INRH (Moroccan Institute of Fisheries Research), Marine Environment Monitoring Laboratory, Tangier, Morocco.
INRH (Moroccan Institute of Fisheries Research), Casablanca, Morocco.
Sci Total Environ. 2024 Dec 1;954:175578. doi: 10.1016/j.scitotenv.2024.175578. Epub 2024 Sep 11.
Harmful algal blooms have been documented in the Moroccan Western Mediterranean region since 1993, primarily associated with the presence of paralytic shellfish toxins (PSTs) produced by the dinoflagellate Gymnodinium catenatum. The proliferation of this neurotoxic species has led to recurring bans on the harvesting of molluscs, resulting in significant socio-economic repercussions and threats to human health. In the present study, we examine the dynamics of G. catenatum and mollusc PST contamination patterns over a 20-year period (2002-2021) in two distinct marine ecosystems: M'diq Bay and the Oued Laou Estuary. For the PST contamination, we considered two commercially important shellfish species: the smooth clam, Callista Chione, and the cockle, Acanthocardia tuberculata. The highest G. catenatum abundances were consistently observed from November to February in both sites. Our data revealed inter-annual variations in G. catenatum abundance, peaking at 91,840 cells.L in November 2011. PST contamination levels in A. tuberculata were significantly higher than those observed in C. chione. Furthermore, we identified a significant correlation (Pearson, P-value <0.05) between PST contamination of smooth clams and the abundance of G. catenatum. The contamination of A. tuberculata by PSTs reached very high levels, with up to 13,500 μg STX di-HCl eq. kg of shellfish meat, exceeding the established safety thresholds by 16-fold. Additionally, there has been an increase in the prevalence and incidence of PSTs over the years. Notably, we observed a substantial increase in G. catenatum blooms and PST events in the Western Mediterranean during the last decade (2010-2021). The examined data suggest that rainfall could play a pivotal role in G. catenatum bloom dynamics by enriching marine waters with nutrients. The statistical model selection approaches indicated that nutrient concentrations (i.e., nitrate and phosphorus) were the most significant parameters for G. catenatum blooms in the studied area.
自 1993 年以来，摩洛哥西地中海地区就有记录表明存在有害藻类大量繁殖，主要与有鳍鞭毛藻冈田软海绵产生的麻痹性贝类毒素（PSTs）有关。这种神经毒性物种的大量繁殖导致贝类捕捞一再被禁止，从而对社会经济产生了重大影响，并对人类健康构成威胁。在本研究中，我们研究了 20 年来（2002-2021 年）两个不同海洋生态系统中冈田软海绵和软体动物 PST 污染模式的动态：M'diq 湾和 Oued Laou 河口。对于 PST 污染，我们考虑了两种商业上重要的贝类：光滑贻贝 Callista Chione 和皱纹盘鲍 Acanthocardia tuberculata。在两个地点，冈田软海绵的数量最高，从 11 月到 2 月一直保持稳定。我们的数据显示冈田软海绵的数量存在年际变化，在 2011 年 11 月达到了 91840 个细胞.L 的峰值。皱纹盘鲍 A. tuberculata 中的 PST 污染水平明显高于光滑贻贝 C. chione。此外，我们发现了贻贝中 PST 污染与冈田软海绵丰度之间存在显著相关性（Pearson，P 值<0.05）。皱纹盘鲍 A. tuberculata 中 PST 的污染水平非常高，贝类肉中 PST 含量高达 13500μg STX di-HCl eq.kg，是设定安全阈值的 16 倍。此外，多年来 PST 的流行率和发病率有所增加。值得注意的是，我们观察到过去十年（2010-2021 年）在西地中海地区冈田软海绵大量繁殖和 PST 事件大量增加。研究数据表明，降雨可能通过向海洋水域富营养化来在冈田软海绵大量繁殖的动态中发挥关键作用。统计模型选择方法表明，营养物质浓度（即硝酸盐和磷）是研究区域中冈田软海绵大量繁殖的最重要参数。
