I find for sea fishing, it's best to gamble with your small catches for bigger ones!
If you catch crabs, use them as bait for mackerel, herring, salmon, bluey and sardine, and then when you catch them, use them as bait for sea bass, tope, catfish, dogfish and sharks!
Gamble your baits in hope of catching more - i works for me!
Or, of course, if you would rather stay on the safe side, just buy some ragworm, sandeel and use it safely!

Thank you so very much.
I get ALL of this information from my own general knowledge - i promise - i don't copy and paste ANY of it. The only time i use the internet for help with this info - is to double check that i've got it right, true and accurate before i submit the post.
The only other place i got information from is a range of fishing books, but i didn't just copy them either, i take them into my knowledge and put it into my own words.