Eucinostomus argenteus is a member of the family Gerreidae. The
Eucinostomus genus is distinguished from other members of the family
Gerreidae by the interhaemal cone, an unusual cone-shaped structure formed
from the first two anal pterygiophores that encloses the posterior end of
the air bladder (Matheson and McEachran 1984).
The spotfin mojarra is a small to medium sized fish with a compressed body
and protrusible mouth. The body depth is 32.3 to 38.5% of the standard
length. It is a silvery fish that is heavily pigmented with a uniform
pattern of 7 dorsal bars separated by 6 dark lateral spots. The snout has
distinct V-shape pigmentation and the dorsal fin is clear with fine
speckling (Matheson and McEachran 1984).
HABITAT AND DISTRIBUTION
Eucinostomus argenteus occurs seasonally in Chesapeake Bay and other
estuaries south to Florida (Kerschner et. al. 1985), to Brazil (Godefroid
et al. 2001), the Bahamas, West Indies and the Gulf of Mexico.
The spotfin mojarra is common in the Indian River Lagoon during the warmer months and usually found in or around inlet areas (Kerschner et. al. 1985). Schools of juveniles as opposed to adults are encountered more frequently in seagrass beds.
LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan
Individuals in the Indian River Lagoon range in size from 10 to 104 mm (Kerschner et. al. 1985). The maximum length of Eucinostomus argenteus is reported to be 150 mm.
Eucinostomus argenteus is an abundant, schooling fish that often dominates the transient (seasonal visitors) species in subtropic and tropic estuaries (Stoner 1986). In the Indian River Lagoon, schools of the spotfin mojarra are recorded to make up 11% of the catch in the family Gerreidae (Kerschner et. al. 1985). In a Brazilian estuary at Pontal do Sul, Paran‡, E. argenteus makes up 78% of the larval and juvenile catch (Godefroid et al. 2001).
The spawning season of Eucinostomus argenteus occurs during the warmer months of December to June in Brazilian waters (Godefroid et al. 2001).
Larval forms and juveniles of the spotfin mojarra are found from December to June in water temperatures of 16-29°C and salinities ranging from 19-34 ppt (Godefroid et al. 2001).
No information is available at this time
Eucinostomus argenteus is a benthic feeder using its highly protrusible mouth to forage for infaunal invertebrates feeding primarily on bivalves, polychaetes, and crustaceans (Kerschner et al. 1985, Bronco et al. 1997).
Used as live bait in the snapper fishery.
Bayly IAE. 1972. Salinity tolerance and osmotic behavior of animals in
athalassic saline and marine hypersaline waters. Annual Review of Ecology and
Blaylock RA. 1993. Distribution and abundance of the cownose ray, Rhinoptera
bonasus, in lower Chesapeake Bay. Estuaries 16:255-263.
Bronco CW, Aguiaro CT, Esteves FA, and EP Caramaschi. 1997. Food sources
of the teleost Eucinostomus argenteus in two coastal lagoons of
Brazil. Studies on Neotropical Fauna and Environment 32:33-40.
Godefroid RS, Santos C, Hofstaetter M, and HL Spach. 2001. Occurrence of
larvae and juveniles of Eucinostomus argeneus, Eucinostomus gula,
Menticirrhus americanus, Menticirrhus littoralis, Umbrina coroides and
Micropogonias furnieri at Pontal do Sul beach, Paran‡. Brazilian
Archives of Biology and Technology 44:411-418.
ITIS. Integrated Taxonomic Information System. Available online.
Kerschner BA, Peterson MS, and RG GIlmore, Jr. 1985. Ecotopic and
ontogenetic trophic variation in mojarras. Estuaries 8:311-322.
Matheson RE, Jr. and JD McEachran. 1984. Taxonomic studies of the
Eucinostomus argenteus complex (Pisces: Gerreidae): preliminary
studies of external morphology. Copeia 4:893-902.
Rookery Bay Field Guide.
PDF document available online.
Stoner AW. 1986. Community structure of the demersal fish species of
Laguna Joyuda, Puerto Rico. Estuaries 9:142-152.
Melany P. Puglisi, Smithsonian Marine Station
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Page last updated: October 1, 2008