Population Dynamics and Stock Assessment of Tigertooth croaker (Otolithes ruber) in the Coast of Balochistan, Pakistan.
- Alternative Title
- 파키스탄 발로치스탄 연안 범이빨 민어 (Otolithes ruber)의 개체군 역학과 자원평가
- Abstract
- Length-frequency based stock assessment of Otolithes ruber was conducted in the Balocistan coast, Pakistan during September 2020 to February 2021. A total of 1,308 samples of Otolithes ruber were collected and length and weight of each individual fish was measured. Then monthly length frequency data were analyzed using FiSAT II computer software package. The mean total length and body weight of the O. ruber was 30.34 (±4.814) cm and 288 (±157) g respectively. Length-weight relationship model was W = 0.0036L3.2815 (r2 = 0.9445) showing a positive allometric growth. The estimated von Bertalanffy growth parameters (L∞ and K) for O. ruber was as L∞ = 54.08 (cm) and K = 0.99 yr-1 , t0 = -0.133yr-1. The longevity (tmax) was 3 years, growth performance index (Φ') was estimated 3.177. The exploitation rate (E) was found to be 0.67 yr-1 which indicates over exploitation of O. ruber. The calculated total mortality rate (Z), natural mortality (M), fishing mortality (F) were 4.57 yr-1, 1.49 yr-1, and 3.08 yr-1. Current length at first capture (Lc50current) was estimated at 28.3 cm while optimal Lc50 was about 32 cm. Main recruitment pulse was from May to September with a peak in July. Current yield -per-recruit (YPR) was 164.8 g, fishing mortality at maximum YPR (Fmax) and fishing mortality corresponding to 10% of the maximum slope in YPR curve (F0.1) were 4.4/year and 1.52/year, respectively. F40%, indicating fishing mortalities at 40% of maximum Spawning biomass-per-recruit (SBPR) was 1.25/year respectively. Effort at MSY (fMSY) 59721 (fishermen) was lower than the current effort (fcurrent) 77265 (fishermen) which indicates 22% overfishing.
- Issued Date
- 2021
- Awarded Date
- 2021. 8
- Type
- Dissertation
- Keyword
- FISAT II Population dynamics yield per recruit spawning biomass per recruit overfishing Balochistan Pakistan.
- Publisher
- 부경대학교
- Affiliation
- 부경대학교 세계수산대학원
- Department
- 세계수산대학원 수산자원관리전공
- Advisor
- S.M. Nurul Amin
- Table Of Contents
- CHAPTER:1 Introduction 1
1.1 Background of the study 1
1.2 Statement of the problem 4
1.3 Specific Objectives 5
CHAPTER:2 Literature Review 6
2.1 Morphometric characteristics of Otolithes ruber 6
2.2 Habitat and distribution 7
2.3 Importance and fishery status of Otolithes ruber 7
2.4 Population dynamics parameters 11
2.4.1 Growth parameters 11
2.4.2 Mortality and exploitation rates 14
2.4.3 Length at first maturity (Lm50) and Length at first capture (Lc50) 15
2.5 Different method used for fish stock assessment 15
2.5.1 FISAT II (FAO-ICLARM Stock Assessment Tools) 16
2.5.2 Surplus production models 18
2.5.3 Yield-per-recruit (YPR) and spawning- biomass-per-recruit (SPR) 18
CHAPTER:3 Material and methods 19
3.1 Study area 19
3.2 Data analysis 22
3.3 Fishing method 23
3.4 Length weight relationship parameters 24
3.5 Age and growth 25
3.6 Growth parameters estimation 26
3.7 Mortality and exploitation rate 26
3.8 Length at first capture (Lc50) 28
3.9 Length at first maturity (Lm50) 28
3.10 Virtual population analysis (VPA) 28
3.11 Yield per recruitment and spawning biomass per recruit 29
3.12 Reference Point of Fishing Mortality (F0.1) 31
3.13 Recruitment Pattern 31
3.14 Estimation of Maximum Sustainable Yield: Surplus production model 31
CHAPTER:4 Results 33
4.1 Population structure 33
4.2 Parameters of length weight relationship 34
4.3 Growth parameters 35
4.4 Mortality and exploitation rate 39
4.5 Length at first capture (Lc50) and length at first maturity (Lm50) 40
4.6 Recruitment pattern 41
4.7 Virtual Population analysis 42
4.8 Yield per recruit 43
4.9 Spawning biomass per recruit (SBPR) 45
4.10 Maximum sustainable yield 48
CHAPTER:5 Discussion 49
5.1 Length-weight relationship 49
5.2 Growth parameters 50
5.3 Mortality and exploitation rate 52
5.4 Yield per recruit 54
5.5 Spawning biomass per recruit (SBPR) 54
5.6 length at first maturity 55
CHAPTER:6 Conclusion and recommendations 56
6.1 Conclusion 56
6.1.1 Length- weight relationship 56
6.1.2 Mortalities and exploitation rates 56
6.1.3 Yield per recruit and spawning biomass per recruit 56
6.1.4 Length at first capture (lc50) and length at first maturity (lm50) 57
6.1.5 Maximum sustainable yield (MSY) 57
6.2 Recommendations 57
References 59
Acknowledgment 75
Dedication 75
- Degree
- Master
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