Because otherwise you can't fish at low levels.

src/main/java/com/gmail/nossr50/skills/fishing/FishingManager.java

@@ -92,7 +92,9 @@ public class FishingManager extends SkillManager {
     }
 
     public void masterAngler(Fish hook) {
-        hook.setBiteChance(Math.min(hook.getBiteChance() * (getSkillLevel() / 10.0), 1.0));
+        System.out.println("BEFORE: " + hook.getBiteChance());
+        hook.setBiteChance(Math.min(hook.getBiteChance() * Math.max((getSkillLevel() / 10.0), 1.0), 1.0));
+        System.out.println("AFTER: " + hook.getBiteChance());
     }
 
     /**