You probably wont be able to catch your intended victim near venice.....more than any other there are brown sand sharks
in the area near venice beach. Blacktips are more of a reef shark, and you would need to relocate further out and fish via a boat or kayak to get where they are. also if you go south to Redondo all the way around the point of Palos Verdes you might be able to catch a leopard shark over the eel grass in shallow water(20-40' deep) about 250 yds off the beach out to 1/2 mile. At 1/2 mile out the water is around 60 -80 ft deep. I used to beach dive at Palos Verdes and speared a 6ft leopard and dragged it right onto the beach a 1/2 mile north where a few people were swimming........I got some interesting looks and questions.
Head further south for the blues or leopards......good luck !