摘要:

Five thousand grass carp (Ctenopharyngodon idella) fry were stocked into a 0.81-hectare pond in Marion County, Florida. The fry grew from 48.2 mm to 186 mm total length in 6 months with a survival rate of less than 7%. Food consumption decreased to near maintenance ration when water temperature fell below 14 C and growth was reduced. The 76 grass carp which contained food (63-220 mm) were strict herbivores, and ate animal material only in trace quantities (<0.1%). Mean electivity indices indicated positive selection for Sagittaria graminea, slight selection for Eleocharis sp., and discrimination against Najas flexilis, Ceratophyllum demersum, and Potamogeton illinoensis.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<149:FSBGCF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The grass carp (Ctenopharyngodon idella), at a density of 50 1- to 2-kg fish per hectare, satisfactorily controlled filamentous algae in fish hatchery ponds. It was not predacious on several abundant forage species, including fingerling channel catfish (Ictalurus punctatus), fingerling F1hybrids of the bluegill (Lepomis macrochirus) × green sunfish (L. cyanellus) and redear (L. microlophus) × green sunfish, crayfish (Procambarus sp.), bullfrog tadpoles (Rand catesbeiana), fathead minnows (Pimephales promelas), green sunfish, and mosquitofish (Gambusia affinis).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<153:OOTGCI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A study was conducted to determine effects of grass carp (Ctenopharyngodon idella) on red swamp crawfish (Procambarus clarkii) in ponds in Louisiana. Grass carp averaging 190 g each, stocked 4 fish per 0.01-hectare pond, significantly reduced the average yield (number and total weight) of harvestable size (⩾74 nm) crawfish. Stomach analysis of carp suggests that competition for food (plant matter) was the cause of lowered crawfish yields. After vegetation was depleted, the amounts of animal matter (mainly cladocerans, crawfish, and gyrinids) in grass carp stomachs increased greatly.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<156:EOGCOF>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Water quality parameters and phytoplankton in ponds stocked with grass carp, Ctenopharyngodon idella (test ponds) and in control ponds were compared during the summers of 1975 and 1976. Grass carp rapidly consumed available aquatic vascular plants. Dissolved oxygen levels in test ponds remained high as long as bottom growths of the filamentous green alga, Spirogyra sp. were present, but consumption of this alga in addition to vascular vegetation led to significantly lower dissolved oxygen concentrations in the water directly above the sediments. The most consistently affected parameters were turbidity and potassium concentrations, both of which were significantly higher in test ponds. Phytoplankton populations consisting primarily of dinoflagellates were not affected by grass carp introduction. As much as 54% of the phosphorus and 42% of the nitrogen released by consumption of plants were incorporated into new fish tissue. Most of the phosphorus not taken up by the fish was sequestered into components other than water or phytoplankton. Estimated potassium incorporation into fish tissue was low (2.5% or less), and recovery in water was approximately 2-to 6-fold higher than phosphorus. Potassium in the water appeared to be an excellent indicator of vegetation consumption by grass carp.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<161:TEOVRB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A 19-month study of effects of high density populations of grass carp, Ctenopharyngodon idella, and carp, Cyprinus carpio, on the reproduction and growth of bluegill, Lepomis macrochirus, and largemouth bass, Micropterus salmoides, was conducted in nine weed-free (0.1-hectare) ponds. Bluegill and largemouth bass were stocked at rates of 375 and 25 per pond, respectively. Three of the ponds were used as a control, three were stocked with 10 grass carp, and three were stocked with 10 carp. Benthic organisms and water quality were monitored. After two growing seasons, bluegill standing crop was significantly lower (P < 0.1) in both the grass carp and carp ponds. Bluegill standing crop was reduced by 52% in combination with grass carp and 67% in combination with carp. There were no significant differences in the standing crop of largemouth bass.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<172:EOGCAC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Stocking of four and eight grass carp/0.04-hectare pond reduced the average weights of individual water hyacinths, and the standing crops of water hyacinth were lower in grass carp ponds than in control ponds. Grass carp stocked at 16/0.04-hectare pond eliminated water hyacinths within 30 days after the fish were stocked. Channel catfish and striped bass growth and production seemed to be adversely affected by the presence of water hyacinths, but not by the presence of grass carp.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<176:GOCCAS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The grass carp, Ctenopharyngodon idella, has been introduced into more than 100 lakes, totaling over 20,000 hectares of water, in Arkansas as a biological weed control agent. The introduction was effective for controlling or eliminating submersed aquatic weeds. There were some significant fluctuations in some aspects of the fish populations in some of these lakes, but the lack of general trends suggests that the introduction of grass carp alone did not produce these fluctuations. An examination of total standing crop, shad biomass, numbers of catchable largemouth bass, sunfish, crappie, and young-of-the-year sunfish and largemouth bass reveals both increases and decreases with no trend in either direction. Plant removal by grass carp did appear to improve the condition factor of largemouth bass, bluegill, and redear sunfish. Other variables such as weather, water level fluctuation, fertilization, or fishing pressure may have a more profound influence upon fish populations. Variation in these parameters, combined with the grass carp introduction, may have produced the conflicting fluctuations. The introduction of grass carp will neither improve nor harm fish populations in every case.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<181:ACOFPB>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

One hundred sixty-three fish from four natural ponds in Florida were examined for parasites. Of these, 40 were grass carp (Ctenopharyngodon idella), an exotic herbivorous fish which had been introduced for research as a possible biological control of aquatic vegetation. The remaining 123 fish included six native species (largemouth bass, Micropterus salmoides; bluegill, Lepomis macrochirus; golden shiner, Notemigonus crysoleucas; lake chubsucker, Erimyzon sucetta; brown bullhead, Ictalurus nebulosus; yellow bullhead, Ictalurus natalis). Parasite faunas of the native fishes and grass carp were compared. Identified were 37 species of parasites from the native fishes and one species from grass carp. No exotic parasites were observed in the grass carp, but the grass carp were infected by a native parasite of the phylum Pentastomida, Sebekia oxycephala.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<207:POGCAN>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The external distance between the cleithrum bones was used to estimate the sizes of grass carp (Ctenopharyngodon idella) that could be ingested by Florida largemouth bass (Micropterus salmoides floridanus). The equations for mouth width vs. total length (TL) of largemouth bass were: Mouth (mm): 0.0968 (mm TL) for bass <200 mm TL (r2= 0.89); and mouth (mm) = −11.102 + 0.1567 (mm TL) for bass >200 mm (r2= 0.95). The equation for body depth vs. total length of grass carp was: depth (mm) = 0.629 + 0.204 (mm TL), r2= 0.98. Five thousand grass carp fingerlings were stocked in a 0.81-hectare vegetated pond. Initial predation was high in the sportfish pond, as only one grass carp was recovered at termination. Stocking of grass carp >450 mm is necessary to totally eliminate the possibility of piscivorous predation in lakes with established Florida largemouth bass populations.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<213:SLTPOG>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Chinese methods of fish culture were evaluated for potential use in animal waste management, pollution control, and the production of protein. Two ponds were stocked with grass carp (Ctenopharyngodon idella), silver carp (Hypophthalmichthys molotrix), bighead carp (Aristichthys nobilis), carp (Cyprinus carpio), northern largemouth bass (Micropterus salmoides salmoides), channel catfish (Ictalurus punctatus), and the hybrid of bigmouth buffalo female (Ictiobus cyprinellus) and black buffalo male (I. niger). One pond (0.127 hectare) received the total wastes from five growing pigs (about 39 pigs/hectare of water area), the other pond (0.121 hectare) received the wastes from eight pigs (66 pigs/hectare). Two consecutive lots of pigs were fattened during the study. Over a fish-growing period of about 170 days (May to October 1975) the net increments in fish biomass were 2,971 kg/hectare in the 0.127-hectare pond and 3,834 kg/hectare in the 0.121-hectare pond. A beneficial influence by the fish on water quality was indicated by continuously adequate levels of dissolved oxygen, and final biochemical oxygen demands in the range of 8-12 mg/liter.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<216:UOSMIA>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor