This is a grapple - it is thrown out over a shoal of fish, mullet being a good choice, and swifly pulled back through the shoal.
I was shown this technique twenty years ago in Yugoslavia by an old fisherman. I have made a few of these over the years varying in size. The spikes should be made from hard wood and fire hardened as they soften at the tips with prolonged use.
Although illegal in the UK, grapple fishing is still a worthwhile skill, as is the pole snare, in the world of bushcraft and wilderness living skills.