultant combined coefficient of instantaneous total mortality (Z) would, given 

common fishery assurptions (see Ricker 

1975), equal 7.2, or an annual mortality rate (A) of over 90.9%. Estimation 

of Z by catch curve analysis of the age 

structure data presented by Etzold and 

Christmas (1979) yields a value of 0.3, 

or an A of 26%. The former estimate 

of Z seems exceedingly high, but the 
latter is perhaps to6 low. Oddly, 

Iversen and itC:offett (1562) presented a 

sraph of length-frcqucncy distribtitiofi, 

but failed to use the data as a check 

on the ~ortality rate estin-ate6 by tasgi ng studies. An approxi~,ation fron-: 

their ~raph~ yielded a total annual mortality estir.:atc of 49% for fish frm 

about 370 to 500 arm: TL. This is strikingly si~ilar to the mean estiratc of 

Taturn (1C6C) for spotted scatrout of 

ages III+ through VI+. Tatusi used data 

col lectea frorr, annual fishins tournanlents in Alabana. For those years in 

which reliable datd could be gathered 

(1966-6s and 15'73-77), the value of A 

ranged frorl 36.2y5 tcj 58.1" with a rcan 

of 45'.G%. Additional expeririental 

investisation or routin? ase-structure 

analysis of the catch should bc carried 

out to provide more reliable cstirates. 

A re vie^ of fisk,ing success in 

Everglades kational Fark for lC5L 

throu~h 1978 indicated that thc chanses 

in ase structure and abucdancr of 

spotted seatrout were attributatle to 

environr.enta1 changes rather than tc 

fishing rortality and that comnlercial 

fisheries had no effect on sport yicld 

or catch rate (Ccivis 1S80). The for~ler 

conclusion of envir~nc~ental control, 

Table 2. The lc74 com~::ercidl catch (metric tons)a of spotted scatrout in the 

Gulf of Mexico by sear type and State (after Perret et al. 1$60).b 

- - - - - - - -- -- - - - - - - - - - - - - - - -- - .-.- - - --- 

Gear type Fla. kla. fliss. La. Tex. Total Percent 

Runaround gill net 

Tramsiel net 

Lon5 (trot) linc 

Hand line 

Conu~~on haul seine 

Stake gill net 

Troll line 

Shrinp otter trawl 

Total 

a~eiSht = round (live) weight 

b~or corlparisor, with sport catch, in l57C the 11iarine sport catch of spotted 

seatrout for the Gulf of C'exico was 4,01(; r:t, or about twice the 2,021 rlt catch 

of tile con,~nercial fishery for that sacie year (National F'arine Fisheries Service 

1961). 
ECOLOGICAL ROLE 

while perhaps valid locally, does not 

see[!! consistent with the relatively 

stable his tory of the spotted seatrout 

Perret et al. (1380) referred to 

the spotted seatrout as an "opportunistic carnivore whose food changes with 

size" (Figure 3). The illustrated pattern of change in diet is apparently 

typical of areas with abundant seagrass, e.g., Florida and Texas coasts, 

but may differ in areas of lower seagrass abundance, e.g., Lake Pontchartrain, Louisiana (Darnel 1 1958). Portioris of Darnell's (1P61) trophic studies of Lake Pontchartrain relating to 

spotted seatrout are given in Table 3. 

Feeding habits between stages nay be 

reasonably distinct, hut feeding within 

stages is apparently non-selective 

(Tabb 1961). Moody (1950) attributed 

the high percentage (54Z) of empty guts 

found in his study to sporadic feeding, 

and Carnell (1958) suggested that 

feeding was heaviest during the early 

to mid-rriorning hours. No quantitative 

study of the role of spotted seatrout 

in estuarine trophic dyna~xics was 

follnd. 

---- - . . . . . . . 

COPEPODS -.-'-'- PEYEDEP 

CARIDEA - FISH 

I 

Figure 3. The percentage of occurrence 

of the four r~ajor food groups in the 

sto~iachs of spotted seatrout of various 

sizes (Floody 195C). 

catch throughout the Gulf cf Mexico. 

The latt?r, regarding cornrrercial and 

sport fisheries, is counter to the 

findings of tiatlock et al. (1377), who 

found greater sport catch froni areas 

where there has no cornn~ercial fishing. 

Eatlock et al. (1977) concluded that 

"commercial netting reduced populations 

of spotted seatrout [and that] this effect was apparently localized. " Localization of the effects is consistent 

with the findings of Iversen and Moffett (1962) and Weinstein and Yerger 

(1976), who susges ted that the spotted 

seatrout populations of different estuaricis constitute separate stocks and 

should be treated as such for fishery 

nanagenient purposes. The effects of 

shrimp by-catch on spotted seatrout 

abundance are unknown. 50 100 150 200 250 300 350 400 

LENGTH lh MM 

The longevity and growth rate of 

spotted seatrout may be affected by 

the structure of the surroundin9 comniuni ty, e. g., the abundance of predators 

and co~~petitors (Klima and Tabb 1959). 

Such differences niay also be due to 

selective (genetic) differences between 

the various populations (Lei nstein and 

Yerger 1976). No pub1 ished experimental 

studies of con7petition or of other community level interactions were found. 

ENVIRONGENTAL REQUIREMENTS 

Spotted seatrout are reportedly 

taken in C!ississippi Katers fror:? 5" to 
Table 3. Food (by percent of diet) of the ~potted~seatrout. Cynoscion nebulosus. 

from Lake Pontchartrain, Louisiana (Darnel 1 1961). 

Food category 

Size (mmTL) 

40-99 100-406 

Zooplankton 

Microi nvertebrates 

Detritus 

Macroi nvertebrates 

Fish 

a~ethod for estimation of percent of diet was not given. 

b~ncludes anchovies and larval fishes in juvenile (40-99 mm) guts. 

34.9"C (41" to 95°F) (Etzold and 

Christmas 1979), but temperatures of 

7" to 10°C (45" to 50°F) have been 

identified as "adverse" (Tabb 1966). 

Mass mortalities occur during cold 

snaps when water temperatures drop to 

4" to 7°C (39" to 45°F) (Gunter 1941; 

Tabb 1958; Moore 1976). Loman (1978) 

reported highest catches from 25" to 

30°C (77" to 86°F) while Tabb (1958) 

suggested 15" to 27°C (59" to 81°F) as 

a suitable temperature range for the 

spotted seatrout. 

Spawning is reported to occur at 

temperatures of 21°C (70°F) or ,greater 

in Texas (Simmons 1951), 24°C (75°F) or 

greater in southwestern Florida (Jannke 

1971), and 25.5" to 28.3"C (78" to 

83°F) in east Florida (Tabb 1966). 

Taniguchi (1980) reported an optimum 

temperature of 28°C (82°F) for eggs 

and larvae, but predicted 100% survival between 23.1" and 32.7"C (74" and 

91°F). Spotted seatrout move to deeper 

waters in conjunction with decreasing 

fall-winter temperatures. In North 

Carolina, Roelofs (1953) reported fa1 1 

emmigration from the estuaries when 

water temperatures neared 10°C (50°F). 

Immigration into the estuaries the 

fol lowing spring occurred when water 

temperature reached 10" to 12°C (50" to 

54°F) in North Carolina (Roelofs 1953), 

17°C (63°F) in Georgia (Mahood 1974), 

and 21°C (70°F) in Texas (Simmons 

1951). Migrations between offshore and 

estuary waters are less distinct in the 

Gulf of Mexico than along the Atlantic 

coast. Pearson (1929) and Tabb (1966) 

both reported concentrations of spotted 

seatrout in deep holes within estuaries 

during colder months. Tabb (1966) also 

mentioned that such holes, distant from 

deepwater routes to outside waters, 

became "death traps" during cold snaps 

and can be the site of mass mortalities. 

Sal i ni ty 

Spotted seatrout have been taken 

in waters with salinities ranging from 

0.2 to 77 ppt (Simmons 1957). However, 

Tabb (1966) suggested that salinities 

below 5 ppt were "intolerable" and 

that larvae and juveniles unable to 

reach more saline waters during poststorm freshets may suffer mass mortalities. Simmons (1957) reported that no 

spawning occurred in the Laguna Madre 
(Texas) at sal ini ties greater than 

45 ppt. Loman (1978) reported highest 

catches from waters of 20 to 35 ppt. 

Wohlschlag and Wakeman (1978) suggested 

that minimum salinity stress occurs at 

20 ppt for spotted seatrout from south 

Texas tested at 28OC (82OF). They a1 so 

suggested that "there may be no excess 

avail able energy beyond ecological 

maintenance requirements" at sal inities 

below 10 ppt or above 45 ppt. Optimum 

salinity for eggs and larvae is reported as 28.1 ppt with 100% survival 

predicted from 18.6 to 37.5 ppt (Taniguchi 1980). 

Habitat 

The importance of estuaries to 

the spotted seatrout was emphasized by 

Etzol d and Christmas (1979) : 

"Since spotted seatrout may spawn 

in estuaries and are dependent upon them for food throughout their 

lives and since the evidence is 

very strong that each estuary 

maintains a distinct subpopulation 

[stock] of seatrout, it is clear 

that the estuarine environment is 

a particularly critical one for 

this species. " 

Most studies suggest that seagrass 

beds are the preferred habitat of post1 arvae, juvenil es, and adul ts (Pearson 

1929; Moody 1950; Tabb 1966). Spotted 

seatrout may, however, occur abundantly 

near areas without extensive seagrass 

beds, e.g., shell reefs, marshes, and 

submerged or emergent i sl ands (Lorio 

and Perret 1980). In a more general 

statement of habitat requirements for 

the species, Perret et a1 . (1980) 

seemed to tie djstribution most strongly to food availability by stating that 

spotted seatrout "are probably found in 

any area offering suitable salinity and 

temperature regimes combined with sufficient primary productivity to support 

a food web suitable to their needs." 

Tahb (1958) suggested that several 

ecological characteristics were important in determining the abundance of 

spotted seatrout in Indian River, Florida: 

1. Large areas of shallow, quiet 

brackish water 

2. Extensive grassy areas usually dominated by Thalassia 

testudinum and Halodul e 

[Perret et a1 . Wwoul drep1 ace "grassy 

areas . . ." with areas of 

primary productivity.] 

3. Areas of 3 to 6 m [lo to 

20 ft] depth adjacent to 

grass flats to be used for 

refuge from winter cold 

4. An abundant food supply, 

viz., grazing crustaceans 

and suitable size fish 

5. Absence of predators [not 

i denti f i ed] 

6. Absence of competitors [not 

identified] 

7. Suitable temperature of 15' 

to 27OC [5g0 to 81°F] [see 

Temperature section] 

Other Environmental Factors 

Minimum metabol ic oxygen demand 

for spotted seatrout tested at 28OC 

(82°F) was 210, 125, and 230 mg 02/kg/ 

hr at salinities of 10, 20, and 30 ppt, 

respectively (Vetter 1977). No reports 

relating dissolved oxygen to distribution or abundance were found, but 

Etzold and Christmas (1979) reported 

that spotted seatrout "have been found 

in oxygen depletion kill s." Pearson 

(1929) suggested a preference by 

spotted seatrout for "less turbid" 

areas, and Tabb and Manning (1961) suggested that excessively turbid waters 

following Hurricane Donna caused mortality in spotted seatrout by packing 

the gill chambers with suspended 

solids. However, no quantitative study 

relating turbidity to spotted seatrout 
distribution or abundance was found. not known to be harmful to man, but 

The reported parasites and diseases of several may alter growth pattern and 

spotted seatrout were reviewed briefly cause scarring in the fish themselves 

by Lorio and Perret (1980). Nost are (Pearson 1929). 
LITERATURE CITED 

Darnell, R. 1958. Food habits of 

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Darnell, R. 1961. Trophic spectrum of 

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Davis, G.E. 1980. Changes in the Everglades National Park red drum and 

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Etzold, D.J., and J.Y. Christmas. 1979. 

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the spotted seatrout, Cynoscion 

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65- 71. 

Gunter, G. 1941. Death of fishes due 

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Harrington, R.A., G.C. Matlock, and J.E. 

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length, total length-whole weight, 

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Hildebrand, S.F., and L.E. Cable. 1934. 

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48:41-17. 

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91: 395-398. 

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spotted seatrout, Cynoscion nebulosus in Florida. Copeia 1962: -., 

544- 548. 

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to season and other variables. 

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shellfish through a natural pass. 

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Ser. 9. 
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contrihution to the bioloqv of the 

spotted weakfish, ~ynoscfon nebulosus (Cuvier), from northwest 

Florida, with a description of the 

fishery. Fla. Board ~onserv. Rar. 

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Loman, M. 1978. Other finfish. Pages 

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~i sheriesassessment and monitoring - Ilississippi. P.L. 88- 

309, 2-215-R, Completion Report, 

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seatrou t (Cynoscion nehul osus Cuvier). Proceedinas of the Colloquium on the ~ioli~~ and Eanagement of the Red Drum and Seatrout. 

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5: 7-13. 

Mahood, R.K. 1974. Seatrout of the 

genus Cynoscion in coastal waters 

of Georgia. Ga. Dep. Nat. Resour. 

Contrib. Ser. 26:l-35. 

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seatrout and red drum abundance in 

Texas coastal waters influenced by 

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Assoc. Gane Fish Comm. : 477-483. 

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of the seatrout Cynoscion =- 

losus and the redfish, Sciaenops 

ocellatus. Tex. Game, Fish and 

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1949-50. (Mimeo. ) 

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growth of spotted seatrout, wscion nebul osus (Cuvier), in IlJest 

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the biology of the spotted seatrout (Cynoscion nebul osus) in the 

Evergl ades National Park, Florida. 

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1962. Fecundity of the spotted 

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(Cuvier), from Lake Porgne area, 

Lousiana. Trans. Am. Fish. Soc. 

91:84-88. 

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estuarine ecology of Florida 

waters and their effect on 

populations of spotted weakfish, 

Cynosci on nebul osus (Cuvier and 

Val enciennenans. 23rd N. 

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the bioloav of the s~otted seatrout, n no scion nebilosus (Cuvier). of east-central Florida. , . Fla. Board Conserv. Mar. Res. 

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checklist of the flora and fauna 

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the period July, 1957 through 

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649. 

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sal ini ty, temperature, and food 

abundance upon survival of spotted 

seatrout eggs and larvae. Proceedings of the Colloquium on the 

Biology and Management of Red Drum 

and Seatrout. Gulf States Mar. 

Fish. Comm. Rep. 5: 16 (Abstract). 

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orowth data from an annual fishino 

tournament, 1364-1977. proceed: 

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Vetter, R.D. 1077. Respiratory metabolism of, and niche separation between, two co-occurring cogeneric 

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Cynoscion arenarius, in a south 

Texas estuary. M .A. Thesis. 

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Bull., u.s. ~~(~$F

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United States coast. Bull. U.S. 

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Sci . Univ. Tex. 21: 171-185. 
1 3. Rec8plent.s Accession No. 

I I I 

5. Report Date 

Species Profiles: Life Histories and Environmental Requirements 

(Gulf of Mexico) -- spotted seatrout 7iPbruar.y 1983 

7. Authorcs) 

Dennis R. Lassuy 

9. Perlormlng Organization Name end Address 

U.S. Fish and Wildlife Service 

Division of Biological Services 

Na ti ona 1 Coastal Ecosys tems Team 

1010 Gause Boulevard 

Slidell, LA 70458 

- I - 

8. Perlorming Organization Rept. No. 

Unit No. 

I 11. ContrrcttC) or Grant(G1 No. 

12. Sponsoring Organization Name and Address 13. Type of Report 6 Pernod Covered National Coastal Ecosystems Team U.S. Army Corps of Engineers 

Fish and Wildlife Service Waterways Experiment Station 

U.S. Department of the Interior P.O. Box 631 

Washington, DC 20240 Vicksburg, MS 39180 

15. Supplementary Notes 

*U.S. Army Corps of Engineers report No. TR EL-82-4. 

16. Abstract (Limit: 200 words) 

Species profiles are 1 i terature summaries of the taxonomy, morphology, range, 1 ife hi story 

and environmental requirements of coastal aquatic species. They are prepared to assist in 

environmental impact assessment. The spotted seatrout, Cynoscion nebulosus, lives in 

estuaries or nearshore areas its entire life. Larvae and juveniles primarily live in 

vegetated parts of estuaries; adults school and occupy both estuaries and nearshore areas. 

Spawning occurs from February to October. Few spotted seatrout live over 5 years and 

females live longer than males. Commercial catches (1950-1977) in the Gulf of Mexico 

ranged from 1572-3374 mt; sport catch usually exceeds commercial harvest. Population 

dynamics data on the species are weak. Adults are opportunistic carnivores; primary foods 

are fish and shrimp. They have been collected in a temperature range of 5-35°C and a 

salinity range of 0.2-77 ppt. 

17. Document Analysis a. Descriptors 

Estuaries 

Fishes 

Growth 

Feeding 

b. Identitien/O~en-Ended Terms 

Spotted seatrout Life history 

Cynosci on nebul osus Spawning 

Temperature requirements 

Habitat requirements 

18. Availability Statement I 19. Security Class (This RepoR) [I. NO^;^ past 

Unl imi ted Unclassified - 20. ecu 'ty Class (Jhi Page) 22. Price dncYassified I 

(See ANSI-239.18) OPTIONAL FORM 272 (4-77) 

(Formerly NTIS-35) 

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