Alassane Sarr | Universite Cheikh Anta Diop De Dakar (original) (raw)
Papers by Alassane Sarr
Acta Ichthyologica et Piscatoria
In Senegal, studies on the family Mugilidae are rare and little data is available on their reprod... more In Senegal, studies on the family Mugilidae are rare and little data is available on their reproductive biology. This study, carried out in the MPA of Niamone–Kalounayes (Casamance River estuary, Senegal) aims to enhance our knowledge of the reproductive biology of the largescale mullet, Parachelon grandisquamis (Valenciennes, 1836), a species highly prized by the local population as a food source. To better understand its reproductive biology, a series of monthly samplings over twelve (12) months from July 2021 to June 2022 was carried out. Experimental fisheries were carried out at six (6) stations located in secondary channels lined with mangroves, using a seine net (250 m long and 25 mm mesh side). A total of 361 individuals were sampled, including 321 female specimens and 40 male specimens. The calculated sex ratio was in favor of females (1:8), with a significant difference between the calculated sex ratio and the theoretical 1:1 sex ratio (χ2 = 218.73; P-value < 0.05). In ...
International Journal of Advanced Research
It is known that the consumption of seafood has several health benefits for humans. However, the ... more It is known that the consumption of seafood has several health benefits for humans. However, the accumulation of organic pollutants, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in their flesh could pose public health problems. Thus, the concentrations of PCBs and OCPs in edible fish species (Mugil bananensis, Sarotherodon melanotheron) from the Sine Saloum Estuary located in central-western Senegal are investigated in order to assess the potential risks of these contaminants to human health. After analysis, PCB52 and chlordane show the highest concentrations in the edible flesh of these two species. The concentration of PCB52 is almost identical in these two species, while that of chlordane is higher in S. melanotheron. Regarding the distribution of PCBs and OCPs in M. bananensis, the highest concentration is found in Fimela for PCBs and in Sokone for OCPs. For S. melanotheron, the highest concentration is found in Toubacouta for PCBs and in Felir ...
Annual Research & Review in Biology
The reproduction of Neochelon falcipinnis was studied in the Marine Protected Area (MPA) of Niamo... more The reproduction of Neochelon falcipinnis was studied in the Marine Protected Area (MPA) of Niamone-Kalounayes located in the Casamance estuary (Senegal) from July 2021 to June 2022. The results of this study are presented after twelve (12) months of experimental seine fishing. Reproductive parameters such as length-weight relationship, condition factor (K), sex ratio (SR), gonadosomatic index (GSI) and size at first maturity (Lm50) were determined. A total of 386 individuals (150 males, 221 females and 15 of undetermined sex) were sampled. The sex ratio was in favour of females (0.68 or 1:1.47). The length-weight relationship showed a minor allometric growth with allometric coefficient b values of 2.70 for both sexes combined, 2.60 for males and 2.79 for females. The ANOVA test showed no significant difference in condition factor in males (P > 0.05). In contrast, in females, there was a significant difference at the beginning of the cold season (P < 0.05). The monthly change...
Journal of Biology and Life Science, 2022
Mugil curema, known as white mullet, was one of the fish species encountered in the fisheries lan... more Mugil curema, known as white mullet, was one of the fish species encountered in the fisheries landings of the Saloum Delta. In this study, the morphometric parameters and the reproductive biology of this species were studied as well as the influence of environmental parameters on its reproduction. Experimental fisheries were carried out monthly in the Saloum Delta. The fish were caught using surface drift nets. The captured individuals were measured and weighed. The gonads were collected to determine the sex and the stages of sexual maturity. Out of a total of 406 individuals sampled in the Saloum Delta, 306 females and 100 males were identified, no individuals of undetermined sex were obtained. The sex ratio was globally in favor of females. Individuals in this study ranged in size from 102 to 385 mm and weight from 34.9 to 395 g. The allometric coefficient b was equal to 2.40 and indicated a negative allometry. The exploitation of the monthly IGS results indicated that reproductio...
Consumption of mugilids is widespread in Senegal, especially in the estuaries, where there produc... more Consumption of mugilids is widespread in Senegal, especially in the estuaries, where there production is of economic importance. The prevalence, mean intensity and pathologic effects of Anisakis sp. and Contracaecum sp. larvae which infected mugilids from Senegalese estuaries were investigated. In 2009, individuals of mugilids belonging to 6 and 5 species were trapped from the estuaries of Saloum, Senegal and Casamance rivers respectively. The prevalence and mean intensity of Anisakis sp. and Contracaecum sp. are higher in Senegal and Saloum estuaries respectively. The increase in the load of Contracaecum sp., related to the season in L. falcipinnis, the season, the size, the weight and/or the sex in M. cephalus from the
Turkish Journal of Fisheries and Aquatic Sciences, 2018
In this study, a total of 64 fishing attempts was performed and a total of 17775 specimens was ca... more In this study, a total of 64 fishing attempts was performed and a total of 17775 specimens was caught. The indirect method of Holt (1963) was used to estimate the selectivity parameters. The optimum selection lengths for E. fimbriata in 30, 32, 36 and 40 mm mesh size were 17.32, 18.48, 20.79 and 21.10 cm, respectively. Estimated values of common selection factor and standard deviation were 5.77 and 1.48, respectively. Results indicated that using monofilament gillnets with 30 and 32 mm mesh size could have an increasing fishing pressure on juvenile population of E. fimbriata but also the use of 40 mm mesh size could affect most fertile females. For the sustainable conservation of E. fimbriata fishery, it can be suggested to use monofilament gillnet with 36 mm mesh size in Senegalese coastal and estuarine waters.
American Scientific Research Journal for Engineering, Technology, and Sciences, 2015
This study was carried out within the context of USAID/COMFISH project for establihing a biologic... more This study was carried out within the context of USAID/COMFISH project for establihing a biological data base for some fish species including shrimp Farfantepenaeus notialis to support management plans for these species. This study on Farfantepenaeus notialis in the Sine-Saloum estuary revealed that the sampled individuals are relatively small sizes. The average cephalothoracic sizes are less than 20 mm at Bettenty (male = 18.0 ± 2.9; female=18.5 ± 3.9) and at Foundiougne (male = 17.6 ± 2.9; female = 18.5 ± 3.8). The allometric rate «b» is more important at Bettenty (b = 2.94) than at Foundiougne (b = 2.75) and condition factor K is higher during the hot season in both locations (Bettenty: K = 0.80 in hot season; K = 0.78 in cold season; Foundiougne: K = 0.82 in hot season, K = 0.75 in cold season). The sex ratio of Farfantepenaeus notialis is in favor of females at Bettenty (54.6%) and at Foundiougne (51.2%). The size classes show that below 15 mm and beyond 20 mm, the number of fe...
International Journal of Fisheries and Aquaculture, 2019
Sardinella aurita is the main species exploited by small-scale fisheries in Senegal and represent... more Sardinella aurita is the main species exploited by small-scale fisheries in Senegal and represents an important source of low cost protein in the Senegalese market. The objective of this study was to determine the age, growth and mortality parameters of S. aurita obtained from the Senegalese coastal waters. Age, growth parameters and mortality rates of this species were estimated using FiSAT II (FAO–ICLARM Stock Assessment Tools) software. A total of 5104 specimens of S. aurita were collected monthly between March 2012 and February 2013 from commercial landings in three sites of Senegalese coasts (Joal, Mbour and Kayar). Mean growth parameters for the entire period were estimated as L∞= 32.82 cm, K= 1.10 year-1 and t0 = -0.14 year. Instantaneous total mortality (Z = 2.77 year-1) coefficients per year were estimated using catch curves and methods based on the mean length of the fish caught. Natural mortality (M = 1.49 year-1) was estimated using the Pauly’s empirical equation and fishing mortality (F = 1.28 year-1) by the difference between total and natural mortality values. The exploitation rate (E) of 0.46 indicated no over-fishing on this species. Key words: Round sardinella, age, growth, mortality, Senegalese coast.
Journal of Oceanography and Marine Science, 2017
Growth and exploitation parameters Ilisha africana were determined from the size frequency for th... more Growth and exploitation parameters Ilisha africana were determined from the size frequency for the first time in Senegal. The size distribution showed average sizes equal to 19.26 ± 1.70 and 19.75 ± 2.03 cm, respectively in the estuary and at the sea. The values of allometric rates of the length-weight relationship were, respectively equal to 2.88 and 2.93 in the estuary and at the sea indicating a negative allometric growth for this species. Von Bertalanffy growth parameters are estimated to L∞ = 24.7 cm, K = 0.33 year-1 , t 0 =-0.53 in the estuary and L∞ = 25.5 cm, K = 0.34 year-1 , t 0 =-0.51 at the sea with growth performance index, respectively equal to Φ' = 2.30 and Φ' = 2.34. The values calculated for the total mortality (Z), natural mortality (M) and the fishing mortality (F) were: Z = 1.08, M = 0.93, and F = 0.14 year-1 in the estuary while at the sea these mortality rates were estimated respectively at Z = 1.25, M = 0.91, and F = 0.33 year-1. The current exploitation rates in the estuary (0.10) and at the sea (0.25) indicated that I. africana was under-exploited in Senegal.
PLOS ONE, 2016
The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senega... more The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senegal, West Africa. Its growth and reproduction parameters are key biological indicators for improving fisheries management. This study reviewed these parameters using landing data from small-scale fisheries in Senegal and literature information dated back more than 25 years. Age was estimated using length-frequency data to calculate growth parameters and assess the growth performance index. With global climate change there has been an increase in the average sea surface temperature along the Senegalese coast but the length-weight parameters, sex ratio, size at first sexual maturity, period of reproduction and condition factor of S. maderensis have not changed significantly. The above parameters of S. maderensis have hardly changed, despite high exploitation and fluctuations in environmental conditions that affect the early development phases of small pelagic fish in West Africa. This lack of plasticity of the species regarding of the biological parameters studied should be considered when planning relevant fishery management plans.
Journal of Biology and Life Science, 2014
The Bonga (Ethmalosa fimbriata) is the third most abundant clupeid in Senegal after the round and... more The Bonga (Ethmalosa fimbriata) is the third most abundant clupeid in Senegal after the round and flat sardines. This study allowed updating some growth parameters of Ethmalosa fimbriata witch can contribute to the management of the fishery. The size frequency distribution showed that bonga whose size range from 19 cm to 21 cm are more common in the landings of the estuary. At sea fisheries generally target individuals of average size from 18 cm to 22 cm with the dominance of class size from 19 cm to 20 cm. The study of the condition factor shows that the diet of Ethmalosa fimbriata is the best during the hot season also in estuary and at sea. This study also allowed estimating the growth parameters of marine and estuarine Ethmalosa fimbriata from size frequency by ELEFAN (Electric Length Frequency Analysis) software. Seasonal growth is faster in hot season in estuary and at sea.
Scientia Marina, 2006
Fish have developed reproductive strategies and traits that ensure the survival of the species un... more Fish have developed reproductive strategies and traits that ensure the survival of the species under variable and often unfavourable conditions (Potts and Wootton, 1984). The reproductive strategy of each species is expressed by certain characteristics such as age and size fecundity, time duration and frequency of spawning, size at first maturity and reproductive behaviour (Potts and Wootton, 1984;
Journal of Biology and Life Science, 2014
Ethmalosa fimbriata is a very abundant species in marine and estuarine waters of Senegal. It is c... more Ethmalosa fimbriata is a very abundant species in marine and estuarine waters of Senegal. It is caught only by artisanal fisheries. Some aspects of its reproduction are studied in order to provide some contribution to a rational and sustainable management of the fishery. To evaluate the reproduction of Ethmalosa fimbriata, the sex ratio, the size at first maturity, the evolution of sexual maturity stages and the gonadosomatic index (GSI) were used. The results show that the sex ratio is 46% of males and 54% of females in the estuary while at sea it is 42% of males against 58% of females. Size at first maturity is 16.2 cm for males and 17.5 cm for females in the estuary, while at sea these sizes are respectively equal to 17.2 and 18.7 cm for females and males. The main breeding periods are during the cold season in the estuary and the hot season at sea. Ethmalosa fimbriata is a species with small eggs and high fecundity. The absolute and relative fecundity are higher in the estuary than at sea.
International Journal of Biological and Chemical Sciences
The present study evaluated the sex ratio, evolution of gonado-somatic index and stages of sexual... more The present study evaluated the sex ratio, evolution of gonado-somatic index and stages of sexual maturity, condition factor and size of first sexual maturity of Chelon dumerili (Mugilidae) to determine its reproductive parameters. From June 2016 to May 2017, a total of 360 individuals of C. dumerili were sampled in Sangomar Marine Protected Area (MPA), In Saloum Delta, Senegal. The sex-ratio was significantly in favor of females (61.67%). Based on the monthly evolution of gonadal maturation stages and gonado-somatic index, the reproductive period of the species was determined to be from March to May. The condition factor varied between 0.60 and 0.88 with an average value of 0.84 ± 0.07. Male individuals of C. dumerili reached the size of first sexual maturity at a lower total length than females (23.6 cm and 24.5 cm respectively). Thus, for this species whose reproductive biology has not been well documented until now, knowledge of the reproductive parameters is essential to...
Journal of Marine Biology & Oceanography
European Scientific Journal ESJ, Mar 31, 2020
Soumbedioune Bay, marked by an intense activity of exploitation and marketing of seafood, is the ... more Soumbedioune Bay, marked by an intense activity of exploitation and marketing of seafood, is the receptacle of huge quantities of wastewater from channel 4 and artisanal activities which are carried out there. That's why a study aiming to determine the level of mercury contamination of mussels (Perna perna) and sea urchins (Echinometra lucunter) and to assess the health risks associated with their consumption was performed. It consisted to collect samples (non-transformed and transformed products) of these two species during the periods of abundance and non-abundance in 2018. The direct mercury analyzer DMA-80 was used to determine the mercury contents contained in these species. The results obtained after analyzes show the presence of this very toxic metal in the edible parts of these species but at concentrations below the standard established by the American agency for the protection of the environment. These concentrations vary between 0.0172 and 0.0475 mg.kg-1 for mussels against 0.0153 and 0.0274 mg.kg-1 for sea urchins. The health risk indices obtained (oscillating between 0.070 and 0.844) less than 1 reveal that the consumption of these species remains safe for the moment. However, they should be consumed moderately due to the ability of mercury to bioaccumulate in organisms.
PLOS ONE, 2016
The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senega... more The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senegal, West Africa. Its growth and reproduction parameters are key biological indicators for improving fisheries management. This study reviewed these parameters using landing data from small-scale fisheries in Senegal and literature information dated back more than 25 years. Age was estimated using length-frequency data to calculate growth parameters and assess the growth performance index. With global climate change there has been an increase in the average sea surface temperature along the Senegalese coast but the length-weight parameters, sex ratio, size at first sexual maturity, period of reproduction and condition factor of S. maderensis have not changed significantly. The above parameters of S. maderensis have hardly changed, despite high exploitation and fluctuations in environmental conditions that affect the early development phases of small pelagic fish in West Africa. This lack of plasticity of the species regarding of the biological parameters studied should be considered when planning relevant fishery management plans.
Fry monosex Nile tilapia (Oreochromis niloticus) were fed in five dietary protein levels (21%, 25... more Fry monosex Nile tilapia (Oreochromis niloticus) were fed in five dietary protein levels (21%, 25%, 32% 37% and 45%) to investigate casual effects on growth performance, carcass composition and survival rate. Tests were carried out in 10 glass tank (50 x 25 x 40 cm) containers (50 L) of reticulating system maintained at 30 ± 1°C. At the beginning of tests, one hundred tilapia fry were randomly divided into five different groups with two replicates. Diets were fed to duplicate groups of ten fry with an initial weight of 1.25 ± 0.25 g/fish during 42 days. The results showed significant effects of dietary protein on growth performance of reared fish. Weight gain (WG) and Specific Growth Rate (SGR) increased significantly with increasing dietary protein levels between 32.38% and 37.63%. However, 45.5% of crude protein showed less important increase in growth parameters. The best Feed Conversion Rate FCR (1.26) was noticed in diet containing 37.63% of crude protein. Accordingly, higher survival rate (%) was recorded in fish fed on diets containing 32.38 and 37.63%. There was no significant difference in protein body content of tilapia fed on five diets as compared to the initial fish. Lipid body content increased significantly with high dietary protein levels from 21.88% to 45.50%. The carcass crude lipid was recorded as higher (9.4%) in the fry fed on diet containing 45.50% protein, followed by fish fed on diet having protein 21.88%. From results, diet containing 37.63% crude protein appears to be more suitable for monosex Nile tilapia growth, in related experience conditions. In this line, it is recommended to feed monosex tilapia fry.
Acta Ichthyologica et Piscatoria
In Senegal, studies on the family Mugilidae are rare and little data is available on their reprod... more In Senegal, studies on the family Mugilidae are rare and little data is available on their reproductive biology. This study, carried out in the MPA of Niamone–Kalounayes (Casamance River estuary, Senegal) aims to enhance our knowledge of the reproductive biology of the largescale mullet, Parachelon grandisquamis (Valenciennes, 1836), a species highly prized by the local population as a food source. To better understand its reproductive biology, a series of monthly samplings over twelve (12) months from July 2021 to June 2022 was carried out. Experimental fisheries were carried out at six (6) stations located in secondary channels lined with mangroves, using a seine net (250 m long and 25 mm mesh side). A total of 361 individuals were sampled, including 321 female specimens and 40 male specimens. The calculated sex ratio was in favor of females (1:8), with a significant difference between the calculated sex ratio and the theoretical 1:1 sex ratio (χ2 = 218.73; P-value < 0.05). In ...
International Journal of Advanced Research
It is known that the consumption of seafood has several health benefits for humans. However, the ... more It is known that the consumption of seafood has several health benefits for humans. However, the accumulation of organic pollutants, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in their flesh could pose public health problems. Thus, the concentrations of PCBs and OCPs in edible fish species (Mugil bananensis, Sarotherodon melanotheron) from the Sine Saloum Estuary located in central-western Senegal are investigated in order to assess the potential risks of these contaminants to human health. After analysis, PCB52 and chlordane show the highest concentrations in the edible flesh of these two species. The concentration of PCB52 is almost identical in these two species, while that of chlordane is higher in S. melanotheron. Regarding the distribution of PCBs and OCPs in M. bananensis, the highest concentration is found in Fimela for PCBs and in Sokone for OCPs. For S. melanotheron, the highest concentration is found in Toubacouta for PCBs and in Felir ...
Annual Research & Review in Biology
The reproduction of Neochelon falcipinnis was studied in the Marine Protected Area (MPA) of Niamo... more The reproduction of Neochelon falcipinnis was studied in the Marine Protected Area (MPA) of Niamone-Kalounayes located in the Casamance estuary (Senegal) from July 2021 to June 2022. The results of this study are presented after twelve (12) months of experimental seine fishing. Reproductive parameters such as length-weight relationship, condition factor (K), sex ratio (SR), gonadosomatic index (GSI) and size at first maturity (Lm50) were determined. A total of 386 individuals (150 males, 221 females and 15 of undetermined sex) were sampled. The sex ratio was in favour of females (0.68 or 1:1.47). The length-weight relationship showed a minor allometric growth with allometric coefficient b values of 2.70 for both sexes combined, 2.60 for males and 2.79 for females. The ANOVA test showed no significant difference in condition factor in males (P > 0.05). In contrast, in females, there was a significant difference at the beginning of the cold season (P < 0.05). The monthly change...
Journal of Biology and Life Science, 2022
Mugil curema, known as white mullet, was one of the fish species encountered in the fisheries lan... more Mugil curema, known as white mullet, was one of the fish species encountered in the fisheries landings of the Saloum Delta. In this study, the morphometric parameters and the reproductive biology of this species were studied as well as the influence of environmental parameters on its reproduction. Experimental fisheries were carried out monthly in the Saloum Delta. The fish were caught using surface drift nets. The captured individuals were measured and weighed. The gonads were collected to determine the sex and the stages of sexual maturity. Out of a total of 406 individuals sampled in the Saloum Delta, 306 females and 100 males were identified, no individuals of undetermined sex were obtained. The sex ratio was globally in favor of females. Individuals in this study ranged in size from 102 to 385 mm and weight from 34.9 to 395 g. The allometric coefficient b was equal to 2.40 and indicated a negative allometry. The exploitation of the monthly IGS results indicated that reproductio...
Consumption of mugilids is widespread in Senegal, especially in the estuaries, where there produc... more Consumption of mugilids is widespread in Senegal, especially in the estuaries, where there production is of economic importance. The prevalence, mean intensity and pathologic effects of Anisakis sp. and Contracaecum sp. larvae which infected mugilids from Senegalese estuaries were investigated. In 2009, individuals of mugilids belonging to 6 and 5 species were trapped from the estuaries of Saloum, Senegal and Casamance rivers respectively. The prevalence and mean intensity of Anisakis sp. and Contracaecum sp. are higher in Senegal and Saloum estuaries respectively. The increase in the load of Contracaecum sp., related to the season in L. falcipinnis, the season, the size, the weight and/or the sex in M. cephalus from the
Turkish Journal of Fisheries and Aquatic Sciences, 2018
In this study, a total of 64 fishing attempts was performed and a total of 17775 specimens was ca... more In this study, a total of 64 fishing attempts was performed and a total of 17775 specimens was caught. The indirect method of Holt (1963) was used to estimate the selectivity parameters. The optimum selection lengths for E. fimbriata in 30, 32, 36 and 40 mm mesh size were 17.32, 18.48, 20.79 and 21.10 cm, respectively. Estimated values of common selection factor and standard deviation were 5.77 and 1.48, respectively. Results indicated that using monofilament gillnets with 30 and 32 mm mesh size could have an increasing fishing pressure on juvenile population of E. fimbriata but also the use of 40 mm mesh size could affect most fertile females. For the sustainable conservation of E. fimbriata fishery, it can be suggested to use monofilament gillnet with 36 mm mesh size in Senegalese coastal and estuarine waters.
American Scientific Research Journal for Engineering, Technology, and Sciences, 2015
This study was carried out within the context of USAID/COMFISH project for establihing a biologic... more This study was carried out within the context of USAID/COMFISH project for establihing a biological data base for some fish species including shrimp Farfantepenaeus notialis to support management plans for these species. This study on Farfantepenaeus notialis in the Sine-Saloum estuary revealed that the sampled individuals are relatively small sizes. The average cephalothoracic sizes are less than 20 mm at Bettenty (male = 18.0 ± 2.9; female=18.5 ± 3.9) and at Foundiougne (male = 17.6 ± 2.9; female = 18.5 ± 3.8). The allometric rate «b» is more important at Bettenty (b = 2.94) than at Foundiougne (b = 2.75) and condition factor K is higher during the hot season in both locations (Bettenty: K = 0.80 in hot season; K = 0.78 in cold season; Foundiougne: K = 0.82 in hot season, K = 0.75 in cold season). The sex ratio of Farfantepenaeus notialis is in favor of females at Bettenty (54.6%) and at Foundiougne (51.2%). The size classes show that below 15 mm and beyond 20 mm, the number of fe...
International Journal of Fisheries and Aquaculture, 2019
Sardinella aurita is the main species exploited by small-scale fisheries in Senegal and represent... more Sardinella aurita is the main species exploited by small-scale fisheries in Senegal and represents an important source of low cost protein in the Senegalese market. The objective of this study was to determine the age, growth and mortality parameters of S. aurita obtained from the Senegalese coastal waters. Age, growth parameters and mortality rates of this species were estimated using FiSAT II (FAO–ICLARM Stock Assessment Tools) software. A total of 5104 specimens of S. aurita were collected monthly between March 2012 and February 2013 from commercial landings in three sites of Senegalese coasts (Joal, Mbour and Kayar). Mean growth parameters for the entire period were estimated as L∞= 32.82 cm, K= 1.10 year-1 and t0 = -0.14 year. Instantaneous total mortality (Z = 2.77 year-1) coefficients per year were estimated using catch curves and methods based on the mean length of the fish caught. Natural mortality (M = 1.49 year-1) was estimated using the Pauly’s empirical equation and fishing mortality (F = 1.28 year-1) by the difference between total and natural mortality values. The exploitation rate (E) of 0.46 indicated no over-fishing on this species. Key words: Round sardinella, age, growth, mortality, Senegalese coast.
Journal of Oceanography and Marine Science, 2017
Growth and exploitation parameters Ilisha africana were determined from the size frequency for th... more Growth and exploitation parameters Ilisha africana were determined from the size frequency for the first time in Senegal. The size distribution showed average sizes equal to 19.26 ± 1.70 and 19.75 ± 2.03 cm, respectively in the estuary and at the sea. The values of allometric rates of the length-weight relationship were, respectively equal to 2.88 and 2.93 in the estuary and at the sea indicating a negative allometric growth for this species. Von Bertalanffy growth parameters are estimated to L∞ = 24.7 cm, K = 0.33 year-1 , t 0 =-0.53 in the estuary and L∞ = 25.5 cm, K = 0.34 year-1 , t 0 =-0.51 at the sea with growth performance index, respectively equal to Φ' = 2.30 and Φ' = 2.34. The values calculated for the total mortality (Z), natural mortality (M) and the fishing mortality (F) were: Z = 1.08, M = 0.93, and F = 0.14 year-1 in the estuary while at the sea these mortality rates were estimated respectively at Z = 1.25, M = 0.91, and F = 0.33 year-1. The current exploitation rates in the estuary (0.10) and at the sea (0.25) indicated that I. africana was under-exploited in Senegal.
PLOS ONE, 2016
The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senega... more The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senegal, West Africa. Its growth and reproduction parameters are key biological indicators for improving fisheries management. This study reviewed these parameters using landing data from small-scale fisheries in Senegal and literature information dated back more than 25 years. Age was estimated using length-frequency data to calculate growth parameters and assess the growth performance index. With global climate change there has been an increase in the average sea surface temperature along the Senegalese coast but the length-weight parameters, sex ratio, size at first sexual maturity, period of reproduction and condition factor of S. maderensis have not changed significantly. The above parameters of S. maderensis have hardly changed, despite high exploitation and fluctuations in environmental conditions that affect the early development phases of small pelagic fish in West Africa. This lack of plasticity of the species regarding of the biological parameters studied should be considered when planning relevant fishery management plans.
Journal of Biology and Life Science, 2014
The Bonga (Ethmalosa fimbriata) is the third most abundant clupeid in Senegal after the round and... more The Bonga (Ethmalosa fimbriata) is the third most abundant clupeid in Senegal after the round and flat sardines. This study allowed updating some growth parameters of Ethmalosa fimbriata witch can contribute to the management of the fishery. The size frequency distribution showed that bonga whose size range from 19 cm to 21 cm are more common in the landings of the estuary. At sea fisheries generally target individuals of average size from 18 cm to 22 cm with the dominance of class size from 19 cm to 20 cm. The study of the condition factor shows that the diet of Ethmalosa fimbriata is the best during the hot season also in estuary and at sea. This study also allowed estimating the growth parameters of marine and estuarine Ethmalosa fimbriata from size frequency by ELEFAN (Electric Length Frequency Analysis) software. Seasonal growth is faster in hot season in estuary and at sea.
Scientia Marina, 2006
Fish have developed reproductive strategies and traits that ensure the survival of the species un... more Fish have developed reproductive strategies and traits that ensure the survival of the species under variable and often unfavourable conditions (Potts and Wootton, 1984). The reproductive strategy of each species is expressed by certain characteristics such as age and size fecundity, time duration and frequency of spawning, size at first maturity and reproductive behaviour (Potts and Wootton, 1984;
Journal of Biology and Life Science, 2014
Ethmalosa fimbriata is a very abundant species in marine and estuarine waters of Senegal. It is c... more Ethmalosa fimbriata is a very abundant species in marine and estuarine waters of Senegal. It is caught only by artisanal fisheries. Some aspects of its reproduction are studied in order to provide some contribution to a rational and sustainable management of the fishery. To evaluate the reproduction of Ethmalosa fimbriata, the sex ratio, the size at first maturity, the evolution of sexual maturity stages and the gonadosomatic index (GSI) were used. The results show that the sex ratio is 46% of males and 54% of females in the estuary while at sea it is 42% of males against 58% of females. Size at first maturity is 16.2 cm for males and 17.5 cm for females in the estuary, while at sea these sizes are respectively equal to 17.2 and 18.7 cm for females and males. The main breeding periods are during the cold season in the estuary and the hot season at sea. Ethmalosa fimbriata is a species with small eggs and high fecundity. The absolute and relative fecundity are higher in the estuary than at sea.
International Journal of Biological and Chemical Sciences
The present study evaluated the sex ratio, evolution of gonado-somatic index and stages of sexual... more The present study evaluated the sex ratio, evolution of gonado-somatic index and stages of sexual maturity, condition factor and size of first sexual maturity of Chelon dumerili (Mugilidae) to determine its reproductive parameters. From June 2016 to May 2017, a total of 360 individuals of C. dumerili were sampled in Sangomar Marine Protected Area (MPA), In Saloum Delta, Senegal. The sex-ratio was significantly in favor of females (61.67%). Based on the monthly evolution of gonadal maturation stages and gonado-somatic index, the reproductive period of the species was determined to be from March to May. The condition factor varied between 0.60 and 0.88 with an average value of 0.84 ± 0.07. Male individuals of C. dumerili reached the size of first sexual maturity at a lower total length than females (23.6 cm and 24.5 cm respectively). Thus, for this species whose reproductive biology has not been well documented until now, knowledge of the reproductive parameters is essential to...
Journal of Marine Biology & Oceanography
European Scientific Journal ESJ, Mar 31, 2020
Soumbedioune Bay, marked by an intense activity of exploitation and marketing of seafood, is the ... more Soumbedioune Bay, marked by an intense activity of exploitation and marketing of seafood, is the receptacle of huge quantities of wastewater from channel 4 and artisanal activities which are carried out there. That's why a study aiming to determine the level of mercury contamination of mussels (Perna perna) and sea urchins (Echinometra lucunter) and to assess the health risks associated with their consumption was performed. It consisted to collect samples (non-transformed and transformed products) of these two species during the periods of abundance and non-abundance in 2018. The direct mercury analyzer DMA-80 was used to determine the mercury contents contained in these species. The results obtained after analyzes show the presence of this very toxic metal in the edible parts of these species but at concentrations below the standard established by the American agency for the protection of the environment. These concentrations vary between 0.0172 and 0.0475 mg.kg-1 for mussels against 0.0153 and 0.0274 mg.kg-1 for sea urchins. The health risk indices obtained (oscillating between 0.070 and 0.844) less than 1 reveal that the consumption of these species remains safe for the moment. However, they should be consumed moderately due to the ability of mercury to bioaccumulate in organisms.
PLOS ONE, 2016
The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senega... more The stock of the Senegalese flat sardinella, Sardinella maderensis, is highly exploited in Senegal, West Africa. Its growth and reproduction parameters are key biological indicators for improving fisheries management. This study reviewed these parameters using landing data from small-scale fisheries in Senegal and literature information dated back more than 25 years. Age was estimated using length-frequency data to calculate growth parameters and assess the growth performance index. With global climate change there has been an increase in the average sea surface temperature along the Senegalese coast but the length-weight parameters, sex ratio, size at first sexual maturity, period of reproduction and condition factor of S. maderensis have not changed significantly. The above parameters of S. maderensis have hardly changed, despite high exploitation and fluctuations in environmental conditions that affect the early development phases of small pelagic fish in West Africa. This lack of plasticity of the species regarding of the biological parameters studied should be considered when planning relevant fishery management plans.
Fry monosex Nile tilapia (Oreochromis niloticus) were fed in five dietary protein levels (21%, 25... more Fry monosex Nile tilapia (Oreochromis niloticus) were fed in five dietary protein levels (21%, 25%, 32% 37% and 45%) to investigate casual effects on growth performance, carcass composition and survival rate. Tests were carried out in 10 glass tank (50 x 25 x 40 cm) containers (50 L) of reticulating system maintained at 30 ± 1°C. At the beginning of tests, one hundred tilapia fry were randomly divided into five different groups with two replicates. Diets were fed to duplicate groups of ten fry with an initial weight of 1.25 ± 0.25 g/fish during 42 days. The results showed significant effects of dietary protein on growth performance of reared fish. Weight gain (WG) and Specific Growth Rate (SGR) increased significantly with increasing dietary protein levels between 32.38% and 37.63%. However, 45.5% of crude protein showed less important increase in growth parameters. The best Feed Conversion Rate FCR (1.26) was noticed in diet containing 37.63% of crude protein. Accordingly, higher survival rate (%) was recorded in fish fed on diets containing 32.38 and 37.63%. There was no significant difference in protein body content of tilapia fed on five diets as compared to the initial fish. Lipid body content increased significantly with high dietary protein levels from 21.88% to 45.50%. The carcass crude lipid was recorded as higher (9.4%) in the fry fed on diet containing 45.50% protein, followed by fish fed on diet having protein 21.88%. From results, diet containing 37.63% crude protein appears to be more suitable for monosex Nile tilapia growth, in related experience conditions. In this line, it is recommended to feed monosex tilapia fry.