3 cups low-sodium vegetable broth
1 1/2 lbs. russet or Yukon Gold potatoes, peeled and cut into 1 1/2-inch chunks
1 leek, white and green parts, washed well, halved lengthwise and thinly sliced
1 lb. carrots, peeled, halved lengthwise and cut into 1/2-inch slices
1/2 lb. parsnips, peeled, halved lengthwise and cut into 1/2-inch slices
2 Tbsp. quick-cooking tapioca, such as Minute Tapioca (found in the Pudding aisle)
2 Tbsp. fresh lemon juice
1/2 tsp. celery salt, or to taste
1/2 tsp. freshly ground black pepper
1/4 tsp. dried thyme, or to taste
1 1/2 lbs. salmon fillets, skinned and cut into 1 1/2-inch chunks
2 cups low-fat evaporated milk
2 Tbsp. finely chopped fresh dill
fresh dill sprigs (optional garnish)