Northern Peru becomes the new aggregation area for whale sharks

The whale shark is worldwide categorized as endangered due to its large population decline. Even though it is a giant, information on its natural history is still scarce. In the Eastern Pacific, the only well known... [ view full abstract ]

The whale shark is worldwide categorized as endangered due to its large population decline. Even though it is a giant, information on its natural history is still scarce. In the Eastern Pacific, the only well known aggregations are the Gulf of California (Mexico) and the Galapagos Islands (Ecuador). Moreover, most of the known aggregations are composed mainly by juvenile males. Our previous studies identified northern Peru as an area used by sharks seasonally. From October 2014 to January 2018, we conducted 62 whale shark boat surveys and collected data on size, gender, behavior, location and took pictures for photo-identification. We also obtained data from non-dedicated surveys and collaborators. Our photos were compared with the database from Mexico to find matches. We encountered a total of 203 sharks, and obtained photos from 195 of them which resulted in 95 unique sharks. The identified sharks were composed by 77% males and 23% females. Males were on average 6m long (range 3-9, n=48) and females 7m (range 3-10, n=14). The highest observations of sharks were in December and November and most of them were observed feeding. No matches were found with the Mexican database. Our findings highlight northern Peru as an important aggregation area in this region, with a new population that, so far, has no connectivity with Mexico and that is composed by both juvenile and adult males and females making it unique and important to study and conserve. This research was essential for issuing the national legislation that now protects them.