We are excited about our giant newcomers – a “risk” of St Paul rock lobsters is now calling the Two Oceans Aquarium their home (and yes, a group of lobsters is called a “risk”).

These St Paul rock lobsters (Jasus paulensis) are all the way from the island of Tristan da Cunha in the south Atlantic Ocean. These lobsters are so famous there that they are actually on the island's coat of arms!

What is a “rock lobster”?

The St Paul rock lobster belongs to a family called Palinuridae – or “crayfish” as we like to call them here in South Africa. They differ from true lobsters (family Nephropidae) in one major way – rock lobsters do not have pincers!

Rock lobsters also have large spiny antennae and often have spikes on their carapaces. The most striking difference between rock lobsters and true lobsters is when they are young – rock lobsters first grow as a “phyllosoma” before taking on their adult body shape.

Tell me more about this new rock lobster!

The St Paul rock lobster is a nocturnal scavenger, hiding in cracks and caves on the rocky sea floor and coming out at night to feed on seaweed and carrion.

It is a large species, growing up to 37cm long. It looks very similar to our local crayfish species, the West Coast rock lobster (Jasus lalandii), or “kreef” – both species display orange-brown spines and have similarly slow growth rates.

Photo by Devon Bowen/Two Oceans Aquarium.

Despite the St Paul rock lobster’s seemingly giant size in our exhibit, it is actually significantly smaller than a kreef – which can grow to 47cm long. Unfortunately, kreef almost never reach these giant sizes due to overexploitation on South African and Namibian coasts.

Why is it called a “St Paul” lobster?

Although these specimens are from Tristan da Cunha, St Paul rock lobsters are actually quite widely dispersed in the Southern Ocean, particularly at Saint Paul Island and on the surrounding seamounts.

At one time, the rock lobsters of Saint Paul and Tristan da Cunha were believed to be different species, but recent mitochondrial DNA studies have revealed them to be the same. Despite this, some authorities, such as the IUCN, retain them as separate species, calling the Tristan da Cunha population Jasus tristani.

Global distribution of the various "Jasus" rock lobster species.  

Why are they such a big deal in Tristan da Cunha?

St Paul rock lobsters have been commercially harvested as a food source in Tristan da Cunha since 1949. Local fisheries use hoop nets and metal traps on lines. There are strict restrictions in place to protect the rock lobster population –  the total catch allowed for each island, the minimum size of the rock lobsters caught and the type of equipment used.

Tristan da Cunha is the most remote permanently inhabited piece of land in the world. The commercial fishing and export of St Paul rock lobsters is the most economically important activity taking place on the island, providing livelihoods for most of the island's families and accounting for 80% of its revenue.

Fisheries of St Paul rock lobster around Tristan da Cunha have been conducted sustainably. The fishery received Marine Stewardship Council certification in 2011 and currently exports lobster to Europe and the Americas.

A box trap used to catch St Paul rock lobsters near Île Amsterdam. Photo courtesy of Le blog de Pat.

Unlike the St Paul rock lobster, the West Coast rock lobster population is not considered stable. The species has been added to the WWF SASSI red-listconsumers should not eat kreef.

Photo by Devon Bowen/Two Oceans Aquarium.
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