Slipper lobster is off the Israeli plate
What has ten legs, a clear skin while a youngster that breaks and turns into a new exoskeleton as it grows, and cracks snails and clams in adulthood?
Meet the slipper lobster.
In addition, it is one of the species most threatened by extinction in the Mediterranean Sea.
The slipper lobster (Kaphan Gushmani in Hebrew) nicknamed “sigal” (Viola) due to its purple shell, is a slow, long-stomach crab with neither claws nor spikes.
A nocturnal creature, residing in underwater rocky habitats, with a look that resembles a creature from another planet, the slipper lobster is classified critically endangered in Israel.
Like the rest of its family, it has ten legs and interesting-looking flat front extensions that probably function as sensors. Its length can reach up to 45 cm (18”), but usually does not exceed 30 cm (12”).
The secret life of the slipper lobster
During the day it is hiding in holes and caves in the rocky reefs or sponge gardens of the Mediterranean (the sponge is a marine animal attached to the sea bed, feeding on small particles by filtering seawater). At night the slipper lobster goes out prowling, with oysters and snails as its favorite food.
The lobster is visible to divers at depths ranging from 2 meters (6.5 ft.) to 50 meters (164ft.), but during several months each year it descends to a depth of 400 meters (1300 ft.) below sea level or even more! and though usually found in groups, not much is known about its social life.
The reproductive cycle of the slipper lobster has not been fully studied, but it is known that each female is capable of producing more than 100,000 eggs. The young larvae that emerge from the eggs are transparent plankton, swimming in the water for several months, probably some of the time close to jellyfish. Then they go through metamorphosis, turning into a small lobster that keeps developing while on the ground of the deep sea. In the spring, as the water gets warm, they most likely rise towards shallow water, for reproduction purposes.
Like all arthropods, the slipper lobster has an exoskeleton – a hard outer casing made of chitin, which provides the support and the external form (in contrast to vertebrates like us that have an internal skeleton made of bones). As the lobster grows the exoskeleton becomes too small, so it grows a new, soft and inflated chitin skin that splits the old skin as it emerges out of it. The new skin hardens, providing a rigid shell for the larger dimensions.
Protected Natural asset
The slipper lobster is not an agile animal, and its protection against predators is based on its outer shell and shelter provided by the reef. However, evolution did not prepare the lobster to defend itself against skilled predators that sometimes use scuba tanks – the fishermen.
The slipper lobster is declared a “protected natural asset" under the National Parks and Nature Reserves law. The law prohibits causing any harm to these lobsters and their natural course of development in any way, including through fishing.
Unfortunately, due to lack of adequate enforcement, lobster fishing is still common, causing population decline resulting in the slipper lobster to be classified as critically endangered. In the '90s of the previous century it was estimated that about 2 tons of slipper lobsters are fished in Israel each year. This is probably why nowadays it is difficult to find large populations of slipper lobster as previously spotted on the shores of Israel.
Even today, though it is illegal, you can still occasionally come across a slipper lobster served as a luxurious dish in restaurants nationwide or displayed for sale at a fish market in Akko, Jaffa or Haifa.
How do we protect it?
SPNI is leading a comprehensive reform to save the Mediterranean fish population, under the "fish responsibly” campaign. As part of this reform we promote fishing restrictions through legislative tools such as the fishing moratorium that was introduced in April, alteration of the fishing fleet and banning of destructive fishing methods, including prohibition of fishing while using oxygen tanks; the primary method used to hunt the slipper lobster.
A great deal of progress is being achieved through SPNI’s on-going collaborating with the public. In the case of the slipper lobster this led to a protest against restaurants that offered slipper lobster dishes. As result of public pressure, the lobster was taken off the menu and the restaurants announced they will no longer be offering dishes containing protected animals.
SPNI also launched the sea watch app that allows the public to report diverse marine incidents and hazards, including fishing or selling of protected creatures. These reports are delivered directly to the mobile devices of the relevant inspectors, and serve as an important tool in monitoring and dealing with offenders.
The slipper lobster may not famous as the sea turtle or the dolphin, but it is a wonderful creature of great importance to the delicate fabric of the Mediterranean eco system. Together, we can protect it.
Based on a Hebrew article by Alon Rothschild,
Biodiversity coordinator, Environment and Nature Conservation Department SPNI