TITLE:
Filamentous Green Algae Reduce Walleye Fingerling Production in Earthen-Substrate Ponds
AUTHORS:
Matthew J. Ward, Ryan A. Rasmus
KEYWORDS:
Filamentous Green Algae, Walleye, Pond Culture
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.11 No.2,
April
8,
2021
ABSTRACT: Reduced
walleye (Sander vitreus)
fingerling production possibly related to nuisance filamentous green algae and overly stable water chemistry
patterns is a concern in earthen-substrate ponds at Blue Dog State Fish
Hatchery, South Dakota, USA. We describe the success of alfalfa (Medicago
sativa) meal (AFM,
n = 2), alfalfa meal plus
soybean (Glycine max)
meal (AFM + SBM, n = 1), and alfalfa meal plus liquid 28N:0P:0K (AFM + 28:0:0, n = 1) at achieving walleye production objectives (>104,000 walleye and 32 kilograms/hectare) as
well as the occurrence of filamentous green algae and the associated patterns of
ammonia-nitrogen, pH, and dissolved oxygen in earthen-substrate ponds. Walleye
production objectives were only achieved when filamentous green algae were
absent preceding harvest, which occurred in one pond that received AFM and in
the pond that received AFM + 28:0:0. The presence of
filamentous green algae preceding harvest was associated with higher dissolved
oxygen and pH, whereas declines in these variables occurred when filamentous
green algae were absent. Organic fertilizer alone exhibited low
ammonia-nitrogen ( favorable
patterns in water chemistry warrant future experimentation with alfalfa meal
supplemented with 28:0:0 in earthen-substrate ponds at this hatchery.