Effects of hydrilla and grass carp on water quality in a Florida lake
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Water Resources Bulletin↗
Geology topics
J.V. Shireman
Publications and source records attributed to J.V. Shireman.
Growth and food habits of hybrid carp, Ctenopharyngodon idella x Aristichthys nobilis, from aerated and non-aerated ponds
Hybrid grass carp fry ( Ctenopharyngodon idella × Aristichthys nobilis ) were stocked into 0·04 ha ponds with and without paddlewheel aeration. Fish in the paddlewheel and non-paddlewheel pond, preyed upon identical organisms, but in different proportions. Fish in the paddlewheel ponds grew at significantly greater rates.
Journal of Fish Biology↗
Consumption and growth of hybrid grass carp fed four vegetation diets and trout chow in circular tanks
Grass carp, Ctenopharyngodon idella , and hybrid grass carp (grass carp ♀× bighead carp ♀ Aristichthys nobilis ), were fed duckweed ( Lemna sp.), hydrilla ( Hydrilla verticillata ), chara ( Chara sp.), filamentous algae ( Odogonium sp., Spirogyra sp.), and trout chow. Grass carp consumed all plants in greater amounts than hybrids. Grass carp grew best when fed hydrilla and trout chow and showed positive growth on all diets. Hybrids grew equal to grass carp when fed trout chow but did not grow on the vegetation diets. Low consumption rates of aquatic plants may indicate that hybrids are questionable as a plant biocontrol agent.
Journal of Fish Biology↗
Use of otoliths to determine age and growth of largemouth bass in Florida
The annual formation of otolith annuli was validated through age 5 for Florida largemouth bass Micropterus salmoides floridanus. Sectioned otoliths (sagittae) gave more reliable ages than whole otoliths. Beginning at age 2, at least one annulus was obscure in some whole‐otolith mounts, a problem that worsened with fish age. By age 5, over 20% of the whole otoliths gave under‐estimates of true age; otoliths producing these errors came from fish with slower than average growth rates. Sectioned otoliths gave poorer regressions (lower coefficients of determination) of otolith radius on body length than intact structures because the sectioning plane varied slightly among otoliths. Nevertheless, back calculations of fish size and growth from sectioned and correctly aged whole otoliths were equally accurate. Otolith sectioning is the procedure of choice for age‐and‐growth analysis of Florida largemouth bass. Whole otoliths, however, require much less time for analysis than sectioned ones and may be used for rapidly growing fish and fish known to be age 3 or younger.
Florida↗