الفهرس 
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Abstract
Summary
Penaeid shrimp are major target species of Arabian Sea demersal fisheries of Sultanate of Oman. Penaeid shrimp are among the most valuable and highly priced species in Oman. Though widely distributed along the entire coasts of Oman, their major fisheries are located in the area of Al-Wusta province. Penaeid shrimp are mainly exploited by the trawl fishery and the annual mean landing was up to 660 ton (Annual Statistical Book 2006-2015).
The present study has been suggested due to the rarity of stock assessment and fisheries studies with respect to the most common species of family Penaeidae found in the Oman waters off Arabian Sea. The present study dealt with identification, analysis of the population dynamics and stock assessment of the three common penaeid species, Penaeus semisulcatus, Fenneropenaeus indicus and Metapenaeus stebbingi as well as developing a management strategy to conserve and optimize their yield.
The results of the present study can be summarized in the following points:
1- Identification of the shrimp catch composition according to the identification catalogues and sheets.
2. Age and growth
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In the present work, the growth in length and weight of the three penaeid species considered was investigated.
Sampling covered the first three months of the shrimp fishing season from September to November during two years 2015 and 2016, where more 96% of shrimp catch was landed. The samples were collected from the commercial catch of the cast net fishery in Mahout area (Khalouf landing site). Growth parameters (K and L∞) were estimated based on age-length data obtained from Bhattachaya (1967) method. Also, the instantaneous rate of total mortality (Z) was estimated using the length converted catch curve, while the natural mortality was estimated using Pauly (1980) equation. Accordingly the fishing mortality was estimated as F= Z-M, and the exploitation ratio was determined as F/Z.
The length weight relationship for each species under study is represented by the following equations:
P. semisulcatus
W = 0.005 L3.1917
r2 = 0.9839
F. indicus
W = 0.0017 L3.5407
r2 = 0.9925
M. stebbingi
W = 0.0054 L3.0892
r2 =0.9732
The growth in weight relative to species size in all investigated penaeid shrimps were isometric.
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The Total-Carapace relationships for males, females and sexes combined for the three investigated penaeid shrimp fromArabian Sea were determined as following 3. Critical lengths
Length at first capture (Lc) and length at first sexual maturity (Lm) were estimated for the three investigated species and the values obtained were:Mortality coefficients and Exploitation Rate
The values of total (Z), natural (M) and fishing (F) mortality coefficients as well as the exploitation rate were estimated for the three species under investigation. These results have shown that the mortality rate from fishing is significantly higher than that of natural factors, and that the rate of exploitation has far exceeded the optimal rates in other evidence of overfishing.
The high values of both fishing mortality coefficients and exploitation rate reflect the high level of exploitation of shrimp species from the Oman waters off Arabian Sea.
4. Stock assessment and Fisheries Management
For evaluating and managing the shrimp fishery in the Oman waters off Arabian Sea, the following models was used
1) Yield per recruit model of Beverton and Holt (1957): It showed that the current yield of each catch under the current conditions of fishing effort and length at the first capture less than the maximum yield of catch, which can be obtained in one of the following ways
1- Reduce fishing effort by reducing the number of fishing units.
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2- Increase the length at the first capture by controlling the size of the fishing net openings.
The decision process in fisheries management is a complex system that includes many essential steps that begins with determination, selection and formulation of objectives and terminates by implementation of the best strategy. Thus, the continuous research on population dynamics and stock assessment for the economic importance penaeid shrimps is needed to develop effective management solution within a broader decision-making framework. Moreover, applying the intensive control on the fishery and accurate data recording are necessary to keep the fishery preserved.