Phytoplankton species abundance (cell/L) and oceanographic conditions (temperature, salinity, chlorophylle-a (mg/m³) for some years and nutrient content (mmol/m³)) at stations of the Harmful Algae Monitoring Programme (HAMP) from1994 to 2016. The layer presents the station positions of the HAMP. Two files are attached to each station: one containing the cell counts and the second the oceanographic conditions. Purpose The summer growth of many toxic and harmful microalgae species poses a serious threat for the public health and commercial or recreational exploitation of some marine species. The Department of Fisheries and Oceans (DFO) initiated the Harmful Algae Monitoring Programme (HAMP) in 1989 in order to complete the monitoring program for paralytic shellfish poisoning (PSP). Under the responsibility of Maurice-Lamontagne Institute scientists, the HAMP is to monitor, by means of a coastal station network, the natural occurrence of toxic and harmful algae in the St. Lawrence in order to determine their spatio-temporal distribution and the environmental conditions leading to their bloom. The network is made up of 11 coastal stations which are sampled every week from April to November and which are established along Quebec eastern shores. It extends from Tadoussac to Tête-à-la-Baleine on the St. Lawrence north shore and from Sainte-Flavie to Carleton on the south shore along the Gaspé peninsula. Another station is located in Havre-Aux-Maisons, Magdalen Islands. The HAMP was discontinued in 2010 but opportunistic samplings are still done at some stations. Additional information The sampling and analysis protocol is described in details in the following publication apart from the fact that the number of identified and counted species significantly has been increasing with time. Phytoplankton samples are preserved in a lugol solution. Blasco D., M. Levasseur, R. Gélinas, R. Larocque, A.D. Cembella, B. Huppertz et E. Bonneau.1998. Monitorage du phytoplancton toxique et des toxines de type IPM dans les mollusques du Saint-Laurent: 1989 à 1994. Rapp. stat. can. hydrogr. sci. océan. 15 1 : x i-117 p.