Mackerel question

Hi Guys , although I’ve been fishing all my life I’ve just started fishing piers this summer. My question is about mackerel. In southern California can you catch them all year round? Or are they more seasonal? Like a warm weather fish?

All year round. They are the most common fish caught off of piers in Southern California. There are some days when you can't avoid catching them almost to the point where it is difficult to fish for anything else. They are fun fish to catch and if you bleed them and put them on ice right away, they are delicious!

Mackerel like warm water. Around SF its appear only at El Niño time.

That's interesting. I used to live in the Bay Area and didn't think that the temperatures were that much different than Southern California. I guess near the water it does get quite cold in the winter and of course during the summer when the fog rolls in. So what is the most common fish caught inshore year round up there? Herring?

Herring here you could caught only 2-3 days in the year at December or January when it came to spawn. There is several places around SF where herrings are spawning during short periods.
Other fishes here is: smelt, anchovy, perch, striped bass, halibut, verrrry seldom - salmon... Unfortunately striped bass become more and more rear...