Fishery Bulletin 96 ( I ), 1 998 
I 10 
identified (listed in Appendix), including five 
uncatalogued lots collected recently by North Caro- 
lina State University researchers from several loca- 
tions in Puerto Rico listed in Van der Veer et al. 
(1994), none were S. plagiusa. These specimens were 
S. plagusia,S. caribbeanus, or S. tessellatus, common 
shallow-water species having widespread distribu- 
tion throughout the Caribbean Antilles ( Munroe, 1991). 
In the absence of voucher specimens, the occurrence of 
S. plagiusa in Puerto Rico is doubtful. 
Bathymetric distribution Symphurus plagiusa pri- 
marily is a shallow-water species inhabiting 
nearshore coastal waters, coastal embayments, and 
estuaries (Ginsburg, 1951). Specimens examined in 
this study were captured at depths from <1 to 183 m 
(Table 10), but the majority (309/324, 95%) were col- 
lected between 1 and 30 m. Throughout the Atlantic 
coast region of this species’ geographic range, it is 
usually the only tongueflsh taken commonly in shal- 
low-water embayments and estuarine environments 
(juvenile S. civitatium occasionally co-occur in At- 
lantic coast environments but are more abundant in 
Gulf of Mexico estuaries; see account for civitatium 
below) and therefore a large part of the S. plagiusa 
population is ecologically separated from other 
tongueflsh species in this region. On the inner conti- 
nental shelf where larger-size S. plagiusa are taken 
(see below), collections also frequently contain speci- 
mens of S. civitatium and S. diomedeanus (Hilde- 
brand, 1954; this study). 
Symphurus plagiusa undergoes ontogenetic shifts 
in the bathymetric environments it inhabits. All life 
history stages occur in nearshore and estuarine habi- 
tats, but the smallest juveniles occur in extremely 
shallow tidal creeks in estuarine saltmarshes 
(Gunter, 1945; Swingle, 1971; Shealy et al., 1974; 
Stickney, 1976; Ogren and Brusher, 1977; Naughton 
and Saloman, 1978; Reichert and Van der Veer, 1991; 
Baltz et al., 1993). Some newly settled juveniles have 
even been captured in small, intertidal tributaries 
(Bozeman and Dean, 1980; Rakocinski et al., 1992). 
As they grow, juveniles move first to deeper areas of 
larger estuarine creeks and rivers and then to more 
open and usually more saline embayments (Topp and 
Hoff, 1972). Baltz et al. (1993) suggested that move- 
ments of this species that are associated with increas- 
ing size may indicate ontogenetic movements to mi- 
crohabitats with higher velocity water movements. 
Although the majority of the S. plagiusa popula- 
tion is centered in inshore waters, the largest indi- 
viduals (usually >100 mm) occur regularly in mod- 
erate depths (10-30 m) on the inner continental shelf 
(Struhsaker, 1969; Franks et al., 1972; Topp and Hoff, 
1972; Yanez-Arancibia and Sanchez-Gil, 1986; 
Wenner and Sedberry, 1989; this study). Of the S. 
plagiusa examined in the present study, most, col- 
lected in deeper waters on the continental shelf, were 
large individuals of over 120 mm. Larger fish (100- 
190 mm TL; x=ca. 140 mm TL) have also been re- 
ported in the shrimp bycatch taken in coastal wa- 
ters off South Carolina (Reiser, 1976). Samples ofS. 
plagiusa collected in coastal waters in the South At- 
lantic Bight at ca. 10 m depth (Wenner and Sedberry, 
1989) were almost entirely large individuals (140- 
210 mm TL, x =140-150 mm TL), whereas smaller 
specimens (<100 mm TL) were unusual in trawls 
made at these locations. Wenner and Sedberry con- 
cluded that juveniles were not collected at deeper 
stations either because they occupied different habi- 
tats or because they did not recruit to the fishing 
gear until reaching a larger size. 
Although most records of S. plagiusa are from 
waters shallower than ca. 40 m, several studies re- 
corded this species from much gr eater depths. Bullis 
and Thompson (1965) and Franks et al. (1972) re- 
ported collecting S. plagiusa at 92 m, Staiger (1970) 
listed one specimen (62 mm) taken at 132 m on the 
Pourtales Terrace (specimen not located during this 
study), and Chittenden and Moore (1977) listed this 
species among those occurring at the 110-m bathy- 
metric contour off Louisiana and northern Texas 
(specimens not examined in this study). The deepest 
records for S. plagiusa examined in this study are 
those of one specimen (USNM 265181) taken at 183 
m off the southern Bahamas (20°54'N, 73°33'W), and 
25 specimens (USNM 159616) purportedly collected 
between 186 and 189 m (101 and 102 fm). The depth of 
capture for this lot is questionable, however, because 
coordinates for this station (RV Silver Bay 156, 29°04'N, 
85°49 W) place it in a region where depths range be- 
tween 70 and 93 m (38 and 50 fm). Because of this un- 
certainty, depth-of-capture data for these specimens 
were not included in Table 10. 
Ecology More ecological information is available for 
S. plagiusa than for any other tongueflsh. Occur- 
rences of all postsettlement stages of S. plagiusa, 
even those taken in neritic waters, generally corre- 
spond with the distribution of substrates with a high 
percentage of silt or fine sand (Reid, 1954; Springer 
and Woodburn, 1960; Reichert and Van der Veer, 
1991; Baltz et al., 1993). Preference for soft mud sub- 
strates is reflected in the almost universal occurrence 
of S. plagiusa in studied fish communities in pro- 
tected waters throughout its range. In protected ar- 
eas where soft substrates abound, this species is 
sometimes found in great abundance. Conversely, S. 
plagiusa occurs only sporadically and generally in 
much lower abundance in coarse sand habitats, such 
