To prepare the wasabi mayonnaise, whisk the egg yolk, vinegar and wasabi powder together then while continuing to whisk add the oil in a steady stream until all of the oil is incorporated. Season with salt to taste.
To prepare the sushi rice, run the rice under cold running water to remove the starch. Continue to do this until the water runs clear. Drain the rice from the water and place in a saucepan, cover with 300 ml of water and bring to the boil.
As soon as the rice boils reduce the heat to its lowest setting and cover the pan with a lid. Cook the rice for a further 18 minutes then remove from the heat.
Leave the rice to rest for another 10 minutes with the lid on then spread the rice in a thin layer on a baking tray.
Whilst the rice is resting, bring the rice wine vinegar, sugar and salt to the boil then remove from the heat.
Using a paper fan or something similar, fan the rice as you fold the vinegar through. It is important to cool the rice as quickly as possible. Once combined, cover with a damp cloth then set aside until required.
Bring a saucepan of salted water to the boil then add the Moreton Bay bugs.
Simmer for 8 minutes then remove the bugs and leave to cool.
Once cool, remove the bug meat from the tail, roughly chop then place in a bowl with the salmon roe and wasabi mayonnaise. Mix together until combined.