Fecundity of the arrow crab Stenorhynchus seticornis in the southern Brazilian coast

Author(s):  
Claudia Melissa Okamori ◽  
Valter José Cobo

The arrow crab Stenorhynchus seticornis (Brachyura, Majidae), is a common inhabitant of the rocky subtidal along the Brazilian coast. Fecundity and the influence of environmental variables on egg production are investigated in this study. Information on egg size and egg loss through incubation are also provided. Monthly samples were conducted using SCUBA diving, from January to December 1998 in the Ubatuba region (23°25′25[double prime or second]S–44°52′03[double prime or second]W), south-eastern Brazilian coast. Early broods were used for the estimation of size-specific relationships of fecundity. Egg loss was assessed by comparing average egg numbers of early and late broods. The fecundity was estimated in 621.1±339.6 eggs, with an average diameter of 0.48±0.1 and 0.57±0.1 mm for early and late eggs, respectively. The number of eggs produced was apparently constant year-round. No significant differences were recorded among monthly fecundity values. The variation of abiotic factors did not show any relationship with temporal variability of fecundity, suggesting that the environmental effect in egg production is slight at best.

2011 ◽  
Vol 68 (3) ◽  
pp. 528-536 ◽  
Author(s):  
Miguel Bernal ◽  
Yorgos Stratoudakis ◽  
Simon Wood ◽  
Leire Ibaibarriaga ◽  
Luis Valdés ◽  
...  

Abstract Bernal, M., Stratoudakis, Y., Wood, S., Ibaibarriaga, L., Uriarte, A., Valdés, L., and Borchers, D. 2011. A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production. – ICES Journal of Marine Science, 68: . A spatially and environmentally explicit egg production model is developed to accommodate a number of assumptions about the relationship between egg production and mortality and associated environmental variables. The general model was tested under different assumptions for Atlanto-Iberian sardine. It provides a flexible estimator of egg production, in which a range of assumptions and hypotheses can be tested in a structured manner within a well-defined statistical framework. Application of the model to Atlanto-Iberian sardine increased the precision of the egg production time-series, and allowed improvements to be made in understanding the spatio-temporal variability in egg production, as well as implications for ecology and stock assessment.


2018 ◽  
Vol 108 (0) ◽  
Author(s):  
Patricio Hernáez

ABSTRACT: Spatial distribution and egg production of squat lobsters is examined from specimens deposited in the collection of the Museu de Zoologia of the Universidade de São Paulo (MZUSP), Brazil. A total of 1,346 specimens of squat lobsters were analyzed, out of which 169 were ovigerous females. Ovigerous females contained ten species of Munididae (n = 165) and three of Munidopsidae (n = 4). Eleven of the thirteen studied species were distributed along the Brazilian coast, while two of the remaining species in other marine regions. The analysis of bathymetric distribution revealed the presence of four species on the continental shelf (< 200 m depth: M. spinifrons, M. pusilla, M. irrasa, M. flinti), two on the first layer of the continental slope (200-500 m: Munida forceps, A. longipes) and five distributed between 500 and 1,048 m (M. erinacea, M. constricta, M. valida, M. microphthalma, M. transtridens). Overall, species belonging to Munididae produced a higher number of eggs (554 ± 619 eggs) but of minor size (0.48 ± 0.120 mm) than species of Munidopsidae (13 ± 10 eggs; 1.12 ± 0.337 mm, respectively). Such tendency is consistent with the phylogeny of both clades whose common origin is reflected in morphological similarities both in larval and adult forms, but not in terms of the reproductive strategy that clearly separates the species belonging to these families. Results also demonstrated that egg size in squat lobsters is strongly associated with depth, which suggests the strong influence of habitat on the duration of larval development of these species.


1989 ◽  
Vol 67 (6) ◽  
pp. 1599-1602 ◽  
Author(s):  
Vital Boulé ◽  
Gerard J. Fitzgerald

Female threespine sticklebacks (Gasterosteus aculeatus) spend only 9–15 days on the spawning grounds, an intertidal salt marsh at Isle Verte, Quebec, during a 2-month breeding season. Individuals average only one spawning. However, in the laboratory they lay clutches of several hundred eggs every 3–5 days for several months. We designed laboratory experiments to determine (i) whether daily temperature fluctuations similar to those encountered in the marsh affect reproduction (number of clutches, number of eggs per clutch, and size of eggs) and (ii) whether the amplitude of the fluctuations encountered by the fish affects reproduction. We compared the reproduction of females held in fluctuating temperatures with that of females kept at 20 °C. Fish kept under fluctuating conditions produced more eggs per clutch but had longer interspawning intervals than those at 20 °C. Total seasonal egg production and egg size did not differ between the two groups. Fish in fluctuating temperatures survived longer and were in better condition than those at 20 °C. We conclude that the amplitude of the fluctuations is less important than mean temperature in determining reproductive performance. Fluctuating temperatures on the spawning grounds are not responsible for the short residency there.


2015 ◽  
Vol 87 (3) ◽  
pp. 1717-1726 ◽  
Author(s):  
JULIANA WOJCIECHOWSKI ◽  
ANDRÉ A. PADIAL

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.


1998 ◽  
Vol 55 (12) ◽  
pp. 2608-2621 ◽  
Author(s):  
N H Augustin ◽  
D L Borchers ◽  
E D Clarke ◽  
S T Buckland ◽  
M Walsh

Generalized additive models (GAMs) are used to model the spatiotemporal distribution of egg density as a function of locational and environmental variables. The main aim of using GAMs is to improve precision of egg abundance estimates needed for the annual egg production method. The application of GAMs requires a survey design with good coverage in space and time. If the only results available are from less optimal survey designs, they can be improved by using historical data for spawning boundaries. The method is applied to plankton egg survey data of Atlantic mackerel (Scomber scombrus) in 1995. The GAM-based method improves the precision of estimates substantially and is also useful in explaining complex space-time trends using environmental variables.


2011 ◽  
Vol 11 (8) ◽  
pp. 3611-3629 ◽  
Author(s):  
T. T. van Leeuwen ◽  
G. R. van der Werf

Abstract. Fires are a major source of trace gases and aerosols to the atmosphere. The amount of biomass burned is becoming better known, most importantly due to improved burned area datasets and a better representation of fuel consumption. The spatial and temporal variability in the partitioning of biomass burned into emitted trace gases and aerosols, however, has received relatively little attention. To convert estimates of biomass burned to trace gas and aerosol emissions, most studies have used emission ratios (or emission factors (EFs)) based on the arithmetic mean of field measurement outcomes, stratified by biome. However, EFs vary substantially in time and space, even within a single biome. In addition, it is unknown whether the available field measurement locations provide a representative sample for the various biomes. Here we used the available body of EF literature in combination with satellite-derived information on vegetation characteristics and climatic conditions to better understand the spatio-temporal variability in EFs. While focusing on CO, CH4, and CO2, our findings are also applicable to other trace gases and aerosols. We explored relations between EFs and different measurements of environmental variables that may correlate with part of the variability in EFs (tree cover density, vegetation greenness, temperature, precipitation, and the length of the dry season). Although reasonable correlations were found for specific case studies, correlations based on the full suite of available measurements were lower and explained about 33%, 38%, 19%, and 34% of the variability for respectively CO, CH4, CO2, and the Modified Combustion Efficiency (MCE). This may be partly due to uncertainties in the environmental variables, differences in measurement techniques for EFs, assumptions on the ratio between flaming and smoldering combustion, and incomplete information on the location and timing of EF measurements. We derived new mean EFs, using the relative importance of each measurement location with regard to fire emissions. These weighted averages were relatively similar to the arithmetic mean. When using relations between the environmental variables and EFs to extrapolate to regional and global scales, we found substantial differences, with for savannas 13% and 22% higher CO and CH4 EFs than the arithmetic mean of the field studies, possibly linked to an underrepresentation of woodland fires in EF measurement locations. We argue that from a global modeling perspective, future measurement campaigns could be more beneficial if measurements are made over the full fire season, and if relations between ambient conditions and EFs receive more attention.


2021 ◽  
Vol 67 ◽  
pp. 78-88
Author(s):  
E. M. Feschenko

The study of ornamental and adaptive qualities of Malus Mill. from the genetic collection of ornamental crops of the Orenburg branch of the Research Center of Horticulture was carried out to assess the gene pool of introduced wild apple tree species and forms and identify suitable for the urban landscaping and the breeding process. Such characteristics as habitus, abundance of flowering, color and number of flowers in the inflorescence, color of vegetative organs, flowers and fruits during the season were taken into account; resistance to major diseases and adverse abiotic factors was evaluated. Additionally, the color of buds and flowers was characterized on the basis of the RHS (Royal Horticultural Society Color Chart). As a result of a preliminary survey on the complex of ornamental qualities and the level of adaptability, 5 most promising species were identified, which received the best ratings on the ornamental scale. Malus sikkimensis (Wenz.) Koehne ex C. K. Schneid. (31 points) was characterized by an attractive habit, the presence of flowers with a diameter of up to 40 mm and subsequently fruits that acquire a yellow-red color. Malus sargentii Rehder (29 points) was notable for its compact rounded crown, a large number of flowers with a diameter of 30 mm, followed by the formation of fruits with a dark red color. Malus floribunda Siebold ex Van Houtte (28 points) was distinguished by a large number of fragrant flowers in an umbrella-shaped inflorescence (5 — 7 pcs) with an average diameter of 30 mm, as well as attractive red-yellow fruits. Malus sieboldii (Regel) Rehder, M. toringo Siebold (28 points) was interesting primarily by the presence of 5 -7 flowers of 20 — 30 mm in the inflorescence and decorative fruits, the color of which varies from yellow to red. Malus niedzwetzkyana Dieck (28 points) attracted attention to the rich purple color of all organs due to the presence of a large number of anthocyanins, it was also worth noting the presence of a pleasant aroma during flowering and large flowers with an average diameter of 40 mm. The selected ornamental types of apple trees are favorable for use in landscaping of various scales, they are recommended for breeding work as initial parent forms.


2021 ◽  
Vol 15 ◽  
pp. 185-196
Author(s):  
M. MONSI ◽  
A. O. AMAKIRI

Four groups of 48 laying hens (Gallus domesticus), midway in their laying cycle were fed diets containing graded levels (0.00%, 1.5%, 2.5% and 3.5%) of dietary Nutrafos 3 for 56 days. The completely randomized experimental arrangement was designed to evaluate the responses of the caged layers to the inclusive levels of the additive under humid tropical conditions. The dietary additive produced statistically significant (P< 0.01) improvements in the rate of egg production of the hens. Significant increases (P< 0.01) in feed consumption and improvements in feed efficiency (P < 0.01) were also observed. Haugh unit was significantly (P < 0.05) depressed by dietary Nutrafos 3, especially at the highest level of inclusion. There was no treatment effect on egg size as well as some major anatomical characteristics. The best overall performance was achieved at the 3.5% level of dietary inclusion in contrast to the proprietary recommendation of 2.5%.


Check List ◽  
2012 ◽  
Vol 8 (5) ◽  
pp. 940 ◽  
Author(s):  
Douglas Fernandes Rodrigues Alves ◽  
Samara De Paiva Barros-Alves ◽  
Valter José Cobo ◽  
Daniel José Marcondes Lima ◽  
Adilson Fransozo

Biodiversity can be useful as an ecosystem indicator for conservation and monitoring, through continuous assessment of its main properties including stability, primary productivity, exploitation tolerance and even global environmental changes. The main purpose of this study was to provide a checklist of the crabs associated with subtidal rocky bottoms at the Vitoria Archipelago, southeastern Brazilian coast. Monthly collections were carried out from February 2004 through January 2006 on three islands at the Vitória Archipelago (23°44’S-45°01’W). The crabs were hand-caught by SCUBA divers during the daytime, in rock subtidal. A total of 3084 individuals were caught, belonging to 42 species, 28 genera, and 12 families, highlighting Mithraculus forceps (1528) and Stenorhynchus seticornis (407) representing more than 60% of the sample. On the other hand, Dromia erythropus, Moreiradromia antilensis, Ebalia stimpsoni, Garthiope spinipes and Tumidotheres maculatus had only one individual sampled.


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