Not to discourage anyone but here is the rest of the story (or at least part of it). This is a long study so only parts are included. Greg very good observation. There are of course pluses and minuses to many aspects to the points in this study but it does confirm , as is often noted here , " it all depends".

North American Journal of Fisheries Management 18:295–307, 1998

Suitability of the Lake Chubsucker as Prey for
Largemouth Bass in Small Impoundments
RONALD C. EBERTS, JR.
Center for Aquatic Ecology, Illinois Natural History Survey
VICTOR J. SANTUCCI, JR.*
Max McGraw Wildlife Foundation
DAVID H. WAHL
Center for Aquatic Ecology, Illinois Natural History Survey


Abstract.—We evaluated the suitability of lake chubsuckers Erimyzon sucetta as prey for largemouth
bass Micropterus salmoides in small impoundments by examining life history, susceptibility
to predation, and effects on predator growth. Characteristics of lake chubsucker life history are
favorable because the fish can produce moderate numbers of young for prey, can reach a size
refuge from most predators and thereby maintain a viable population, and do not consume fish
eggs or fry. In laboratory pools, largemouth bass consumed lake chubsuckers more often than
they consumed bluegills Lepomis macrochirus. Largemouth bass growth was similar between
experimental ponds containing either bluegills or lake chubsuckers, and although mortality was
lower for age-0 and small largemouth bass in ponds with lake chubsuckers than ponds with
bluegills, it was not lower for larger fish. In a lake manipulation experiment, largemouth bass
growth was not changed by the introduction of lake chubsuckers. We recommend that lake chubsuckers
not be stocked to supplement available prey in waters supporting bluegills or other abundant
prey populations and that they never be stocked outside of their native range. However, lake
chubsuckers may benefit largemouth bass in small impoundments in which bluegills are not present.


Under laboratory conditions, lake chubsuckers
appeared more suitable as prey than bluegills.
Largemouth bass struck at lake chubsuckers more
often than at bluegills and consumed them far more
often. A fusiform body and soft-rayed fins may
have contributed to the higher vulnerability to predation
for the lake chubsucker than for the deepbodied,
spiny-rayed bluegill (Wahl and Stein 1988;
Einfalt and Wahl 1997). Previous work has shown
that largemouth bass (Lewis and Helms 1964) and
other piscivores (esocids and walleye; Parsons
1971; Gillen et al. 1981; Knight et al. 1984) select
soft-rayed prey over spiny-rayed prey.
Based on optimal-foraging theory, we anticipated
that largemouth bass might consume lake
chubsuckers more than bluegills in field experiments,
but this was not the case. Greater occurrence
of bluegills in bass diets probably was due
to their higher abundance in our experimental
ponds and lakes. However, lake chubsuckers also
exhibited antipredatory behaviors that may partially
explain their low frequency in the diets. Like bluegills, lake chubsuckers spent most of their
time in near-motionless aggregations associated
with the lower sidewall and bottom of experimental
pools. In ponds and lakes, we observed lake
chubsuckers using submersed vegetation as cover
when largemouth bass predators approached. Associating
with vegetation or other structure (Savino
and Stein 1989) and remaining motionless
(Wahl and Stein 1988) are behaviors known to
decrease the likelihood of attack by predators.

Although unavailable to age-0 fish, lake chubsuckers
were vulnerable to predation by older
largemouth bass. Based on our estimates of optimal
prey size, lake chubsuckers 200 mm in length
or larger would be effectively excluded from predation
by most centrarchid predators. Electrofishing
catch rates in Shady Lake confirmed high survival
of adult lake chubsuckers in a lake with a
high percentage of large predators; largemouth
bass over 350 mm made up 17% of the sample
each fall. Based on our estimates of lake chubsucker
growth, they could be available as prey for
largemouth bass for up to 4 years. This long period of vulnerability may benefit predators, but it may
also compromise prey population stability by allowing
elimination of lake chubsucker young before
they recruit to non vulnerable sizes. Self sustaining
populations of lake chubsuckers may be
particularly difficult to maintain in impoundments
with abundant predator populations (Carline et al.
1986) or where protective habitat and alternate
prey are lacking (Carline et al. 1986; Wahl 1995).

Lake chubsuckers spawn around
the time of largemouth bass (Kramer and Smith
1960), and their young grow rapidly during the first
year. In our ponds, age-0 largemouth bass never
gained enough of a size advantage to allow consumption
of lake chubsucker young. In contrast, by
initiating spawning later in the year and spawning
repeatedly during the summer, bluegills produced a
continuous supply of vulnerable-sized prey that
were used by age-0 largemouth bass. In impoundments
in which bluegills are not overly abundant,
they may benefit age-0 largemouth bass more than
lake chubsuckers would.


The intent of many prey fish introductions is to
increase growth of piscivores and ultimately to
increase their recruitment to the fishery. Our evaluation
provided an initial assessment of the potential
for lake chubsuckers to serve as a prey species
in small impoundments. We found that stocking
lake chubsuckers in a lake with an established
centrarchid community produced little change in
the diets and growth of largemouth bass and that
production of lake chubsucker juveniles was low.
From these results, it appears that lake chubsuckers
should not be stocked in waters containing established
largemouth bass and bluegill populations.
In contrast, our life history assessment, prey
selection experiments, and pond experiments suggested
that lake chubsuckers may benefit largemouth
bass at least as much as bluegill prey in
new or renovated ponds in which bluegills are not
desired. Because lake chubsucker young appear
highly vulnerable to predators, stocking adults 1
year before largemouth bass may be warranted.We
stress, however, that stocking should take place
only within the native range of lake chubsuckers.
Further, we recommend additional evaluations of
the effects of lake chubsuckers on fish and other
components of aquatic communities and long-term
assessments of predator and prey population dynamics
before proceeding with widespread use of
lake chubsuckers as prey for largemouth bass.