This collection of footage by the Coral Bay crew shows the 3 day progression of what happens when a humpback whale died and washed over the reef.
Please watch and share to increase the understanding of the value of sharks as apex predators, which are vital for the health of our marine ecosystems.
The tail flukes of a humpback whale as it takes a dive on the Ningaloo Reef
NINGALOO REEF DIVE 2012 Coral Bay
An important behavioural aspect of humpback whales (Megaptera novaeangliae) is a complex
vocalization by the males known as a "song". All singing whales that have been sexed, by either genital
region observation or molecular analysis, have been male. Male humpback singing
occurs primarily during migration en route to and at winter breeding grounds.While on their
winter breeding grounds of the North West Australian coast (primarily June –
November), male humpback whales produce these long sequences of structured
vocalizations –
“songs” – These males may be “singing” to their
ladies.
One of the intriguing aspects of song is its dynamic
character and may be structurally described as a succession of four to seven
themes during a song session, which may last for hours and then be repeated all
over again. The song undergoes change throughout the season in a given
geographical winter region (such as the NW coast of Australia and Hawaii),
however all whales in the region adopt the new changes, apparently through a
process of vocal mimicry. Singers are typically found alone and stationary at
depths of around 15-30 m, although, it has also been noted that they sing en
route or occasionally while accompanying a mother-calf pair.
Various functions have been proposed for song,
including sexual advertisement, the maintenance of spacing between males, the
synchronization of ovulation in females, and a means for male-male assessment
of each other, although the functions of song continue to be elusive.
The concentration of singing humpback whales exhibit
many features typical of a “lek” mating system. Defined in simple terms, a lek
is a group display of males that females attend primarily for the purpose of
mating during the breeding season. Because individual males do not appear to be
territorial, as would be the case on a classic lek, it has been suggested that
the humpback whale mating system may be classified as a "floating
lek". The broad participation of males may be interpreted as a lekking
aggregation and the asynchronous singing chorus as an occurrence of resulting mutualism.
The participation of many singers may attract more females to the singing “hotspot”
area by a heightened signal level. Sexually mature males can benefit through
access to more females while immature males may gain deferred “hotshot” benefits
through increased opportunities to learn and practice the social, behavioural,
and acoustical skills of singing, along with the conventions of the winter
grounds, which can be applied in later years.
The humpbacks are already making their way up the
Coral Coast and will be sure to make a song and a splash about it!
A humpback whale breaches full body out of the water at the Ningaloo Reef on the Coral Coast.
MIGRATION MEDIA 2013 Coral Bay.
BIBLIOGRAPHY
Dawbin, W.H. (1997) Temporal segregation of humpback whales during
migrations in Southern Hemisphere waters. Memoirs of the Queensland Museum, 42,
105-138.
Herman, L. M., Pack, A. A., Spitz, S. S., Herman, E. Y. K.,
Rose, K., Hakala, S., & Deakos, M. H. (2013) Humpback whale song: Who
sings? Behavioral Ecology and Sociobiology, 67(10), 1653-1663.
The Dolphin Institute (2002) Humpback Whale: Natural History and Ecology.
The Dolphin Institute, viewed May
2014 <http://www.dolphin-institute.org/resource_guide/gettingtoknowhumpbackwhales.htm>.
Valsecchi, E., Hale, P., Corkeron, P., & Amos, W. (2002)
Social structure in migrating humpback whales (Megaptera novaeangliae). Molecular
Ecology, 11, 507-518
Winn, H.E., & Winn, L.K. (1978) The song of the humpback whale (Megaptera
novaeangliae) in the West Indies. Marine
Biology,47, 97-114.
… Moving on from whale sharks to update you
on sharks eating whales!
-
Earning their stripes as the appropriately nicknamed “garbage man of the sea”.
MIGRATION MEDIA 2014 Coral Bay
A deceased humpback whale was recently washed across the Ningaloo Reef at Coral Bay.
In-tow was a pretty impressive cohort of tiger sharks.
The entire carcass was munched to the bone in under 12 hours, which highlights the efficiency of these ‘Coral Coast Crew’ members at cleaning up a big mess. Imagine the stinking mess on the shore-line without this proper garbage removal system.
Tiger sharks truly are the ‘garbage men of the ocean’ and are vital to the health of the marine ecosystem as an apex predator.
All photos by MIGRATION MEDIA 2014 Coral Bay
There is wicked footage by I am having trouble getting it on here... check out the facebook group (Post: May 21)
The tiger shark (Galeocerdo cuvier) is a species of requiem shark and the only member
of their genus.This relatively large macropredator is capable
of attaining a length of over 5 m and is found in many tropical and temperate waters.
Renowned for its voracious appetite and indiscriminate
feeding habits, the tiger shark has been known to consume an incredible array
of items (including human rubbish) besides its standard fishy prey. This
behaviour enables these sharks to overcome food shortage problems, which can
affect species that feed more selectively. The tiger shark’s curiosity and
tendency to sample such a wide variety of objects has unfortunately, meant that
on occasion it has been responsible for attacks on humans. These
misunderstanding can be fatal as a result of its large size, but are extremely
rare in spite of a great deal of media hype. They are actually an incredibly
beautiful creature and it is an exhilarating experience to swim beside them in
a peaceful and respectful manner.
Apart from these occasional gatherings to feast, the tiger
shark is a solitary species that usually
more active at night, moving to inshore locations where it engages in active
hunting of prey, as well as scavenging, before returning to deeper waters where
it spends the day.
and this is all that remains 3 days later... totally stripped clean, down to the bone!! MIGRATION MEDIA 2014, Coral Bay
BIBLIOGRAPHY:
Arkive
(2013) The Tiger Shark (Galeocerdo cuvier).
Arkive organisation, viewed 22 May 2014
<http://www.arkive.org/tiger-shark/galeocerdo-cuvier/>.
Heithaus, M.
R. (2001) The biology of tiger sharks, Galeocerdo
cuvier, in Shark Bay, Western Australia: Sex ratio, size distribution,
diet, and seasonal changes in catch rates. Environmental Biology of Fishes, 61(1),
25-36. All photos by MIGRATION MEDIA 2014 Coral Bay
Flowing on from my previous blog post, there may be some
curiosity as to why there are other species of fish that feature alongside, in
front of and even attached to the whale shark.
Photo courtesy of Ningaloo Reef Dive - Migration Media 2014
These cosmopolitan
gentle giants of the Coral Coast are relatively slow moving cruisers of the
open ocean.
Hence, they
are actually like a moving reef sanctuary!
It is very
rare to see a large wild whale shark without an entourage...
Photo courtesy of Ningaloo Reef Dive, by Migration Media 2014
This little whale shark came with his own entourage of juvenile golden trevally! This was an amazing day with over 40 whale sharks spotted in the area by Coral Bay's spotter plane!!
Remoras, pilot fish, and juvenile golden trevallies are
often seen “hitching a ride” on or in its wake, even around their mouths. In
these symbiotic relationships are
generally ‘commensalistic’, in which the smaller fish are benefiting while the
whale shark is unaffected. The smaller fish gain protection, in some cases a
free ride, and a meal catching scraps of food. However, the whale sharks may still
gain some benefit if any skin parasites are eaten and [in the case of the footage featured in the previous blog, see below]
the occasional snack out of the shoal themselves. This may be considered as an
example of a ‘trade-off’ for the
protection that the small school of fish receives as a whole. Often larger
pelagic fish (like cobia) will also shadow the whale sharks, including other shark
species such as bronze whalers, which lurk in the depths below, in perchance of
an easy side-meal from its entourage.
Watch: Remoras, Cobias
& Rainbow Runners
As they are
typically thought lead a life of solitude, the whale sharks may actually 'enjoy
the company' out on the open ocean, although, I have found that this may not
always be the case.
Whilst working as a ‘lead swimmer’ guiding on whale shark
swim tours, I have had a tiring experience trying to keep up swimming with a 6m
juvenile whale shark that visibly seemed distressed about all the attention it
was receiving from its entourage. This whale shark was swimming unusually
erratically, seemingly trying to rid itself of the cloud of trevally, pilot
fish and remoras encircling it and clearly ‘getting in its face’. We left him in peace to deal with his 'frustrations' and to come to terms with his relationship with the remoras that would inevitably "stick around" for a life-long relationship.
BIBLIOGRAPHY:
Stewart, B. S., & Wilson, S. G. (2005). Threatened
fishes of the world: Rhincodon typus (smith 1828) (rhincodontidae). Environmental
Biology of Fishes, 74(2), 184-185.
Wilson SG, Polovina JJ, Stewart BS, Meekan MG (2006)
Movements of whale sharks (Rhincodon typus) tagged at Ningaloo Reef,
Western Australia. Marine Biology, 148, 1157–1166.
Wolfson, F.H. & Notarbartolo-di-Sciara,
G. (1980) Whale Shark Bibliography.Scripps
Institution of Oceanography Library. UC
San Diego: Scripps Institution of Oceanography Library. Retrieved from: https://escholarship.org/uc/item/4xd5r8q6
Along
the Coral Coast, on Australia's most accessible coral reef system, the Ningaloo
Reef is one of the most reliable places on the planet to encounter the world's largest extant fish; the majestic
WHALE SHARK (Rhincodon typus).
A whale shark with particularly striking pattern morphology, Coral Bay, Ningaloo Reef - Migration Media 2014
The whale shark(Rhincodon typus) is the sole member of its genus and the family, Rhincodontidae.
The
reason for their possibly confusing title is because this species of shark, like
many whales, are filter-feeders, and so along with their large size, they have
been so-called ‘whale sharks’. These "large, dopey, spotty fish" (as I
affectionately call them) are harmless, unless you are a tiny piece of
plankton, or get in the way of their powerful caudal fin (tail). Their diet
comprises mostly of tiny krill and plankton which they sift out of the water through
their gills.
Whale sharks are large migratory marine filter-feeders that aggregate in the Ningaloo waters annually from February/March to June/July.Their arrival of whale sharks to the waters of the Ningaloo Reef coincides with the cascading biomass production that follows the coral spawning events.
Coral Spawn - Migration Media 2014
A whale shark cruising the outer Ningaloo Reef - Migration Media 2014
Check out the footage of this interesting behaviour.
Plankton, it seems, is not the only food for a whale shark...
They are the largest extant shark (hence the largest fish) species in the world!
Of this largest known
extant fish species, the largest confirmed individual was 12.65 m with a weight
of more than 21.5 metric tons (unconfirmed reports of considerably larger whale
sharks exist). Claims of individuals over 14 m long and weighing at least 30 mt
are not uncommon (they really are HUGE; the biggest that I have swum with were
as big as our 12m charter vessel!). The whale shark boasts many titles for
sheer size in the animal kingdom, most notably being by far the largest living
non-mammalian vertebrate, rivalling many of the largest dinosaurs in weight,
owing to its aquatic life.Whale
sharks are found in warm tropical waters and live in the open ocean, reaching
sexual maturity at around 30 years with a lifespan estimated to be 70-100 years
(there is much unknown!).
What is the purpose of their distinctive spotty patterns?
Like many species that frequent the ocean’s surface, whale
sharks are counter-shaded. They have white bellies (which makes them hard to
see if a potential predator is underwater and looking up at them) and dark
backs (which makes them difficult to see if the predator is looking down on
them). It has been suggested that the pale spots and lines on their backs act
as camouflage. Each whale shark has its own unique pattern of
spots (behind its gills and above its pectoral fin) that can be used, along
with size, sex and scar marks, to identify individual whale sharks.
Interesting fact! – The whale shark has the thickest Dermal layer (skin) in the animal kingdom,up to 14cm thick! – which is fortunate, as the increased shipping and boating traffic across the ocean poses a serious threat to any marine life in their direct path. Deep scars, gouges and even missing fins are often noted while encountering these docile creatures.
Remarkably,
neither mating nor pupping of the world’s largest fish has been observed!…
although, she’s a “mega-mumma”!
It
has been found that they are ovoviviparous (producing eggs that are hatched
within the body, so that the offspring are born alive but without placental
attachment), with the females giving birth to live young 40 to 60 cm long.
Evidence has suggested that around 300 embryos are at different stages of
development and so the ‘pups’ are not all born at once, but rather the female
retains sperm from one mating and produces a steady stream of pups over a
prolonged period.
A young whale shark, Ningaloo Reef - Blue Media 2014
Sharks
have existed for over 350 million years, evolving over 100 million years before
the dinosaurs did. It has been suggested that the whale shark has been around
for the past 60 million years, yet there is much that is unknown of the world’s
largest shark. Their filter-feeding system is likely to be the greatest
evolutionary element for them, since only three species of shark are actually
filter-feeding organisms.
Recent
studies have relied almost exclusively on mark–recapture data from
photo-identification to estimate population size, age structure and survival
rates of this mysterious creature.
Some
individuals do return semi-regularly to the same aggregation site over time,
but where they go and what they do in between is largely unknown. It is
believed that they tend to stay within equatorial waters, possibly following
currents and patterns of food production (such as coral spawnings). Information
collected by tracking devices and satellite telemetry has provided some
insights on short-term movements. However, a major issue with some of the radio-transmitting tracking
devices that are used is that they only transmit a signal when at the surface.
The issue is, that whale sharks are fish – they do not require to come to the
surface to breathe, and so may not transmit reliable data.
Their
large size and apparently slow reproductive rates suggest a particular
vulnerability to overexploitation and rapid environmental change. Whale sharks
appear to have a high dispersal capacity, and so an ocean-wide approach is
necessary for the understanding and management of these ecologically important
species.
This documentary goes for
~28mins: to cut it down a bit for you, I suggest at least watching: 0:52–3:15;
9:30-10:10, 13:52–18.15, 19:45-(feeding)-20:37; 24:50-(breeding)-26:58. I was
very pleased to see the emphasis made on education for future generations to
“protect and nurture”.
This documentary follows
the story of the Research trip off the coast of Qatar undertaken by the Maersk
Oil Research and Technology Centre (MO-RTC) in partnership with the Ministry of
the Environment's Whale Shark Research Project. Amongst the towering structures
beneath the oil rigs is a gathering place for giant fish, a wonder of the
world's oceans: Whale sharks, the largest known extant fish species.All the footage was captured on
the Red Epic and, as such, has captured the majestic nature of these mysterious
ocean wanderers.
A previous “job”
of mine for a few years was to help deliver the “experience of a lifetime” in
encountering and swimming with these majestic creatures in the wild. I have
been blessed with uncountable
I have also been fortunate enough to guide for, assist and
work alongside some of the world’s leading experts on whale sharks on a few research
expeditions.
Whale shark and Encounter II - 2014 season, Coral Bay - Migration Media
It was really hard for me to
sort through my own ‘references’ of images and footage (I have personal permission to share). These short films,
made by (and featuring) my friends and colleagues on the Ningaloo Reef, will
hopefully provide insight and enjoyment.
Another
short video to give you a taste of a ‘Coral Coast’ experience which also
features a few other Coral Coast crew members, including some fury ones! (I
also used to work with this charter company featured: Ocean Eco AdventuresJ)
BIBLIOGRAPHY
Bradshaw
CJA, Mollet HF, Meekan MG (2007) Inferring population trends for the world’s
largest fish from mark–recapture estimates of survival. Journal of Animal Ecology,
76,
480–489.
Colman, J.
(1997). A review of the biology and ecology of the whale shark. Journal of Fish Biology, 51(6), 1219-1234.
Joung, S., Chen, C., Clark, E., Uchida,
S., & Huang, W. (1996). The whale shark, rhincodon typus, is a livebearer: 300 embryos found in one
'megamamma' supreme. Environmental
Biology of Fishes, 46(3),
219-223.
Stewart, B. S., & Wilson, S. G.
(2005). Threatened fishes of the world: Rhincodon
typus (smith 1828) (rhincodontidae). Environmental
Biology of Fishes, 74(2),
184-185.
Wilson
SG, Polovina JJ, Stewart BS, Meekan MG (2006) Movements of whale sharks (Rhincodon typus) tagged
at Ningaloo Reef, Western Australia. Marine
Biology, 148, 1157–1166.
