摘要:

Effect of seven artificial diets, having protein contents ranging from 10 to 48%, on the growth and food conversion in young Tilapia nilotica of mean weight 24 mg were tested in 0‰, 5 ‰, 10‰, and 15‰ salinities. Growth of young T. nilotica was consistently better on diets containing 28–30% protein. For diets up to 30% protein, the fish grew best at 10‰, and for diets of higher protein contents, fish grew best in fresh water. Efficiency of food conversion increased with dietary protein content up to 30% protein level and then decreased at higher contents. Food conversion efficiency was greater for young fish raised in 10‰ than in other salinities.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<584:EODPLO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In March-April 1983, 2.5 × 106yolk-sac Atlantic cod larvae were released in a dammed estuarine pond. One month later, more than half a million metamorphosed. The larvae and metamorphosed juveniles depleted the natural food supply by mid-May, but the fish accepted small pellets containing 30% krill meal dispensed from automatic feeders. From mid-June, young Atlantic cod primarily ate the pellets, supplemented with minor amounts of wild calanoid and harpacticoid copepods. The population declined during summer probably due to cannibalism and predation from birds. No outbreaks of disease were observed, and infestation with parasites (nematodes) was less than 20%. Altogether, 75,000 juvenile Atlantic cod were captured alive from late May to October. By October, about 20,000 15-cm-long juveniles were tagged and released in the Austevoll region in a first attempt to augment the fishery for Atlantic cod.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<590:MPOACJ>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

There is a large demand for rainbow smelt as a bait and food fish, and culture of the species has economic potential. In 1979, we began experiments to define optimum conditions for incubation of eggs and growth of larvae and juveniles. Hatching success was 40–80% in fresh and brackish water, but zero in full-strength seawater. The timing of hatching was determined for incubation temperatures of 6 to 20°C. Larvae fed most successfully in full-strength seawater on the cultured marine rotifer Brachionus plicatilis. Eyed eggs were also stocked in two ponds, one newly constructed and one with a well-established food base. Larval fish raised exclusively with natural foods (primarily cyclopoid copepods, chironomids, and Chaoborus sp.) reached 44 mm total length within 6 months in the newly constructed freshwater pond, and 83 mm in the established pond; rates of 0.22 and 0.41 mm/day, respectively. Rainbow smelt in the latter pond reached commercial baitfish size before the first winter of life. Fish in the established pond averaged 119 mm in less than 13 months, including a long period of minimal winter growth.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<596:ECOYRS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The near-surface ichthyoplankton of Georges Bank, Nantucket Shoals, and Gulf of Maine was collected with a modified David neuston katamaran during November 1972–1977. The gear sampled the top 10 cm of the water column with one net and the 20–35-cm-deep stratum with a second. Hake larvae were concentrated in warmer waters of Georges Bank and Nantucket Shoals, including the continental slope; fourbeard rocklings were most abundant in cooler coastal waters of the Gulf of Maine and near Cape Cod. Distribution of the two taxa overlapped only in the temperature range 11–13°C. Hake larvae were more abundant in the upper net during the day than at night, implying diel migrations from the neuston. Fourbeard rocklings were always most abundant in the surface net.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<604:DONLOH>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Fish larvae and juveniles were collected in the waters of wading depth along sandy beaches of western Japan with a 0.7-mm-mesh, 1.3- by 5-m seine. Presence of Chanos chanos, Salangichthys microdon, Plecoglossus altivelis, Allanetta bleekeri, Gerres oyena, Sparus sarba, Acanthopagrus schlegeli, A. latus, and Lateolabrax latus and absence of Engraulis japonica, Gonorhynchus abbreviatus, Upeneus bensasi, and Macrorhamphosus scolopax distinguished the larval ichthyofauna of surf zones from those in other known biotopes of fish nursery. The surfichthyofauna was usually more diverse in spring and summer than in autumn and winter. Monthly total catches of individuals fluctuated greatly according to the abundances of a few influential species such as Clupanodon punctatus in spring and Plecoglossus altivelis in autumn to winter. Most larval fishes seemed to inhabit surf zones only during daytime. An influence of tidal phases on occurrence of larval fishes was not apparent. Categories of pelagic and demersal components were suggested for surf zone ichthyofauna.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<609:LAJFOI>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A radioimmunoassay of trypsin and trypsinogen in fish has been developed. The antibodies detect both trypsin and trypsinogen, and the presence of trypsin inhibitors in the assay extract does not affect the readings. The radioimmunoassay, used in combination with conventional enzyme assay, is very suitable for mechanistic studies of the production and activation of trypsin in fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1985)114<619:EORAAM>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1984.10492798

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor