Dinophysis spp. can produce diarrhetic shellfish toxins (DST) including okadaic acid and dinophysistoxins, and some strains can also produce non-diarrheic pectenotoxins. Although DSTs are of human health concern and have motivated environmental monitoring programs in many locations, these monitoring programs often have temporal data gaps (e.g., days without measurements). This paper presents a model for the historical time-series, on a daily basis, of DST-producing toxigenic Dinophysis in 8 monitored locations in western Andalucía over 2015–2020, incorporating measurements of algae counts and DST levels. We fitted a bivariate hidden Markov Model (HMM) incorporating an autoregressive correlation among the observed DST measurements to account for environmental persistence of DST. We then reconstruct the maximum-likelihood profile of algae presence in the water column at daily intervals using the Viterbi algorithm. Using historical monitoring data from Andalucía, the model estimated that potentially toxigenic Dinophysis algae is present at greater than or equal to 250 cells/L between< 1% and>10% of the year depending on the site and year. The historical time-series reconstruction enabled by this method may facilitate future investigations into temporal dynamics of toxigenic Dinophysis blooms.

龙藻属 可产生腹泻性贝类毒素 (DST)，包括冈田酸和甲藻毒素，部分菌株还可产生非腹泻性果胶毒素。尽管夏令时与人类健康息息相关，并在许多地方推动了环境监测计划，但这些监测计划通常存在时间数据缺口（例如，没有测量的天数）。本文提出了一个历史时间序列模型，以每天为基础，产生 DST 的产毒甲鱼2015-2020 年在安达卢西亚西部的 8 个监测地点，结合了藻类数量和 DST 水平的测量。我们拟合了一个双变量隐马尔可夫模型 (HMM)，该模型在观察到的 DST 测量值之间加入了自回归相关性，以解释 DST 的环境持久性。然后，我们使用 Viterbi 算法以每日间隔重建水柱中藻类存在的最大似然分布。使用来自安达卢西亚的历史监测数据，该模型估计，根据地点和年份，每年 < 1% 和 >10% 之间存在潜在产毒的Dinophysis藻类的数量大于或等于 250 个细胞/升。通过这种方法实现的历史时间序列重建可能有助于未来对产毒物质时间动态的研究恐龙开花。