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The mysids, Orientomysis spp., are common in shallow coastal waters and estuaries in Japan, and are reported to be one of the main prey items for juveniles of many commercially important fish species. Some studies have suggested that the seasonal dynamics of mysids are an important factor determining the biomass and production structure of demersal fish communities. In this study, seasonal variation in the population structure and reproductive traits of Orientomysis japonica Marukawa, 1928 were investigated in Tango Bay, the western part of Wakasa Bay, Japan, from April 2007 to April 2009. Mean densities at depths of 5 and 10 m were highest in spring (ca. 100 ind. m-2), decreasing drastically in early summer to nearly 0 ind. m-2. Juveniles and immature individuals dominated the population (>80%) in spring and decreased in summer (<50%). Brooding females were captured year-round with mean body lengths ranging from 6.9 (August 2007) to 13.1 mm (February 2008). Body lengths of brooding females were negatively correlated with temperature. Brood size ranged from 1 to 102 and increased with female body length. The body sizes of all embryonic/ larval stages within the marsupium were also negatively correlated with temperature. These results suggest that numerous large offspring released by the highly reproductive overwintering generation led to density increases and the maintenance of a high population density, while conversely, the summer-autumn generation exhibited repetitive shortterm reproduction under high temperatures. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate relationships between reproductive traits in heifers and cows and yield traits for Holsteins in Japan. Insemination and lactation records for cows calved between 1990 and 2003 in Hokkaido region were obtained. Age at first service, age at conception, and conception rate for first service were calculated for heifers. Days from calving to first service, days open, and conception rate for first service were calculated for first- and second-parity cows. The yield traits used were 305-d milk, fat, and protein yields. A threshold animal model was applied for the conception rate for first service, and a linear animal model was applied for the other traits. Single-trait and 2-trait genetic analyses were performed by the Bayesian method using Gibbs sampling. Heritability estimates ranged from 0.027 to 0.051 for conception rate for first service, and from 0.074 to 0.128 for the other reproductive traits. If the relationships of other traits were not considered, days from calving to first service was favorable to genetic selection for reproductive traits because of relatively high heritability and because it can be available earlier than the days open. Genetic correlations among reproductive traits were high, especially in cows. The genetic correlations between reproductive traits for heifers and those for cows were lower than the genetic correlations between reproductive traits for first parity and those of second parity, suggesting that reproductive traits for heifers should be evaluated separately from reproductive traits for cows. Genetic correlations between yield and reproductive traits in cows were antagonistic. In contrast, genetic correlations between reproductive traits for heifers and yield traits were slightly desirable. Depending on the reporting rate of insemination records for heifers and the results of investigations for relationships with productive maturity, selection by reproductive traits for heifers will enable the improvement of reproductive performance without a loss in genetic progress for yield traits. [ABSTRACT FROM AUTHOR]

The dominance genetic effects for reproductive and calf growth abilities in the practical Japanese Black populations were examined using average information (AI) algorithm restricted maximum likelihood (REML) under animal models. The reproductive traits were observed in Japanese Black cattle maintained at Tottori and Okinawa prefectures, and growth traits of calves were observed in cattle at Okinawa. The average of dominance relationships in Tottori ranged from 0.2 to 0.4%, while the level in Okinawa was lower and sparse compared with Tottori. The proportions of the dominance variances to sum of additive and dominance variances ( ) were all 0.02 for reproductive traits in Tottori. In contrast, the proportion was 0.02–0.64 in Okinawa regardless of the level of dominance relationships. These proportions suggested that the dominance might affect the expression of calving interval, days open and gestation length in Okinawa, where breeding units were spread over many islands. Although the dominance variances could not estimate birthweight, w as 0.34 for calf market weight and 0.27 for average daily gain from birth to calf market in Okinawa. These values also suggested that the dominance might affect the early growth of calves. In the near future, genetic relationships will become more complicated with continuation of the current selection and mating systems. Therefore, genetic evaluation accounting for dominance effects would be necessary for particular traits and populations. [ABSTRACT FROM AUTHOR]

Jujiroa estriata Sasakawa (Coleoptera: Carabidae: Platynini) was recently described based on a single male from a mountain in Kyushu, southwest Japan (type locality: Hagi, Gokanoshô). Here we report collection of the species from a new locality, Mount Osuzuyama. We also describe some reproductive traits based on the materials obtained (one male and four females, collected in late May). The male formed sperm bundles in which the head of each spermatozoon was embedded in a rod-shaped structure (spermatodesm). Each spermatodesm was elongate (average length 2.44 mm; cf. male body length 10.8 mm), without a conspicuous spiral structure. Three of the females were dissected, and were found to have 11 or 12 mature eggs in their oviducts. This study provides the first description of sperm bundle morphology for a species of the tribe Platynini and preliminary data on the breeding type of Jujiroa Uéno. [ABSTRACT FROM AUTHOR]