Factors determining spawning success in Penaeus monodon Fabricius

Spawning success in relation to the size of spawner, clumping of eggs, percentage of spawning and frequency of spawning was studied in Penaeus monodon collected off Tamil Nadu, India. The results indicated positive correlation between the size of spawner and the fecundity and hatching percentage, but not the start of hatching. Hatching characteristics were influenced by clumping of eggs or abortive spawning; the greater the clumping, the longer the time taken for hatching, resulting in a lower hatching percentage. The start of hatching time increased when the frequency of spawning increased. Lower hatching rate was observed as the frequency of spawning increased

The development of egg hatching and storage machines equipped with cooling and heating systems and iot

The development of egg hatching and storage machines equipped with cooling and heating systems and IoT was for helping chicken breeders to address the issue of chicken production shortages. To produce large numbers of poultry production, eggs hatching is one of the major step that needs to pay attention to. There are several reasons why egg hatching process fails, such as lack of care by hen, eaten by rooster, and unsuitable hatching environment and temperature. In addition, if the eggs are not incubated within 1 week, the eggs will be damaged having producing a hatching machine and egg storage can help the chicken breeders to produce a better amount of chicken production. Internet of Things (IoT) elements such as the Arduino and Blynk are also used to make this egg hatching and storage machine attractive and to meet the needs and requirements of users. The objectives of this study were to design, develop and evaluate the functionality of egg hatching and storage machines in combination with cooling and heating systems along with IoT. Methodology is a technique and method that incorporates methods and approaches used to achieve the objectives and objectives of the study. The model used is the ADDIE model which consists of 5 phases namely Analysis, Design, Development, Implementation, and Evaluation. This product has received expert confirmation in terms of design and functionality. The results show that the egg hatching and storage machine is well developed and can attract users when using this hatching and storage machine

Effect of type of otolith and preparation technique on age estimation of larval and juvenile spot (Leiostomus xanthurus)

Otoliths of larval and juvenile fish provide a record of age, size, growth, and development (Campana and Neilson, 1985; Thorrold and Hare, 2002). However, determining the time of first increment formation in otoliths (Campana, 2001) and assessing the accuracy (deviation from real age) and precision (repeatability of increment counts from the same otolith) of increment counts are prerequisites for using otoliths to study the life history of fish (Campana and Moksness, 1991). For most fish species, first increment deposition occurs either at hatching, a day after hatching, or after first feeding and yolksac absorption (Jones, 1986; Thorrold and Hare, 2002). Increment deposition before hatching also occurs (Barkmann and Beck, 1976; Radtke and Dean, 1982). If first increment deposition does not occur at hatching, the standard procedure is to add a predetermined number to increment counts to estimate fish age (Campana and Neilson, 1985)

Hatching Strategies in Monogenean (Platyhelminth) Parasites that Facilitate Host Infection

In parasites, environmental cues may influence hatching of eggs and enhance the success of infections. The two major endoparasitic groups of parasitic platyhelminths, cestodes (tapeworms) and digeneans (flukes), typically have high fecundity, infect more than one host species, and transmit trophically. Monogeneans are parasitic flatworms that are among the most host specific of all parasites. Most are ectoparasites with relatively low fecundity and direct life cycles tied to water. They infect a single host species, usually a fish, although some are endoparasites of amphibians and aquatic chelonian reptiles. Monogenean eggs have strong shells and mostly release ciliated larvae, which, against all odds, must find, identify, and infect a suitable specific host. Some monogeneans increase their chances of finding a host by greatly extending the hatching period (possible bet-hedging). Others respond to cues for hatching such as shadows, chemicals, mechanical disturbance, and osmotic changes, most of which may be generated by the host. Hatching may be rhythmical, larvae emerging at times when the host is more vulnerable to invasion, and this may be combined with responses to other environmental cues. Different monogenean species that infect the same host species may adopt different strategies of hatching, indicating that tactics may be more complex than first thought. Control of egg assembly and egg-laying, possibly by host hormones, has permitted colonization of frogs and toads by polystomatid monogeneans. Some monogeneans further improve the chances of infection by attaching eggs to the host or by retaining eggs on, or in, the body of the parasite. The latter adaptation has led ultimately to viviparity in gyrodactylid monogeneans

Efecto de la sequía continua y la inmersión sobre la respuesta de eclosión de los huevos de Ochlerotatus albifasciatus (Diptera: Culicidae) almacenados a baja temperatura

Se estudió el rol de los factores ambientales sobre la eclosión de los huevos de O. albifasciatus (Macquart), simulando condiciones de invierno. La hipótesis planteada fue que la respuesta de eclosión de los huevos depende de: (1) tiempo de permanencia a baja temperatura, (2) condiciones de almacenamiento, y (3) tiempo de aclimatación. Los huevos fueron almacenados a 5º C en condiciones de sequía y sumergidos durante 7, 21, 35, 90 y 146 días; luego fueron aclimatados a 22º C durante 24, 72, y 168 horas y posteriormente inundados para inducir la eclosión. El porcentaje de huevos eclosionados se analizó con un Modelo Lineal Generalizado con distribución binomial. Los resultados mostraron que: (1) largos períodos de almacenamiento en frío y largos tiempos de aclimatación mejoran la respuesta de eclosión, (2) la condición de almacenamiento tiene un efecto moderado en la eclosión, siendo más marcada en los huevos almacenados en seco; (3) tiempos prolongados de aclimatación mejoran aún más las eclosiones de los huevos sumergidos, que los almacenados en seco; (4) largo tiempo en frío mejora la eclosión de los huevos almacenados en seco, que los sumergidos; (5) los huevos que permanecieron más tiempo en frío respondieron mejor cuando el tiempo de aclimatación fue prolongado.The role of environmental factors on the hatching response of O. albifasciatus (Macquart) eggs is studied by simulating winter conditions in the laboratory. The hypothesis tested was that hatching response is affected by: (1) time that eggs remain at low temperature, (2) storage conditions, and (3) acclimatization time. Eggs were stored at 5ºC in drought and immersion conditions during 7, 21, 35, 90 and 146 days, immediately after, they were acclimatized at 22ºC during 24, 72, and 168 hours, and then eggs were flooded to induce hatching. Percent of hatched eggs was analyzed with a Generalized Lineal Model with a binomial distribution. Results show that: (1) a long storage period at cold temperature and long acclimatization periods improve the hatching response; (2) storage conditions have a moderate effect on hatching, being more evident in eggs stored dry; (3) a long time of acclimatization favors the hatching response in submerged eggs more than in eggs stored dry; (4) long time at cold favors the hatching response in eggs stored dry more than in submerged eggs; (5) the hatching response of eggs that remain for a long time at low temperature is higher when the time of acclimatization is long.Fil: Sy, Victoria Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología ; ArgentinaFil: Campos, Raul Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología ; ArgentinaFil: Castro, Luis Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The effects of temperature on hatching and survival of northern rock sole larvae (Lepidopsetta polyxystra)

Northern rock sole (Lepidopsetta polyxystra) is a commercially important flatfish in Alaska and was recently classified as a distinct species from southern rock sole (L. bilineata). Taxonomic and vital rate data for northern rock sole are still not fully described, notably at early egg and larval stages. In this study, we provide new taxonomic descriptions of late-stage eggs and newly hatched larvae, as well as temperature-response models of hatching (timing, duration, success), and larval size-at-hatch and posthatch survival at four temperatures (2°, 5°, 9°, and 12°C). Time-to-first-hatch, hatch cycle duration, and overall hatching success showed a negative relationship with temperature. Early hatching larvae within each temperature treatment were smaller and had larger yolk sacs, but larvae incubated at higher temperatures (9° and 12°C) had the largest yolk reserves overall. Despite having smaller yolks, size-at-hatch and the maximum size achieved during the hatching cycle was highest for larvae reared at cold temperatures (2° and 5°C), indicating that endogenous reserves are more efficiently used for growth at these temperatures. In addition, larvae reared at high temperatures died more rapidly in the absence of food despite having more yolk reserves than cold-incubated larvae. Overall, northern rock sole eggs and larvae display early life history traits consistent with coldwater adaptation for winter spawning in the North Pacific

Cryopreservation of common carp sperm

Experiments were carried out to investigate the effect of five extenders (sucrose, glucose, fructose, KCl and a saline carp sperm extender) and two cryoprotectants (dimethyl-sulfoxide (DMSO) and methanol) on the cryopreservation of common carp sperm. Freezing of sperm using glucose extender and methanol as cryoprotectant resulted in the highest post-thaw motility, fertilization as well as hatching rates (63 ± 9%, 74 ± 15% and 67 ± 17% vs. 87 ± 5%, 84 ± 14% and 69 ± 14% using fresh sperm, respectively). In general, sugar-based extenders combined with methanol as cryoprotectant yielded higher motility, fertilization and hatching rates than ionic extenders in combination with DMSO. The jelly-like agglutination observed after thawing in samples frozen with sugar-based extenders did not reduce fertilization and hatching rates. Frozen–thawed sperm samples were able to successfully fertilize 10 g (8000) eggs

EFFICIENCY AND ENERGETICS OF ARTEMIA (Artemia salina) CYSTS HATCHING IN DIFFERENT OSMOLARITY MEDIA

Hatching rate of Artemia salina cysts in the hatching process is variable due to many factors. Osmolarity of the medium is one of the factors determining hatching process of A. salina cysts. The purpose of this study is to assess the hatching process of A. salina cysts in a various osmotic condition on the hatching energetics efficiency and rate. The experimental design used was a 2 x 5 factorial completely randomized design. The first factor is an addition of chlorine (non-decapsulation and decapsulation) and the second factor is osmolarity of medium (640.27; 787.02; 901.76; 1080.51 and 1227.25 mOsm.L-1H2O). The results showed that hatching of A. salina cyst on various osmotic condition has significantly differed the hatching rate. No significant differences in the hatching energetics efficiency were obtained from each experimental groups. Media with osmolarity level of iso-osmotic to hyperosmotic (901.76-1227,25 mOsm.L-1H2O) provides a high hatching rate. Energetics efficiency of artemia cysts hatching is ranged from 640.27 to 1227.25 mOsm.L-1H2O in both hypoosmotic, isosmotic and hyperosmotic media. Keywords: artemia, decapsulation, energetics, hatching, salinity Tingkat penetasan kista Artemia salina dalam proses penetasan bervariasi karena banyak faktor. Osmolaritas medium merupakan salah satu faktor yang menentukan proses penetasan kista A. salina. Tujuan dari penelitian ini adalah untuk menilai proses penetasan kista A. salina dalam berbagai kondisi osmotik pada efisiensi dan laju penetasan energetika. Desain eksperimen yang digunakan adalah rancangan acak lengkap 2 x 5 faktorial. Faktor pertama adalah penambahan klorin (non-dekapsulasi dan dekapsulasi) dan faktor kedua adalah osmolaritas medium (640,27; 787,02; 901,76; 1080,51 dan 1227,25 mOsm.L-1H2O). Hasil penelitian menunjukkan bahwa penetasan kista A. salina pada berbagai kondisi osmotik secara signifikan berbeda dengan tingkat penetasan. Tidak ada perbedaan yang signifikan dalam efisiensi energetika penetasan yang diperoleh dari masing-masing kelompok eksperimen. Media dengan tingkat osmolaritas iso-osmotik menjadi hyperosmotic (901,76-1227,25 mOsm.L-1H2O) memberikan tingkat penetasan yang tinggi. Energetika efisiensi penetrasi kista A. salina berkisar antara 640,27 sampai 1227,25 mOsm.L-1H2O pada media hypoosmotic, isosmotic dan hyperosmotic. Kata kunci: artemia, dekapsulasi, energetika, penetasan, salinita

A new molecular diagnostic tool for surveying and monitoring Triops cancriformis populations

© 2017 Sellers et al. The tadpole shrimp, Triops cancriformis, is a freshwater crustacean listed as endangered in the UK and Europe living in ephemeral pools. Populations are threatened by habitat destruction due to land development for agriculture and increased urbanisation. Despite this, there is a lack of efficient methods for discovering and monitoring populations. Established macroinvertebrate monitoring methods, such as net sampling, are unsuitable given the organism's life history, that include long lived diapausing eggs, benthic habits and ephemerally active populations. Conventional hatching methods, such as sediment incubation, are both time consuming and potentially confounded by bet-hedging hatching strategies of diapausing eggs. Here we develop a new molecular diagnostic method to detect viable egg banks of T. cancriformis, and compare its performance to two conventional monitoring methods involving diapausing egg hatching. We apply this method to a collection of pond sediments from the Wildfowl & Wetlands Trust Caerlaverock National Nature Reserve, which holds one of the two remaining British populations of T. cancriformis. DNA barcoding of isolated eggs, using newly designed species-specific primers for a large region of mtDNA, was used to estimate egg viability. These estimates were compared to those obtained by the conventional methods of sediment and isolation hatching. Our method outperformed the conventional methods, revealing six ponds holding viable T. cancriformis diapausing egg banks in Caerlaverock. Additionally, designed species-specific primers for a short region of mtDNA identified degraded, inviable eggs and were used to ascertain the levels of recent mortality within an egg bank. Together with efficient sugar flotation techniques to extract eggs from sediment samples, our molecular method proved to be a faster and more powerful alternative for assessing the viability and condition of T. cancriformis diapausing egg banks

Spawning and hatching performance of the silvery black porgy Sparidentex hasta under hypersaline conditions

Abu Al Abyad island is characterized by harsh environmental conditions. A preliminary trial conducted at the island to investigate the spawning and hatching performance of the blue finned sea bream Sparidentex hasta indicated that the fish can be successfully bred at high salinity levels exceeding 50 ppt.Salinity tolerance, Spawning, Hatching, United Arab Emirates, Sparidentex hasta