Female Risso’s dolphin stranding at Kidd’s Beach, South Africa

The 2.96 m female Risso’s dolphin which stranded at Kidd’s Beach after being reported alive at Cove Rock two days earlier

The museum was alerted on Monday 9 Sept 2019 (via the aquarium – Ms Siani Tinley) that a fisherman Juan Wessels had come across a live dolphin in the surf zone west of Cove Rock on Sunday 8 Sept 2019. A video of the dolphin indicated that the animal was in distress. With some effort he managed to get the dolphin to deeper water and it swam away.

Museum scientist Kevin Cole made a comment to Juan Wessels after viewing the video that its chances of survival were slim and that he thought it may strand within a day or two. Juan advised where he thought the animal may come out (somewhere west of the location where he had found it).

Mrs Jacky Biller of Palm Springs called to report that a dolphin had stranded west of the Kidd’s Beach Village (Tuesday 10 September 2019). Her husband Sean Biller is also thanked for securing the specimen overnight so that it would not be lost to the sea at the high tide. An investigation revealed that it was a deep water 2.96 m female Risso’s dolphin.

This is the largest dolphin not to be called a whale and anatomically has a very ‘top-heavy’ head section. Their appearance presents with a blunt head (carrying a very distinctive vertical furrow in its face) and a very erect centrally placed dorsal fin. The colour of the animal changes from birth to adulthood and most notably in adulthood it has an anchor shaped mark on the chest. As they grow older, they accumulate characteristics body scarring which was very visible on the stranded specimen. They only have teeth on the front of the lower jaw in our waters. A robust, conical tooth was collected from the animal with a diameter of 7.2 mm at the gum base.

A necropsy was undertaken on Wednesday 12 September 2019 by Kevin Cole with the kind assistance of Kidd’s Beach resident Barry Marshall. All internal organs were examined and the stomach removed for a detailed investigation.

No food or plastic was found in the latter and all organs (liver, lungs, lower intestine, ovaries and kidneys) appeared normal with the exception of the 1.653 kg heart. A hard chestnut sized lump was detected and it was removed and preserved for an investigation by Bayworld and Nelson Mandela University scientists. Other samples included blubber, skin, blood and muscle.

Kidd’s Beach resident Barry Marshall kindly assisted Kevin Cole with the necropsy on the female Risso’s dolphin

These dolphins can grow to a length of 3.41 m (males) and 3.18 m (females). They normally move in small groups (10 – 30 individuals) and occur worldwide in temperate and tropical seas. In our seas they are associated in waters of 350 – 600 m of the upper continental slope.  Their main diet consists of squid and it is presumed they feed mostly at night.

The 1.6 kg heart from the dolphin has been preserved at the museum for further studies by cetacean scientists

This is the 4th Risso’s dolphin record for the museum since 2011 with the last being at Morgan Bay (March 2019). Four mass strandings of the species have been recorded in South Africa – May 1983 (4 males and 4 females). April 1989 (10 males and 11 females), February 1990 (1 male and 6 females) and August 1991 (9 males and 2 females). There still a lot we need to learn about these cetaceans and they are listed as data deficient in the South African Red Data Book.

Reference: Whales and dolphins of the southern African subregion by Peter B. Best

Advertisements
Posted in Uncategorized | Leave a comment

Notes on the oarfish stranding (Regalecus glesne) at Chintsa East (East London, SA)

Head section of a model of the oarfish, Regalecus glesne, on display at the East London Museum

On the 28th August 2019 a very unusual oarfish washed ashore at Chintsa East. It was reported to the museum by Geoff Philipps and was alive when first sighted and later died. Sheila Gill of Chintsa East (pictured below) responded quickly to a museum request to secure the specimen by saving it from being washed out by the tide.

Sheila Gill holds the 1.56 m oarfish which washed out at Chintsa East. Photo Kevin Cole ELM

The 1.56 m fish was identified by museum scientist Kevin Cole and is only a third record for the museum. These fish have a worldwide distribution and live in the open ocean of tropical and temperate seas. Most noticeable when alive is the brilliant silver colour of the head and body with crimson dorsal and pelvic fins. A good mount of the specimen can be seen in the Oceanic display in the marine gallery. The SA Institute of Aquatic Biodiversity (SAIAB) was contacted and a tissue sample taken before the fish was frozen.

Specimens are normally washed ashore after stormy weather. They are rarely trawled by fishing boats. The ‘oars’ (elongate pelvic fins) are not used for locomotion through the water but act as ‘tastebuds’ (chemo-receptive organs) which may be useful in selecting prey species.

The flesh is not palatable, even when cooked, as it is watery and soft.

One of the behavioral traits of the fish is that it adopts a vertical position in the water column to spot its food (planktonic crustaceans) which are normally silhouetted against the light from the surface. The oarfish is a most likely source of sea serpent myths. They are also known in ancient Japanese fishermen tales to warn of pending tsunamis when sighted close to the surface or beached. They can grow to a length of 8 m and weigh well over a 100 kg’s.

The Oceanic display in the museum marine gallery has a model of an oarfish on display

Reference: Coastal fishes of southern Africa by Phil and Elaine Heemstra

Posted in Uncategorized | Leave a comment

Humpback whale stranding at Hamburg, Eastern Cape

Daily Dispatch, Monday 26 August 2019

Posted in Uncategorized | Leave a comment

Two cetacean strandings this past weekend – striped dolphin at Chintsa bay and a humpback whale at Cebe (Wild Coast)

Posted in Uncategorized | Leave a comment

Warm winter weather – ideal for hiking the Strandloper Trail

The past number of weeks have produced some fine sunny and sometimes hot weather (berg winds). May, June and July are great months to get out along the coast north of East London and to do the 4 night, 5 day Strandloper Hiking Trail.

Folk that have passed through recently have had a magic experience along some of South Africa’s best coastline.

The East London Museum has been involved with the Strandloper Trail since its inception in 1996. Museum scientist Kevin Cole has been Chairperson of the Strandloper Ecotourism Board for the past 21 years. Other long standing members still active on the Board are Sean Price (founder member), Dave Marais (project Director), Velile Ndlumbini and Janna Cooper.

Bryan and Erica Church are also long serving, hard working management staff (Trail Manager and Reservations Manager respectively) having joined the trail in 1998. Senior coastal ranger John Pakamile and coastal ranger Johnson Mila have also made a great contribution to the success of this coastal ecotourism experience.

Posted in Uncategorized | Leave a comment

The Nahoon Estuary Nature Reserve delights as usual ….

This gem of a reserve accessible from Beacon Bay provided an avifaunal and mammal treat this past weekend. The warm winter weather (hot in fact, around 27 C) had lots of birds and at least 7 individual blue duiker drink at the water fountain in the reserve.

The museum is working with Buffalo City Metro Municipality to have the reserve extended and the additional portions proclaimed a provincial reserve. A meeting with officials was held last week to discuss this. The Eastern Cape Parks and Tourism Agency will be assisting in the process.

From top left: Tambourine dove (male), Cape white eye and a yellow weaver, olive thrush, helmeted guineafowl and a blue duiker (male)
Posted in Uncategorized | Leave a comment

A note of thanks from young Seth

Last week I had the privilege of interacting with young 7 year old Seth at the museum. His interest in the natural world was encouraging and I was taken by his enthusiasm during our gallery tour. As much as a spark may have been ignited in him he kept my enthusiasm fired up as well and it was a treat to have him visit.

I also appreciated the kind note received from his grandmother Mrs Carol Flint who arranged the visit.

Posted in Uncategorized | 1 Comment