In one of the driest years on record in our area, I decided to build a new pond. This is the second one I have built. This one is much bigger, maybe 1.5 acres, but complex shore line makes it tough to measure. It will be about 14 feet deep when full, but probably an average of 5 feet deep. Lots of shallow areas and a lot of brush will get flooded. What I don't have any of is gravel. Or I don't have any naturally. Most of the soil is heavy clay. I want to add gravel beds to promote bluegill spawning.

The other pond I manage has bluegill, CC, LMB, FHM, and Black Crappie. The bass do great, the bluegill are there, but not in large numbers, The cats are good, but I've seen no evidence of spawning. I removed a lot of crappie before I stocked the bass and bluegill. They are there, also limited numbers. Definitely not overpopulating. I really need more bluegill for long term sustainability. I'm trying to set this new pond up to make sure bluegill get a head start. It is extremely difficult and expensive to stock any warm water species here, so I want to do it right the first time.

So my question, does the type of gravel make a difference? Pea gravel and round rock is very hard to come by in this area and is very expensive. Does angular, crushed rock work as well? At all? If there are larger rocks (baseball) mixed in, does it prevent them from using that area?

I'm sure I'll come up with more questions with the first few answers.

I use crushed limestone. Not claiming it is the best but it works and is what is available locally in bulk.

Rocks of various sizes are good. The fish will move them around to suit. Some larger rocks give new fry some cover from nest raiders.

Do you see your bluegill using it?

Small pea gravel is ideal, but spawning BG will also use clean sand. You might fill up small kiddie plastic pools with sand and put them in 1 to 3 feet of water.

I found this out when we created a sandy beach area for swimming. The BG had other ideas...

Mixed road gravel a little bigger than pea gravel is best.

8 - 32 mm is optimum

See this thread.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=199269&page=1

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.


Some points of interest:

Our data from
Virginia implicated juvenile bluegills as the major
predators on bluegill larvae, followed in importance
by pumpkinseed. Dominey (1981)
drew the same conclusions from a New York....


In addition to direct protection afforded larval
bluegills by nest-guarding males, nest preparation
by the male parent influenced survival
of larvae in Lake Caroline. The availability of
suitable nesting substrate has been recognized
as a major factor affecting reproductive success
of centrarchid fishes (Breder 1936; Kramer and
Smith 1962; Muncy et al. 1979).

In laboratory observationss,
coarse particles provided suitable interstitial
space to accommodate yolk-sac bluegill larvae.
That coarse substrate may function as protective
shelter for larvae was supported by field
data: ....


Although
other factors undoubtedly influence
mortality of tested larvae, our data suggest that
predation, particularly intraspecific predation
(cannibalism), can be a major cause of early
bluegill mortality.

Last pic shows rock size.

Yes, they use it. Now I can not say that they prefer it over mud or something else, but they do use the spawning areas I have provided with the crushed limestone. I have used various sizes but what I use most is what we call AB3 and it has everything from maybe an inch or maybe as big as an inch and a quarter with all sizes in between all the way down to ag lime.

I don't think there is any need to over think it. I made beds out of the "small stuff" from the creek. It mostly ranged from sand sizes to 1 inch pieces with some rocks up to baseball size. The majority of this gravel was flint-like, some jagged, but some smooth. At any rate, I just grabbed some from the creek and made a 15 by 15 foot area for spawning and the first year out of the gate they made beds. I will admit that I have seen no evidence of YOY, but my fish were HBG and 3 to 5 inches long at that.

I will say that if ewest says "Mixed road gravel a little bigger than pea gravel is best." then it's the best.

Thanks for the vote of confidence. However I think its the science that says that. Most ponds do just fine with BG spawning on clay , sand or mixed gravel. If you want higher BG fry/yoy/baby survival then some gravel should help as will being sure there is enough food for them. Another survival help is thick cover nearby to reduce predation. On the other hand if you have too many BG then don't encourage survival. It just depends.