The number of students in Scotland taking most science subjects has fallen markedly, it has emerged.
The government says it has invested millions in science education
Scottish Executive statistics have revealed about a 20% fall in students of physics and electronic engineering at Scottish universities in a decade.
The figures obtained by the Scottish National Party also showed a fall of about 32% in chemistry.
The SNP expressed concern at the decline but the executive said it was working to increase science uptake.
The total number of enrolments in physics fell from 1,970 in 1994-1995 to 1,545 in 2004-2005 and the number of institutions offering the subject dropped from 12 to nine over that period.
Chemistry saw a fall from 2,990 to 2,020, with a total of 12 institutions catering for the subject.
The total for electrical and electronic engineering fell from 4,510 to 3,500 at the 12 institutions.
However, there was an increase in biology enrolments from 3,610 to 4,080 with 15 institutions offering the subject, a rise of two.
SNP education spokeswoman Fiona Hyslop said: "I think that's a big problem for the economy.
"We need to make sure we have pupils and students who can take these subjects to further their own careers but, as importantly, make sure that Scotland has an economy that is based on knowledge, based on ideas and invention and these subjects are core and key to that."
Ms Hyslop said a major element in addressing the problem should be a close look at "choice and curriculum" in schools.
A Scottish Executive spokesman said: "Our policy is to ensure that pupils, students and parents are provided with high quality information to enable them to make informed career choices rather than to attempt to control the uptake of particular subjects.
"We have implemented a range of measures to help make science more appealing. As well as investing £13m in Scotland's four centres we have recently appointed a new chief scientific adviser who will help raise the profile of science.
"We are also working with Future Skills Scotland and the Scottish Funding Council on a study into the supply and demand for scientists, engineers and mathematicians in Scotland. A preliminary report is expected later this year."