Oysters have a hard life. Some detractors might cite their sedantry nature, “sit and wait” feeding style and lethargic reproductive processes as reasons to the contrary, but its a small wonder they are alive at all. I recently spent a few months at the Port Stephens Fisheries Research Centre, working with the invasive Pacific Oyster, Crassostrea gigas, and found they are fickle things. They’re worse than a spoilt eight year old. The water temp has to be just right, the light cycle spot on, they need regular water changes and a constant supply of food. If any of these conditions are not met they will stomp their feet, shake their fist whilst screaming that they hate you, until you give them a wowwy pop. If you dont, they will die. Talk about cutting your nose off despite your face.

And then the teenage years come along. It’s at this stage that you start to feel for them. Pelagic larvae experience over 99% mortality in the water column. There’s nothing much stopping anything with a larger mouth (which is pretty much everything) eating the poor little guys. They’re the fast food of the ocean. Fish swarm to these guys like fat kids to doughnuts. Even worse, they are completely at the whim of the tides, so many will simply be washed out to see before geting the chance to settle on a nice rock, grow old and fat, and expell some gametes to keep the grandparants happy.

Its at the late teen stage where it just becomes unfair; a joke instigated by the cruel hand of evolution. When I was working with the oysters, I wanted to see whether increasing the numbers of oyster arrivals into a community would increase the numbers that would survive to adulthood (yes, this is an oversimplified explanation… not by much though!). It turns out that increasing the amount of settling oysters didn’t do anything. No matter how many oyster larvae I would introduce into the system, fish would simply decimate the population until only a few lucky ones survived. In some communities, I successfully introduced over 1000 early “pre teen” oysters, only to have 15 left after five weeks. They were shown no mercy. It was Peter O’Toole in Lawrance of Arabia all over again; “No Prisoners! No Prisoners!”.

While you do have to feel sorry for the little guys, one has to remember these Pacific Oysters are invasive. Like marauding hordes, they have taken over much of our natural Sydney Rock Oyster habitats. Which leads us to the question; if these exotics can so comprehensively invade Australian shorelines despite their inadaquacies, how wimpy must our native oysters be?