scholarly journals Reproduction of Megapitaria squalida (Bivalvia: Veneridae) in the Southeast Gulf of California, Mexico

2017 ◽  
Vol 65 (3) ◽  
pp. 881 ◽  
Author(s):  
Ernesto Álvarez-Dagnino ◽  
Apolinar Santamaría-Miranda ◽  
Manuel García-Ulloa ◽  
Andrés Martín Góngora-Gómez
Keyword(s):  
Reproductive Cycle ◽  
Gulf Of California ◽  
Histological Analysis ◽  
Conservation Strategies ◽  
Oocyte Size ◽  
Spawning Activity ◽  
Two Peaks ◽  
Management And Conservation ◽  
Clam Population ◽  
Resting Period

Bivalves reproductive cycle varies according to the particular environmental conditions where they are found, and these reproductive details represent basic information for their capture, management and conservation strategies. With this objective, the reproductive cycle of the clam Megapitaria squalida, inhabiting the Southeast of the Gulf of California (Altata Bay, Sinaloa, Mexico), was studied using histology and changes in the number and size of oocytes, from June 2013 to June 2014. Histological analysis of the gonads showed spawning activity throughout the year, with two peaks. The first was registered in October and it was accompanied by the highest decrease of weight; the second was in February with the highest percentage of spawning population; besides, a resting period was observed in December. The sex-ratio (female:male) of the clam population was 1.08:1 (χ2 = 5.72, d.f. = 1, P < 0.05). Mean oocyte size and number were different (P < 0.05) among all sampling months and fluctuated from 34.6 ± 5.8 µm in June 2014, to 41.9 ± 6.8 µm in February 2014, and from 443.8 ± 424.5 in February 2014, to 1 214.4 ± 267.6 counted in April, respectively. With these results we suggest a protection season from October to November, when the most intense release of gametes occur in this population.

Reproductive cycles and fecundities of four common eastern Australian archaeogastropod limpets (Mollusca : Gastropoda)

1980 ◽  
Vol 31 (1) ◽  
pp. 49 ◽  
Author(s):  
RG Creese
Keyword(s):  
Reproductive Activity ◽  
Adaptive Significance ◽  
First Year ◽  
Spawning Activity ◽  
Long Period ◽  
Wet Weight ◽  
Quantitative Analyses ◽  
Reproductive Cycles ◽  
Two Peaks ◽  
Resting Period

Reproductive cycles of four species of limpets were determined using quantitative analyses of counts of eggs and weights of gonads. Montfortula rugosa has a breeding season extending for 8-9 months, but does not show marked peaks of reproductive activity. It spawns small numbers of eggs over a long period, and never has a very large gonad. Notoacmea petterdi has a very short spawning season in May or June. Prior to spawning the gonad may account for over half the wet weight of an individual. After spawning there is a long resting period, after which the size of the gonad and the number and proportion of mature eggs increases gradually over the next 7-8 months. Patelloida alticostata and P. latistrigata have strategies which are intermediate between the other two species. Spawning may occur over a 4-6 month period during which time there are two peaks of spawning activity. The production of mature oocytes recommences soon after spawning has ceased in July, and the gonad rapidly increases in size during the following 4 months. Estimates of fecundity are given for the three species of acmaeid limpet. In these species, fecundity increases with increasing size; yet individuals are capable of producing and spawning mature eggs at the end of their first year on the shore. The adaptive significance of such a strategy is discussed.

Reproductive cycle and maternal-embryonic nutritional relationship of shovelnose guitarfishPseudobatos productusin the Gulf of California

2016 ◽  
Vol 90 (3) ◽  
pp. 889-905 ◽  
Author(s):  
A. E. Romo-Curiel ◽  
O. Sosa-Nishizaki ◽  
J. C. Pérez-Jiménez ◽  
M. C. Rodríguez-Medrano
Keyword(s):  
Reproductive Cycle ◽  
Gulf Of California ◽  
Relationship Of

scholarly journals Diversity and composition of plant species in the forest over limestone of Rajah Sikatuna Protected Landscape, Bohol, Philippines

2020 ◽  
Vol 8 ◽  
Author(s):  
Wilbert Aureo ◽  
Tomas Reyes ◽  
Francis Carlo Mutia ◽  
Reizl Jose ◽  
Mary Beth Sarnowski
Keyword(s):  
Plant Species ◽  
Conservation Strategies ◽  
Importance Value ◽  
Accumulation Curve ◽  
Representative Species ◽  
Special Area ◽  
Plant Families ◽  
Area Of Concern ◽  
Common Plant ◽  
Management And Conservation

Rajah Sikatuna Protected Landscape (RSPL), considered the last frontier within the Central Visayas region, is an ideal location for flora and fauna research due to its rich biodiversity. This recent study was conducted to determine the plant species composition and diversity and to select priority areas for conservation to update management strategy. A field survey was carried out in fifteen (15) 20 m x 100 m nested plots established randomly in the forest over limestone of RSPL from July to October 2019. Three hundred and sixty eight (368) species of plants were identified up to species level. This represented 327 angiosperms, one gymnosperm and 40 pteridophytes. Common plant families with more than 10 representative species were Moraceae, Meliaceae, Lauraceae, Dipterocarpaceae, Rubiaceae, Myrtaceae, Phyllanthaceae, Annonaceae, Araceae and Lauraceae. There were 93 (28%) endemic and 46 (14%) threatened species (vulnerable to critically endangered) observed. The cluster analysis and species accumulation curve suggests that plant species are not homogeneously distributed which implies that different management and conservation strategies should be implemented across RSPL. These results not only indicate the importance of RSPL, but also highlights areas with higher diversity and concentration of threatened and endemic species as a special area of concern. Furthermore, areas with high biodiversity value were recommended for immediate protection, while areas with low biodiversity value were recommended for reforestation programmes using species with high importance value.

scholarly journals Reproductive cycle of male wall lizard, Podarcis vaucheri (Reptilia: Sauria: Lacertidae), in Djurdjura, Northern Algeria

2017 ◽  
Author(s):  
Rabah Mamou ◽  
Elara Moudilou ◽  
Jean-Marie Exbrayat ◽  
Mansour Amroun
Keyword(s):  
Sexual Activity ◽  
Reproductive Cycle ◽  
Mixed Type ◽  
Progressive Increase ◽  
Early Summer ◽  
Seminiferous Tubules ◽  
Testis Weight ◽  
Field Observations ◽  
Testicular Weight ◽  
Resting Period

The reproductive cycle of male wall lizard Podarcis vaucheri (Boulenger, 1905) living in Djurdjura mountain, was analyzed from April till October 2014. Its seasonal mixed-type cycle was characterized by three phases: sexual activity, quiescence and recrudescence. After the emergence of lizard from hibernation an intense sexual activity was observed in spring (April, May, and June) at which the testicular weight and seminiferous tubules diameter reached their maximal values. At this period, spermiogenesis was also maximal and the spermiation allowed the release of a large quantity of spermatozoa in both the seminiferous tubules and epididymis lumen. In July, a short sexual resting period followed, during which the testes mass and seminiferous tubules diameter decreased. Spermatogonia and some primary spermatocytes were observed against the wall of seminiferous tubules. The recrudescence period (August, September and October) was characterized by a progressive increase of the testis weight and seminiferous tubules diameter. Spermatocytogenesis began in August, and spermiogenesis occurred in September and October, before the diapause period. But the presence of spermatozoids was not signaled in the epididymis lumen. Field observations and microscopic evidence of testis showed that both sexes reproduced synchronously during spring and early summer.

scholarly journals New records of Hippocampus patagonicus Piacentino & Luzzatto, 2004 (Teleostei: Syngnathidae) from the coast of Paraná, southern Brazil

Check List ◽  
2016 ◽  
Vol 12 (1) ◽  
pp. 1822
Author(s):  
Luci F. Pereira ◽  
Rosana B. Silveira ◽  
Vinícius Abilhoa
Keyword(s):  
New Records ◽  
Conservation Strategies ◽  
Brazilian Coast ◽  
Southwestern Atlantic ◽  
Southern Brazil ◽  
Incidental Capture ◽  
Additional Information ◽  
Trawl Fishery ◽  
Shrimp Trawl ◽  
Management And Conservation

Abstract: The seahorse Hippocampus patagonicus (Teleostei: Syngnathidae) is the southernmost occurring species of its genus in the South Atlantic Ocean. Its distribution seems to be restricted to the Southwestern Atlantic, along the coasts of Argentina and Brazil. Herein we report the incidental capture of six individuals as bycatch in the shrimp trawl fishery off the coast of Paraná, southern Brazil. Additional information on the geographic distribution of H. patagonicus, together with its ecology and life history, is important for conservation of this threatened species. These data can promote the development of appropriate management and conservation strategies for populations along the Brazilian coast. 

Reproductive patterns of the black starry sea urchin Arbacia stellata in Punta Banda, Baja California, Mexico

2019 ◽  
Vol 99 (06) ◽  
pp. 1379-1391 ◽  
Author(s):  
Julia Patricia Díaz-Martínez ◽  
Eugenio De Jesús Carpizo-Ituarte ◽  
Francisco Benítez-Villalobos
Keyword(s):  
Size Distribution ◽  
Sea Urchin ◽  
Reproductive Cycle ◽  
Net Primary Production ◽  
Gonadosomatic Index ◽  
Sampling Site ◽  
Gonadal Development ◽  
Oocyte Size ◽  
Local Conditions ◽  
Positive Correlation

AbstractWidely distributed species such as Arbacia stellata adjust patterns of their life history according to local conditions. In the present study the reproductive cycle of this species was analysed throughout a sampling year. Gonadal development cycle, sex ratio, actual fecundity and oocyte size distribution were characterized and the relationship of these reproductive characteristics with environmental variables such as sea surface temperature, photoperiod, chlorophyll a and net primary production evaluated. Our results showed that A. stellata is a gonochoric sea urchin. Gametogenesis was classified into six stages for both sexes (immature, growth, pre-maturity I, pre-maturity II, mature and spawning) and no synchrony was observed for the gonads between individuals. The female to male ratio was close to 1:1 in most months. The gonadosomatic index (GSI) showed significant differences between sexes or months; however, the highest values were observed during spring, with positive correlation with chlorophyll a. No significant differences were observed in the maturity index (MI) between sexes, with a positive correlation with temperature but negative with chlorophyll. Actual fecundity showed wide variations throughout the year and correlation with chlorophyll a and temperature. Oocyte size distribution was unimodal and the predominant frequency was that of mature oocytes. The reproductive cycle of A. stellata has a semi-continuous pattern for both sexes and partial spawning throughout the year in the sampling site. We observed nutrient assimilation in the gonads during spring and a larger reproductive activity from late summer to early winter.

scholarly journals First observations of hermaphroditism in the patellid limpet Patella piperata Gould, 1846

2019 ◽  
Vol 99 (7) ◽  
pp. 1615-1620
Author(s):  
Ricardo Sousa ◽  
Paulo Henriques ◽  
Joana Vasconcelos ◽  
Graça Faria ◽  
Rodrigo Riera ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Direct Effect ◽  
Shell Length ◽  
Histological Analysis ◽  
Size Classes ◽  
Sequential Hermaphroditism ◽  
North Eastern ◽  
Intermediate Size ◽  
Transitional Forms ◽  
Management And Conservation

AbstractHermaphroditism is thought to be an advantageous strategy common in marine molluscs that exhibit simultaneous, sequential or alternating hermaphroditism. Several species of patellid limpets have previously been shown to be protandrous hermaphrodites. The present study aimed to confirm whether this phenomenon occurs in Patella piperata. Transitional forms of simultaneous protandrous hermaphroditism were found in intermediate size classes of P. piperata, in Madeira (North-eastern Atlantic). Sequential hermaphroditism was confirmed after histological analysis. The overall sex-ratio was biased towards females but approached similar proportions in the larger size classes. Analysis of size at sex change showed that at a shell length of 36 mm 50% of the population probably have changed sex. The results reported confirm the occurrence of sequential hermaphroditism. These findings are of utmost importance to the understanding of the reproductive biology of this species with direct effect on management and conservation of this traditionally harvested limpet.

Reproduction of the water snake Helicops infrataeniatus (Colubridae) in southern Brazil

2005 ◽  
Vol 26 (4) ◽  
pp. 527-533 ◽  
Author(s):  
Luís Felipe Schmidt de Aguiar ◽  
Marcos Di-Bernardo
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Cycle ◽  
Sexual Maturity ◽  
Statistical Difference ◽  
Rio Grande ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Water Snake ◽  
Males And Females ◽  
Two Peaks

AbstractThe reproductive cycle, sexual maturity, fecundity, and sexual dimorphism of Helicops infrataeniatus Jan, 1865, were inferred from the analysis of 374 preserved specimens (110 males, 140 females) from the eastern Central Depression of Rio Grande do Sul, Brazil. There was no statistical difference between the SVL of newborn males and females, but mature females attained greater length than mature males. The tail of mature individuals was proportionally longer in males than in females. Males matured at a smaller size than females. The reproductive cycle of this species was longer than what is known for oviparous colubrids from subtropical and temperate zones of Brazil. In the studied population, vitellogenesis occurred from September to February. Oviductal embryos were found from September to May. Births took place in September, January, February and March, and occurred in two peaks. Litter size ranged from 5 to 22 offspring. The differences between the number of vitellogenic follicles and embryos, and between embryos and newborns were not significant, thus practically all follicles were generally converted into embryos and embryos into newborns.

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