Biology of sea cucumber Marine Ecosystem, biodiversity and conservation

1. Sea cucumber
RAGHUNATH
MFSc-1st yr
FSM-2021-20-07

2. Introduction
• Sea cucumbers are echinoderms from the class Holothuroidea.
• Their closest relatives are starfish and sea urchins
• species worldwide is about 1716 with the greatest number being in the Asia Pacific
region.
• serve a useful role in the marine ecosystem as they help recycle nutrients, breaking
down detritus and other organic matter after which bacteria can continue the
degradation process
• Smallest species can reach 0.12 inches, while largest species can reach 3.3 feet in
length. Most species are usually 3.9 to 12 inches long.

3. • Sea cucumbers use yet another interesting technique when they are faced
with danger. They are able to expel internal organs along with toxic
substance (called holothurin) toward the predators. All missing organs will be
regenerated in the next 1.5 to 5 weeks.
• Diet of sea cucumbers consists of decaying organic matter (from the sea
floor) and plankton.
• Sea cucumbers are nocturnal creatures

4. • Sea cucumbers can be often seen in large colonies. 1000 sea cucumbers per
one square meter can be found along the coasts of New Zealand.
• Sea cucumber are able for self-reproduction
• Most species live between 5 and 10 years in the wild.

6. Sea cucumber biology
• Digestive system
Many species possess an oesophagus and stomach, but in some the pharynx
opens directly into the intestine.
The intestine is typically long and coiled, and loops through the body

7. • Nervous system
Sea cucumbers have no true brain.
A ring of neural tissue surrounds the oral cavity, and sends nerves to the
tentacles and the pharynx.

8. • Respiratory system
Sea cucumbers extract oxygen from water in a pair of "respiratory trees"
that branch off the cloaca just inside the anus, so that they "breathe" by
drawing water in through the anus and then expelling it.
The respiratory trees also act as excretory organs.

9. • Reproductive biology
No distinct sexual dimorphism
Breed twice in a year, spawning season – March to May
October to December

10. Life cycle of sea cucumber

11. How they are protected ?
• Legal protection: at present, in India, protection is equivalent to tigers.
• Hunting restrictions:
• External breeding:
• People’s organization: Sea shepherd conservation society.

12. THANK YOU