Stock assessment and management implications of African catfish (Clarias gariepinus) in Lake Mai-Ndombe, the Democratic Republic of Congo (DRC)
- Alternative Title
- DRC Mai-Ndombe 호수에서 아프리카 메기 (Clarias gariepinus)의 자원 평가 및 관리 방안
- Abstract
- This study aimed to conduct a stock assessment and management implications of African catfish (Clarias gariepinus) in Lake Mai-Ndombe, DRC. Data on length frequencies of African catfish samples from May 2020 to February 2021 and catch and effort data from 2008 to 2018 were used in this study. Population parameters using ELEFAN in FISAT package were estimated and the estimated asymptotic length (L∞), the growth coefficient (K) and the age at time zero (to) were 55.65 cm, 0.28/y-1, and -0.50 year, respectively. The instantaneous rate of natural, fishing and total mortality were 0.35/y, 0.7/y and 1.05/y, respectively. The mean length at first capture was 23cm. Based on surplus production model approach, MSY, Bmsy and Bc were estimated at 337tons, 1,814tons and 3,051tons, respectively. The yield per recruit analysis showed that the optimal fishing mortality (Fmax) was 0.8/y and the optimal length at first capture was 31cm. As a management measure for this stock, a total allowable catch (TAC) system is recommended. Moreover, to avoid any sudden alteration in the resources abundance or availability, it is required to conduct more advanced stock assessment in the near future, such as the ecosystem-based fisheries assessment (EBFA), to determine additional parameters of biodiversity, habitat quality and socio-economic factors, which are also important to understand for the fishery management.
- Issued Date
- 2021
- Awarded Date
- 2021. 8
- Type
- Dissertation
- Publisher
- 부경대학교
- Affiliation
- 부경대학교 세계수산대학원
- Department
- 세계수산대학원 수산자원관리전공
- Advisor
- Chang-Ik Zhang
- Table Of Contents
- I. Introduction 1
1.1. Overview of stock assessment 3
1.2. Overview of C. gariepinus 4
1.2.1. Description 4
1.2.2. Distribution 6
1.2.3. Natural spawning 7
1.3. Overview of the Lake Mai-Ndombe Fisheries 7
1.3.1. Description of ecosystem 7
1.3.2. Type of fishing gears 8
1.3.3. Type of vessels 8
II. Materials and Methods 11
2.1. Materials 13
2.2. Methods 14
2.2.1. Electronic Length Frequency Analysis (ELEFAN) 15
2.2.2. Von Bertalanffy growth model 15
2.2.3. Estimation of natural mortality (M) 16
2.2.4. Estimation of total mortality (Z) 17
2.2.5. Estimation of length at first capture (Lc) 18
2.2.6. Estimation of management reference points 18
III. Results 21
3.1. Estimation of population parameters 21
3.1.1. Growth in length 22
3 1.2. Growth in weight 24
3.1.3. Natural mortality (M) 25
3.1.4. Catch curve 27
3.2. Management reference points 28
3.2.1. Surplus production model 28
3.2.1.1. Equilibrium model (Schaefer model) 28
3.2.1.2. Non-equilibrium model results (Before Excel solver) 30
3.2.1.3. Non-equilibrium model results (After Excel solver) 32
3.2.1.4. Determination of overfished and overfishing conditions 35
3.2.2. Yield per recruit analysis and results 38
IV. Discussion 42
4.1. Population parameters 43
4.1.1. Growth in length 43
4.1.2. Growth in weight 44
4.1.3. Growth parameters of Lake Mai-Ndombe versus other studies 45
4.2. Management reference points from surplus production model 47
4.3. Management reference points from yield per recruit analysis 47
Conclusion 49
References 50
Acknowledgement 56
Appendices 58
Appendix 1. Length frequency data and class size of C. gariepinus in Lake Mai-Ndombe, DRC. 59
Appendix 2. Length and weight data of C. gariepinus in Lake Mai-Ndombe, DRC (January 2021). 62
Appendix 3. Length frequency data of C. gariepinus in Lake Mai-Ndombe, DRC (10 Months). 64
- Degree
- Master
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