Groupers (family Epinephelidae, subfamily Epinephelinae) are reef fishes of high value as food resources that generate export revenue to Sri Lanka. Yet, with less attention and poor resource management, grouper population dynamics remain understudied. This paper investigates the temporal variation of grouper species on the continental shelf of Sri Lanka in relation to seasonal, regional, and seafloor depth variables using data based on quantitative sampling of demersal fish conducted in 1978, 1979, 1980, and 2018 with a bottom trawl on the R/V Dr. Fridtjof Nansen, where the authors joined the 2018 survey. A total of 277 trawl samples were included in the analysis. The analysis of variance of all the grouper species found that the average density significantly declined from 0.89 t/NM² (tonnes per square nautical mile) in 1979 to 0.28 t/NM² in 2018. The contribution of groupers to the total catch (by weight) was also higher in 1979 (9.06 %) than in 2018 (1.28 %). The distribution patterns significantly differed among the six regions of the Sri Lankan shelf. In addition, seafloor depth was negatively correlated with grouper density. The results point to an urgent need for better management and conservation of the grouper resources.

石斑鱼（石斑鱼科，石斑鱼亚科）是高价值的礁石鱼类，可作为粮食资源，为斯里兰卡带来出口收入。然而，由于注意力不足和资源管理不善，石斑鱼种群动态仍未得到充分研究。本文使用基于1978年，1979年，1980年和2018年海底拖网定量采样的数据，调查了斯里兰卡大陆架上石斑鱼种类随季节，区域和海底深度变量的时间变化。在R / V Fridtjof Nansen博士身上，作者加入了2018年的调查。分析中总共包括277个拖网样品。对所有石斑鱼物种的方差分析发现，平均密度从0.89 t / NM ²显着下降1979年（吨海里/平方英里）至2018年为0.28 t / NM ²。1979年石斑鱼对总渔获量的贡献（以重量计）也高于2018年（9.06％）（1.28％）。斯里兰卡架子的六个区域之间的分布模式明显不同。此外，海底深度与石斑鱼密度呈负相关。结果表明迫切需要更好地管理和保护石斑鱼资源。