Vagrant Southern Elephant Seal and Human Disturbance in Mossel Bay, South Africa

Abstract

An opportunistic observational study on human disturbance of a vagrant southern elephant seal that was hauled out on a tourist beach in Mossel Bay, South Africa, is presented. Incidences of pedestrians ignoring signage and the demarcation barrier around the seal raise questions about the management of such haulout events, pubic safety and the effects of disturbance.Key words: human disturbance, Mirounga leonina, Mossel Bay, pinnipeds, southern elephant seal, tourism management, vagrant.Southern elephant seals Mirounga leonina have a circumpolar distribution in the Southern Ocean with major breeding populations close to the Antarctic Polar Front (Laws 1994). Approximately 54% of the world population breeds at South Georgia (Boyd et al. 1996) some 4750 km from South Africa (Bester 1989). The closest breeding colonies to Mossel Bay, South Africa are the Prince Edward Islands (~46°46'S, 37°51'E) 1933 km to the southeast, Bouvet (54°25'S, 3°24'E) 2697 km to the south, and Gough Island (40°20'S, 9°54'W) 2922 km to the southwest (Bester 1980(Bester , 1989Kirkman et al. 2001). Southern elephant seals are capable of travelling very long distances at sea covering hundreds to thousands of kilometres annually (e.g. Bester 1989;Jonker & Bester 1998; Tosh et al. 2009;Reisinger & Bester 2010). The longest recorded movement is of a juvenile female sighted on Peter Øy Island after being branded on Macquarie Island, approximately 5200 km away, returning to Macquarie Island subsequently (Hindell & McMahon 2000). It therefore comes as no surprise that Oosthuizen et al. (1988) reported on records of southern elephant seals on the South African coastline, and that an unconfirmed number has been recorded since then by three separate regional authorities (M. Meyer, pers. comm., November 2010 ) resulting in a need to work towards a combined dataset in South Africa. It is unclear if these records of elephant seals on the South African coastline represent true vagrants or the outer fringe of normal dispersal (Oosthuizen et al. 1988). Oosthuizen et al. (1988) also reported that a high number of sighted animals were tagged upon discovery, which would counter the likely overestimate of vagrant presence due to re-sightings of unmarked animals, although an unknown number of individuals probably go unnoticed.Occasionally, vagrant elephant seals may occupy beaches for a short period and create tremendous local interest. Recently an adult female southern elephant seal hauled out onto the popular Diaz tourist beach in Mossel Bay (34°09'32"S, 22°06'37"E) at 14:48 on 12 October 2010. The elephant seal had injuries which included a cut below the right eye (~5 cm) as well as through the left upper lip (~5 cm) and a tear on the lower abdomen (~15 cm) that did not penetrate very deeply (<5 cm). The abdominal wound was bleeding lightly on arrival on the first day, then stopped bleeding by that evening and the wounds appeared to be healing on the third day. She remained onshore for four days and was last seen at about 8:30 on 16 October.While on land, th...

Dispersion of a southern elephant seal Mirounga leonina to Possession Island, Namibia

“…Similarly, a possible return of SES breeding populations is unlikely in temperate and sub-tropical Southern Africa. Despite the numerous documented, yet uncollated, sightings of SES in the Southern African subregion (see Mertz and Bester 2011), these usually occur from November to February (Oosthuizen et al 1988) primarily during the moulting season of immatures/sub-adults of both sexes and of adult females (Kirkman et al 2003). The few sightings of adult female SES with pups on the South African coastline do not include repeated pupping by the same individual (Oosthuizen et al 1988;Port Elizabeth Museum unpublished data).…”

“…The frequent recording of SES on the Southern African coastline (e.g. Ross 1969;Best et al 1981;Oosthuizen et al 1988;Mertz and Bester 2011) deserves collation and spatial and temporal interpretation.…”

“…Vagrants have been sighted as far north as the Sultanate of Oman (Johnson 1990) and Sri Lanka (de Vos 2021). SES sightings on the coasts of South Africa abound, with an unconfirmed number recorded by three separate regional authorities (Mertz and Bester 2011). To date, the records of SES hauling out, and in some cases, producing pups, on the Southern African coasts remain unpublished, except for a dated summary of sightings (Oosthuizen et al 1988).…”

Extreme dispersal or human-transport? The enigmatic case of an extralimital freshwater occurrence of a Southern elephant seal from Indiana

“…In particular, vagrant Southern elephant seals have been recorded on the coasts of Argentina, Uruguay, Brazil, Chile, Peru, Ecuador, Galapagos Islands, Panama, South Africa, Australia, New Zealand, Oman, and Mexico ( Fig. 2A ) ( Alava & Carvajal, 2005 ; Magalhães et al, 2003 ; Mayorga et al, 2017 ; Redwood & Felix, 2018 ; Acevedo et al, 2016 ; Johnson, 1990 ; Sepúlveda et al, 2007 ; De Moura et al, 2010 ; Pacheco, Silva & Riascos, 2014 ; Cárcamo et al, 2019 ; Sepúlveda et al, 2018 ; De Moura, Di Dario & Siciliano, 2011 ; Mertz & Bester, 2011 ; Mayorga et al, 2016 ; Shaughnessy, Kemper & Ling, 2012 ; Elorriaga-Verplancken et al, 2020 ).…”