Saturday, October 5, 2013

Redbreast sunfish fry development

A large male redbreast Lepomis auritus in breeding colors

The term "sunfish" generally refers to fishes from the Family Centrarchidae, comprised of 30 species (including several bass species and crappie), but to most people "sunfish" are species from the Genus Lepomis: bluegill, pumpkinseed, longear, warmouth, redear, green, and redbreast sunfishes. To further complicate matters, Lepomis species can - and often do - hybridize with each other especially in captivity (see below). 
 A large male pumpkinseed/redbreast hybrid Lepomis gibbosus on his nest

Most sunfishes spawn in early to mid summer, when the water temperatures begin to approach 70 degrees F. However, in captivity many species - not just sunfishes - are triggered to spawn at unusual times of the year, due to unnatural light cycles and seasonal temperature fluctuations within the facility. For example, two species of sunfish in our Woodland Pond exhibit, the pumpkinseeds and redbreasts are currently spawning, but are several months past their spawning period in the wild.

Breeding or "nuptial" males of all sunfish species fan out broad, saucer-shaped nests with their tails in hopes of attracting a female. The males then aggressively guard these nests which are often quite close together, and chase off all intruders. During this period males become brilliantly colored, showing off their best and brightest for the ladies. If the male successfully attracts a mate, he will fertilize from 1000's to 10's of thousands of eggs, depending upon the size of the female (and species), which she has deposited in the nest. After releasing her eggs, she moves on with no further commitment to the young. The males remain to guard their young from predators as the young develop from eggs to yolk sac larvae to free-swimming larvae. Once the young are swimming and feeding on their own, the job of the male is finally done.

 Eggs are approximately 1 mm


Redbreast fry that have just lost their yolk sac

Fry one week later ( 2 -3 weeks total)
...another week older (4- 5 weeks)
Fry seven to eight weeks after hatching.







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