The effects of brood stock size on the economy of catfish (Clarias anguillaris) fry production using the hormone induced natural breeding technique

89 ripe female brooders of the catfish, Clarias anguillaris (Body wt. Range 150g-1, 200g) were induced to spawn by hormone (Ovaprim) induced natural spawning technique over a period of 10 weeks. Matching ripe males were used for pairing the females at the ratio of two males to a female. Six ranges of brood stock body weights were considered as follows; 1000g and the number of fry produced by each female brooder was scored/recorded against the corresponding body weight range. The number of fry per unit quantity of hormone and the cost of production a fry based on the current price of Ovaprim (hormon) were determined so as to ascertain most economic size range. The best and most economic size range was between 400g-599g body weight with about 20,000 fry per ml of hormone and N0.028 per fry, while the females above 1000g gave the poorest results of 9,519 fry per ml of hormone and N0.059 per fry. For optimum production of Clarias anguillaris fry and maximum return on investment female brooders of body weights ranging between 400g-599g are recommended for hormone induced natural breeding exercise

Visuality and the haptic qualities of the line in generative art

The line has an important and particular relationship with the generative artwork distinct from other elements such as the ‘pixel’, ‘voxel’ or the ‘points’ that make up point clouds. The line has a dual nature as both continuous and discrete which makes it perhaps uniquely placed to straddle the analog and digital worlds. It has a haptic or felt quality as well as an inherent ambiguity that promotes a relatively active interpretive role for the audience. There is an extensive history of the line in generative systems and artworks, taking both analog and digital forms. That it continues to play an important role, alongside other more photographically inspired ‘perceptual schemas’, may be a testament to its enduring usefulness and unique character. This paper considers the particular affordances and the ‘visuality’ of the line in relation to generative artworks. This includes asking how we might account for the felt quality of lines and the socially and culturally constructed aspects that shape our relationship with them. It asks whether, in what has been described as a ‘post digital’ or even ‘post post digital’ world, the line may offer a way to re-emphasise a more human scale and a materiality that can push back, gently, against other more dominant perceptual schemas. It also asks what generative art can learn from drawing theory, many of the concerns of which parallel and intersect with those of generative art

Salinity preference of the milkfish Chanos chanos Forskal

Salinity preference of the milkfish fry is described. Milkfish fry which were acclimatized to different salinities have preference for certain salinity which is 32 ppt. Majority of the fry in the control tanks usually prefer to stay either at the bottom or at the uppermost layer; only a few stay at the middle layer. This strongly suggests that milkfish fry that are not caught along the shore by fishermen usually tend to migrate to waters of high salinity. Furthermore, salinity preference of milkfish fry does not change with age

Relative Survival of Three Sizes of Walleyes Stocked into Illinois Lakes

The ability to differentially batch-mark several size-groups of fish stocked concurrently in lakes or rivers makes it possible to compare survival within a single year. We evaluated stocking of walleyes Stizostedion vitreum in Illinois during 1991–1996. Ten lakes were stocked with combinations of two or three sizes of walleyes, including fry and small (50-mm) and large (100-mm) fingerlings. This permitted a total of 73 lake-year comparisons: fry versus large fingerlings (23 lake-years), fry versus small fingerlings (29 lake-years), and small versus large fingerlings (21 lake-years). Stocked fish were differentially marked with oxytetracycline or fin clips. Electrofishing catch per effort, relative survival, and population estimates were used in conjunction with production costs to compare size-based contributions and survival. Survival generally favored fingerlings over fry (70% of lake-years for small fingerlings, 67% for large fingerlings) and small fingerlings over large fingerlings (72% of lake-years). In some lake-years, fry and large fingerlings had the highest survival. Fish stocked as fry and small fingerlings were larger than large fingerlings beginning their third year of growth. Based on our results, stocking small fingerlings will generally be more cost-effective than stocking fry or large fingerlings. However, if fry or large fingerlings are available, stocking assessment on specific lakes may allow biologists to determine particular lakes where alternative sizes could be economically feasible

Effects of High Salinity on Survival, Growth, and Reproductive performance of Red Tilapia (Oreochromis urolepis hornorum ♀× Oreochromis mossambicus ♂)

This study estimated the survival, growth, and fry production of red tilapia (Oreochromis urolepis hornorum ♀× Oreochromis mossambicus ♂) broodstock in outdoors farming conditions at various salinity levels (1‰, 25‰, 33‰, 39‰, and 42‰) at 25.3°C–39.0°C. The experiments were conducted in triplicates in 2020 using 300 broodstock per group. The survival rate, growth performance, and fry production were monitored. Our results showed that red tilapia fry production and grow-out farming were feasible under high salinity conditions; however, the various levels of salinity condition exhibited significant differences in terms of survival rate, growth performance, fry production. The results suggest that red tilapia broodstock was maintained under salinity as high as 33‰ without impairing fry production; above 33‰ was feasible for the grow-out stage, implying that the fry production in euryhaline tilapia farming would be practical in regions where freshwater acclimation is limited

Modalités spatio-temporelles de la dispersion d'alevins de saumon atlantique (Salmo salar L.) à l'émergence

Nous avons étudié la dispersion (vitesse, durée, distance) d'alevins de saumon atlantique à l'émergence dans un ruisseau expérimental.Le rythme journalier de dévalaison suit étroitement le rythme d'émergence des alevins, ce qui montre une bonne corrélation entre les deux activités, tout au moins en début de période. Les histogrammes de capture des alevins échantillonnés tous les 10 m présentent des caractéristiques de forme similaires (durée, asymétrie et aplatissement). Jusqu'au pic des captures, près de 50 % des alevins dévalent en 5 jours. Ils se dispersent à partir de la frayère sur 50 m en 3 ou 4 nuits et forment une cohorte homogène d'après leur rythme de dévalaison et leur taille. Après le mode, les captures sont plus étalées dans le temps (environ 10 jours) et montrent plus de variabilité en fonction de la distance. Les alevins résidents ne sont pas distribués uniformément dans les cinq biefs : les densités, de même que les poids moyens, tendent à augmenter vers l'aval. Plus de 50 % de la population d'alevins survivants s'est établi dans les 50 m en aval de la frayère. Les résultats révèlent deux vagues de dévalants. La première vague de dispersion, aussitôt après l'émergence, est rapide et importante. Elle ne dépendrait pas directement de la compétition territoriale et de la densité, mais permettrait d'éviter des densités localement trop élevées et d'utiliser plus efficacement les zones productives situées en aval de la frayère. La deuxième vague d'alevins dévalants correspondrait aux émergents tardifs et aux poissons soumis aux effets de la compétition territoriale.We have analysed the dispersal patterns (rate, duration, extent) of Atlantic salmon fry at emergence. The rate and duration of movement, and the distance travelled were measured in an experimental stream, located near S-Pée-sur-Nivelle, in SW France. A batch of 8 850 eyed eggs, from the grilse wild stock of the Nivelle River, was buried in the gravel substrate at the upstream end of a series of 5 sections, each 10 m long by 3 m wide. Shortly before emergence, drift nets equipped with fry traps were installed at the downstream end of each section. The nets sampled about 1/10 of the flow, except for those nets at the downstream end of the last section which collected all downstream moving fry. The traps were visited every morning and the fry enumerated. At the time of peak movements, samples were collected for length-weight measurements. At the end of the dispersal period, fry which had settled in the different sections (residents) were captured with electro-fishing gear and measured.The pattern of downstream movement of fry in a set of drift nets was closely related to the pattern of emergence from an artificial redd upstream of the nets. Hence, emergence and downstream dispersion were well synchronized, at least during the first part of the dispersal from the redd. The time-frequency histograms of fry sampled every 10 m showed the same pattern and general shape (duration, skewness and kurtosis). Until the peak of captures, nearly 50 % of all downstream moving fry were caught within 5 days in each section. Dispersion from the redd over 50 m occurred within 3-4 nights. During this first period, the fry exhibited similar characteristics with respect to activity patterns and sizes. After the modal day of capture, catches were more evenly spread over time (about 10 days) and showed greater variability in relation to the distance travelled from the redd.Resident fry were not uniformly distributed in the 5 sections : densities, as well as average weights, increased from upstream to downstream. Over 50 % of the surviving fry (75.3 % of planted eggs) settled within 50 m downstream from the redd.Our results showed two waves of downstream dispersion. The first dispersal wave, occurring soon after emergence, was swift and implied large numbers of fry. It was not the result of territorial competition or density, since it occurred before the onset of aggressive behaviour. Rather, this first wave appeared as process to avoid the formation of clumps and allow for a more efficient use of the more productive zones, generally located downstream from the redd. The second wave of downstream moving fry corresponded to late emerging fry and to those fry which, 10-12 days after emergence, were displaced by territorial competition

Bangus (Chanos Chanos) Fry Counter

Agriculture has a key role in the Philippines economy, particularly the fisheries industry, which contributes 15% of the country’s overall income. The sector offers significant employment and income for various parts of population, contributes to export earnings, and meets a large portion of the population’s nutritional protein requirements. In terms of employment, the fisheries sector employs over one million people, or about 5% of the nation. The general objective of the study is to develop a portable bangus fry counter for the University of Antique – Hamtic Campus, Hamtic, Antique, and an affordable fry counter for the local fish fry vendor, fish pond owner and others that can benefit in this thesis. The researchers used the Arduino for the operating system and the light censor for the input and the LCD for the output. For the data gathering, the researchers used the ISO 25010 characteristic, the weighted mean formula to solve the mean and the Likert scale. The prototype showed excellent performance in terms of counting the bangus fry quantities. Based on the results of the evaluation, the participants strongly agreed with the functionality, reliability, portability, maintainability, security, compatibility, performance efficiency and usability of the device.Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP) © Copyright: All rights reserved

Encounters with Errors: How the error shapes relationships with digital media practice

This paper considers how the ‘error’ shapes our relationship with computation and creative practice. It also considers how rethinking the ‘error’ can aid undergraduate students when learning about digital media practice. Comparing conceptions of the ‘error’ with those of other key concepts from digital and creative practice such as ‘glitch’, reveals the defining character of the ‘error’ and the way it shapes creative processes. As well as surveying the role of the ‘error’ in digital arts practice, this paper also discusses the author’s experiences of teaching undergraduates on a digital and interdisciplinary arts programme. It reflects on the impact that challenging conceptions of the ‘error’ can have on students’ understanding of computation and creativity

Certainty and Fragility: reassessing the role of automatically generated aids to the making process

This paper considers the role of automatically generated guides, supports and other material that are intended to aid the making process. Increasingly, work and even daily life are supported by systems that automatically create text, lines, images and other forms as an aid for numerous types of activity. These include the auto-suggestions of search engines and messaging apps, and the guides and supports generated by graphics and 3D modelling software. This study focuses on the role of these assistants in the production of media artefacts. It revaluates the temporary creations which support creative processes but which are rarely considered at great length beyond their originally intended purpose. This paper will discuss how a repurposed 3D printer has been used to reinvent the support material generated by 3D slicer software as drawings and images in their own right. In doing so it describes how the transition from digital proposition to analog realisation often traverses a line between certainty and fragility. It will reflect on what this might reveal about the perceived relationship between human and machine, and between the manmade and the mechanically produced. This in turn invites a reassessment and rebalancing of these roles