scholarly journals Effets saisonniers sur les relations poids-longueurs et coefficients de condition pour 16 espèces de poissons de la Lagune Mvassa, basse Guinée, République du Congo

2020 ◽  
Vol 44.1 ◽  
pp. 7540-7552
Author(s):  
Hélène Dembe Louvinguila Tenda ◽  
Armel Ibala Zamba ◽  
Joseph Goma-Tchimbakala ◽  
Lérège Batiabo Mikembi ◽  
Honest Freedom Poaty Ngot ◽  
...  
Keyword(s):  
Rainy Season ◽  
Condition Factor ◽  
Abundant Species ◽  
Common Species ◽  
Dry Season ◽  
Mugil Cephalus ◽  
Seasonal Effects ◽  
Length Relationship ◽  
Fish Samples ◽  
Sarotherodon Melanotheron

Objectifs : La présente étude a été initiée pour établir les relations poids-longueur et les facteurs de condition de Ethmalosa fimbriata, Sardinella maderensis, Coptodon guinensis, Oreochromis schwebischi, Neochelon falcipinnis, Mugil cephalus, Parachelon grandisquamis, Eucinostomus melanopterus, Hemichromis elongatus, Pomadasys jubelini, Eleotris daganensis, Bathygobius soporator, Trachinotus teraia, Lutjanus goreensis, Mugil banannensis, et Sarotherodon melanotheron, 16 espèces les plus abondantes de la lagune Mvassa en République du Congo. Méthodologie et résultats : Les échantillonnages des poissons ont été réalisés sur 9 stations à l’aide des filets maillants de 8, 10, 20 et 30 mm de côté de la maille. Les relations poidslongueur ont été réalisées en utilisant l’équation P = aLSb et leurs coefficients de condition en utilisant l’équation K = 100*(P ⁄ LSb ). Au total, 1566 spécimens, réparties en 5 ordres, 8 familles, 16 espèces dont 10 ont été capturées en saison sèche, 14 en saison des pluies et 8 espèces communes pour les deux saisons ont été utilisés dans le cadre de cette étude. Le coefficient de détermination r 2 était significatif pour les deux saisons et variait de 0,91 pour Neochelon falcipinnis et 0,99 pour Pomadasys jubelini avec une moyenne de 0,97 ± 0,02. En saison sèche, le coefficient d’allométrie b de la relation poids-longueur variait de 2,04 pour Mugil cephalus à 3,48 Sardinella maderensis avec une moyenne de 2,79 ± 0,03. Le facteur de condition variait en moyenne de 0,66 ± 0,06 pour Sardinella maderensis à 12,22± 0,28 pour Mugil cephalus. En saison des pluies, le coefficient d’allométrie b variait de 2,41 pour Eucinostomus melanopterus à 3,94 pour Sardinella maderensis, avec une moyenne de 3,01 ± 0,05. Le facteur de condition variait de 0,02± 0,002 pour Parachelon grandisquamis à 6,73 ± 0,41 pour Eucinostomus malanopterus. Pour les huit espèces communes, le coefficient d’allométrie b était plus élevé en saison de pluie qu’en saison sèche pour la plupart des espèces (63 %). Conclusion et application des résultats : Ces résultats rapportent des informations relatives à la biologie des poissons rencontrés dans la lagune Mvassa, mais aussi sur l’influence de la saison sur les relations poids-longueur et les coefficients de condition. Dembe Louvinguila et al., 2020 Journal of Animal & Plant Sciences (J.Anim.Plant Sci. ISSN 2071-7024) Vol.44 (1) : 7540-7552 https://doi.org/10.35759/JAnmPlSci.v44-1.1 7541 Seasonal effects on weight-length relationships and condition factors for 16 fish species from the Mvassa Lagoon, Lower Guinea, Republic of the Congo ABSTRACT Objectives: This study was initiated to establish weight-length relationships and condition factors of Ethmalosa fimbriata, Sardinella maderensis, Coptodon guinensis, Oreochromis schwebischi, Neochelon falcipinnis, Mugil cephalus, Parachelon grandisquamis, Eucinostomus melanopterus, Hemichromis elongatus, Pomadasys jubelini, Eleotris daganensis, Bathygobius soporator, Trachinotus teraia, Lutjanus goreensis, Mugil banannensis, et Sarotherodon melanotheron, 16 most abundant species of the Mvassa lagoon in the Republic of Congo. Methodology and results: Fish samples were taken at 9 stations utilizing 8, 10, 20 and 30 mm mesh gillnets. The weight-length relationships were performed using equation P = aLSb and their condition coefficients using equation K = 100*(P/LSb ). A total of 1566 specimens, divided into 5 orders, 8 families, 16 species of which 10 were caught in the dry season, 14 in the rainy season and 8 common species for both seasons were used in this study. The correlation coefficient r 2 was significant for both seasons and ranged from 0.91 for Neochelon falcipinnis and 0.99 for Pomadasys jubelini with an average of 0.97 ± 0.02. In the dry season, the allometry coefficient b of the weight-length relationship ranged from 2.04 for Mugil cephalus to 3.48 Sardinella maderensis with an average of 2.79 ± 0.03. The condition factor ranged on average from 0.66 ± 0.06 for Sardinella maderensis to 12.22 ± 0.28 for Mugil cephalus. In the rainy season, the allometry coefficient b ranged from 2.41 for Eucinostomus melanopterus to 3.940 for Sardinella maderensis, with an average of 3.014 ± 0.05. The condition factor ranged from 0.02 ± 0.002 for Parachelon grandisquamis to 6.73 ± 0.41 for Eucinostomus malanopterus. For the eight common species, the allometry coefficient b was higher in the rainy season than in the dry season for most species (63%). Conclusion and application of the results: These results report information on the biology of the fish encountered in the Mvassa lagoon, but also on the influence of the season on weight- length relationships and condition coefficients

scholarly journals Seasonal Differences in Cyclospora cayetanensis Prevalence in Colombian Indigenous People

2021 ◽  
Vol 9 (3) ◽  
pp. 627
Author(s):  
Hagen Frickmann ◽  
Juliane Alker ◽  
Jessica Hansen ◽  
Juan Carlos Dib ◽  
Andrés Aristizabal ◽  
...  
Keyword(s):  
Indigenous People ◽  
Rainy Season ◽  
Gastrointestinal Symptoms ◽  
Dry Season ◽  
Seasonal Effects ◽  
Chain Reaction ◽  
Resource Limited Settings ◽  
Resource Limited ◽  
Stool Samples ◽  
Polymerase Chain

Fecal-orally transmitted cyclosporiasis is frequent in remote resource-limited settings in Central and South America with poor hygiene conditions. In this study, we aimed at assessing seasonal effects on the epidemiology of colonization or infection with C. cayetanensis in Colombian indigenous people living under very restricted conditions. In the rainy season between July and November and in the dry season between January and April, stool samples from indigenous people with and without gastrointestinal symptoms were collected and screened for C. cayetanensis applying in-house real-time polymerase chain reaction (PCR). In the rainy season and in the dry season, positive PCR results were observed for 11.8% (16/136) and 5.1% (15/292), respectively, with cycle threshold (Ct) values of 30.6 (±3.4) and 34.4 (±1.6), respectively. Despite higher parasite loads in the rainy season, fewer individuals (2/16, 12.5%) reported gastrointestinal symptoms compared to the dry season (6/15, 40%). In conclusion, considerable prevalence of C. cayetanensis in Colombian indigenous people persists in the dry season. Low proportions of gastrointestinal symptoms along with higher parasite loads make colonization likely rather than infection.

scholarly journals Length-weight relation, condition factor and gonadosomatic index of the whitemouth croaker, Micropogonias furnieri (Desmarest, 1823) (Actinopterygii: Sciaenidae), caught in Lençóis Bay, state of Maranhão, eastern Amazon, Brazil

2017 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
James Werllen de Jesus Azevedo ◽  
Antonio Carlos Leal de Castro ◽  
Marcelo Henrique Lopes Silva
Keyword(s):  
Sex Ratio ◽  
Rainy Season ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Length Distribution ◽  
The State ◽  
Allometric Growth ◽  
First Semester ◽  
Length Relationship ◽  
Micropogonias Furnieri

Abstract The whitemouth croaker, Micropogonias furnieri, which is exploited off the state of Maranhão, Brazil, reinforces the need for maintenance programs of natural stocks of this species to assist in the management of this exploited resource. The aim of the present study was to describe aspects regarding its reproductive characteristics (gonadosomatic index and condition factor) and also the length distribution and weight-length relationships. The fish were caught in Lençóis Bay in the state of Maranhão (eastern Amazon) between June 2010 and July 2011. A total of 570 individuals were caught (318 males and 252 females). Differences in length were found between the sexes, with females larger than males. The sex ratio indicated a tendency for females to be more abundant in the rainy season (first semester), whereas males predominated in the dry season (second semester). The weight-length relationship indicated negative allometric growth for both sexes. The analysis of the variation in the condition factor suggests that lower values coincided with higher gonadosomatic index values and that this factor is a good reproductive indicator for M. furnieri in the region.

Nocturnal Mosquitoes of Pará State in the Brazilian Amazon: Species Composition, Habitat Segregation, and Seasonal Variation

2020 ◽  
Vol 57 (6) ◽  
pp. 1913-1919
Author(s):  
Walter Santos de Araújo ◽  
Thallyta Maria Vieira ◽  
Guilherme Antunes de Souza ◽  
Isaque Clementino Bezerra ◽  
Paulo Henrique Costa Corgosinho ◽  
...  
Keyword(s):  
Culex Quinquefasciatus ◽  
Disease Transmission ◽  
Rainy Season ◽  
Mosquito Species ◽  
Species Abundance ◽  
Abundant Species ◽  
Dry Season ◽  
Habitat Segregation ◽  
Vector Species ◽  
High Degree

Abstract Mosquitoes (Diptera: Culicidae) are one of the most important disease vector species in the world. Many species have a high degree of anthropophilia and are often found in human habitations. In the present study, we have inventoried the nocturnal mosquito assemblage in intra-, peri-, and extradomicile environments in four municipalities in Pará, Brazil. At each municipality, a residence was selected and the mosquitoes were sampled using the protected human attraction capture and Shannon trap methods in April (rainy season) and August 2018 (dry season). We have collected a total of 696 mosquito specimens belonging to 8 genera and 17 species. The most abundant species were Mansonia (Mansonoides) titillans (Walker) (366/696, 52.6%), Anopheles (Nyssorhynchus) albitarsis Lynch-Arribálzaga (97/696, 13.9%), and Culex (Culex) quinquefasciatus Say (93/696, 13.4%). Mosquito richness, abundance, and composition did not differ between intra-, peri-, and extradomicile environments suggesting limited habitat segregation among the different species. However, mosquito species richness and mosquito species abundance were significantly higher during the rainy season than during the dry season, suggesting increased mosquito activity during the rainy season. We detected several important vector species of human diseases including Aedes (Stegomyia) aegypti (Linnaeus), Anopheles (Nyssorhynchus) darlingi Root, Haemagogus (Conopostegus) leucocelaenus (Dyar and Shannon), Coquillettidia (Coquillettidia) venezuelensis (Theobald), and Culex (Culex) quinquefasciatus which are the main transmitters of dengue, malaria, yellow fever, mayaro, and oropouche fever, respectively. As inventories of disease-carrying mosquitoes in the region are very scarce, mainly in residential environments, our results suggest high potential for mosquito-borne disease transmission in Pará State.

scholarly journals Patterns of Fish Assemblage, Growth, and Diet Composition in a Tropical River between Two Cascading Hydropower Dams

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Lee Nyanti ◽  
Chen-Lin Soo ◽  
Afina-Yian Chundi ◽  
Elsa-Cordelia-Durie Lambat ◽  
Alvinna Tram ◽  
...  
Keyword(s):  
Fish Species ◽  
Diet Composition ◽  
Fish Assemblages ◽  
Condition Factor ◽  
Dry Season ◽  
Growth Patterns ◽  
Native Fish ◽  
Wet Season ◽  
Fish Samples ◽  
The Impact

Construction of cascade dams has been shown to have impacts on fish assemblages and biodiversity. Yet, there is no literature on fish assemblages in the Murum River that connects the cascading Bakun and Murum dams in Sarawak, Malaysia. Hence, study on this modified ecosystem is necessitated to better understand the effects of the cascade dam construction on fish fauna. For this, fish samples were caught at five stations located along the river during both dry and wet seasons. Environmental parameters were taken concurrently with fish sampling. Length-weight relationship, condition factors, and diet composition of selected fish species in the river were also determined. The present study demonstrated that there are indications of the impact of cascading dams on the formation of a complex ecosystem in the Murum River, that is, changing from the shallow downstream of the Murum Dam to the deep transitional and inundated zone of the Bakun reservoir. The transitional zone in the Murum River exhibited the lowest fish species diversity, richness, and evenness during the dry season due to low pH and DO coupled with high turbidity. The biological indices improved when the water quality improved during the wet season. On the contrary, the diversity and evenness indices at the inundated tributary station decreased remarkably during the wet season, likely due to the migration of fish during the onset of the rainy season. This study showed that Barbonymus schwanenfeldii has a wider feeding habit which contributes to its higher distribution and abundance in the Murum River. The growth patterns of B. schwanenfeldii, Cyclocheilichthys apogon, Hampala macrolepidota, Lobocheilos ovalis, and Osteochilus enneaporos were better during wet than dry season. Overall, the condition factor of all native fish species in the Murum River was in poor to fair condition, whereas the exotic species, Oreochromis mossambicus, exhibited excellent condition (K value > 2) for both seasons. The increase in the number of O. mossambicus coupled with its high condition factor indicates biological intrusion and a potential threat to the native fish species in the Murum River. Continuous monitoring is essential to detect in-time risk issues associated with environmental degradation and biological invasion in this regulated and inundated river ecosystem.

scholarly journals Short-term variability of copepod abundance in Jurumirim Reservoir, São Paulo, Brazil

2001 ◽  
Vol 61 (4) ◽  
pp. 577-598 ◽  
Author(s):  
E. A. PANARELLI ◽  
M. G. NOGUEIRA ◽  
R. HENRY
Keyword(s):  
Rainy Season ◽  
Sampling Period ◽  
Abundant Species ◽  
Sao Paulo ◽  
Dry Season ◽  
Dispersion Pattern ◽  
São Paulo ◽  
Short Term ◽  
Copepod Abundance ◽  
Short Term Variability

Short-term variability in composition and abundance of copepod populations were studied during the dry (winter) and rainy (summer) seasons, at the dam region of Jurumirim Reservoir, São Paulo, Brazil. An intensive sampling program was carried out during 30 days in each period of the year. Samples and measurements were taken every other day at 0, 5, 10, 15, 20 and 25 m depths. The relationship between variability of the populations and some environmental factors was analyzed. The main species were: Argyrodiaptomus furcatus (Sars), Notodiaptomus iheringi (Wright), Mesocyclops longisetus (Thiébaud), Thermocyclops decipiens (Fischer), and T. minutus (Lowndes). Thermocyclops minutus was the most abundant species in dry season and its abundance varied significantly between sampling days. A large increase in abundance of calanoids occurred during the rainy season. This increase was correlated with higher temperature values. At that time, Notodiaptomus iheringi was dominant. This species showed significant short-term variations in abundance in both dry and rainy seasons. Significant variation in density of populations within the same sampling period might result from either the dispersion pattern of the populations or continuous substitution of the water masses. Significant correlation was observed between copepod abundance and temperature, especially for species of calanoids and there was also some correlations between densities of particular species of copepods and some phytoplankton taxa, mainly during the dry season. As for vertical distribution, most organisms were found between the surface and 15 m deep. During the rainy season, there was some evidence of the occurrence of spatial segregation between species of cyclopoids and calanoids, with the cyclopoids in a deeper position within the water column.

scholarly journals The diversity of intertidal fish in Sundak Beach, Yogyakarta, Indonesia, during dry and rainy seasons

2020 ◽  
Vol 147 ◽  
pp. 02020
Author(s):  
Ratih Ida Adharini ◽  
Namastra Probosunu ◽  
Atika Arifati ◽  
Tika Drastiana ◽  
Fitriana C. Rusnasari
Keyword(s):  
Intertidal Zone ◽  
Rainy Season ◽  
Good Condition ◽  
Dry Season ◽  
Quality Data ◽  
Water Quality Data ◽  
Transition Area ◽  
Fish Samples ◽  
Low Diversity ◽  
Dry And Rainy Seasons

The intertidal zone is a transition area between sea and land with unique characteristics. This research aimed to determine the diversity and types of fish in the intertidal zone of Sundak Beach, Yogyakarta, Indonesia. This research was conducted in December 2016–September 2017 along the intertidal zone of Sundak Beach. Fish samples were collected by fishermen twice a month using a hand net and hand line in an area of 22,000 m2 by random sampling. Water quality data included air and water temperatures, pH, salinity, tides, rainfall intensity, and substratum. Fish samples were identified, and the total length and weight were measured. Results showed that carnivores and herbivores were dominant during the rainy season, whereas carnivores and omnivores were dominant during the dry season. Total of 179 fish, which were grouped into 18 families and 31 species. The diversity species index was 1.067 (intermediate diversity) during the rainy season but 0.19 (low diversity) during the dry season. The dominancy index was low (0.11–0.34) during the dry season, whereas during the rainy season was higher (0.18–0.72). The study concluded that the intertidal zone of Sundak Beach has a good condition as nursery, feeding, and spawning grounds for fishes.

scholarly journals Population Aspects of Fishes in Geba and Sor Rivers, White Nile System in Ethiopia, East Africa

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Simagegnew Melaku ◽  
Abebe Getahun ◽  
Mulugeta Wakjira
Keyword(s):  
Sex Ratio ◽  
Fish Species ◽  
Condition Factor ◽  
Diversity Index ◽  
Abundant Species ◽  
Fish Diversity ◽  
Reproductive Behaviors ◽  
Fish Samples ◽  
The Mean ◽  
White Nile

This study was carried out to assess the diversity, condition factor, length-weight relationship, and sex ratio of fishes in Geba and Sor Rivers located in Baro-Akobo Basin, White Nile system within Ethiopia. Fish samples were collected in one wet and one dry season. The length-weight relationships were fitted using power equation for the most abundant species. A total of 348 fish specimens were collected using gillnets and hooks. These were identified into eight species and one Garra sp. representing seven genera and four families. Family Cyprinidae was the most dominant with six species (66.7%). Labeobarbus intermedius, Labeobarbus nedgia, and Labeo cylindricus were the most abundant fish species, respectively, with 60.72%, 16.83%, and 14.66% index of relative importance (IRI). The diversity index was higher for Geba River (H′ = 1.50) than for Sor River (H′ = 1.10). All the three most abundant species had negative allometric growth. Seasonal variations in the mean Fulton condition factor (FCF) were statistically significant for L. cylindricus (p<0.05). There was variation in the sex ratio with the females dominating in all the three most abundant species. Further investigation into the fish diversity, food, feeding, and reproductive behaviors of fish species especially in the tributaries of these rivers and their socioeconomic aspects is recommended.

scholarly journals Diversity and structure of the ichthyological population of the Gueumbeul Special Wildlife Reserve (Saint-Louis / Senegal)

2021 ◽  
Vol 14 (9) ◽  
pp. 3129-3143
Author(s):  
Amadou Guisse ◽  
Farokh Niass
Keyword(s):  
Marine Species ◽  
Geographic Area ◽  
Abundant Species ◽  
Diversity Indices ◽  
Mugil Cephalus ◽  
Saint Louis ◽  
Base De Données ◽  
Food Needs ◽  
Wildlife Reserve ◽  
Sarotherodon Melanotheron

The Gueumbeul Special Wildlife Reserve (RSFG) is a very important eco-geographic area. It is frequented by a variety of predominantly piscivorous birds that come to occupy its waters for reproduction and food needs. The present study aimed to make an inventory of the ichthyofauna of the RSFG in order to make available the database of the different species present in this body of water. The ichthyofauna were sampled monthly from March 2019 to February 2020 with the help of artisanal fishermen. The fish populations were studied using statistical analyzes and population descriptors (species richness, density, biomass and diversity indices). In total 16 species of fish divided into 15 genus and 11 families have been identified, cichlids (4 species), mugilids (3 species) being the most diverse families. The most abundant species in the catches were: Sarotherodon melanotheron and Mugil cephalus. The presence of marine species has been noted. These are Dicentrarchus punctatus, Eucinostomus melanopterus and Lichia amia but catches are very low. The calculated diversity indices showed that the ichthyofauna in the reserve has moderate diversity and a poor distribution of individuals within families. The ecosystem of the Gueumbeul basin shows signs of degradation. This degradation is materialized by an overexploitation of fishery resources by the fishing populations and a decrease in mangroves. La Réserve Spéciale de la Faune de Gueumbeul (RSFG) est une zone éco-géographique très importante. Elle est fréquentée par une diversité d’oiseaux majoritairement piscivores qui viennent occuper la zone pour des besoins de reproduction et d’alimentation. La présente étude visait à faire l’inventaire de la faune ichtyologique de la RSFG afin de rendre disponible la base de données des différentes espèces présentes dans ce plan d’eau. L’ichtyofaune a été échantillonnée de mars 2019 à février 2020 avec l’aide de pêcheurs artisans. Les peuplements de poissons ont été étudiés au moyen d’analyses statistiques et de descripteurs populationnels (la richesse spécifique, la densité, la biomasse et les indices de diversité). Au total 16 espèces de poisson réparties en 11 familles ont été recensées. Les cichlidés (4 espèces), les mugilidés (3 espèces) étant les familles les plus diverses. Les espèces les plus abondantes dans les captures sont : Sarotherodon melanotheron et Mugil cephalus. La présence d’une très faible quantité de poissons d’espèce marine a été notée, il s’agit de Dicentrarchus punctatus, Eucinostomus melanopterus et Lichia amia. Les indices de diversité calculés ont montré que l’ichtyofaune de la réserve a une diversité modérée et une mauvaise répartition des individus au sein des familles. L’écosystème de la cuvette de Gueumbeul présente des signes de dégradation. Cette dégradation est matérialisée par une surexploitation des ressources halieutiques par les populations de pêcheurs et une diminution de la mangrove.

scholarly journals Weight-length relationship and condition factor of Mugil cephalus (Linnaeus 1758, Mugilidea) in the special wildlife reserve of Gueumbeul (RSFG) in Senegal

2021 ◽  
Vol 9 (1) ◽  
pp. 104-110
Author(s):  
Amadou GUISSE ◽  
Guillaume KOUSSOVI ◽  
Farokh NIASS
Keyword(s):  
Condition Factor ◽  
Mugil Cephalus ◽  
Fish Ecology ◽  
Artisanal Fishery ◽  
Allometric Growth ◽  
Fundamental Parameters ◽  
Length Relationship ◽  
Significant Difference ◽  
Males And Females ◽  
Wildlife Reserve

The weight-length relationship and the condition factors are fundamental parameters with several uses in biology, fish ecology and fisheries management. Thus, in the Special Wildlife Reserve of Gueumbeul (SWRG) in Senegal, the weight-length relationship and condition factor were established for Mugil cephalus (Linnaeus 1758). A total of 311 individuals (97 females and 214 males) of M. cephalus were collected by the artisanal fishery using cast nets. The total length and weight ranged from 11.1 to 25 cm and 15.9 to 145.26 g, respectively. The results showed that in the SWRG, both in females (b = 2.60) and males (b = 2.899), M. cephalus had negative allometric growth. The analysis of variance showed no significant difference (p > 0.05) in the coefficients of determination between females (R = 0.96) and males (R = 0.84). Condition factors (K) were 3.07 and 1.23 for males and females respectively for M. cephalus in the reserve.

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