Operational interactions between humans and Indo-Pacific Finless Porpoises, Neophocaena phocaenoides: An integrated spatial model in the northern Strait of Hormuz

Abstract

The Indo-Pacific Finless Porpoise (Neophocaena phocaenoides) is a little-known cetacean under human pressure in the Persian Gulf and the Gulf of Oman. In Iran, most sightings have been reported from the northern coasts of the Strait of Hormuz. We invested the spatial overlap between finless porpoise habitats and human activities in the Harra Protected Area and Biosphere Reserve in the north of the Strait of Hormuz. Suitable porpoise habitats were modeled using the Maxent model, employing 112 presence points and an array of physical seascape variables. A detailed (30 m) Landsat 8-derived depth layer was found as the most important factor determining porpoise distribution. The multi-criteria evaluation procedure was calibrated using a set of pairwise weighted and fuzzified layers including ship routes, and distance from main boat routes, coastal and port cities, and fishing zones to determine the intensity of human sea use. Results showed a significant spatial overlap of over 3,500 ha (8.7% of the region) between highly suitable porpoise habitats and human sea use areas, covering the whole entrance of the estuary where high-speed boats sail between northern and southern cities. Since the porpoise population is found in the study area only within the borders of the Harra Protected Area, limited fishing activities and low-speed boat movement inside the zone of overlap are suggested to lower the human-porpoise interaction in the region.