reproductive activity
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2022 ◽  
pp. 074873042110694
Author(s):  
Miguel F. Perea ◽  
Daniel A. Perdomo ◽  
Zenaida A. Corredor ◽  
Mario González ◽  
Hugo Hernandez-Fonseca ◽  
...  

A robust body of evidence has demonstrated that the lunar cycle plays an important role in the reproduction of fish living in natural environments. However, little is known about the influence of the moon on tilapia reproductive activity in intensive fish farming systems. This study aims to evaluate the influence of the lunar cycle on the reproductive performance of tilapias in an intensive outdoor tropical production system in Latin America. Records of two tilapia strains (Nile tilapia [ Oreochromis niloticus; n = 75] and Red tilapia [ Oreochromis spp.; n = 1335]) reared in concrete tanks in a commercial fish farm were analyzed. Over a 3-year period, 60,136 captures were made in intervals of 12 to 14 days and 6,600 females were manually spawned. The number of females spawned and the volume of eggs collected from each tank ( n = 9) were recorded. Data was analyzed by the general linear model and means were compared by least squares means method. A very slight or no variation was observed when the lunar cycle was split into two halves (crescent and waning). The proportions of females spawned and the volume of eggs per spawned female and per female in the tank varied considerably across the eight periods of the lunar cycle, with greater values in the waning than in the crescent phase. A significantly greater proportion of tilapia spawned and yielded more eggs around the full moon than around the new moon and remaining days of the lunar cycle. The moon cycle affected the reproductive activity of tilapia, which were more reproductively active around the full moon and most of the waning phase.


2022 ◽  
Vol 82 ◽  
Author(s):  
R. Z. Gomes ◽  
A. L. Paschoalini ◽  
A. A. Weber ◽  
K. B. Santiago ◽  
E. Rizzo ◽  
...  

Abstract The release of water from the reservoir hypolimnion, lower concentration of oxygen and the anthropogenic regulation of the river flow, could affect the reproduction of fish, especially migratory species. However, little is known about the effects of these changes in water on non-migratory species. In this sense, the reproduction of Acestrohynchus lacustris was evaluated in two sections of São Francisco River, Minas Gerais, Brazil. Section 1, located immediately downstream from Três Marias Dam (18°09’31.65”S and 45°13’36.00”W) and section 2, located at the confluence of the São Francisco and the Abaeté Rivers (18°02’47.78”S and 45°10’57.95”W). For this, we obtained the physico-chemical parameters of water of each study section. Additionally, biometric data and biological indices of all specimens were measured. Fecundity and follicles diameters were measured in females. Temperature, dissolved oxygen and flow showed lower values in section 1. Fish captured in this section, had lower values of GSI in both sexes, and females presented decreased values of fecundity and follicles diameter. This species showed reproductive activity in the two sections analyzed, however, in section 1 where the temperature and dissolved oxygen presented significant lower values, the reproductive capacity of A. lacustris, was negatively affected.


Author(s):  
Luisa F. Saavedra ◽  
Yadi X. Figueroa ◽  
Víctor H. Serrano-Cardozo ◽  
Martha P. Ramírez-Pinilla

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fanny Girard ◽  
Sidonie Catteau ◽  
Delphine Gambaiani ◽  
Olivia Gérigny ◽  
Jean Baptiste Sénégas ◽  
...  

AbstractClimate-induced environmental changes are profoundly impacting marine ecosystems and altering species distribution worldwide. Migratory organisms, including sea turtles, are expected to be particularly sensitive to these variations. Here, we studied changes in the size structure and reproductive activity of loggerhead turtles in the French Mediterranean over 30 years. Overall, there was a significant increase in the size of observed loggerheads between 1990 and 2020. However, this increase was only significant during the breeding/nesting season (May to September) and was driven by the increased presence of adults. Furthermore, nesting activity along the French coast was detected in 2002 for the first time in more than 50 years, and has become frequent after 2014, with nests discovered every year. The number of eggs laid as well as incubation duration and success varied among sites but fell within the range reported at established Mediterranean nesting sites. These observations, along with recent reports of breeding activity and evidence of significant sea surface warming, suggest that the north-western Mediterranean basin has become increasingly suitable to loggerhead turtles. We postulate that this range expansion is the result of climate change and propose that emerging nesting activity in France should be closely monitored and guarded against human activities.


2021 ◽  
Author(s):  
Steven H. Ferguson ◽  
David J. Yurkowski ◽  
Justine M. Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  

2021 ◽  
Author(s):  
◽  
Geoffrey Richard Frederick Hicks

<p>A quantitative seasonal study has been made on aspects of the ecology of marine algal-dwelling harpacticoid copepods at Island Bay, Wellington, New Zealand. Results are based on 154 samples collected from six species of macro-algae between April 1973 and March 1974 and is the first integrated research programme into the population dynamics of members of the phytal meiobenthos. Harpacticoid species collected are listed and brief taxonomic and zoogeographic notes on selected species is given. An analysis is made of the southern hemisphere zoogeographic relationships of the N. Z. marine harpacticoid fauna and this suggests distinct affinities with the Magellanic region of South America. The numerical contribution of harpacticoids to the total phytal meiofauna shows them to be the dominant taxon. Density comparisons are made with parallel studies on the sediment meiobenthos; in general the phytal is comparable with those from sandy bottoms. Species occurrence on each algal substrate, their specific association between each seaweed and within the rocky shore algal biotope as a whole is assessed. Seasonal periodicity in population .density is variable and is dependent on the reproductive activity of individual species. Breeding data are analysed for twenty species and reveal continuous or protracted breeding seasons, providing useful comparisons with interstitial and epibenthic representatives. Substrate preference for particular algae by truly phytal-dwelling harpacticoids is demonstrated for the first time.</p>


2021 ◽  
Author(s):  
◽  
Geoffrey Richard Frederick Hicks

<p>A quantitative seasonal study has been made on aspects of the ecology of marine algal-dwelling harpacticoid copepods at Island Bay, Wellington, New Zealand. Results are based on 154 samples collected from six species of macro-algae between April 1973 and March 1974 and is the first integrated research programme into the population dynamics of members of the phytal meiobenthos. Harpacticoid species collected are listed and brief taxonomic and zoogeographic notes on selected species is given. An analysis is made of the southern hemisphere zoogeographic relationships of the N. Z. marine harpacticoid fauna and this suggests distinct affinities with the Magellanic region of South America. The numerical contribution of harpacticoids to the total phytal meiofauna shows them to be the dominant taxon. Density comparisons are made with parallel studies on the sediment meiobenthos; in general the phytal is comparable with those from sandy bottoms. Species occurrence on each algal substrate, their specific association between each seaweed and within the rocky shore algal biotope as a whole is assessed. Seasonal periodicity in population .density is variable and is dependent on the reproductive activity of individual species. Breeding data are analysed for twenty species and reveal continuous or protracted breeding seasons, providing useful comparisons with interstitial and epibenthic representatives. Substrate preference for particular algae by truly phytal-dwelling harpacticoids is demonstrated for the first time.</p>


Author(s):  
Anayansi Ivette Ramírez Ramírez ◽  
Tania Arellano Lezama ◽  
Zadi Méndez Roblero1 ◽  
Guadalupe Idilia Delgado Tiburcio ◽  
Jaime Gallegos-Sánchez

Objective: To describe the seasonal variations throughout the year (day length), as one of the main environmental cues used by ewes to determine the most favorable time for breeding. Design/methodology/approach: A description of the main factors affecting ewe reproduction (photoperiod, suckling, postpartum period, nutrition, sociosexual effects) was assessed by a review of documentary information. Results: The inhibition of reproductive activity during one time of the year is a common process in most animal species to prevent births from occurring at an unfavorable time for the survival of the offspring. The seasonality of reproduction (northern latitude) allows births to occur in late winter or early spring when climatic conditions are the most favorable for the offspring development. Limitations/implications: The duration of the anestrus season (seasonal or postpartum) is influenced by the photoperiod and other factors. In Mexico, a small percentage of Criollo and Pelibuey ewes show a short duration of seasonal anestrus; that is, they show almost continuous annual reproductive activity. Therefore, to improve the reproductive efficiency of ewes, it is important to precisely determine the factors that affect their reproduction to improve management and increase the profits in the production units. Findings/Conclusions: Photoperiod is the main environmental factor regulating the annual reproductive cycle of the ewes, it occurs through very complex and varied mechanisms that communicate the visual system with the gonads through nervous and endocrine pathways.


Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3069
Author(s):  
Mara Bertocchi ◽  
Enrico Bigliardi ◽  
Igor Pelizzone ◽  
Alessandro Vetere ◽  
Sabrina Manfredi ◽  
...  

The Boa constrictor is one of the most common reptiles bred in captivity. To achieve a successful breeding season, thorough knowledge of the females’ reproductive activity is necessary. In this regard, information on the Boa constrictor is still rather scarce. The aim of the present study was to monitor the ovarian activity and the embryonic development of boas by ultrasound. We performed brief scans on thirty non-anaesthetized snakes using a portable ultrasound system and a 7.5–10 MHz linear array transducer (Esaote MyLab™ Classic). Ultrasound features, dimensions, and echogenicity of the preovulatory and postovulatory follicles were determined. As gestation progresses, the postovulatory follicle size increases, and the embryonic silhouette becomes increasingly recognizable. During the second month after ovulation, by using color Doppler, early embryos’ heart activity could be evaluated. It is possible to highlight vascular connections between the mother and the membrane covering the embryonic structures. Ultrasound also allows one to identify follicular regression or slugs (nonfertilized eggs) early. The present study suggests that ultrasound could be an excellent noninvasive technique to evaluate the reproductive activity of Boa constrictor, allowing us to precisely identify the correct time for mating, monitor embryo development and viability, and allow the early diagnosis of follicular regression.


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