The tiger crab, Orithyia sinica, is an extraordinary species known for its unique stripes and digging prowess. Found in the subtropical Northwest Pacific, this nocturnal burrower thrives in muddy-sandy coastal habitats. From reproduction to survival strategies, the tiger crab is a fascinating creature worth exploring.
Discover the tiger crab’s striking appearance, fascinating larval development, and impressive adaptability. Learn how this unique species thrives in its coastal habitat, and uncover the factors that influence its growth and survival.
Quick overview of tiger crab
| Common names | TIger crab, Tiger face crab |
| Scientific name | Orithyia sinica |
| Temperature | 20°C to 30°C (68°F to 86°F) |
| Color | Yellow, orange and black |
| Sleeping nature | Nocturnal |
About the species
O. sinica (the tiger crab) is a unique crab species that is so different it belongs to its own genus (Orithyia), family (Orithyiidae), and superfamily (Orithyioidea).The name Orithyia comes from a character in Greek mythology; Orithyia was the daughter of Erechtheus, King of Athens.
Sometimes the species Austrothelphusa tigrina and trapezia tigrina are also called the tiger crab.
Habitat and distribution
The tiger crab, Orithyia sinica, lives in the subtropical Northwest Pacific, primarily along the coast of mainland Asia, from South Korea to Hong Kong. It prefers subtidal habitats with muddy-sandy substrates, such as those in the Yellow Sea and coastal regions of China, Japan, Korea, and Chinese Taipei. The tiger crab has also been reported along the coast of Pusong Lhokseumawe, Indonesia, extending its range into parts of the Indo-Pacific region.
Appearence
The tiger crab, or Orithyia sinica, has a distinctive appearance with striking stripes on its legs and prominent eyespots on its shell, which resemble tiger patterns, giving the crab its common name. Its legs are adapted for digging in the sand rather than swimming, making it a skilled burrower.
Females have a narrow abdomen that leaves the vulvae exposed, while males are larger with stronger claws and a slimmer tail. Females have smaller claws and a broader tail, often carrying eggs during breeding seasons.
Egg production and larval development in tiger crabs
The tiger crab (Orithyia sinica) has a fascinating reproductive process. Females can produce up to 30,000 larvae, which undergo three zoea stages before transitioning to the megalopa stage. This development from zoea to megalopa takes around 14 days.
Larvae thrive better in temperatures around 20°C, where their survival rates improve compared to normal room temperature. Interestingly, as the crabs progress through their stages, the time between molts generally increases, though a decrease is observed between the fifth and seventh crab stages. The size of zoea and megalopa stages diminishes at higher temperatures, but temperature doesn’t seem to impact the size of the later crab stages.
Egg production in tiger crabs is impressive, with the number of eggs ranging from 240,000 to over a million depending on the size of the female. Larger females tend to produce more eggs. The eggs themselves measure between 547 and 913 micrometers, averaging around 712 micrometers in diameter.
Male tiger crabs typically mature at a carapace width of 5 cm, while females mature slightly larger, at around 5.5 cm. Growth rates during the zoea stages range from 35.65% to 41.4%, while during the crab stages, they fall between 18% and 30.91%.
Ammonia Effects
An experiment was conducted where tiger crabs were exposed to different levels of ammonia and nitrite for 30 days. The time between molts shortened, and crabs exposed to higher concentrations molted more often than those in normal conditions.
Sand Advantage
Another experiment conducted to see which substrate is best for their survival rate. Soft sand had the best results, with a 78% survival rate, faster growth, and better feeding. Mud was the worst option for their health.
Is tiger crab edible?
Yes, the tiger crab is edible and highly valued. It’s fished on a small scale due to its ability to thrive in specific coastal environments. Local fisheries prize it for its rich flavor and market demand, making it a delicacy with high prices in certain regions.
What does tiger crab eat?
Tiger crabs eat a variety of foods, including Manila clams, brine shrimp and marine diatoms. This diverse diet helps them thrive in their coastal habitats, making them resilient and adaptable.
Final thoughts
I don’t know if someone tried to pet this species. If you do or thinking of petting them, then let me know your experience and thoughts.
Related Species: Frog crab
