Ten drowned, 485 migrants picked up off Algeria
Thousands regularly risk the dangerous crossing crammed onto small boats heading north across the Mediterranean Sea to reach Europe.
Coast guard patrols picked up the migrants during 42 separate operations between September 15 and 19, the defence ministry said in a statement.
Algeria, Africa's largest nation and home to 43 million people, is currently battling high unemployment and political instability.
The drop in oil prices and restrictions to stem the spread of the novel coronavirus have hit its economy hard.
According to the European Union border protection agency Frontex, 6,090 Algerians crossed the Mediterranean during the first eight months of 2020.
However, some say the figure is likely to be higher.
Spanish media reported that during the last weekend of July, more than 800 Algerians arrived by sea.
In Algeria, the migrants are sometimes dubbed "harragas" -- or, those who "burn" their identity papers, to avoid being repatriated on arrival.
Algeria passed a law in 2009 aimed at "combating illegal emigration", with jail sentences of up to six months, but it has not stopped departures.
The driving factors are many but include high unemployment rates, hopes of a better life and dreams of freedom.
Anti-government protests last year swept ailing president Abdelaziz Bouteflika from power, but the government has since cracked down on demonstrators.