Species Description: The bay whiff, Citharichthys spilopterus, is a relatively small flatfish of the family Bothidae. Members of this group are known as "lefteye flounders" because both eyes and pigmentation are on the left side of the body. Bothids are also characterized by separate dorsal and anal fins and large eyes. As with other species of Citharichthys, the lateral line of C. spilopterus is nearly straight and the mouth is moderate in size (Robins & Ray 1986). The body is mostly brown, often with small, obscure spots. Unlike some other closely-related species, the opercle or gill cover on the blind side has no cirri. Pelvic fins are asymmetrical, with those of the eyed side located on the midline of the belly. Average fin ray and other meristic counts documented for some collected specimens are as follows: dorsal fin rays = 77-78; anal fin rays = 56-59; pectoral fin rays = 9-10; lateral line scales = 45; vertebrae = 33 (Castillo-Rivera & Kobelkowsky 1992, Ruiz-Carus & Rider 1998). Some species of flatfishes often exhibit reversal of the external and/or internal organs, with bothids appearing as dextral or righteye flounders. Such a process is rare for C. spilopterus, but a few isolated cases of reversal in eye symmetry, pigmentation, the olfactory system, liver and intestines have been reported in Mexico, Florida and North Carolina (Castillo-Rivera & Kobelkowsky 1992, Ruiz-Carus & Rider 1998, Wilkins & Lewis 1971).
Potentially Misidentified Species: The bay whiff overlaps with the ranges of several flatfishes. Of these, three similarly-sized species of Citharichthys have been found in the Indian River Lagoon: the Gulf Stream flounder, C. arctifrons; the sand whiff, C. arenaceus; and the spotted whiff, C. macrops. Although specimens have been located in the IRL, the usual depth range for C. arctifrons is 46-365 m (Robins & Ray 1986). This species also exhibits no obvious color pattern, has a more elongated body than the bay whiff, and hornlike projections originating from the snout. The sand whiff is brown with dark flecks, and the dorsal and anal fins are spotted or barred. Its range overlaps with C. spilopterus from southeastern Florida to Brazil (Robins & Ray 1986). The spotted whiff is pale yellowish to brown with multiple dark spots on the body and fins. Unlike the bay whiff, the opercle on the blind side has cirri. This species also prefers sandier substrata than C. spilopterus.
Regional Occurrence: The range of C. spilopterus extends from New Jersey to the Gulf of Mexico and from the Antilles to Brazil (Robins & Ray 1986). Populations can be found in a variety of shallow coastal habitats to a depth of 75 m. Because of its wide environmental tolerances, the bay whiff thrives at multiple latitudes and habitat types. Large numbers have been found in several temperate to tropical locations, including: Newport River and Back Sound estuaries, North Carolina (Walsh et al. 1999); Barataria Bay, Louisiana (Allen & Baltz 1997; Toepfer & Fleeger 1995a, 1995b); Tampamachoco Lagoon, Mexico (Castillo-Rivera & Kobelkowsky 1992, Castillo-Rivera et al. 2000); Mamananguá Inlet and Sepetiba Bay, Rio de Janeiro, Brazil (Dias et al. 2005, Guedes & Araújo 2008).
IRL Distribution: The bay whiff is found throughout the IRL on muddy substrata in and around seagrass beds, mangroves and salt marshes, including mosquito impoundments.
Age, Size, Lifespan: The maximum age and lifespan for C. spilopterus is unknown. The maximum reported size for the bay whiff is 20 cm (Robins & Ray 1986), but most specimens collected in the field are between 1 and 10 cm (Allen & Baltz 1997). Dias et al. (2005) found that the majority of individuals larger than 17 cm were females, and males predominated in size classes less than 13 cm. Because C. spilopterus is a gonochorist, maintaining the same sex throughout its life, the discrepancy in size is likely due to varying growth rates between the sexes.
Abundance: Broad surveys on the abundance of C. spilopterus throughout its range are lacking. However, it is reported to be the most common flatfish in several estuaries along the Gulf of Mexico (eg. Castillo-Rivera et al. 2000). It is the second most abundant flatfish in Barataria Bay, Louisiana, with a total catch of 2,531 individuals over a two-year period (Allen & Baltz 1997). Although common, the bay whiff is often solitary and densities of individuals can be quite low. Surveys in North Carolina found between 0.01 and 0.37 fish m-2.
Reproduction: Spawning seasons for C. spilopterus vary with location, and is most likely a factor of water temperature (Joyex et al. 1995). Populations in Brazil spawn from March to May and November, the North Carolina season is restricted to February and March, and Puerto Rico fishes spawn from November to May (Joyex et al. 1995), and peak spawning occurs in both winter and spring in Louisiana (Allen & Baltz 1997). In Florida, the large presence of juveniles in May suggests a spring spawning season. Dias et al. (2005) found that C. spilopterus females in Brazil prefer to migrate to deeper waters to spawn, returning to shallow areas at the end of the season.
Embryology: The reproductive behavior and embryology of the bay whiff is poorly reported. However, Joyeux et al. (1995) studied the growth rates of the species in Puerto Rico and North Carolina. After spawning, larvae of C. spilopterus usually metamorphose and settle in coastal habitats after approximately 40-50 days. Depending on water temperature and other factors, growth in post-settlement juveniles can range from 0.44 to 0.69 mm per day.
Temperature: The bay whiff is most abundant in tropical and subtropical waters, but can be found in mild temperate climates as well. In addition, the estuarine nature of the species often subjects it to large variations in water temperature. Field temperatures during specimen collections in Louisiana, North Carolina, Florida, Mexico and Brazil ranged from 7 to 32°C (Joyeux et al. 1995; Toepfer & Fleeger 1995a, 1995b). Spawning times and seasonal migrations are likely tied to water temperature fluctuations as well. Winter offshore movement of the flatfish in Texas and Louisiana has been attributed to cooling water temperatures (Gunter 1938, 1945), with documented inshore return of populations along the Texas coast during the summer months (Miller 1965).
Salinity: As a euryhaline species, the bay whiff has a wide salinity tolerance. Individuals have been found near freshwater areas as low as 0.9 psu to coastal waters exceeding 35 psu (Allen & Baltz 1997, Dias et al. 2005).
Trophic Mode: Like many benthic and demersal organisms, flatfishes are ambush predators. Juveniles and adults camouflage themselves on or just below the sediment surface. When prey swims overhead, the fish elevates itself with the benthic pectoral fin to observe the organism before swiftly attacking and returning to the benthos (Stickney et al. 1973). Ontogenetic shifts in dietary preferences have been documented for the bay whiff, with prey items varying with age or size of individuals. Juvenile fishes prefer a wider range of foods, including: the calanoid copepod, Acartia tonsa; amphipods; mysid shrimps; and detritus. As the bay whiff grows, it begins to consume mostly other fishes and larger crustaceans (Castillo-Rivera et al. 2000, Guedes & Araújo 2008, Toepfer & Fleeger 1995a). Changes in feeding habits with growth usually occur in order to utilize available food resources, avoid competition, and catch the largest and most nutritious prey for the least energetic cost (Beyst et al. 1999, Amara et al. 2001, Amezcua et al. 2003), a behavior often known as "minimum capture effort" (eg. Castillo-Rivera et al. 2000).
Predators: Little information exists concerning the predators of C. spilopterus. However, it is likely that larvae are consumed by a variety of planktonic and filter-feeding organisms. Cannibalism has even been reported among smaller juveniles (Castillo-Rivera et al. 2000). Once settled, the ability of the bay whiff to camouflage itself on the benthos likely reduces predation risk. Still, this species is a relatively small flatfish, and could be preyed upon by larger fishes and invertebrates.
Associated Species: As inhabitants of a variety of coastal ecosystems, bay whiffs are associated with several organisms common to mangroves, seagrass beds and sand flats. For extensive lists of organisms found throughout the ecosystems in which C. spilopterus occurs, please refer to the Habitats of the IRL page on this site.
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