MPAs are discrete marine or estuarine areas seaward of the high tide line that are designated by law or voter initiative to protect or conserve marine life or habitat. These areas may allow some specified forms of take while prohibiting others. MPAs may also be designated "no-take" or reserves where no extractive uses or fishing are allowed. The state classifies MPAs into three categories with each having different general guidelines for the kinds of fishing or extractive uses that are permitted. State Marine Reserves (SMR) prohibit all extractive uses, State Marine Parks (SMP) prohibit commercial take but allows recreational take and State Marine Conservation Areas (SMCA) may allow both commercial and recreational use with various restrictions. An example of an SMCA is an area where all bottom fishing is prohibited, both commercial and recreational, but fishing in the mid-water for things like salmon is allowed.
The Marine Life Protection Act (MLPA) was passed in 1999. The MLPA requires that the Department of Fish and Game develop a plan for establishing networks of marine protected areas in California waters to protect habitats and preserve ecosystem integrity, among other things. Prior to the implementation of the MLPA only 0.2% state waters (mean high tide line out to 3 miles) were fully protected marine reserves. The MLPA states that the previous collection of MPAs was ineffective because they were ". . . established on a piecemeal basis rather than according to a coherent plan and sound scientific guidelines. As a result, the array of MPAs created the illusion of protection while falling far short of its potential to protect and conserve living marine life and habitat. Moreover, many of them lacked clearly defined purposes, effective management measures and enforcement." Two new networks of MPAs have been established over the past few years as first steps in fully implementing the MLPA. The Channel Islands MPAs were implemented in 2003. These consist of 12 MPAs, 10 SMR and 2 SMCA, covering 142 square miles, on the 5 northern most Channel Islands. The second group of MPAs were adopted by the Fish and Commission on August 15, 2005 along the central coast and are scheduled for implementation in 2007. These MPAs range from Pigeon Pt. to Pt. Conception and include 12 MPAs covering approximately 200 square miles.