Species Description: The red-ear sardine, Harengula humeralis, is one of several schooling bait fishes in Florida belonging to the family Clupeidae. Species from this group are characterized by several features, including: small, fusiform to subcylindrical bodies; pelvic scutes; and a terminal mouth with a short, deep lower jaw (Munroe & Nizinski 2002). As the name implies, the red-ear sardine is distinguished by a reddish spot near the opercle (top bone of the gill cover). The jaw is yellowish, the upper body is marked with 3-4 dark yellowish broken streaks or dotted lines, the tip of the dorsal fin is dusky, and the scales are easily shed (Robins et al. 1986; Munroe & Nizinski 2002). A series of ventral scutes (25-29, usually 27-28) line the abdomen on both sides of the pelvic fin, which bears 7 branched fin rays. Along with the dorsal fin, the pelvic fin is slightly anterior to the midpoint of the body.
Regional Occurrence: The range of H. humeralis extends from southern Florida through the Bahamas and Caribbean south to Brazil (Robins et al. 1986; Munroe & Nizinski 2002). Small schools are found in a variety of coastal habitats, from brackish estuaries to nearshore and coral reefs (Randall 1967; Robins et al. 1986; Ortaz et al. 1996; Munroe & Nizinski 2002). Studies have shown that larger individuals move offshore to feed and reproduce, while juveniles often occupy protected estuarine habitats such as mangroves and seagrass beds (Ortaz et al. 1996).
Age, Size, Lifespan: The maximum recorded length for red-ear sardine is 22 cm, although most adult specimens measure only about 12 cm (Munroe & Nizinski 2002). Lifespan varies with environmental conditions and other factors.
Abundance: Detailed abundance records for H. humeralis populations within the IRL are scarce. However, red-ear sardines often form several small schools that contribute to the overall abundance of the species within its native range.
Reproduction & Embryology: Other than reported offshore spawning (see 'Regional Occurrence' above), little information is available concerning the reproduction and embryology of H. humeralis. However, laboratory studies have been conducted on eggs and larvae of the related scaled sardine, H. jaguana, and it is likely that the two species share similar developmental processes. Eggs of H. jaguana 1.6 to 1.8 mm in diameter were collected from populations in south Florida (Houde et al. 1974). Larvae measuring about 2.4 mm and bearing a large yolk sac emerged from the eggs within 24 hours post-fertilization. After about 48 hours, the yolk sac was absorbed and the larvae began to actively feed on plankton. Juvenile and adult characteristics developed when larvae reached a length of 22-24 mm. Concurrent studies by Houde et al. (1974) suggested that spawning occurs at night and extends from February through July near Miami, Florida. It is possible that spawning seasons are abbreviated for false herring populations in and around the IRL, where water temperatures may fluctuate seasonally on a larger scale than those in south Florida.
Trophic Mode: Red-ear sardines are nocturnal predators, consuming a variety of organisms, including plant and algal material, small fishes, polychaete worms, copepods, and larvae of shrimp, crabs and stomatopods (Randall 1967; Ortaz et al. 1996; Munroe & Nizinski 2002; Nagelkerken et al. 2006).
Parasites: The red-ear sardine is documented as a host for the parasitic trematode worm, Parahemiurus merus (Dyer et al. 1986).
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Ortaz, M, Rocha, ME & JM Posada. 1996. Food habits of the sympatric fishes Harengula humeralis and H. clupeola (Clupeidae) in the Archipelago de Los Roques National Park, Venezuela. Carib. J. Sci. 32: 26-32.
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