Stock assessment of Kingfish (Scomberomorus commerson) in the Omani waters
- Abstract
- Stock assessment were estimated for the kingfish Scomberomorus commerson in the Sultanate of Oman waters. A total of 1748 samples of kingfish were collected from January to December 2019, and length-frequency data were measured. A length-based analysis was employed to analyze population biological characteristics and biological reference points for S. commerson. Asymptotic length (L∝) and growth coefficient (K) was estimated at 185.85 cm and 0.17 〖yr〗^(-1), respectively. Total mortality (Z) for S. commerson was 0.70 〖yr〗^(-1). While natural mortality (M) and fishing mortality (F) was calculated at 0.21 〖yr〗^(-1) and 0.49 〖yr〗^(-1), respectively. Fishing mortality was 0.49 〖yr〗^(-1) were higher than the optimal fishing mortalities (F40%) of 0.19 〖yr〗^(-1) that indicated the overfishing condition. The current length at first capture 67 cm of S. commerson is much lower than its optimal length at first capture that indicated growth overfishing for S. commerson 101 cm. The spawning potential ratios (SPR) were from 20%. The spawning potential ratio of S. commerson was much lower than the reference point of 40%, indicating the recruitment overfishing. The maximum sustainable yield for S. commerson was 4978.68 mt. The fishing effort in 2019 is 94-unit vessels that were lower than the effort at maximum sustainable yield (fMSY) of 442 unit vessels. Over discrepancies in annual fishing mortality suggest overexploitation of this species. Therefore, it could be concluded that the stock of S. commerson is overexploited condition in the coastal waters of the Sultanate of Oman. Therefore, there are some recommendations based on the results of this study such as (i) keep reducing the numbers of vessels to prevent overfishing condition, (ii) the length at first capture should be limited to more than 80 cm as the minimum legal size to reach 40% of the spawning potential ratio to avoid the growth overfishing, (iii) the strong monitoring, control and surveillance (MCS) system is required and should be established during the implementation of management of kingfish in the Omani waters.
- Issued Date
- 2021
- Awarded Date
- 2021. 8
- Type
- Dissertation
- Publisher
- 부경대학교
- Affiliation
- 부경대학교 세계수산대학원
- Department
- 세계수산대학원 수산자원관리전공
- Advisor
- S. M. Nurul Amin
- Table Of Contents
- I. Introduction 1
1.1 Background information 1
1.2 Problem statement 2
1.3 Specific Objectives 4
II. Literature review 5
2.1 Taxonomic status 5
2.2 Habitat Distribution of Scomberomorus commerson 6
2.3 Importance of S. commerson 7
2.4 Fishery status of S. commerson 7
2.5 Length weight relationship 8
2.6 Age and growth 9
2.7 Mortalities and exploitation rate 11
2.8 Yield-per recruit model (Y/R) 12
2.9 Spawning stock biomass per recruit (SSBR) 13
2.10 Maximum sustainable yield (MSY) 13
2.11 Conclusion 14
III. Materials and Methods 16
3.1. Study area and sampling 16
3.2 Growth parameters 17
3.3 Mortalities and exploitation rate 18
3.4 Length at first capture 19
3.5 Biomass and fishing mortality 20
3.6 Optimal Length at first capture and optimal fishing mortality 21
3.7 Spawning stock biomass per recruit 23
3.8 Maximum sustainable yield 24
IV. Results 25
4.1 Size frequency distribution 25
4.2 Growth parameters 25
4.3 Mortalities and exploitation rate 28
4.4 Length at first capture 29
4.5 Biomass and fishing mortality 30
4.6 Optimal Length at first capture 31
4.7 Optimal fishing mortality 33
4.8 Spawning potential ratio 34
4.9 Maximum sustainable yield 34
V. Discussion 36
VI. Acknowledgement 42
VII. References 44
- Degree
- Master
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