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Abstract
This study was conducted in the soutthern coastal and inshore waters of Da Nang City to determine the species diversity, catch per unit effort (CPUE), yield, and distribution of demersal marine fishery resources. A single bottom trawl was utilized for resource surveys across 20 fixed stations, completing a total of 40 hauls representative of the Northeast (12/2025-01/2026) and Southwest (07/2025) monsoon seasons. Descriptive statistics and the swept area method were applied for data analysis. The research results showed that 278 species belonging to 180 genera and 103 families of marine organisms were recorded. Demersal fishes dominated the species composition with 120 species, while reef-associated fishes predominated in terms of catch yield, accounting for 35.6%. The catch per unit effort showed statistically significant differences between the two monsoon seasons, with the mean CPUE during the NE monsoon being 13.6 ± 9.8 kg/hour and 31.5 ± 15.6 kg/hour during the SW monsoon. The average density of marine fishery resources was estimated at 369.5 ± 243.4 kg/km². Specifically, the resource density was 367.3 ± 192.0 kg/km² in coastal waters and 348.5 ± 274.5 kg/km² in inshore waters. Seasonally, the density reached 247.8 ± 182.6 kg/km² during the NE monsoon and peaked at 491.3 ± 235.5 kg/km² during the SW monsoon. Threadfin porgy (Evynnis cardinalis) was the dominant species in the catch composition of both marine regions.
Keywords: Monsoon seasons, CPUE, density distribution, species composition, Da Nang City.