摘要:

Scales and otoliths were used to determine age of vermilion snapper, but only scales were used to back-calculate lengths. Scale annulae are laid down in March-April and their formation is well correlated with increasing photoperiod, preparation for spawning, and rising bottom water temperature. The von Bertalanffy growth equation fitted to back-calculated lengths (L, mm total length; t, years) is: Lt= 626.5 [1 - e-0.198(t-0.198)]. Maximum longevity of females is at least 10 years but males may only live 8 years. The length-weight (W, g) relationship (r = 0.97) is: W = 0.00001722 L2.946.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<454:AGALRO>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Female pirate perch (Aphredoderus sayanus) were more numerous and grew faster in their second and third years than males. The life spans of the sexes were about equal and did not exceed 4 years. Total length (L, mm)-weight (W, g) relationships of the sexes did not differ, and the combined equation for 419 fish is W = 0.0000376L2.768. Frequent food items were Cladocera (particularly for young of the year), aquatic Diptera larvae, Isopoda, and Amphipoda.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<457:AGADOT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Satinfin shiners (Notropis analostanus) proved to be fractional spawners and pairs of them in outdoor wading pools spawned up to 11 times between June 3 and August 11, 1977 (totals 381 to 3,268 eggs per pair). They released from 6 to 634 eggs per fish per session at intervals of 3 to 31 days (mean 7.6 days; modes 5 and 8 days). Spawning behavior was similar to that of spotfin shiner (Notropis spilopterus). Overall, eggs averaged 1.5 mm in diameter. Significant differences (P < 0.001) were found in the size of eggs spawned by different females. Eggs in the first spawn were significantly (P < 0.001) larger than those in the last spawn. Spawning occurred during the day and activity was most intense between 0600 and 1000 h. Only 12.2% of 7,290 eggs were spawned after 1200 h.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<460:SFAFOS>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Seasonal variations in reproductive condition and fat content of cyprinodontids from eight populations in Florida and southern Texas were examined. In all species the spawning period is protracted. Cyprinodon variegatus may spawn throughout the year. Spawning in Fundulus similis apparently occurs during all months except November, December, and January, but is terminated during September in F. grandis. Cessation of spawning occurs during September in F. lineolatus, but during July in F. chrysotus. Adinia xenica may have a longer spawning season than the species of the Fundulus investigated. A seasonal variation in body fat content was observed in C. variegatus, A. xenica, F. grandis, F. lineolatus, and F. similis (from Texas, but not Florida). Maximum fat reserves and the seasonal variation in fat levels differed among the species studied. Seasonal variations in body fat content and gonadal size were not correlated in any of the species. Seasonal changes in standing crops of zooplankton and phytoplankton were compared to annual variations of body fat content and gonadal size in C. variegatus and F. similis from Texas. Neither gonadal size nor fat content correlated with zooplankton or phytoplankton standing crops.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<464:SVORAL>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Erythrocyte nuclear volumes were measured in brook trout (Salvelinus fontinalis) from Phillips Hatchery in Maine to document naturally occurring polyploid sterility. In eight brook trout in which gonads were lacking or undeveloped, the nuclei were large, suggesting polyploidy. The average size of the erythrocyte nuclei in other sterile fish fell within the normal range but all of the eight fish appeared to have some erythrocytes that were polyploid. All polyploids appeared to be mosaics, containing diploid, triploid, tetraploid, or pentaploid cells. The cause of the polyploidy was not determined but may have been caused by the inadvertent exposure of the eggs to low temperatures after fertilization.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<473:RSIPBT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Juvenile Tilapia aurea were fed diets containing fish meal, soybean meal, or mixtures of these to provide 15, 22, 29, or 36% dietary protein. Average daily gain and food conversions were determined over a 12-week period. Growth rates of fish fed the 36% protein diets were greater than those fed the other protein levels. Within each protein level, the 100% fish meal diets produced the greatest growth, although no differences were observed between any of the protein sources when fed at the 36% protein level. No significant correlations were observed between protein level or source and body protein composition.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<479:GROTAT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Consumption of O2by planktonic communities of pond waters may be predicted from chemical oxygen demand (COD) and temperature (r2= 0.85). In ponds where planktonic organisms are the major source of turbidity, Secchi disk visibility may also be used to estimate COD (r2= 0.81) or consumption of O2by planktonic communities (r2= 0.82).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<484:PEMDOC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Larval chironomids Chironomus longilobus (Kieffer) are serious competitors with milkfish Chanos chanos (Forskal) for benthic algae in commercial milkfish ponds in Taiwan. Chironomid larvae were effectively killed with temephos (Abate(R), O, O, O', O'-tetramethyl O, O'-thiodi-p-phenylene phosphorolhioate) 50% emulsifiable concentrate when it was diluted 1:2,000 with seawater and applied to milkfish ponds to establish a concentration of 0.050 mg/liter of the active ingredient. This treatment did not harm milkfish and benthic algae. Residues found in the edible portions of milkfish after seven applications of Abate 50% emulsifiable concentrate ranged from 0.02 to 0.08 mg/kg, well below the 1.0 mg/liter approved by the World Health Organization for presence in human drinking water. The acute toxicity of Abate 50% EC to 13 other species of aquatic animals was determined in the laboratory.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<493:COCIMC>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Food consumption and growth rates of a predator, the largemouth bass (Micropterus salmoides), and the behavior of both the predator and its prey, the mosquitofish (Gambusia affinis), were sensitive indices of sublethal effects of ammonia on predator-prey interactions. Prey consumption and growth rates of bass in control tests increased with increasing prey densities. Ammonia concentrations of 0.63 and 0.86 mg/liter NH3substantially decreased prey consumption and growth of bass in test tanks stocked with densities of 30, 60, and 120 mosquitofish. At a given ammonia concentration, there were greater decreases in prey consumption and growth of bass at higher prey densities. This can be attributed in part to the bass being more sensitive than mosquitofish to ammonia and to the harassment of the predator by the prey which occurred at high ammonia concentrations and high prey densities.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1978)107<500:PIOFUT>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor