West coast rock lobster on the BOS 400 wreck

Sea life: Rock lobster

Many of Tony’s students come to him with extensive skin diving experience. Living in Cape Town, it’s almost obligatory to enjoy at least one lobster braai during the season (and often many more). Sometimes the veteran lobster-divers struggle at first with breathing through a regulator – their instinct while under water is to hold their breath (it’s illegal to take lobster when you’re on scuba). But their comfort in the water (and being used to the cold) stands them in good stead, once Tony’s tapped them on the regulator a few times to remind them to inhale!

Lobster on a wreck at Long Beach
Lobster on a wreck at Long Beach

We see West Coast rock lobster (not crayfish – those are freshwater creatures) in both False Bay and on the Atlantic side. They are gregarious, and can often be found sheltering in cracks and under overhangs, in quite large groups.

West coast rock lobster on the BOS 400 wreck
West coast rock lobster on the BOS 400 wreck

It’s a pleasure to do a deep wreck dive such as on the Maori and on the BOS 400, and see hordes of good-sized rock lobster teeming all over the wreck. Some of the shallower sites are definitely over-fished, and we only see really big specimens when we dive beyond the range of your average skin diving lobster hunter. On Gerard’s first deep wreck dive in Smitswinkel Bay, we hadn’t been on the wreck for three minutes when I turned around to see him excitedly waving a MASSIVE lobster at me, the biggest either of us had ever seen. Some finger waggling and head shaking convinced him to replace Mr Lobster in his home, but I think Gerard was heartbroken.

Small rock lobster at Long Beach
Small rock lobster at Long Beach

Rock lobster are almost impossible to farm. At the Two Oceans Aquarium on our crash course in marine biology we learned that there are 13 larval stages, during which time the creature drifts hundreds of kilometres offshore through a huge variety of water conditions that it would be impossible to replicate in a mariculture setting. The larval phases can last up to two years. Lobsters grow very, very slowly and can live to the age of 50. There’s some nice detail on the Two Oceans Aquarium website.

Rock lobsters on the Maori
Rock lobsters on the Maori

They eat crabs, abalone, starfish, snails and sea urchins – this latter fact makes them quite important in the ecosystem as a whole. I’ve mentioned before that juvenile abalone shelter among sea urchins. If there are too many lobsters, they eat too many urchins (and too many abalone) and this leads to a decline in the population of abalone. It’s a fine balance.

Rock lobster at Long Beach
Rock lobster at Long Beach

Lobsters are incredibly sensitive to the level of oxygen in the water, which sometimes leads to what look like mass walkouts onto the beach when there’s a red tide or similar event leading to (near-)anoxic conditions on our coastline. What actually happens is that they move away from the de-oxygenated water where the red tide has died, and get stranded on the beach by a retreating tide. Once when Tony was landing a dive boat at Miller’s Point, he was waiting for a chance to use the slipway next to a fishing boat that was packed to the gills with lobster. The captain said they’d found a spot where thousands of lobster were strolling together in orderly formation across the ocean floor, and he’d just scooped them up. (He would not share where this magical location was, but the lobster were probably moving to more highly oxygenated waters.) Having substantially exceeded his quota, the fisherman was somewhat twitchy about being pulled over by the authorities!

Rock lobster on the move on the Maori
Rock lobster on the move on the Maori

Poaching of rock lobster is a big problem in South Africa. They’re a very valuable commodity – you just need to go and have a seafood platter at a Camps Bay restaurant to see what damage it can do to your wallet – and easily accessible to anyone who can hold their breath and is prepared to do a bit of rock scrambling. The government Department of Environmental Affairs tries to manage stocks by implementing a closed season, catch and size limits.

  • Currently, you may only take lobster that measure greater than 8 centimetres from the front of their head to the end of their carapace (NOT to the tip of their tails, as I used to think – fortunately I’m not a lobster fisherman!);
  • You must have a MPA permit to take lobster (same form at the post office as the scuba diving one);
  • The season runs from November to April (the dates vary by year);
  • You may only take lobster during the day – between sunrise and sunset;
  • You’re not allowed to sell them;
  • You are not allowed to take females in berry (with eggs), or lobsters with soft shells that have just moulted;
  • There are also regulations about the number of rock lobster you may transport at once, or have in your possession.

If you’re in doubt as to the utility of this array of regulations, check out the graph in the middle of this page on the Department of Environmental Affairs website. Depressing.

Published by

Clare

Lapsed mathematician, creator of order, formulator of hypotheses. Lover of the ocean, being outdoors, the bush, reading, photography, travelling (especially in Africa) and road trips.

3 thoughts on “Sea life: Rock lobster”

Leave a Reply