diff --git a/marine/marine.py b/marine/marine.py
index c04ccff..4af77fb 100644
--- a/marine/marine.py
+++ b/marine/marine.py
@@ -30,6 +30,13 @@ def __init__(self, lib_path: str, epan_auto_reset_count: Optional[int] = None):
         self._marine.marine_free.argtypes = [MARINE_RESULT_POINTER]
         return_code = self._marine.init_marine()
         if return_code < 0:
+            if (
+                return_code
+                == c_int.in_dll(
+                    self._marine, "MARINE_ALREADY_INITIALIZED_ERROR_CODE"
+                ).value
+            ):
+                raise RuntimeError("Marine is already initialized")
             raise RuntimeError("Could not initialize Marine")
 
         if epan_auto_reset_count: