Redbreast sunfish (Lepomis auritus) COSEWIC assessment and status report: chapter 6

Biology

Life cycle and reproduction

Across its range, redbreast sunfish spawn from spring to summer with the peak occurring when the water temperature is 16.7 – 27.8°C (Scott and Crossman 1998). Males move to the spawning grounds before the females where they will occupy and defend a territory. The male excavates a nest (redd) 61 – 102 cm in diameter and in 15 – 40 cm of water (Scott and Crossman 1998). Gautreau and Curry (2006) reported spawning in Yoho and Oromocto lakes from late June to early July when the water temperature approached 20°C. Redbreast sunfish nests in Yoho (n = 43) and Oromocto lakes (n = 20) had average nest diameters of 50.9 ± 10.1 cm, excavated depths of 7.1 ± 2.5 cm, and were in water depths of 43.2 ± 8.4 cm. The majority of the nests were excavated through a dense vegetative mat to spawning substrate of coarse sand to fine gravel. In Yoho Lake, 72% of the nests were associated with sparse vegetation and lacked cover structures. Conversely, Oromocto Lake had 85% of the nests within 1 m of a rock or log, and 13 of the cover structures were at the edge of nests. The nests were not closely spaced:58% of them were > 5 m from another nest and the remainder were about 2 m apart (Gautreau and Curry 2006).

In rivers, the nests are in areas of low current, or are protected from the current by a structure (Lukas and Orth 1993; Scott and Crossman 1998). The female redbreast sunfish enters the nest without courtship from the male. Spawning is quick, with the female depositing small (~ 2 mm) amber-coloured and adhesive eggs, after which the male chases the female out of the nest and begins to defend and aerate the eggs (Lukas and Orth 1993; Scott and Crossman 1998). They have been reported to utilize redds of other centrarchids (Scott and Crossman 1998), and not surprisingly, hybridization with other closely related species including: bluegill (Lepomis macrochirus), redear sunfish (Lepomis microlophus), green sunfish (Lepomis cyanellus) warmouth (Lepomis gulosus), and pumpkinseed is common (Carlander 1977).

There is no information on age of maturity, generation times, and fecundities of redbreast sunfish in Canada. Carlander (1977) reports that redbreast sunfish reach maturity at a weight of 23 g or in their second year. Longevity is not known, but individuals to age eight have been recorded (Carlander 1977), suggesting an average generation time of 4 years.

The average fork lengths of guarding male redbreast sunfish in Yoho Lake for 2005 (n=18) and 2006 (n= 32) were 16.6 cm and 15.7 cm respectively (Gautreau and Curry 2005; Gautreau and Curry 2006 unpublished data). Redbreast sunfish from two southeastern North Carolina rivers had fecundities of 963 – 8250 eggs for fish 139 – 235 mm in total length (Davis 1972). In the Santa Fe River, Florida, fecundities ranged from 1396 – 4138 eggs for redbreast sunfish having total lengths of 100 – 175 mm (Bass and Hitt 1974). Upon hatching, larval redbreast sunfish in the Susquehanna River, Pennsylvania, averaged 4.9 mm in total length (Buynak and Mohr, 1978). Larval redbreast sunfish remain in the nest for one to two weeks before dispersing (DeWoody et al. 1998).

Diet

Adult redbreast sunfish feed primarily on small aquatic insects, molluscs, benthic invertebrates and small fishes (Sandowet al. 1974; Coomer et al. 1977; Scott and Crossman 1998; Schultz 2004). The diet of sub-yearling redbreast sunfish consists mainly of cladocera and copepods (Johnson and Johnson 1984). Adult redbreast sunfish in the southeastern U.S. actively select chironomids throughout the year but are opportunistic feeders taking anything available of suitable size (Coomer et al. 1977). Food items may also include vegetation and debris, as well as eggs from the unguarded nests (Scott and Crossman 1998). Bass and Hitt (1974) examined the diet of redbreast sunfish from the Suwannee and Santa Fe rivers of Florida where vegetation and debris comprised 32.2 – 36.2 % by volume of the diet. The remainder was made up of invertebrates: mainly midges, caddisfly, mayfly, and dragonfly larvae.

Stomach contents of redbreast sunfish captured in Yoho Lake, NB, included aquatic invertebrates (Table 4), mostly caddisflies, but also ants, beetles, and two young of the year sunfish of unknown species (Gautreau and Curry 2006).

Predation

Larger piscivorous fish are the main predators of smaller redbreast sunfish. In New Brunswick, this may include species such as the chain pickerel, Esox niger, smallmouth bass, Micropterus dolomieu, brown bullhead, Ameiurus nebulosus, and American eel, Anguillarostrata, all of which are found in the same waters as the redbreast sunfish. Cannibalism has been evidenced in Yoho Lake (Gautreau and Curry 2006). The eggs of the redbreast sunfish can fall prey to a variety of cyprinids and other sunfishes (Scott and Crossman 1998). Due to its small size, the redbreast sunfish has not been sought after in the recreational fisheries of New Brunswick. Hoffman (1967) listed parasitic infestations, none of which appear to be limiting.

Growth

Recent studies on Yoho Lake represent the first look at redbreast sunfish growth in Canada. Length-frequency distributions of redbreast sunfish captured in Yoho Lake showed two distinct age classes, 2+ and 3+, which averaged 91 and 117 mm in total length (Figure 4). Scales from 27 redbreast sunfish were used for age determination. These scales were then measured and direct proportional back calculation applied to estimate the lengths of other age classes at the end of the growing season (Figure 5) The back calculation predicted average total lengths for 0+ through 5+ fish, which were 36.2, 64.4, 87.8, 110.6, 127.2, and 140.9 mm, respectively (Gautreau and Curry 2006). Davis (1972) reported length/age data for redbreast sunfish from three rivers in southeastern North Carolina. The total lengths of the 17 samples were age 2+ = 139 – 142 mm, age 3+ = 150 – 155 mm, age 4+ = 171 – 184 mm, age 5+ = 184 – 203 mm, and age 6+ = 229 – 235 mm. This suggests that Yoho Lake redbreast sunfish are smaller at a given age than those from North Carolina. This is not surprising considering New Brunswick is at the northern limit of the species range, and has a shorter growing season. Redbreast sunfish from Yoho and Oromocto lakes (Figure 6) have total lengths of 126 ± 26 .mm (mean + 1 SD) and 143 ± 33 mm, and average weights of 42.4 ± 24.8 g, and 80.9 ± 52.5 g respectively (Gautreau and Curry 2006).

Figure 4. Length frequency histogram for redbreast sunfish sampled in YohoLake, September 2005 (Gautreau and Curry 2006)

Figure 4. Length frequency histogram for redbreast sunfish sampled in YohoLake, September 2005 (Gautreau and Curry 2006)

Figure 5. Back calculation of growth from scales of 27 redbreast sunfish from YohoLake, 2005 (diamonds are average TL at the end of growing season) (Gautreau and Curry 2006).

Figure 5. Back calculation of growth from scales of 27 redbreast sunfish from YohoLake, 2005 (diamonds are average TL at the end of growing season) (Gautreau and Curry 2006).

Figure 6. Length/weight relationship for redbreast sunfish captured in Yoho and Oromocto lakes, 2005 (Gautreau and Curry 2006).

Figure 6. Length/weight relationship for redbreast sunfish captured in Yoho and Oromocto lakes, 2005 (Gautreau and Curry 2006).

Dispersal/migration

Gatz and Adams (1994) examined the movement of individually tagged redbreast sunfish in Tennessee over a three-year period. Their observations suggest that the redbreast sunfish is somewhat sedentary with some fish being located within 50 metres of their capture site for a period of six months or greater, and with two thirds of all fish moving less than 100 metres. The greatest movement (4 – 9 km) was by a few individuals, however, they were later captured near their original tagging site. Freeman (1995) marked juvenile redbreast sunfish based on capture site and monitored them by recapture over a period of 18 months. Most of the recaptures were within 33 metres of the original capture site and very few (n=3) moved >100 m suggesting strong site fidelity.

There may be some seasonal migrations relative to ambient water temperatures. They appear to aggregate in deeper waters to overwinter when water temperature falls below 5ºC (Breder and Nigrelli 1935, Scott and Crossman 1998). In spring, when water temperatures go above 16.7ºC, they may be found in the shallower areas of lakes (15 - 46 cm), or downstream of rapids in streams, apparently for spawning, dispersing for the summer following spawning (Houston 1989).

Interspecific interactions 

Lepomis species are known to hybridize (Hartel et al. 2002). This may occur in New Brunswick since the pumpkin seed and redbreast sunfish inhabit the same waters and are regularly sampled coincidently. In some states, Lepomis spp. hybrids are raised for sustaining sunfish sport fishing in rivers and lakes (Bronson and Morris 2000).

Adaptability

The redbreast sunfish has been introduced into regions outside of its North American native range and into several other countries where it has become an established member of the fish communities (Page and Burr 1991; Scott and Crossman 1998; Maitland 2000; Schultz 2004).

Unlike other sunfishes, the species reacts to disturbance by darting under rocks or bottom cover, much like rock bass (Scott and Crossman 1998).

Page details

Date modified: