There isn't a widely accepted international standard for a "nautical league." The nautical mile (nmi) is the more common and internationally recognized unit of measurement for distances at sea. A nautical mile is approximately equal to one minute of latitude along a meridian, and it is used worldwide for maritime and aviation navigation.
In some regions, historical or localized variations of the league may have been used in the past, but these are not part of the modern international system of measurement. It's important to note that such variations can differ by country and even within different historical periods.
For precise and internationally recognized measurements in maritime and aviation contexts, the nautical mile is the preferred unit of distance. One nautical mile is equal to approximately 1.852 kilometers or 1.15078 statute miles (land miles).
A perch is a unit of length that was historically used in some English-speaking countries, primarily in the United Kingdom. It is equivalent to 5.5 yards or 16.5 feet (about 5.0292 meters). The term "perch" is relatively old and is not commonly used in modern measurements.
Perches were often used in land measurement, particularly in agriculture and real estate. They were also sometimes used in surveying. However, the use of the perch as a standard unit of measurement has largely been replaced by more modern and standardized systems such as the metric system or the imperial system based on feet and yards. As a result, the perch is considered an archaic or historical unit of measurement today.