Fishery and Reproductive Cycle of the Red Sea Urchin, Strongylocentrotus franciscanus, in British Columbia

1977 ◽  
Vol 34 (5) ◽  
pp. 604-610 ◽  
Author(s):  
F. R. Bernard
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Sex Ratio ◽  
Local Conditions ◽  
Strongylocentrotus Franciscanus ◽  
Male And Female ◽  
Glycogen Accumulation ◽  
Fishing Season ◽  
Gonadal Index ◽  
Red Sea Urchin

Gametogenesis and gonadal index undergo an annual cycle with minima in September and maxima in May for a population of red urchins, Strongylocentrotus franciscanus, from southwestern Vancouver Island. Postspawning recovery is rapid and there are no significant differences between male and female gonadal indices, but a small gonad to body-size correlation is evident. Gonadal index is not the product of gametogenesis, but is correlated to glycogen accumulation which may reach 13% gonad total weight. The fishing season for roe in southern British Columbia extends from October to April with several weeks variability depending on local conditions and weather. Yields constitute up to 25% total drained weight. Key words: urchins, fishery, gametogenesis, glycogen, hermaphroditism, sex ratio

Diving behaviour of male and female western grebes

1988 ◽  
Vol 66 (12) ◽  
pp. 2695-2698 ◽  
Author(s):  
L. Scott Forbes ◽  
Spencer G. Sealy
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Water Depth ◽  
Wave Action ◽  
Diving Behaviour ◽  
Sexually Dimorphic ◽  
Habitat Conditions ◽  
Male And Female ◽  
Males And Females

We studied diving in western grebes (Aechmophorus occidentalis), which are sexually dimorphic, at Duck and Kootenay lakes in southeastern British Columbia to determine if differences in sex, and hence body size, resulted in differences in behaviour. Springing dives were used more frequently in deeper water and when wave action was higher, but there were no clear differences between males and females. As well, the dive–pause regressions for males and females did not differ. We conclude that differences in body size are not important determinants of diving behaviour in western grebes, but that habitat conditions (e.g., water depth, wave action) are.

First description of Metridia okhotensis Brodsky, 1950 (Crustacea: Copepoda) male, with female, fifth copepodites, and notes on distribution in British Columbia inlets

1986 ◽  
Vol 64 (7) ◽  
pp. 1555-1562
Author(s):  
Ildy Szabo ◽  
Grant A. Gardner
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Pacific Ocean ◽  
Relative Length ◽  
Similar Species ◽  
Male And Female ◽  
Northeast Pacific ◽  
Zooplankton Dynamics ◽  
First Time ◽  
Northeast Pacific Ocean

The male of Metridia okhotensis (Copepoda: Calanoida) is described here for the first time. It can be separated from similar species, including M. longa, a morphologically similar species found in the Atlantic and Arctic oceans, on the basis of body size, the relative length of the first antennae, and the shape of the fifth leg. Here we describe both the fifth and sixth copepodite stages of male and female M. okhotensis, and present a tabular key to members of the genus reported from the northeast Pacific Ocean. In addition, we show that M. okhotensis is widely distributed in the protected waterways of the British Columbia coast, and at times and in some places it is numerically dominant. Particularly high numbers are found in Loughborough and Portland inlets and Douglas Channel. The size of the copepod and of its population suggest it plays an important role in the zooplankton dynamics of British Columbia nearshore waters.

scholarly journals Distribution and Size of Crab (Portunus pelagicus) in Betahwalang Waters, Demak, Central JavaSex Ratio, Size Distribution and Length-Weight Relationship of Portunus pelagicus Linnaeus, 1758 (Malacostraca : Portunidae) in Betahwalang, Demak, Central Java

2021 ◽  
Vol 24 (1) ◽  
pp. 133-140
Author(s):  
Sri Redjeki ◽  
Muhammad Zainuri ◽  
Ita Widowati ◽  
Ambariyanto Ambariyanto ◽  
Rudhi Pribadi ◽  
...  
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Sex Ratio ◽  
Size Distribution ◽  
Growth Parameters ◽  
Carapace Width ◽  
The Body ◽  
Swimming Crab ◽  
Portunus Pelagicus ◽  
Male And Female

Blue Swimming Crab (P. pelagicus, Linnaeus, 1758) is the main fisheries product from Betahwalang peoples. Fishing activity of Blue Swimming Crab by the fisherman almost every day in Betahwalang waters. Distribution and body size data of Blue Swimming Crab can be used for sustain management reference. The purpose of this study was to determine distribution pattern and body size of Blue Swimming Crab, started from July to November 2018 in Betahwalang waters, Demak. The data analyze consist of sex ratio, carapace width distribution and relationship between carapace width and body weight. 11790 samples Blue Swimming crab from Betahwalang waters consist of 7070 female crabs and 4720 male crabs. The result showed that sex-ratio between male and female crabs are balanced (1.0:1.37), with the most female crabs found at July and August. Body size distribution of male and female crabs are dominated in class 103-111 mm carapace width. Male and female crabs have a positive allometric on growth parameters, that means growth of the body weight is faster than carapace width. The result showed that Blue Swimming Crab in Betahwalang waters are support for sustainable fisheries. 

The DEVELOPMENT OF Elaeidobius kamerunicus FAUST POPULATION AFTER INTRODUCTION AND THE IMPROVEMENT OF OIL PALM FRUIT SET IN SERAM ISLAND, MOLLUCAS, INDONESIA

2016 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto
Keyword(s):  
Sex Ratio ◽  
Oil Palm ◽  
Fruit Set ◽  
Average Risk ◽  
Palm Fruit ◽  
Male And Female ◽  
Risk Of Death ◽  
North Sumatra ◽  
Female Flowers ◽  
Elaeidobius Kamerunicus

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.

The DEVELOPMENT OF Elaeidobius kamerunicus FAUST POPULATION AFTER INTRODUCTION AND THE IMPROVEMENT OF OIL PALM FRUIT SET IN SERAM ISLAND, MOLLUCAS, INDONESIA

2018 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto
Keyword(s):  
Sex Ratio ◽  
Oil Palm ◽  
Fruit Set ◽  
Average Risk ◽  
Palm Fruit ◽  
Male And Female ◽  
Risk Of Death ◽  
North Sumatra ◽  
Female Flowers ◽  
Elaeidobius Kamerunicus

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.

II.—Hidden Divergence in Laboratory Strains of Drosophila pseudo-obscura

1944 ◽  
Vol 62 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Rowena Lamy
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Genetic Constitution ◽  
Low Grade ◽  
Testis Size ◽  
Hybrid Female ◽  
Back Cross ◽  
Pure Race ◽  
Range Of Variation

The Race A/Race B hybrid females of D. pseudo-obscura have a high percentage of fertility, comparable with that of females of pure race. The number and viability of their offspring, however, are largely affected by the genetic constitution of the hybrid female as well as by that of the male to which she is mated in the backcross. Hence the performance of any given hybrid is determined in the first instance by the actual strains of the pure races which are used in making the P1 racial cross. Generally speaking the results are of the same order whenever the same strains are used. The progenies of hybrid females of different genetic constitution may differ in three main aspects: (1) The total number of offspring may be comparable with that usually obtained in a pure race cross; it may be reduced to any extent; in certain matings it is consistently at zero. (2) The sex ratio may be completely normal or male-deficient or female-deficient in any degree; completely uni-sexual progenies are sometimes obtained. (The above observations are mainly in agreement with reports of earlier writers; cf. Lancefield, 1929, Dobzhansky, 1936, Mampell, 1941, Sturtevant, 1937.) (3) “Viability characters,” i.e. those affecting general vigour and physical normality, may be of a high or a low grade; some progenies are comparable in this respect with the pure race, the only exception being that they show a much greater range of variation in body-size of both sexes, and in the testis size of males, abnormalities which are common to all back-cross progenies whatever the genetic constitution of the mother or father. Some progenies show in addition deformities of a peculiar type usually affecting the abdomen and occasionally the legs and wings.

Sperm Competition and the Dynamics of X Chromosome Drive: Stability and Extinction

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1721-1731 ◽  
Author(s):  
Jesse E Taylor ◽  
John Jaenike
Keyword(s):  
Sex Ratio ◽  
Sperm Competition ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Basin Of Attraction ◽  
Male Mating ◽  
Male And Female ◽  
Mating Rate ◽  
Female Mating ◽  
Balanced Polymorphism

AbstractSeveral empirical studies of sperm competition in populations polymorphic for a driving X chromosome have revealed that Sex-ratio males (those carrying a driving X) are at a disadvantage relative to Standard males. Because the frequency of the driving X chromosome determines the population-level sex ratio and thus alters male and female mating rates, the evolutionary consequences of sperm competition for sex chromosome meiotic drive are subtle. As the SR allele increases in frequency, the ratio of females to males also increases, causing an increase in the male mating rate and a decrease in the female mating rate. While the former change may exacerbate the disadvantage of Sex-ratio males during sperm competition, the latter change decreases the incidence of sperm competition within the population. We analyze a model of the effects of sperm competition on a driving X chromosome and show that these opposing trends in male and female mating rates can result in two coexisting locally stable equilibria, one corresponding to a balanced polymorphism of the SR and ST alleles and the second to fixation of the ST allele. Stochastic fluctuations of either the population sex ratio or the SR frequency can then drive the population away from the balanced polymorphism and into the basin of attraction for the second equilibrium, resulting in fixation of the SR allele and extinction of the population.

Variation in Weight, Size, and Sex Ratio of Coccinellid Adults (Coleoptera: Coccinellidae)

1966 ◽  
Vol 98 (6) ◽  
pp. 639-644 ◽  
Author(s):  
B. C. Smith
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Water Content ◽  
Food Supply ◽  
Sexual Differences ◽  
Intraspecies Variation ◽  
Food Scarcity ◽  
Food Requirement ◽  
Males And Females

AbstractThe weight and size of coccinellid adults varied with species, sex, and feeding. Intraspecies variation in weight was generally similar in the eight species studied. Females were more variable than males in body size. Females of some species were heavier and larger than males, and species can be classified on a basis of difference in the weight and size of the sexes.An increase in the food supply after a period of food scarcity affected the sex ratio, as the minimum food requirement of females was greater than males. Females increased in weight more rapidly than males after feeding. The availability of food in the field affected the weight and size of some species. Adult water content was influenced by feeding but not by sex or the quantity of food given to the larva.Males were more abundant in species with small sexual differences in weight and size. The degree of difference in weight and size between males and females may be used as a criterion to select species that are best adapted to survive when food is scarce.

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