Yes BG will spawn where they can. The main reason to add gravel is not initial spawning but survival of the eggs and yoy for the first few days. See below. It is a numbers/weight matter. The more #s that survive for a while longer adds numbers and weight to the forage base.

Role of Male Parental Care in Survival of
Larval Bluegills
MARK B. BAIN AND LOUIS A. HELFRICH
Department of Fisheries and Wildlife Science•
Virginia Polytechinc Institute and State U niversity
Blacksburg, Virginia 24061

Abstract
Mortality of larval bluegills Lepomis macrochirus from predation was measured in 56 nests
guarded by males and 21 nests from which the male guard was removed. Mortality was s ignificantly greater in unguarded nests(median= 68%)than in guardian nests (median= 14%).Fish
traps placed in unguarded nests captured significantly more predators than traps placed in
guarded nests. Bluegills( 3-12 cm total length)w ere the most abundant nest predators Pumpkinseed Lepomis gibbosus (7• -11 cm),largemouth bass M icropterus salmoides(4- 5 cm),and whitefin
shiners Notropis niveus(5 -6 cm) also were nest predators. Nest preparation by male bluegills
exposed coarse gravel( 8-32 mm diameter)and pebbles(3 2-64 mm) in nest substrate and removed particles smaller than 2 mm. Particles larger than 8 mm provided suitable interstitial
space to accommodate bluegill larvae. Survival of larvae was directly correlated with the proportion
of coarse substrate in the nest.

Last edited by ewest; 11/04/17 10:19 AM.