The Starfish of Hong Kong, Part 3

Cholcolate Chip Starfish (Nidorella armata)

image by Steve Ryan, cc-by-sa 2.0.

Nidorellia armata is also known as the chocolate chip star which leads to confusion with Protoreaster nodosus which is also know as the cholcolate chip starfsih in english. It has a diameter of about 23 cm and lives on rocky surfaces with algae and seagrass at depths of 5 – 70 m. They feed on small invertebrates and algae which they digest externally by turning their stomachs inside out  and covering their prey with it. They are found in tropical waters clinging on corals and rocky reefs.

Sand Star (Archaster typicus)

image by Rie Tan cc-by-sa 2.0 .

It is found in shallow waters in the western Indian Ocean and the Indo-Pacific , incouding the Maldive Islands, the Bay of Bengal, Singapore, northern Australia, New Caledonia, the Philippines, China, southern Japan and Hawaii. It usually occurs in areas of the seabed with soft sediments such as sand, silt and seagrass meadows at depths down to 60 m. Larvae settle among mangroves and the young adult individuals gradually move to seagrass and sandy habitats as they age.  It eats detritus and anything edible it comes across by everting its stomach through its mouth and on to its food item. The food is then engulfed and brought inside the starfish where the stomach is returned to its normal position.

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Stranded Whale Rescued by Beachgoers in South China

According to the Southern Metropolis Daily, a dwarf sperm whale (Kogia simus) was stranded at a beach in Daya Bay on the 23rd of May. The report stated that over a dozen people joined in the rescue effort, using their hands to spread seawater over the cetacean to help moisten its skin before pushing the animal to deeper water. The animal eventually swam away on its own.

Staff at the Daya Bay Fisheries Provincial Nature Reserve Management Office said that dwarf sperm whales are “very rare” in the waters around Daya Bay. The species is known to generally live in deeper water near the continental shelf. The animal was noted to have red blotches and scars indicating disease or parasites.

on the 12 of May 2016 I posted about a dwarf or pygmy sperm whale that washed up dead at Sao Wan Ho (Hong Kong), click here for the blog post and images.

Chinese White dolphin seen in San Niang Wan sea area, Guangxi Province

Pictures published by Xinhuanet this week show a Chinese White Dolphin swimming in the San Niang Wan area of Guangxi, far west of Hong Kong.

Images posted here

Whale Shark Sighting

Earlier this week an online video of a whale shark in Hong Kong went viral.

Unfortunately there is no specific protection for this species in Hong Kong, so experts are calling on the government to introduce laws to protect whale sharks which are infrequent visitors to Hong Kong waters in the summer months.

The footage was posted by a Lamma Island resident Robert Lockyer, who said the footage was sent to him by one of the fishermen who encountered the shark on Tuesday.

Lockyer said there had been another local sighting on May 22, but he believed it was a different shark at another location.

The fisherman who took the video did not wish for his identity or the location of the sighting to be known.

Finless porpoise reported greed from fishing net on social media

A HK fishing groups social media account has reported a finless porpoise (Neophocaena phocaenoides) being freed from a floating fishing net on the 18th of February.

It’s not clear who the net belonged to and how long the animal was trapped in it.

Source here

The Living Fossils of Hong Kong and Richard Fortey’s Survivors – Part 1

Having briefly worked in the Natural History Museum in London, i had the pleasure of listening to a lecture by Richard Fortey who is known for a whole list of popular science books. One of these books, as ibrecently found out has nearly a whole chapter set in Hong Kong and dealing with some of Hong Kong’s lesser known marine animals.

In “Survivors: the Animals and Plants That Time Has Left Behind”, Richard Fortey visits East Sai Kung Country Park with Professor Paul Shin of City University, to explore some mudflats looking for creatures that are rare survivors of past geological ages millions of years ago.

You may be familiar with this animal:

Credit Citron / CC-BY-SA-

The coelacanth is a lobe-finned fish thought to be the ancestor of all land vertebrates. Having evolved 400 million years ago, it was thought extinct for 66 million years until famously it was discovered living in 1938. That made it the poster boy for living fossils. But few Hongkongers would suspect a living fossil in their city, let alone 4!!!

One of these is Lingula anatina. It consists of two valves forming a clasped shell and a long stalk or pedicle. The pedicle is buried vertically in the sediment to anchor the animal while its valves open to filter tiny edible pieces out of the sea water at the sediment surface. 

Lingula anatina (via Wikicommons)

To an untrained eye this might seem like mussel or clam or other mollusc. But it is in fact a brachiopod, a group of animals that has been around for about 500 million years. To put that into context, the colonisation of land by plants happened 400 million years ago. How a brachiopod differs from a mussel or clam is its internal organs and body structure – but that’s a matter for undergraduate invertebrate textbooks….

Lingula for all its similarity to a mussel, is not a mollusc, but the next living fossil is.  The chiton Acanthopleura japonica is very ancient and primitive mollusc.

A chiton preserved in its rolled up state after becoming detached from its rock surface

The animal is similar to a snail but instead of a shell it has 8 armoured plates which it locks together to form a shield. They use a muscular foot to glide around rocks scraping algae off them. If scared or at low tide they suck themselves onto the rock with their foot and at the same time lift their shell to form a vacuum – so prying them off rocks is not recommended as you will only end up breaking and killing them. If they do get pried off rocks they roll up a bit like a wood louse. Acanthopleura is a common sight around Hong Kong’s rocky shores. And chitons very similar to it started appearing about 450 million years ago…for context, dinosaurs appeared about 200 million years later…and in all that time they really haven’t changed much.

The third living fossil is a type of worm. The Peanut-worm to be precise, so named because it can bunch itself into a peanut-shaped blob. Its proper name is sipunculid worms, and they too have been around for almost 500 million years. As with brachiopod sand mussels, the difference between a sipunculid and a ‘regular’ marine worm is in its internal body structure and organs. Hong Kong actually hosts at least two species of sipunculid worm. One of these is Siphonosoma cumanenses, pictured below. It makes burrows on fine sandy shores.

Live specimen of Siphonosoma cumanenses collected in Fort Pierce, Florida. Photo by Kawauchi, Gisele Y. by myspecies.info licensed under CC BY-NC-SA

The other is Sipunculus nudus, pictured below, which is – not surprisingly – also eaten in Southern China.

A bucket of deliciously-looking purple worms (labeled 即劏北海沙虫 – “‘Sand worms’ from Beihai, at a street vendor in Guangzhou. Photo by Vmenkov via WikiCommons licensed under CC-BY-SA 3.0
Live specimen of Sipunculus nudus (dorsal view) collected in Fort Pierce, Florida. Photo by Kawauchi, Gisele Y. From myspecies.info licensed under CC BY-NC-SA
 
Finally, there are the horseshoe crabs, but that is for Part 2…

Finless Porpoise Stranded on Lantau

According to Around DB magazine a porpoise was found stranded at Palm Beach (presumably Cheung Sha Beach) on the 26th of October (2017). Judging from the images the dead animal looks to be a finless porpoise (Neophocaena phocaenoides) and about 120 cm in length (adult).

Source: AroundDb