Effects of swim‐with‐dolphin tourism on the behaviour of spinner dolphins, at Samadai Reef in the Egyptian Red Sea

Abstract

1. Spinner dolphins, Stenella longirostris, are the primary target for marine mammal tourism in Egypt. The present study investigated the short-term effects of tourist presence on the behaviour of spinner dolphins at Sha'ab Samadai (Samadai Reef), in the southern Egyptian Red Sea.2. The reef has a large central lagoon where a population of spinner dolphin regularly rest from mid-morning to mid-afternoon; visitors are permitted to snorkel in the southern part of the lagoon, but not in the northern closed zone that the dolphins mainly use.3. Dolphin behaviour was monitored both on days when tourist boats were present and on days when they were absent. In the presence of tourists the proportion of time that the dolphins spent resting was reduced by two-thirds, whereas the times spent milling, travelling, and showing avoidance behaviour all increased. 4. Furthermore, upon using Markov chain modelling to investigate the effect of tourist presence on the transition probabilities between dolphin activity states, significant changes were found in 10 of the 25 possible behavioural transitions, including increased probabilities of transitioning from resting to milling or travelling, from milling to travelling or avoiding, and from travelling to avoiding. 5. These findings raise concerns that despite the management measures in place, tourist activities affect the dolphins' behaviour to a greater extent than was previously apparent, with potential long-term negative effects on their energy budget.The study led to proposals for amending the zoning of the site and for strengthening the regulations for tourist vessels.

Dolphin Watching and Compliance to Guidelines Affect Spinner Dolphins’ (Stenella longirostris) Behaviour in Reunion Island

“…These short-term changes in behaviour have commonly been reported in previous studies as a direct avoidance strategy towards approaching vessels [ 11 , 13 , 15 , 16 , 71 , 72 ], which culminated in higher behavioural budget allocation for travelling and milling when vessels were present. Similar trends were reported in spinner dolphins in Hawaii [ 12 , 22 , 63 ] and Egypt [ 37 ] and in common bottlenose dolphins in Panama [ 16 ] and New Zealand [ 14 ]. In the presence of vessels, the recovery times for these behaviours are smaller, suggesting that when disturbed, dolphins tend to favour these activities.…”

“…In Reunion Island, as a first step to minimise disturbance during critical periods for the species, the decree amended in July 2020 established a quiet period from 6 p.m. to 9 a.m., during which no cetacean species can be approached closer than 300 m [ 43 ]. For other dolphin species, spatio-temporal mitigation measures to reduce the pressure during vital periods have been widely suggested as an effective management tool [ 9 , 14 , 18 , 21 , 37 , 67 ]. This study was, however, carried out before the implementation of this period of quietness.…”

“…Its core habitat lays between 45 and 75 m depth in front of Saint-Gilles Port, where most of the maritime and touristic activities occur [ 35 ]. Spinner dolphins typically spend the morning resting and socialising in shallow waters close to the coast before travelling offshore to forage at night [ 25 , 37 , 38 ]. The particular ecology of spinner dolphins, with predictable daily migrations across spatially limited areas, facilitates dolphin-watching vessels to observe them [ 25 , 26 , 37 , 39 , 40 , 41 ].…”

“…Spinner dolphins typically spend the morning resting and socialising in shallow waters close to the coast before travelling offshore to forage at night [ 25 , 37 , 38 ]. The particular ecology of spinner dolphins, with predictable daily migrations across spatially limited areas, facilitates dolphin-watching vessels to observe them [ 25 , 26 , 37 , 39 , 40 , 41 ]. Due to the easiness of encounters, especially in the morning, the population of spinner dolphins is the most consistent main target of the cetacean-watching activities in Reunion Island [ 31 ].…”

Status of Indo-Pacific Bottlenose Dolphin, Tursiops aduncus (Family Delphinidae: Order Cetacea) in the Northern Protected Islands, Hurghada, Red Sea, Egypt

“…Sighting of dolphins became the most attractive ecotourism in the Red Sea; it attracts thousands of tourists to watch dolphins at Satayeh in Wadi El-Gemal national parks and Samadai reef in the Marsa Alam city (Notarbartolo di Sciara et al, 2009;Shawky et al, 2020). The wonderful biodiversity of the Red Sea marine life, however, makes Hurghada one of the best tourist destinations in the world for wild dolphin sighting by snorkeling and diving .…”