Effects of Egg Concentrations of DDT and Dieldrin on Development in Winter Flounder (Pseudopleuronectes americanus)

1973 ◽  
Vol 30 (12) ◽  
pp. 1894-1898 ◽  
Author(s):  
Roderick M. Smith ◽  
Charles F. Cole
Keyword(s):  
Direct Effect ◽  
Lower Incidence ◽  
Bone Erosion ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Observable Effect ◽  
Control Male ◽  
Vertebral Deformities ◽  
High Incidence ◽  
Sublethal Concentrations

Abnormal gastrulation and a high incidence (mean = 39%) of vertebral deformities at hatching were encountered in developing eggs from winter flounder, Pseudopleuronectes americanus, experimentally exposed as adults to sublethal concentrations of DDT. Bone erosion and hemorrhaging at the vertebral junctures were often observed in conjunction with the vertebral deformities. No abnormal gastrulation and a lower incidence (mean < 1%) of vertebral deformities without bone erosion and hemorrhaging were encountered in controls. DDT concentrations in the eggs ranged from 0.39 to 4.60 (mean = 2.42 ppm) compared to 0.11–0.57 ppm (mean = 0.22 ppm) in the eggs from control flounder. No observable effect on development was noted in eggs from adults exposed experimentally only to dieldrin except in two lots of eggs most of which were dead and necrotic at spawning and contained 1.74 and 1.21 ppm dieldrin. No direct effect on fertilization mortality was due to gamete concentrations of DDT and dieldrin and no residues of either insecticide were detected in the milt from exposed or control male flounder.

Influence of Lead and other Metals on Fish δ-Aminolevulinate Dehydrase Activity

1973 ◽  
Vol 30 (4) ◽  
pp. 560-562 ◽  
Author(s):  
Eugene Jackim
Keyword(s):  
Heavy Metals ◽  
Fundulus Heteroclitus ◽  
Aminolevulinic Acid ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Estuarine Waters ◽  
Liver And Kidney ◽  
Sublethal Concentrations

Exposing mummichog (Fundulus heteroclitus) and winter flounder (Pseudopleuronectes americanus) to sublethal concentrations of lead resulted in reduction of liver and kidney δ-aminolevulinic acid dehydrase activity. The results of this project are expected to afford an index of response to heavy metals in estuarine waters.

scholarly journals Spatial Proximity of ‘Ataulfo’ to ‘Haden’ Cultivar Increases Mango Yield and Decreases Incidence of Nubbins

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 450
Author(s):  
Rodrigo Lucas-García ◽  
Víctor Rosas-Guerrero ◽  
Lorena Alemán-Figueroa ◽  
R. Carlos Almazán-Núñez ◽  
Juan Violante-González ◽  
...  
Keyword(s):  
Lower Incidence ◽  
International Market ◽  
Spatial Proximity ◽  
Self Incompatibility ◽  
Total Income ◽  
High Incidence ◽  
Increasing Demand ◽  
Economic Income

Mexico is the leading exporter of mangos worldwide, and ‘Ataulfo’ is one of the most popular cultivars. However, their production has dramatically dropped in recent years due to the high incidence of nubbins. One of the possible causes is the presence of a delayed self-incompatibility found in this cultivar; thus, proximity to compatible cultivars may help to reduce this incidence. Nevertheless, there is a lack of studies that have rigorously tested this hypothesis in this cultivar. For two consecutive years, the present study evaluated the incidence of nubbins, as well as the quality and quantity of commercial fruits of ‘Ataulfo’ trees located at 10, 30, and 50 m away from ‘Haden’ cultivar. Additionally, the yield and economic income of different planting designs were estimated. During both sampling periods, our results clearly indicated that at 10 m away from ‘Haden’ individuals, ‘Ataulfo’ trees presented a lower incidence of nubbins and higher production of commercial fruits, and higher yield and total income per hectare than at 30 or 50 m away from them. These results indicate that planting designs of ‘Ataulfo’ trees located 10 m away from ‘Haden’ will help to satisfy the increasing demand for mangos of this cultivar in the international market.

The Winter Flounder (Pseudopleuronectes americanus) in Long Pond, Conception Bay, Newfoundland

1971 ◽  
Vol 28 (8) ◽  
pp. 1153-1165 ◽  
Author(s):  
V. S. Kennedy ◽  
D. H. Steele
Keyword(s):  
Food Intake ◽  
Growth Rates ◽  
Plant Material ◽  
Early Growth ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Food Items ◽  
Fish Remains ◽  
Males And Females ◽  
Conception Bay

Monthly samples of winter flounder taken in Long Pond from November 1962 to October 1963 indicated that the flounder moved into deeper water (7–10 m) during the summer and returned to shallow water (1–2 m) from September to June. These movements corresponded to the end of the spawning season and the ripening of the gonads respectively. Spawning occurred from March until early June, most of it in May and early June. Most males were mature at age 6 and most females at age 7. Fifty percent of the males and females were mature at 21 and 25 cm respectively. The growth rates of the males and females were similar until the age of 8, after which the females apparently outgrew the males. Early growth and fecundity were similar to those reported for other areas. No feeding took place in December or January but the flounder fed in March and continued to feed throughout the summer; food intake decreased in the fall. They were omnivorous and the type of food eaten varied with the locality. Polychaetes, plant material, and molluscs were the most common food items throughout the year. Capelin eggs and fish remains were found only during a few months of the year but were eaten in great quantities.

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