Date of Defense
6-5-2026 1:00 PM
Location
F3-035
Document Type
Dissertation Defense
Degree Name
Doctor of Philosophy in Ecology and Environmental Sciences
College
COS
Department
Biology
First Advisor
Sabir Bin Muzaffar
Keywords
Scomberomorus commerson, life history, stock assessment, PSAT, Arabian Gulf, fisheries management
Abstract
The narrow-barred Spanish mackerel, Scomberomorus commerson, is the most commercially valuable pelagic fish species in the Arabian Gulf. This thesis integrated three studies to comprehensively assess the life history, stock status, and movement ecology of this species in Abu Dhabi waters. Life history traits were characterized from data collected during a 15-month monitoring program (January 2019–May 2020). Fork length ranged from 30.5 to 132 cm. Growth parameters were k = 0.14–0.15 year⁻¹ and L∞ = 128.9–135.4 cm for males and females, respectively. Size-at-maturity (Lm₅₀) was 78.7 cm FL for females and 69.7 cm FL for males. The spawning season occurred from March to June with a peak in April. Mortality estimates indicated an exploitation rate of 0.69, with spawning biomass ratio estimated at 20.5%, indicating high exploitation especially on juveniles. Stock status was evaluated using four length-based models (LBI, LBB, LBSPR, and LIME) applied to length frequency data from 13,552 fish sampled between 2011 and 2023. All models indicated overfishing, with low proportions of mature and optimal-sized individuals. However, following the 2019 gillnet ban, signs of recovery were evident, with B/Bmsy reaching 1.0 by 2023. Movement ecology was investigated through the first PSAT deployment on this species in the Arabian Gulf. Nine tags were deployed between November 2022 and May 2023, with three (33.3%) successfully transmitting data. A seasonal pattern in tag performance was observed: 100% winter success versus 25% spring success, coinciding with the spawning season. The three reporting tags provided approximately 15 days of combined tracking data, revealing limited horizontal displacement, depth utilization to 42 m, and clear diel diving patterns. Out of this study, two scientific articles have been published in peer-reviewed journals, in which the candidate was the first and corresponding author (AlMusallami et al., 2025a; AlMusallami et al., 2025b). These integrated findings support continued management interventions including gear restrictions and implementation of minimum size limits to ensure long-term sustainability of this important fishery resource.
Included in
LIFE HISTORY, STOCK STATUS, AND MOVEMENT ECOLOGY OF NARROW-BARRED SPANISH MACKEREL, SCOMBEROMORUS COMMERSON (LACÉPÈDE, 1800) IN THE SOUTHERN ARABIAN GULF
F3-035
The narrow-barred Spanish mackerel, Scomberomorus commerson, is the most commercially valuable pelagic fish species in the Arabian Gulf. This thesis integrated three studies to comprehensively assess the life history, stock status, and movement ecology of this species in Abu Dhabi waters. Life history traits were characterized from data collected during a 15-month monitoring program (January 2019–May 2020). Fork length ranged from 30.5 to 132 cm. Growth parameters were k = 0.14–0.15 year⁻¹ and L∞ = 128.9–135.4 cm for males and females, respectively. Size-at-maturity (Lm₅₀) was 78.7 cm FL for females and 69.7 cm FL for males. The spawning season occurred from March to June with a peak in April. Mortality estimates indicated an exploitation rate of 0.69, with spawning biomass ratio estimated at 20.5%, indicating high exploitation especially on juveniles. Stock status was evaluated using four length-based models (LBI, LBB, LBSPR, and LIME) applied to length frequency data from 13,552 fish sampled between 2011 and 2023. All models indicated overfishing, with low proportions of mature and optimal-sized individuals. However, following the 2019 gillnet ban, signs of recovery were evident, with B/Bmsy reaching 1.0 by 2023. Movement ecology was investigated through the first PSAT deployment on this species in the Arabian Gulf. Nine tags were deployed between November 2022 and May 2023, with three (33.3%) successfully transmitting data. A seasonal pattern in tag performance was observed: 100% winter success versus 25% spring success, coinciding with the spawning season. The three reporting tags provided approximately 15 days of combined tracking data, revealing limited horizontal displacement, depth utilization to 42 m, and clear diel diving patterns. Out of this study, two scientific articles have been published in peer-reviewed journals, in which the candidate was the first and corresponding author (AlMusallami et al., 2025a; AlMusallami et al., 2025b). These integrated findings support continued management interventions including gear restrictions and implementation of minimum size limits to ensure long-term sustainability of this important fishery resource.