diff --git a/echopype/mask/shoal.py b/echopype/mask/shoal.py
index 1408d4693..013504deb 100644
--- a/echopype/mask/shoal.py
+++ b/echopype/mask/shoal.py
@@ -151,6 +151,6 @@ def _weill(
         ).compute()
         dask_mask = da.asarray(dask_mask, allow_unknown_chunksizes=False)
 
-    mask.values = dask_mask
+    mask.values = dask_mask.compute()
 
     return mask