Some aspects of population dynamics of juvenile hilsa shad (Tenualosa ilisha Ham.) from the Meghna river, Bangladesh

Population dynamics of the juvenile hilsa shad (Tenualosa ilisha) in the nursery ground of the Meghna River have been studied on the basis of the length cohort analysis of 8023 specimens. The growth parameters viz; asymptotic length (Lα), curvature character (K) and initial time (t0) were found to be 30.69 cm, 1.2 yrˉ¹ and 0.45 yrˉ¹ respectively. Curvature parameter indicates that jatka is a fast growth performer. The natural, fishing and total mortality were found to be 1.37 yrˉ¹, 1.41 yrˉ¹ and 2.78 yrˉ¹ respectively. Survival rate (S) was found to be 6.2%. A small difference was found between the age at first capture (Tc) and the recruitment age (Tr). Stocks of jatka seem to be overexploited and need to be conserved.

Nutritional characteristics of the two fermented fish products: Hentak and Ngari of Manipur

Proximate composition and nutritional characteristics of the two fermented fish products Hentak and Ngari of Manipur (India) were evaluated. Percentage of moisture, protein, lipid and ash contents in Hentak and Ngari were respectively: 36.30 versus 36.03; 33.33 versus 38.38; 13.60 versus 13.34 and 11.43 versus 5.49. Digestibility values in feeding trials in laboratory rats for 28 days were 82.37% for Hentak 89.46% for Ngari and that of Casein was 92.69%. The biological value, food conversion ratio and protein efficiency ratio (PER) of Hentak were 96.94, 4.83 and 1.8 respectively and that of Ngari were 97.83, 3.17 and 1.8 respectively. The α amino nitrogen of Hentak and Ngari in Pepsin + Trypsin phase were 28.40 and 28.92 respectively. The TBA number, peroxide value and TVBN were within the acceptable limits.

Elevating fishers of Dal Lake in Jammu and Kashmir

The deteriorating condition of one of the most magnificent lakes of India, the Dal Lake, has provoked a lot of research interest from the biological and ecological points of view. However, the impact of deterioration of the ecology on the inhabitant fisher folk around Dal Lake has not been given much importance. In this study, the three major beats of the lake, namely, Hazratbal, Nishat and Nehru Park, were surveyed, randomly taking 10% of the fishermen families. It was observed that the summer mean catch per day (5.18 ± 0.69 kg) was more than the mean winter catch per day (2.85 ± 0.40 kg). However, the total annual catch per person was only 1195.56 ± 211.63 kg. Moreover, marketing through middlemen, especially, during summer, was observed to be very low fetching in terms of mean price per kilogram fish, amounting to Rs 37.50 ± 2.54 for local fish and Rs 22.50 ± 2.88 for the carp. It was also observed that the fisher folk had borrowed a good amount of money for the repair and construction of their houses and boats. Therefore, on the whole, the fishing business around Dal Lake was observed to be under severe stress. In this context, this paper has come out with recommendations to uplift the socio-economic conditions of the fishers.

Quality assessment of rotating and solar tunnel dried marine fish product

Studies were conducted to evaluate the quality aspects of marine dried fish i.e. silver jew fish (Johnius argentatus), Bombay duck (Harpodon nehereus) and ribbon fish (Trichiums haumela) products produced in rotating and solar tunnel dryers. On the basis of organoleptic characteristics such as colour, odour, texture, broken pieces, insect infestation and overall quality, four member panels of experts evaluated the quality of the dried products obtained from both rotating and solar tunnel dryers and all the products were found in acceptable quality. Reconstitutions properties of samples were in the range of 51.05 to 98.75% for the dried fish produced in rotating dryer, while 24.64 to 76.76% for dried fish produced in solar tunnel dryer. The highest reconstitution rate was found in dried silver jew fish and lowest in ribbon fish produced in rotating dryer. On the other hand, the highest reconstitution was observed in dried silver jew fish and lowest in dried Bombay duck produced in solar tunnel dryer. Proximate composition such as moisture, crude protein, lipid and ash content of the dried fish muscles produced in rotating dryer ranged from 16.36% to 19.1%, 62.35% to 67.37%, 6.37% to 10.75% and 7.00% to 8.05%, respectively and in solar tunnel dried fish products, they were in the range of 14.05% to 19.71%,57.64% to 69. 21%,6.92% to 15.40%and 7.69% to 8.80 %, respectively. The TVBN values of dried fish products obtained from rotating dryer were in the range of 15.02 to 19.05 mg/100g, while in solar tunnel dried fish products, the values were in the range of 15.46 to 19.21 mg/100g. The results of the studies indicated that dried fish produced from both rotating and solar tunnel drier were acceptable quality in terms of organoleptic and food quality aspects.

Genetic diversity of Chinese native pigs inferred from protein electrophoresis

We examined protein polymorphism of 20 native pig breeds in China and 3 introduced pig breeds. Thirty loci have been investigated, among which six loci were found to be polymorphic. Especially, the polymorphism of malate dehydrogenase (MDH), adenylate kinase (AK), and two new alleles of adenosine deaminase (ADA) had not been reported in domestic pigs and wild pigs. The percentage of polymorphic loci (P), the mean heterozygosity (H), and the mean number of alleles (A) are 0.200, 0.065, and 1.300, respectively. The degree of genetic variability of Chinese pigs as a whole was higher than that of goats, lower than that of cattle and horses, and similar to that of sheep. Using the gene frequencies of the 30 loci, Nei's genetic distance among the 20 native breeds in China and 3 introduced pig breeds was calculated by the formula of Nei. The program NEIGHBOR in PHYLIP 3.5c was chosen to construct an UPGMA tree and a NJ tree. Our results show that, of the total genetic variation found in the native pig breeds in China, 31% (0.31) is ascribable to genetic differences among breeds. About 69% of the total genetic variation is found within breeds. Most breeds are in linkage disequilibrium. The patterns of genetic similarities between the Chinese native pig breeds were not in agreement with the proposed pig type classification.

Survival, maturation, fecundity and hatching rates of unablated and ablated Penaeus indicus H.M. Edwards from brackishwater ponds

Penaeus indicus harvested after three months of rearing in brackishwater ponds and averaging 6.9 g for females and 5.6 g for males were stocked in two 12 cu m flowthrough ferrocement tanks at 240 females and 200 males per tank. The females were ablated on one eyestalk in one tank and remained unablated in the other tank; all males were unablated. Ablated females spawned up to 7 times per female; unablated females spawned up to only 3 times during the two month duration of the experiment. Ablated females produced a total number of 17.5 x 10⁶ eggs, 6.6 x 10⁶ nauplii, and an average of 23,480 eggs/spawning and 37.8% hatching rate from a total of 757 spawnings. Unablated females produced a total of 2.0 x 10⁶ eggs, 1.1 x 10⁶ nauplii, and an average of 26.990 eggs/spawning and 53.9% hatching rate from a total of 74 spawnings. Survival of ablated females was 53.5% compared to 69.4% for unablated females; males in both tanks averaged more than 90% survival.

Effects of fish and prawn culture on physico-chemical parameters of water and rice yield in rice fields

An experiment was conducted with five treatments i.e. rice combined with fish having regular urea fertilization (T1), rice combined with prawn having regular urea fertilization (T2), rice combined with fish with supplementary feeding (T3), rice combined with prawn with supplementary feeding (T4) and without fish and prawn (T5) was kept as control. The dissolved oxygen values obtained in treatments with fish both in morning and afternoon were lower than the values of prawn containing treatments and control. The values of nitrate-N, ammonia-N, phosphate-P and chlorophyll-a were higher in fish containing treatments than the prawn containing treatments and control. Between the two fish containing treatments the higher gross (539.44 kg/ha) and net (440.14 kg/ha) yield were obtained in T3 with supplementary feeding and the lower gross (424.88 kg/ha) and net (314.32 kg/ha) yield were recorded in T1 without supplementary feeding. Again, between two prawn containing treatments the higher gross (108.69 kg/ha) and net (81.92 kg/ha) yield were obtained in T4 with supplementary feeding and lower gross (64.32 kg/ha) and net (30.98 kg/ha) yield were recorded in T2 without supplementary feeding. The highest yield of rice grain (3.45 mt/ha) and straw (6.37 mt/ha) were obtained in T1 with fish having urea fertilization without feeding.

目标物体尺寸的大小对小鼠空间深度感知的影响

探索了小鼠在排除透视、遮挡等空间深度的线索下,是否是依靠视觉目标的尺寸大小来感知空间深度.小鼠放置于可以调节高度的高台上,高台位于仅底面有光线照明、四周黑暗的实验箱内.将由格子构成底部面板的尺寸设计为小鼠估计高度距离的唯一线索,设置了3个空间尺度的底板,分别按2/3的比例缩小,并设置7个高度.在同一高度下每测试一轮即对底板的尺寸进行随机变换.记录小鼠跳落前在高台上停留的时间,研究小鼠对高度的判断是否受到底板尺寸的影响.结果表明所有大小线索条件下小鼠在高台上停留的时间随高度的增加而延长.在20～30cm的高度范围,小鼠不以大小为线索的信息来判断深度,可能主要以双眼视差产生的深度信息来判断高度.而在小于20cm和大于30cm的高度范围,特别是在更高的距离上如50cm、60cm和70cm,小鼠以目标大小信息为线索来对深度进行判断,以弥补在这些条件下双眼深度信息的不足.在理论上说这是由于小鼠只有三分之一的(中央)视野为双眼视野区.实验的行为范式可以应用到以转基因鼠为模式生物的实验中,以研究此类行为与基因之间的关系.

Biological characteristics and determination of population dynamics parameters of Nemipterus japonicus in the coastal waters of Province Bushehr, Persian Gulf

This study was conducted to determine biological characteristics and population dynamics parameters of threadfin bream (Nemipterus japonicus) in Persian Gulf (Bushehr Province), during November 2006 and October 2007. The minimum and maximum specimens were 75-273 mm FL and their weight was 7.6 - 351.9 g. Based on the exponential relationship between fork length and weight, slope (b) for individuals, males and females was 2.987321, 2.992546 and 3.007314, respectively. The emptiness value (V) was 45.6% and it shows that N. japonicus is a moderate feeder. The results of Fp indicates that crustacean with 78.2% are main foods, mollusca (27.7%), fishes (20.7%), polychaeta (19.2%) and Foraminifera (11.7%) were identified as minor foods and phytoplanktons (9.9%), nematoda(8.0%), echinodermata (2.3%) and sea weeds (0.3%) were random foods. The reproduction studies showed the spawning season extended within 2 peaks, from April- May and September and main spawning occurs in spring season.The mean absolute and relative fecundities were 472388±42633 and 3817±293 (X±SE), respectively. The maximum, minimum and mean of oocyte diameter were 0.448, 0.022 and 0.221mm (SE=0.071), respectively.The fork length at 50% maturity estimated to be 20.25 cm for females. The growth coefficient (K) , length infinity (L∞ ) and ɸ' was estimated 0.42/yr , 34.17 cm and 2.69, respectively. The coefficient of total mortality, fishing mortality, natural mortality and E was 1.37, 0.43, 0.94 and 0.31, respectively.

Distribution and abundance of cirripede larvae (Cirripedia: Thoracica) in the northern Arabian Sea

Cirripede larvae obtained in the zooplankton samples of the North Arabian Sea Ecological and Environmental Research (NASEER) cruise I (January, 1992) have been studied for their distribution and abundance. They were collected in the northern Arabian Sea waters (22°51'N to 24°58'N, 60°05'E to 65°59'E). Thirty- two samples were taken at 18 stations. The maximum number of larvae were collected from a station near Indus cone (Sta. 8), whereas an off shore station (Sta. 37) and one near the Makran coast (Sta. 60) had poor representation. Regular coastal collections from Manora Channel (24°48'N, 66°59'E), during the study period of one year (1994), have been also included to supplement the NASEER samples. Only one naupliar stage (VI) and a cyprid stage were identified. Relative abundance in day and night samples were also studied.

The Effects of Visual Object Size in The Depth Perception in KM Mouse

Whether mice perceive the depth of space dependent on the visual size of object targets was explored when visual cues such as perspective and partial occlusion in space were excluded. A mouse was placed on a platform the height of which is adjustable. The platform located inside a box in which all other walls were dark exception its bottom through that light was projected as a sole visual cue. The visual object cue was composed of 4x4 grids to allow a mouse estimating the distance of the platform relative to the grids. Three sizes of grids reduced in a proportion of 2/3 and seven distances with an equal interval between the platform and the grids at the bottom were applied in the experiments. The duration of a mouse staying on the platform at each height was recorded when the different sizes of the grids were presented randomly to test whether the Judgment of the mouse for the depth of the platform from the bottom was affected by the size information of the visual target. The results from all conditions of three object sizes show that time of mice staying on the platform became longer with the increase in height. In distance of 20 similar to 30 cm, the mice did not use the size information of a target to judge the depth, while mainly used the information of binocular disparity. In distance less than 20 cm or more than 30 cm, however, especially in much higher distance 50 cm, 60 cm and 70 cm, the mice were able to use the size information to do so in order to compensate the lack of binocular disparity information from both eyes. Because the mice have only 1/3 of the visual field that is binocular. This behavioral paradigm established in the current study is a useful model and can be applied to the experiments using transgenic mouse as an animal model to investigate the relationships between behaviors and gene functions.

Product intelligence in industrial control: Theory and practice

This paper explores the evolving industrial control paradigm of product intelligence. The approach seeks to give a customer greater control over the processing of an order - by integrating technologies which allow for greater tracking of the order and methodologies which allow the customer [via the order] to dynamically influence the way the order is produced, stored or transported. The paper examines developments from four distinct perspectives: conceptual developments, theoretical issues, practical deployment and business opportunities. In each area, existing work is reviewed and open challenges for research are identified. The paper concludes by identifying four key obstacles to be overcome in order to successfully deploy product intelligence in an industrial application. © 2013 Elsevier Ltd. All rights reserved.

武汉东湖短尾秀体溞的种群变动和生产量

测定浮游动物的生产量是水生态系统结构、功能和生物生产力研究中的一个重要环节,通过生产量的测算可客观地评价不同种群对系统作用的大小。短尾秀体溞在我国广为分布,但其生产量在我国尚未见报道,为此笔者测定研究了东湖麦秋季的优势枝角类——短尾秀体溞(Diaphanosoma brachyurum)的种群变化和生产量。在1983—1985年间,这种秀体搔在Ⅰ站的平均种群密度依次为7.67±12.39,11.15±20.58和10.14±11.19个/升;Ⅱ站则分别为7.36±11.07,7.37±16.16和9.69

Changes in benthic algal communities following construction of a run-of-river dam

Ecological responses to dam construction are poorly understood, especially for downstream benthic algal communities. We examined the responses of benthic algal communities in downstream reaches of a tributary of the Xiangxi River, China, to the construction of a small run-of-river dam. From February 2003 to August 2006, benthic algae, chemical factors, and habitat characteristics were monitored upstream and downstream of the dam site. This period spanned 6 mo before dam construction and 37 mo after dam construction. Benthic algal sampling yielded 199 taxa in 59 genera that belonged to Bacillariophyta, Chlorophyta, and Cyanophyta. Some physical factors (flow velocity, water depth, and channel width) and 3 algal metrics (diatom species richness, Margalef diversity, and % erect individuals) were significantly affected by the dam construction, whereas chemical factors (e.g., NH4-N, total N, SiO2) were not. Nonmetric multidimensional scaling (NMS) ordinations showed that overall algal assemblage structure downstream of the dam sites was similar to that of upstream control sites before dam construction and for 1 year after dam construction (p > 0.05). However, sites belonging to upstream and downstream reaches were well separated on NMS axis 1 during the 2(nd) and 3(rd) years after dam construction. Our results suggest that impacts of dam construction on benthic algal communities took 2 to 3 y to emerge. Further development of a complete set of indicators is needed to address the impact of small-dam construction. Our observations underscore the need for additional studies that quantify ecological responses to dam construction over longer time spans.