Last week Croatian maritime authorities restricted navigation off the Adriatic coast to allow two stray whales to find their way out to deep water, Reuters reported. An operation was mounted near the port of Split to rescue the finback whales, a 30-m (100 ft) long female and her calf, which are rarely found in shallow coastal waters. The whales were first spotted near the resort of Makarska, south of Split, some 10 days ago and appeared unable to make their way out because of intense maritime traffic, including tourists trying to approach them in speedboats. The Ministry of Environment warned holidaymakers to keep at least 400 m (0.25 miles) away. Rescue coordinator Melita Peharda of the Institute of Oceanography said the whales' natural sonar could be disturbed by ships' radars.