Mussel and chorizo soup

1 kg mussels

3 tbsp golden rapeseed oil

½ tsp fennel seed

1 onion, finely diced

1 carrot, finely sliced

1 celery stalk, finely diced

1 small bulb fennel,  finely diced

3 cloves garlic, minced

1 tsp rosemary, finely chopped

100g chorizo, finely diced

1 tsp smoked paprika

150ml white wine

2x 400g tins of chopped tomato

300ml fish or vegetable stock

Sea salt

Cracked black pepper