Sixty years ago, the population of kelp bass was significantly larger than it is today. There are several reason for the reduction in population. While many like to blame over fishing, the cause is more complex.
While the human population on the west coast has exploded in the last fifty years, the most significant reduction in population first occured during the sixties and seventies. At this time, the globe was undergoing a global cooling trend that lasted for about fourty years and ended in the early 80s, leading to a warming phase.
However, while global temperatures were the first to cause a reduction in numbers, the increased human population has overfished the area and also caused a further reduction in their population even as the climate warmed.
To keep the population healthy and help it grow, we need to practice catch and release and use barbless hooks to reduce the stress, which reduces the risk of death once the fish has been released. Also, when releasing Kelp Bass or any other fish, hold it upright in the water to give it a chance to catch its breath.
See here for more information on catch and release: http://bassfishing-gurus.com/catch-and-release.php