Parts of Long Island are seeing algae bloom very early on in the season this year -- a big problem for fish and shellfish.

Word of a mahogany tide showing up on Long Island spread Monday, appearing much earlier than its typical timeframe in the late summer.

The tide is caused by high nitrogen pollution, which can come from antiquated cesspools and fertilizer runoff.

The bloom sucks oxygen out of the water and has the ability to be toxic to fish and shellfish. It is not toxic to humans.

The tide has been reported from the Great South Bay to the Moriches Bay in Southampton.

The group Save the Great South Bay and other experts are working to bring attention to the issue and say residents must start at home in order to make a difference.

Stony Brook University's Dr. Chris Gobler says upgrading septic systems is one of the main ways of attacking the root cause of the bloom.

"There are studies done at Stony Brook University that link water quality to home value, so in fact if you do make an improvement in water quality ... the price of the home can be higher," says Gobler.

Other solutions presented include avoiding fertilizer use and planting certain native plants that absorb nitrogen.