Sort, wash and spin dry the lettuces. Cut off the larger leaves.
Wash the radishes, hull them and cut them into thin rings.
Peel the celery stalks with a paring knife to remove the threads, slice the stalks very finely.
Peel the pears, cut them in half and remove the core and seeds, slice them into thin strips. Using a large, sharp knife, slice the haddock fillet into thin strips.
Arrange all the salad ingredients in a large salad bowl or on individual plates.
Whisk the vinegar with the olive oil, salt and a few turns of the pepper mill, coat the salad at the very last moment and serve chilled.
