Sparkplug sounds like you know about HBG very well. Good results are good news. You hit the nail on the head WRT aggressiveness. Hybrid vigor can result in traits in excess of both parental species be it growth , aggressiveness , heart function have all been noted in Lepomis. Problem is that is generally followed by outbreeding depression in the offspring. Here is some info from IMO one of the very top HBG PhD fisheries scientists around.
NorthA merican Journal of Fisherie Msnagemen6t: 156-167, 1986
¸ Copyrighbt y the AmericanF isheriesS ociety1 986
Evaluation of Male Bluegill X Female Green Sunfish Hybrids for
Stocking Mississippi Farm Ponds
MARTIN W. BRUNSON and H. RANDALL ROBINETTE
The use of hybrid sunfishes in ponds has been
suggesteda s an attractive alternative to the more
traditional stocking policies involving the bluegill
(Lepomism acrochirus)o r redears unfish( Lepomis
microlophus), or both, in combination with the
largemouth bass (Micropterus salmoides) (Lewis
and Heidinger 1978a).
Ellison and Heidinger
(1978) surveyed 30 privately owned hybrid
sunfish ponds in southern Illinois and determined
that the presence of largemouth bass and supplemental
feeding were the two most important variables
related to growth of hybrids.
Growth of redear
sunfish x green sunfish and bluegill x green
sunfish (BG x GS) hybrids exceeded the average
growth for bluegill in Illinois (Lopinot 1972). The
BG x GS hybrids reached an acceptable catch size
in a shorter time than channel catfish (Ictalurus
punctatus), and they were easier to catch where
both were stocked for recreational fishing.
Several hybrid combinations have been recognized
as having potential in pond management
(Lewis and Heidinger 1978b), but the BG x GS
hybrid appears to have the most attractive combination
of desirable attributes. Like other hybrids,
the BG x GS hybrid exhibits rapid growth
(Childers 1967; Ellison and Heidinger 1978) and
probable hybrid vigor (Brunson and Robinette
1985), produces mostly males (Childers and Bennett
1961; Laarman 1973; Brunson 1983), and is
highly vulnerable to capture by hook and line
(Henderson and Whiteside 1976; Crandall and
Durocher 1980; Brunson 1983). Only the BG x
GS hybrid, however, is well suited to artificial
feeding (Lewis and Heidinger 1978a) and frequents
shallow water areas, where it may be more
accessiblet o the pond angler than some other hybrids.
The BG x GS hybrid is probably the most
common commercially produced hybrid sunfish
in the southeastern United States.
From an angler's viewpoint, increased growth is
highly desirable.H owever, perhapsm ore important
to the angler is the presumed high catchability of
hybrid sunfish. This vulnerability to hook-andline
capture has been alluded to by many authors
but relatively few experimental data exist to substantiate
such statements. Childers (1967) cited
one instance where a population of more than
10,000 BG x GS hybrids was decimated by anglers
during the first week of fishing. Childers and
Bennett (1967) reported hook-and-line yields in a
0.4-hectare pond stocked with redear x green sunfish
hybrids and largemouth bass that surpassed
those of comparably fished bluegill ponds. They
concluded that hybrids were more aggressive, less
wary, and less able to learn how to avoid being
caught than their parent species. Henderson and
Whiteside (1976) confirmed the vulnerability of
hybrids to angling, and Ellison and Heidinger
(1978) reported that hybrid sunfish were much
easier to catch than channel catfish when both were
stocked for recreational fishing. They also confirmed
the aggressivenesos f hybrid sunfisha s reported
by swimmers who were nipped by these
fish. Crandall and Durocher (1980) reported that
catchability of the BG x GS hybrid was significantly
higher than that ofbluegill x redear sunfish
or green x redear sunfish hybrids.
Other than theses tudies,t he literature on hybrid
sunfishes is the result of laboratory or controlled,
short-term pond studies with relatively narrow objectives.
The total catch of
146 hybrids during the 2-h period was 21% of the
population.
These high catch rates,
especially at Britt Pond, once again confirm the
aggressivenessa nd vulnerability of the BG x GS
hybrid, and point to the importance of strict control
of harvest in hybrid ponds. Especially significant
is the effect that poachers can have on a
hybrid population.
Though hybrid sunfish are not a panacea
for all farm pond management problems, they can
be used under certain conditions to produce desirable
populations of rapidly growing fish. With
a rapid growth rate, low population fecundity, and
high catchability, these fish can be used to create
high quality bream fishing when properly managed