Pond Boss Forums INTRO Questions & Observations Observation on Feed Fed Largemouth Bass

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North American Journal of Fisheries Management 38:794–802, 2018
© 2018 American Fisheries Society


Effect of Rearing Experience on the Survival, Growth, and Behavior of
Hatchery-Reared Largemouth Bass
Matthew J. Diana,*1 Brett J. Diffin,2 Lisa M. Einfalt, and David H. Wahl

Abstract
Largemouth Bass Micropterus salmoides are commonly stocked throughout their native range, but survival of
stocked fish is variable and often low. Hatchery fish may have difficulty switching to natural forage; therefore, providing
feeding experience with natural prey in the rearing environment could result in improved growth and survival of
Largemouth Bass after stocking. We conducted pond experiments to evaluate differences in growth and survival of
Largemouth Bass reared in raceways and fed pellets or in ponds and fed either Bluegill Lepomis macrochirus prey or
Fathead Minnow Pimephales promelas prey. Largemouth Bass reared on one of these three diets were stocked into
ponds containing Bluegill prey. After 2 months, pellet-reared Largemouth Bass were significantly smaller than fish
reared either on Fathead Minnows or Bluegills, whereas fish reared on either Fathead Minnows or Bluegills were similar.
Fathead Minnow-reared Largemouth Bass had lower survival than Bluegill-reared fish, but no other survival differences
were observed. To determine possible mechanisms influencing differential growth and survival of juvenile
Largemouth Bass, we also conducted laboratory experiments examining the influence of prior feeding experience (pellets,
Bluegills, or Red Shiners Cyprinella lutrensis) on foraging behavior and prey capture success in pools. Largemouth
Bass reared on live forage captured prey faster, ingested more prey, and had higher capture efficiencies than
did fish reared on pellets. Combined, pond and laboratory experiments show prior acclimation to live prey may ultimately
be beneficial to increasing growth of stocked hatchery Largemouth Bass and could result in increased recruitment.
We recommend additional exploration of acclimation of Largemouth Bass fingerlings to natural prey,
preferably Bluegills, prior to stocking to determine whether hatchery managers should consider alternative rearing
techniques.

Rearing Largemouth Bass Micropterus salmoides for
supplemental stocking is a common practice throughout
their range. Hatchery rearing techniques vary, but fish are
most often raised on a pellet diet in artificial systems.
Although this method is efficient at producing large quantities
of fish, poststocking survival rates can be low or
variable (Boxrucker 1986; Porak et al. 2002; Hoffman and
Bettoli 2005; Diana and Wahl 2008, 2009). Less-common
rearing techniques for Largemouth Bass include rearing in
ponds with minnow prey or introducing natural prey into
the hatchery diet. In these conditions, hatchery fish gain
experience foraging on live prey or acclimate to a more
natural environment before being stocked, and these methods
can be beneficial to poststocking growth or survival
for other species (Szendrey and Wahl 1995; Larscheid
et al. 1999; Czerniawski et al. 2015). Using more natural
pond environments and prey for rearing Largemouth Bass
may increase growth and survival after stocking.

Largemouth Bass that had prior experience preying on
natural prey exhibited advantages in growth and feeding
success than did pellet-reared fish. While all treatments
showed equal recognition of prey by initiating follow
behavior and engaging similarly in precapture behaviors
(follows, strikes, time moving), prior experience with live
prey improved capture success. Largemouth Bass reared
on live prey captured prey faster, captured more prey, and
had higher capture efficiencies than did pellet-reared bass.
When exposed to natural prey, fish become more effective
at capturing prey, as observed for tiger muskellunge
(Muskellunge Esox masquinongy × Northern Pike E.
lucius) (Gillen et al. 1981), Walleye (Wahl et al. 1995),
Chinook Salmon Oncorhynchus tshawytscha (Maynard
et al. 1996), Brown Trout (Sundstrom and Johnsson
2001), and Spotted Seatrout Cynoscion nebulosus (Jackson
et al. 2013). Pellet-reared Largemouth Bass had difficulty
capturing either prey type within a laboratory pool, and
we would expect these results to be magnified in a field
setting, where prey are not confined and can escape. Since
Largemouth Bass acclimated to live prey performed similarly
in pond and laboratory experiments, feeding experience
with any live prey may be more important for
Largemouth Bass than is prey type. However, we did
observe evidence of increased feeding success for Bluegillreared
Largemouth Bass in extended feeding trials (2 h) as
they captured more Bluegills than Red Shiners compared
with minnow-reared fish.
Even small differences in feeding efficiency can result in
growth differences that may have implications for survival.
Size of age-0 Largemouth Bass in the fall has been
related to overwinter survival with smaller fish experiencing
greater mortality (Miranda and Hubbard 1994; Ludsin
and Devries 1997; Garvey et al. 1998; Post et al. 1998).
Stocked Largemouth Bass overwinter survival is also size
dependent, and larger-sized individuals in the fall have
better survival (Diana and Wahl 2008). Throughout the
growing season, larger-sized juvenile piscivores can maintain
a competitive advantage over smaller cohorts (Ludsin
and Devries 1997). Larger individuals have a wider gape
resulting in better prey capture and lower handling times
(Einfalt et al. 2015; Detmer et al. 2018) and can also feed
on a larger proportion of the prey population resulting in
a greater availability of fish prey (Hambright et al. 1991).
In this study, the weight of pellet-reared Largemouth Bass
was only 80% of the weight of fish that had prior exposure
to fish prey. The smaller size of the pellet-reared fish could
result in differential recruitment due to higher overwinter
mortality.