Spear fish season.....

For Northern California = When does it start and when does it end?

There is no closed season on rockfish, cabezone, halibut, greenlings, perch, sheepshead.  Lingcod is open to divers and shore-based anglers from April 1 through November 30.  The closure protects them when they're guarding nests.

I belive april 1 is also the abalone opener, so the spring is a good time to be a diver when the weather cooperates.  It's also the opposite side of the year from when the seals are pupping and attracting sharks to shore as well.

Stripers, salmon and sturgeon are closed to spearing, as is most freshwater.

"No closed season on rockfish" is gonna get Smooch underwater FAST!

There is no closed season on rockfish, cabezone, halibut, greenlings, perch, sheepshead.  Lingcod is open to divers and shore-based anglers from April 1 through November 30.  The closure protects them when they're guarding nests.

I belive april 1 is also the abalone opener, so the spring is a good time to be a diver when the weather cooperates.  It's also the opposite side of the year from when the seals are pupping and attracting sharks to shore as well.

Stripers, salmon and sturgeon are closed to spearing, as is most freshwater.

is there any freshwater that isn't closed?

Freshwater could be kinda cool.

There are some freshwater areas where you are allowed to shoot carp and squawfish.  I haven't done anything in freshwater other than pan for gold in 5 years though...

I have spearfished in the American River for carp and suckers near the near the fish hatchery at Folsom dam.  There is a specific season for this.  I cannot remember the exact dates off the top of my head but I do remember that it is when there are no salmon in the river.   I lived in Fair Oaks about 10 years ago and used to swim in the river all the time for exercise.  I just started taking my gun down and shooting suckers for fun.  I would occasionally have a big striper come in on me to snarf down a wounded sucker.  That was pretty cool to see.  You can also dive and get tons of lures off the submerged rocks and metal in the river.  It is a pretty cool place.
Dave

. You can also dive and get tons of lures off the submerged rocks and metal in the river

I remember seeing free divers with buckets full of iron jigs just below a particular bridge (forgot which one)....apparently, the Salmon were being snagged with these Iron jigs...to my surprise, no DFG's were around. The salmon were visible from the top of the bridge and when someone snagged one, they would free spool and run down at the base of the bridge and reel in their catch....it was disturbing to see but this was almost 10 years ago and I did not know any of the rules regarding salmon fishing on the Sac river....