scholarly journals Histomorphological study of the gut developmental pattern in early life history stages of featherback, Chitala chitala (Hamilton)

2015 ◽  
Vol 23 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Anisa Mitra ◽  
Pratap Kumar Mukhopadhyay ◽  
Sumit Homechaudhuri

Abstract The present study was conducted to observe morphological and histological changes in the developing digestive system during the ontogeny of featherback, Chitala chitala (Hamilton), from hatching to 30 days post hatch (dph). Three significant stages were identified during digestive tract development in featherback: (1) endotrophic (0-8 dph), (2) endoexotrophic (8-12 dph), and (3) exotrophic (12-30 dph). At hatching, the mouth was closed and the digestive tract was a straight tube. At 8 dph, the mouth was opened and the appearance of the esophagus was observed. Between 6-8 dph, the primordial liver and exocrine pancreas were observed. Intestinal enterocyte activity was observed before stomach development. The esophageal goblet cells, teeth, and taste buds developed 2 days after the opening of the mouth, at the time of exogenous feeding. The development of the stomach, gastric glands, and pyloric caeca took place between the 7 and 12 dph. Except the increase in size and complexity of the structures, no noticeable changes were observed after 12 dphin C. chitala during the experiment. Our findings in the current work provide valuable information which might be useful for improving current larval rearing techniques of this promising new candidate species for freshwater aquaculture diversification.

Zygote ◽  
2020 ◽  
Vol 28 (3) ◽  
pp. 208-216
Author(s):  
Erika Neumann ◽  
Maria do Carmo Faria Paes ◽  
José Mário Ribeiro Mendes ◽  
Francisco Manoel de Souza Braga ◽  
Laura Satiko Okada Nakaghi

SummaryIn the present study, the morphological development of the Brycon amazonicus digestive tract is described to provide basic knowledge for nutritional studies and, therefore, increase the survival of this species during larviculture. Samples were collected from hatching up to 25 days of age, measured, processed and observed under a stereomicroscope and light microscopy. Newly hatched larvae presented their digestive tract as a straight tube, dorsal to the yolk sac, lined with a single layer of undifferentiated cells. At 24 h post-hatching (hPH), the buccopharyngeal cavity was open, but the posterior region of the digestive tube remained closed. At 25 hPH, the digestive tube was completely open and could be divided into buccopharyngeal cavity, oesophagus and intestine. At 35 hPH, the intestine presented a dilatation in the proximal region, which had the function of storing food. Differentiation of the stomach started at 83 hPH, and mucous cells were observed in the epithelium. These cells are important in the production of mucus, whose function is to protect the organ against acidity, although the gastric glands began developing only from 171 hPH, when three stomach regions were observed: cardiac, fundic and pyloric. The gastric glands were observed in the cardiac region, indicating that this organ already had digestive functionality. From 243 hPH, the absorption and assimilation of nutrients were already possible but, only from 412 hPH, the digestive tract was completely developed and functional.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 768
Author(s):  
Jerónimo Vázquez-Ramírez ◽  
Susanna E. Venn

The early life-history stages of plants, such as germination and seedling establishment, depend on favorable environmental conditions. Changes in the environment at high altitude and high latitude regions, as a consequence of climate change, will significantly affect these life stages and may have profound effects on species recruitment and survival. Here, we synthesize the current knowledge of climate change effects on treeline, tundra, and alpine plants’ early life-history stages. We systematically searched the available literature on this subject up until February 2020 and recovered 835 potential articles that matched our search terms. From these, we found 39 studies that matched our selection criteria. We characterized the studies within our review and performed a qualitative and quantitative analysis of the extracted meta-data regarding the climatic effects likely to change in these regions, including projected warming, early snowmelt, changes in precipitation, nutrient availability and their effects on seed maturation, seed dormancy, germination, seedling emergence and seedling establishment. Although the studies showed high variability in their methods and studied species, the qualitative and quantitative analysis of the extracted data allowed us to detect existing patterns and knowledge gaps. For example, warming temperatures seemed to favor all studied life stages except seedling establishment, a decrease in precipitation had a strong negative effect on seed stages and, surprisingly, early snowmelt had a neutral effect on seed dormancy and germination but a positive effect on seedling establishment. For some of the studied life stages, data within the literature were too limited to identify a precise effect. There is still a need for investigations that increase our understanding of the climate change impacts on high altitude and high latitude plants’ reproductive processes, as this is crucial for plant conservation and evidence-based management of these environments. Finally, we make recommendations for further research based on the identified knowledge gaps.


2000 ◽  
Vol 78 (11) ◽  
pp. 1420-1429 ◽  
Author(s):  
Theresa M Culley

Few studies of inbreeding depression have focused on species producing both showy, chasmogamous (CH) flowers and self-pollinated, cleistogamous (CL) flowers. The goals of this investigation were to measure the level of inbreeding depression in the North American violet, Viola canadensis L., and to determine if any fitness differences were linked to floral type (CH versus CL) rather than to cross type (self versus outcross). Hand pollinations were carried out to produce self- and outcross-pollinated CH progeny, and CL seeds were also collected. In a greenhouse, selfed and outcrossed CH flowers produced similar numbers of seeds, and both types of progeny had similar survival rates and comparable numbers of CH flowers, although outcrossed CH progeny had 14% greater vegetative biomass than selfed CH progeny. The level of inbreeding depression in V. canadensis was low, indicating that there may be few drawbacks to selfing in this species. A comparison of CL and self-pollinated CH progeny showed that, although there were differences in CH flower number, overall fitness differences were minimal. The similar performance of selfed (CL and CH) and outcrossed progeny in early life-history stages of V. canadensis suggests a history of inbreeding in the population.Key words: cleistogamy, inbreeding depression, outcrossing, selfing, Viola canadensis.


1991 ◽  
Vol 48 (10) ◽  
pp. 1820-1828 ◽  
Author(s):  
Pierre Pepin ◽  
Ransom A. Myers

Recruitment variability is commonly associated with fluctuations in abundance of marine fish populations. Previous studies have focussed on stock-specific correlative or mechanistic models or on comparisons of recruitment variations of several stocks or species. The purpose of this study is to determine whether recruitment variability of commercial marine fish populations is associated with either size or the duration of early life history stages. The analysis was performed with data from 86 stocks representing 21 species of commercial marine fish. Univariate analysis shows that neither egg size nor the length at hatch is significantly correlated with recruitment variability. The change in length during the larval phase, which is representative of the duration of the stage, is significantly positively correlated with recruitment variability. Multivariate analysis shows that recruitment variability increases with increasing length at metamorphosis but that recruitment variability is poorly associated with length at hatch. The degree of serial correlation is related to the relative duration of egg and larval stages. The results clearly indicate that recruitment variability is linked to characteristics of early life history stages.


2010 ◽  
Vol 41 (3) ◽  
pp. 433-449 ◽  
Author(s):  
Francisco Javier Roo ◽  
Carmen María Hernández-Cruz ◽  
Juan Antonio Socorro ◽  
Hipólito Fernández-Palacios ◽  
María Soledad Izquierdo

2021 ◽  
Vol 325 (4) ◽  
pp. 457-468
Author(s):  
L.A. Jawad ◽  
F. Mutlak ◽  
A.R.M. Mohamed ◽  
J.M. Al-Mamry ◽  
E.K. Hameed ◽  
...  

The finding of larval and juvenile specimens from the Omani coast of the Arabian Sea and the Arabian Gulf waters of Saudi Arabia and Iraq is reported for the first time. Based on available information, one larva was a leptocephalus, Conger sp. (family Congridae) and one larva of an acronurus stage belonging to the genus Acanthurus (family Acanthuridae). Also juveniles of the following families are included in the present study: Clupeidae – Tenualosa ilisha (Hamilton, 1822) and Nematalosa sp.; Dactylopteridae – Dactyloptena orientalis (Cuvier, 1829); Gobiidae – Acentrogobius sp.; Bothidae – Arnoglossus aspilos (Bleeker, 1851); Scatophagidae – Scatophagus argus (Linnaeus, 1766); Sparidae – Acanthopagrus arabicus Iwatsuki, 2013 and Sparidentex hasta (Valenciennes, 1830); Tetraodontidae – Lagocephalus sp. The discovery of the barred rather than spotted juveniles of S. argus collected from pure freshwater environment of the Shatt al-Arab River, Basrah, Iraq was remarkable; it raises questions whether there is more than one species within the nominal S. argus. For both larvae and juveniles of bothid flounders, the olfactory organ is a useful character for the examination of the developmental stage of the metamorphosing specimens. The occurrence of the different early life history stages of fishes from the three Arabian countries shows the needs them to be studied further so that inferences about the areas and periods of spawning and development of these fishes can be made more accurately.


<em>Abstract.</em>—We examined the spatial and temporal variability of native and alien ichthyoplankton in three habitat types (marsh edge, shallow open-water, and river channel) in one reference and three restored marshes in the Sacramento–San Joaquin Delta, California, during 1998 and 1999. More than 6,700 fish embryos and 25,000 larvae represented by 10 families were collected in 240 tows during the 2-year study. Overall, the assemblage was dominated by alien fishes, but natives were more abundant during winter and spring, whereas aliens were more abundant during summer. Overall abundance was highest in marsh edge habitats, suggesting that this habitat provides favorable larval rearing habitats for many fishes. The reference marsh was dominated by alien species making it difficult to assess whether it had attributes that promoted use by native fish. Ichthyoplankton abundance varied comparably at restored sites of similar configuration. The restored site, with minimal tidal exchange and greater lower trophic productivity, supported the highest densities of alien fish. We conclude that restoration projects in this region of the estuary must consider the potential impacts of alien fishes on natives and evaluate strategies designed to improve recruitment success of native fishes. Specifically, we suggest that restored wetlands that offer only winter and spring inundation periods may provide maximum benefits to natives while limiting access by many alien fishes regardless of specific habitat-use requirements.


2003 ◽  
Vol 111 (13) ◽  
pp. 1601-1607 ◽  
Author(s):  
Ruth H Milston ◽  
Martin S Fitzpatrick ◽  
Anthony T Vella ◽  
Shaun Clements ◽  
Deke Gundersen ◽  
...  

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