The present study elucidates the socio-ecological status of the marine ornamental reef fish (MORF) fishery in Trincomalee, Sri Lanka, through strategic SWOT analysis. Data were collected through interviews with full-time fishers (n = 49) fishing at Pulmodai, Sampur, and Kuchchaweli reef sites, focus group discussions (n = 3), and participant observations during 2019–2020. Data gathered in-situ were further investigated in detail, analyzed, and grouped into attributes of SWOT analysis. Results revealed higher fishing income (90–900 USD) by 91.84% of respondents as the major strength of the fishery, followed by low production costs (24–240 USD), a low labor force, and others. Seasonality of the fishery, multiple ownership of reefs, and the limited number of fishing hours (4-6 hrs.) were the main weaknesses identified in the system. High global demand, the fish-to-order concept, and the intervention of local buyers were the major opportunities for the fishery. Long market chains, bopyrid isopod infection on Pacific cleaner shrimp, and poor monitoring systems were the major threats to the industry. The MORF fishery in Trincomalee, Sri Lanka, results in higher living standards for fisher communities and empowers them. The present study has policy implications for the MORF fishery and the long-term sustainability of the industry.

Giant Freshwater Prawn (Macrobrachium rosenbergii) is an essential crustacean species in culture-based fisheries of Sri Lanka. Studying the morphometric characteristics and empirical models in fishing and aquaculture is highly beneficial; thus, it is the most accurate way of analyzing growth patterns. The present study aimed to establish the length-weight relationship and compute the relative condition factor for the M. rosenbergii cultured in trophically different perennial reservoirs in Sri Lanka, considering the trophic status of the reservoirs. The allometric coefficient and condition factor of M. rosenbergii concerning the trophic state of the reservoir were empirically ascertained from the samples collected from twenty-five dry-zone perennial reservoirs of Sri Lanka. Carlson's Trophic State Index (TSI) was calculated based on the chlorophyll-a content. The allometric coefficient and relative condition factor were computed using the total length and weight of the M. rosenbergii. The TSI ranging between 44.09±0.47 and 65.15±0.24 differed significantly (p<0.05). Sexual dimorphism in the growth of males over the female M. rosenbergii was ascertained with the aid of allometric coefficient (b value) 3.2306 (positive allometric growth) and 2.9534 (negative allometric growth), respectively. In eutrophic perennial reservoirs, Giant Freshwater Prawns showed the highest allometric coefficient in both sexes. There was a positive correlation between the allometric coefficient and TSI among males, r(23)=0.7210, p<0.001, and combined sexes, r(23)=0.7900, p<0.001, respectively. The results of the present study revealed that the trophic state of the reservoir influences the allometric coefficient and condition factor of M. rosenbergii cultured in perennial reservoirs of Sri Lanka.

Exhaustive scrutiny of Vibrios, one of the preeminent autochthonous microbes in the Giant Freshwater Prawn, GFP (Macrobrachium rosenbergii), is pivotal, as they can profoundly influence the production of GFP. This study aimed to enumerate Vibrio populations isolated from GFP and examine their relationship with the physicochemical properties of seven reservoirs in Sri Lanka. GFP samples were collected, homogenized, and plated using the spread plate technique on Thiosulfate Citrate Bile Salt (TCBS) agar to isolate Vibrio spp. In-situ measurements of water parameters temperature, pH, conductivity, dissolved oxygen (DO), and Secchi disk depth were taken from each reservoir. Chlorophyll-a and organic matter contents were analyzed in the laboratory. To identify significant variations, Kruskal-Wallis pairwise comparisons were used to compare Vibrio abundance and water parameters across reservoirs. Regression analyses assessed the relationships between Vibrio abundance and environmental factors. Results showed significant differences in Vibrio sp. abundance among reservoirs. The highest mean Vibrio count was observed in GFP from Muthukandiya Wewa (8.19±0.74 log CFU g⁻¹), significantly exceeding counts from Bandagiriya, Handapanagala, and Urusita reservoirs. Among the water quality variables, only pH in Urusita Wewa showed a significant positive correlation (r = 0.740, p = 0.006) with Vibrio abundance.The study infers that the abundance of Vibrios is high in Muthukandiya Wewa. Furthermore, the abundance of Vibrios in Urusita Wewa is regulated by reservoir pH. An assiduous and perpetual analysis of Vibrio abundance and factors of lasting repercussions on its abundance helps facilitate mitigation measures to control Vibrios.