diff --git a/skimage/morphology/_watershed.pyx b/skimage/morphology/_watershed.pyx
index beaf874b..a0857707 100644
--- a/skimage/morphology/_watershed.pyx
+++ b/skimage/morphology/_watershed.pyx
@@ -23,12 +23,12 @@ include "heap_watershed.pxi"
 
 
 @cython.boundscheck(False)
-def watershed(DTYPE_INT32_t[:] image,
+def watershed(DTYPE_INT32_t[::1] image,
               DTYPE_INT32_t[:, ::1] pq,
               Py_ssize_t age,
               DTYPE_INT32_t[:, ::1] structure,
-              DTYPE_BOOL_t[:] mask,
-              DTYPE_INT32_t[:] output):
+              DTYPE_BOOL_t[::1] mask,
+              DTYPE_INT32_t[::1] output):
     """Do heavy lifting of watershed algorithm
 
     Parameters
diff --git a/skimage/morphology/watershed.py b/skimage/morphology/watershed.py
index c9fb1789..2bdb57b2 100644
--- a/skimage/morphology/watershed.py
+++ b/skimage/morphology/watershed.py
@@ -202,7 +202,7 @@ def watershed(image, markers, connectivity=None, offset=None, mask=None):
             stride = np.dot(image_stride, np.array(offs))
             offs.insert(0, stride)
             c.append(offs)
-    c = np.array(c, np.int32)
+    c = np.array(c, dtype=np.int32)
 
     pq, age = __heapify_markers(c_markers, c_image)
     pq = np.ascontiguousarray(pq, dtype=np.int32)