by Clinton Duffy, Science & Research Unit, Department of Conservation
Whale sharks are generally considered to be a tropical species, and have only recently been formally reported from New Zealand waters. Despite this they appear to be regular summer visitors to the northeast North Island, and have been observed from the Three Kings Islands to Te Kaha, eastern Bay of Plenty. In general their distribution coincides with the path of the East Auckland Current, and sea surface temperatures of 21 to 24oC. However, sightings have been reported during years when sea surface temperatures are colder than average. Satellite tracking of whale sharks in the North Pacific has shown they can tolerate temperatures as low as 10 oC. Whale sharks are reported to reach a maximum length of about 18m. Estimated lengths of New Zealand whale sharks range from 3.5 to 15m, with most being between 6-9m long.
The peak month for sightings is February but they have been reported from November to April. Whale sharks are often sighted over the shelf, and a number of sightings have been made close to shore off North Cape, Rangaunu Harbour, Waiheke Island and most recently Tutukaka. The area off Whakatane between Rurima and Motuhora (Whale) Islands and White Island appears to be a favoured location for whale sharks, and several have been observed feeding on schools of anchovies. Whether or not this is an aggregation site or simply an artefact of the concentration of game fishers targeting tuna around the meatballs is difficult to say without more information on the distribution and behaviour of the sharks around northern New Zealand. Prior to 2002 I was only able to obtain data from 36 New Zealand sightings, all made since 1980. During the mid to late 1990s the number of sightings reported annually ranged from three to five. Already this year there have been 11 sightings reported from Waiheke Island, Rangaunu Bay, Bay of Islands, Tutukaka and the western Bay of Plenty.
Despite this being an exceptional number of sightings, it is not possible to say if this is an exceptional year for whale sharks because we know so little about them. Divers encountering whale sharks can provide valuable information on the species. Details such as date, location, length, sex (males have a pair of elongated claspers on the inside of their pelvic fins), water temperature and behaviour. Photographs of distinctive marks can also be used to identify sharks re-sighted in New Zealand and elsewhere in the Indo-Pacific and South Pacific.
Whale Sharks off Tutukaka
by Pete Atkinson
While Vigia was motoring to Tutukaka from Whangarei (28 January), Anna Cherry spotted a disturbance in the water. âDolphinsâ she thought, âSunfishâ was my guess.
Whale sharks are hard to mistake for anything else. When we saw the tail and dorsal together we realised what this seven metre fish must be. I had never heard of whale sharks in New Zealand and had never seen one in 19 years in the Pacific. As we motored discretely towards it the huge shark came right up to the boat, curious about us. Because the sun was obscured and it was 7pm I decided to shoot some topside pictures and motored on to Tutukaka.
In the calm the following day we spotted makos and hammerheads, common dolphins and a Brydeâs whale. It wasnât until we were three miles from Tutukaka on our way home that Anna spotted another whale shark. Again it was late, but there was light. Anna dropped me in and I intercepted the shark. In the thick plankton visibility was less than a metre. I was worried that the Brydeâs whale feeding not far away would lunge through the plankton without seeing me. Outside the clouds of plankton the water was green with 15m visibility.
The female shark, feeding on the thick plankton seemed almost oblivious of me.
I shot some pictures with my Nikonos 3 / 15mm lens, then measured the light. I pushed Velvia 100 film two stops and shot with the aperture wide open. The pushed film elevated the blues.
I was able to shoot 30 frames. The first frame of a whale shark ever taken in New Zealand was the best. Tobi Bernhard scanned it and lifted the exposure. It ran on the cover of the Northern Advocate, page two of the New Zealand Herald and on TV3âs 6pm news.
by Angie Belcher. Photo from www.andybelcher.com
It started on a lazy, wet holiday Friday (6 Feb) while cruising home from the movies with my daughter, Oceane when I received a text message from Andy. âGt 2 boat ramp qikâ It was 6.30pm. Had something dreadful happened?
We rushed to the Kaituna ramp to find wet-suited Andy with our friend Rosco and his boat. They all shouted at us to get on board and before I even knew what was happening we were heading off at 30 knots.
I must be mad!
What was the rush about? Well, Rosco and the skipper had been returning from a fishing trip and nearly ran over four whale sharks feeding on the surface, just 10 miles off Maketu!
Finding them again would be like finding a needle in a haystack … but we did it! We chose to stay with one of the fish, which was about 12 metres long with a mouth about one and a half metres wide. To swim with a whale shark was the most amazing experience. Iâve never swum so fast in my life to keep with the fish as it fed on small baitfish darting about near the surface.
Andy tried to take a few pictures but the light was fading fast so he got out and opted for topside shots. Rosco dressed in Andyâs gear and he and I hopped back into the water. This experience was even better. I was swimming alongside the fish and Rosco was just above it. The poor old whale shark didnât know he was there and started to rise towards the surface. All of a sudden the fin was right in front of Roscoeâs hand and he just couldnât help himself – he reached out and tried to grab hold of the fin! I think he saw the movie Whale Rider too many times! The fish suddenly flicked its tail. The flick was enough to give Rosco a fright and he glanced back at me with eyes like footballs! With that one flick the shark had moved 20 metres ahead of us. Andy remarked many times âIâve never seen a whale shark in 32 years of diving and bugger me, here they are, right on our door stepâ.
We went out again next morning looking for them but had no luck, only saw dolphins which kept Oceane very happy. I think she was quite relieved because we had her gear with us and told her that she would have to snorkel with the whales because she might never get the chance again!
Foot note: It must be noted that the practice of trying to ride marine creatures is not condoned or recommended for two reasons: Touching any marine creature can remove the protective coating on its skin and leave it open to infection; A large creature like a whale shark is extremely powerful and certainly capable of knocking a diver unconscious with one flick of its huge tail! You should treat all wild creatures with the greatest of respect.
Report sightings to: Clinton Duffy, Department of Conservation, P.O. Box 112, Hamilton. email@example.com. For more information refer to: Duffy, C. A. J. (2002). Distribution, seasonality, lengths, and feeding of whale sharks (Rhincodon typus) in New Zealand waters. New Zealand journal of marine and freshwater research, 36: 565-570.