BIOLOGY OF PSEUDOTOLITHUS TYPUS PDF

A total of and samples of P. Spawning periods of the two fish species were determined following the monthly variation of the mean gonadosomatic index. Fish condition factor for both genders of P. The length-weight relationship of both species shows negative allometric growth.

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A total of and samples of P. Spawning periods of the two fish species were determined following the monthly variation of the mean gonadosomatic index. Fish condition factor for both genders of P. The length-weight relationship of both species shows negative allometric growth. There were dominants of males to females for the two assessed species. From the results urgent management interventions in form of close seasons are needed to safeguard these commercially important fish species from possible stress in the future to avert natural mortality dominants.

Keywords: liberia, pseudotolithus senegalensis, pseudotolithus typus, population structure and biology 1. Introduction However, in Liberia, information on the biology and growth P. Such limitation of scientific [11].

Sciaenids constitute a large and varied family of fishes information on fish biology and growth pattern renders closely related to snappers but differing in that the spinous fisheries management options geared toward sustainable dorsal fin is short and the adipose tissue is much longer than exploitation of commercial fishes in Liberia ineffective.

In the anal fin, which has only one or two spines Edwards et al. Information gained from this study will not only eyes and large mouth with lower jaw projecting, while P. Longhurst, [6, 18]. Materials and Methods fish species that is widely consumed locally by Liberian 2. Liberia is a relatively small coastal state located in West Pseudotolithus species were among the highest landed catch in Africa with geographical coordinates as 6. And also W. The coastline of Liberia is kilometers comprising of the total marine landed catch for Liberia was estimated at relatively warm waters and low nutrient contents BNF, [5] 1, However, the study focused on two fish landing sampling speedily to tonnes in Selection of the two fish landing sampling sites vulnerable to a decline in fisheries due to its low adaptive was based on the level of fishing activity and geographical capacity and the importance of fish from a food security location.

The main source of livelihood for the majority of the perspective. Liberia annual per capita fish consumption is inhabitants residing within the selected two fish landing among the lowest in the region and has decreased over time sampling stations is fishing and its related activities such as due to damage to fisheries infrastructure during the civil war, fish processing and fish trade.

However, a few of the over-exploitation of resources in some areas, and a shift from indigenes are engaged in alternative forms of livelihoods subsistence to trade-based fisheries. Fish sample collection was performed from 2. Morphometric The fluctuations of the sex ratio according to fish size provide measurements of the obtained fish samples including standard a useful tool to examine the biological characteristics of the length and weights were recorded in the lab at the Bureau of fish species, such as sexual inversion, longevity in relation to National Fisheries.

The standard length was measured using sex, vulnerability to fishing gear and the spatial, seasonal and the cm Measuring Board to the nearest 0. With the numerical weight was measured using the electronic weighing scale to abundance by sex, the following ratio was computed: the nearest 0. Fish samples were identified to the species level using fish identification keys by Schneider [25].

The length- weight relationship was used to fish collected from the two sampling sites and the frequency determine the growth pattern of the fish species, whether distributions determined at 1.

The sex ratio was tested for equality for different weight W g of the fish. The maturity stages were months using Chi-square test. The Gonadosomatic Index determined within five categories, based on morphological GSI was used to determine the spawning period.

MS excel spreadsheet was stage 3: mature, stage 4: ripe or running, and stage 5: recently used in generating graphs and tables. The significance of spent. The spawning period was graphically determined for parameters was statistically tested at p-value of 0. Results 3. Figure 2. While the modal length of The size range was 14 cm - 63 cm for P. Fig 2. Comparison of the lengths of P. Table 1: Summary of the length frequency distribution of P.

From Figures 3. The weight of the fish strongly correlated with the standard length SL and total length TL r2 range 0. For P. The expected range of the exponent b in all cases lies in between the range of 2. Figure 3. The K-value however increases with if environmental factors influence this biological parameter.

In comparison The monthly condition factors for P. Males showed a maximum GSI of female P. The minor peak in temperature was 0. This could be a minimum of 0. The probable indication of spawning. There is weaker correlation maximum GSI of P. Whereas, P. Mean values from this study strong correlation between the temperature and GSI females, ranged from 0. Fig 4. Table 2: Monthly variations in sex ratios of P. Month Total No. Discussions seine throughout the year indicating the dependence on the The population structure for P.

This is supported by the small modal length irrespective showed a negative allometric growth with b values less than 3, of the sex.

The dominant lengths for P. The current modal class weight Ricker, [22]. However, this negative allometric size of the current study for the both species is greater than growth pattern reported in the current study does not agree what was reported by Sossoukpe [26] from Benin. This with the results reported by other authors Table 3. They could probably be due to the type of gears used in these reported isometric growth, which implies that the fish length localities and the areas in which these species were caught.

In increases in equal proportion with it body weight. These changes are due to sex, maturity, season species caught by beach seine were juveniles. According to Lauer et healthiness of fish from different habitats or to indicate the al. The catchability may result in The mean condition factors for both species was greater than skewed sex ratios Adams et al.

In this study it is suggested that males were more sound. Sossoukpe [26] made similar report for the vulnerable to fishing pressure, resulting in skewed sex ratios, species encountered in the waters of Benin. The physiological with males dominating in the catches. Dominance of females wellbeing of the species could be linked to the notable change over males was recorded in studies by Sidibe [24] and in the environment Sossoukpe, [26].

Further, the mean Troadec [28]. Conclusions to small sized male fishes. The present study has revealed that P. These two species spawning is associated weight as a percentage of the whole body weight.

There have with the hydrological seasons. Therefore, urgent management been numerous studies in which GSI has been used as an interventions in form of close seasons are needed to safeguard indicator of gonad development, i. Gonadosomatic index is generally used for the study of maturation and spawning biology. It is also used to assess the 6. Acknowledgement degree of ripeness of the ovary. The in September and a minor peak in August and November.

The authors acknowledge the financial support by the United minor peak in November confirmed the spawning period States Agency for International Development, as part of the reported by Sossoukpe [26] from Benin.

The highest peak in 7. References September coincided with warm temperature whereas the 1. An overview of the commencement of spawning in November coincided with the Cuban commercial fishing industry and recent changes in rising temperature. From literature, it was reported by management structure and objectives.

This assertion was 2. Anato CB. There were a slight dominance of males over females. Bagenal TB. Aspects of Fish fecundity. In: S. Blackwell until a certain size, from which it increases in favor of females Scientific Publications, Oxford.

Bleeker P. Rowe S, Hutching JA. Mating systems and the Natuurk. Trends Ecol Evol.

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Conditions of the area could play a fundamental role in the regulation of recruitment by their influence on the survival of eggs, larvae and juvenile as well as on the fertility of the reproductive stock probably based on trophic relationships. Pseudotoithus maturation stages were also examined. The distribution of population size structure was unimodal Figure 3 with a modal class interval of Morphometric The fluctuations of the sex ratio according to fish size provide measurements of the obtained fish samples including standard a useful tool to examine the biological characteristics of the length and weights were recorded in the lab at the Bureau of fish species, such as sexual inversion, longevity in relation to National Fisheries. This work is part of a Ph. Class Actinopterygii ray-finned fishes. From literature, it was reported by management structure and objectives. Length frequency distribution of Pseudotolithus typus females.

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Kagakinos As the fish approaches the spawning season, the most advanced group of ova at 0. Approximately 70 genera and species are known, with 14 species occurring along the Gulf of Guinea on the coast of Tgpus Africa Edwards et al. The K-value however increases with if environmental factors influence this biological parameter. The maturity stages were months using Chi-square test. Anterior pseudotoolithus of the swimbladder with a pair of complicated tube-like appendages, divided into a group of a few short tubes anteriorly and a group of numerous long tubules running backward along ventral and lateral sides of bladder up to base of anal fin.

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