The redear sunfish ( Lepomis microlophus ), a member of the Centrarchidae family, has earned its reputation as a popular panfish and a valuable addition to aquatic ecosystems. Often called a "shellcracker" due to its specialized diet, this species exhibits unique feeding habits and preferences that distinguish it from other sunfish. This article delves into the diet and feeding behaviors of the redear sunfish, exploring its development from fry to adult, its preferred habitats, and its ecological role.
Identification and Range
Redear sunfish get their name from the red margin color found on the outer edge of the opercular flap on the gill covering. This color can slightly vary from a light orange as juveniles and will develop into a much more prominent red color as the fish matures. The opercular itself for redear sunfish will be stiff and not elongated. The pectoral fins of redear are elongated with the tips of the fins ending in a knife shaped point. The pectoral fins will be light in color with 13 to 14 rays. The first and second dorsal fins are connected. The sides of the redear sunfish will be silver to brown with pale spotting. Spotting will continue onto the cheeks of the fish. The back coloration will typically be darker black to brown and the breast area will be white to yellow. The redear sunfish will have a slightly elongated snout and a small terminal protruding mouth. Pectoral fins can be folded forward to tough the edges of the mouth.
The native range of the redear sunfish was historically limited to the United States with the majority of fish being found from the Atlantic coast down into the Florida peninsula. To the west the redear sunfish could be found along the Gulf coast into Texas. Today through expanded stocking efforts and their popularity as parasite control in small impoundments they are found throughout the United States and commercially available from private fish hatcheries. Redear sunfish are found statewide.
Habitat Preferences
Redear sunfish prefer warm and calm or stagnant waters. Redears prefer deeper water, so fish small baited hooks near or on the bottom of the waterbody or can jig the bait up and down off the bottom. Redear normally inhabits deeper water than bluegill and congregate around stumps, logs, and roots. Weedbeds are ideal habitat for really big bluegill and redear sunfish. Later in the summer, slip-bobber rigs can be used to fish deeper waters.
Also, redear sunfish favor waterbodies with relatively clear water and aquatic vegetation. Due to diet preferences they will typically be found lower in the water column and around hard surfaces. They spend the majority of their lives within the littoral zone of a fishery, venturing out into deep water primarily during winter months. Juveniles rarely leave the shelter of aquatic vegetation in the littoral zone. Their growth rates will be much higher in clear water compared to turbid water.
Read also: Bluegill Sunfish and Their Diet
Diet and Feeding Habits
Redear sunfish are mainly bottom feeders. Redear typically feed during the day and are considered opportunistic sight feeders. Redear sunfish eat food similar to that of the bluegill. Food consists largely of insect larvae, snails and cladocerans. They will feed on minute plant and animal life when the fish are small, but as they grow larger they will eat various insects and insect larvae (primarily midge fly larvae and blood worms), various crustaceans and snails.
Development of Diet
As redear increase in size, they will begin to prefer mollusks including snails. The preference of the redear to consume small mollusks has been utilized by pond and reservoir managers to attempt to eliminate snail vector parasites from fish communities. This created a market for millions of redear sunfish to be produced and stocked each year.
- Fry: Fry will feed on the yolk sac of the egg for around 3 days. Once the yolk sacs have been used, the fry will swim out of the nest and disperse into vegetation. The fry will feed on zooplankton, growing quickly.
- Juveniles: Juveniles eat insects, insect larvae, and small snails. Juvenile redear will graze on aquatic invertebrates around submerged plants and crustaceans around rocks or wood.
- Adults: Redear sunfish are known to feed heavily on snails. Their ability to crush the shell of crustaceans is due to an enlarged pharyngeal jaw and additional musculature. Once a snail is grabbed in the mouth the redear crushes the shell and separates the majority of the shell from the meat of the snail. When eating snails, the shell is completely crushed and most of it is expelled from the mouth.
Feeding Behavior
Redears prefer deeper water, so fish small baited hooks near or on the bottom of the waterbody or can jig the bait up and down off the bottom.
Reproduction
Redear sunfish will have a major spawn in the warmer months, usually late spring to early summer, when temperatures reach 70℉ to 89℉. Like many sunfish species, redear are nest guarding community spawners. Male redear sunfish create round or saucer shaped depression nests, selecting sites with hard substrate and fanning out fine sediment using their tail to expose gravel. Redear sunfish will spawn in the same area, making the spawning beds close together in a community. Once the nest is built, the male redear sunfish will attract a female, and they will both begin to circle the nest. The male will make a popping sound to trigger females to release their eggs. The eggs are tiny and highly adhesive. They immediately stick to the sediment. A single female can produce 2,000 to 80,000 eggs per spawning season but drop 2,000 to 10,000 in each spawning attempt. The male will stay with the nest protecting the eggs and periodically fanning them using their tails to remove sediment and provide oxygen.
They reproduce in the spring (May-June) when water temperatures reach around 68Fº, male redear move into the shallows to build their nests. When a female approaches the nest, the two fish swim around over the nest in circular fashion and form a V figure with their vents pressed together. The female releases eggs on each dip, and the male simultaneously releases milt (sperm). The eggs are fertilized as they fall into the nest. Several spawnings may occur after which the female leaves and the male redear takes a position over the nest to guard the eggs from predators and to fan the water above the eggs so it will circulate and aerate the eggs until they hatch. After hatching, the fry will stay in the nest for about a week with a male still standing guard. After this time, they leave the nest in search of food and then they are on their own.
Read also: Marine Giant's Diet
Conservation Status and Management
At this time there are no threats to redear sunfish populations throughout the US.
Redear sunfish are often stocked in combination with blue gill, as they do not provide forage for larger fish but prey upon snails, thus reducing the incidence of snail-borne fish parasites. They make excellent forage for largemouth bass.
Read also: Feeding Habits of Green Sunfish