This is roe, the same roe that appears orange in cooked prawns. The darker in colour the prawn, the darker the roe - tiger prawns have a dark grey/green roe, whereas king prawns have a lighter grey/ brown roe. Regardless of colour when raw, as with all crustaceans, the roe turns orange/red when cooked (it’s just thousands of little baby prawns).

RSPCA Australia demands that all crustaceans killed for food or other purposes are killed humanely. The most acceptable method of killing crustaceans is to chill them to render them insensible, followed by killing through splitting or spiking to destroy the animals' nerve centres. Crustaceans are ‘cold blooded’ animals; when their temperature is reduced their activity slows and eventually they become insensible.

Chilling should preferably be carried out in air (in a refrigerator or freezer) at a temperature below 4ºC. The length of time required will vary across species and conditions but chilling must be maintained until the animal appears insensible before further processing. 

See NSW Department of Primary Industries and RSPCA for more details.

Some species, especially oily fish, have a strip of dark, blood-rich muscle running down the centre of the fillet; it is edible, but has a stronger taste than the paler flesh. Some people enjoy the stronger, fishy flavour and are happy to eat it, others prefer to remove it for visual or taste reasons. Cutting it out is also a quick and easy way to remove the pinbones that run down the centre of most fillets. The bloodline is a good indicator of freshness, it’s bright pink-red in very fresh fish, becoming duller and turning brown as the fish deteriorates. For this reason it is sometimes left on sashimi-grade fish to show freshness, however eating it raw is an acquired taste, so many people choose to remove it if serving fish raw or rare. The choice is yours.

There are two methods of smoking: 

• Cold-smoking, where fish is immersed in smoke at a low temperature (usually below 26°C) so that the flavour of the smoke penetrates the flesh but it still appears raw, as with sliced smoked salmon; 
• Hot-smoking, where fish is initially cold-smoked, then the temperature is raised and the fish is cooked in the smoky environment, such as smoked whole rainbow trout. 

Both types are ready to eat without further cooking, tossed through pasta or salad, in an omelette or piled onto hot buttered toast as a quick, substantial snack or smart entrée. Horseradish, lemon and dill are great flavour companions.

Scaling fish can be very messy as sticky scales fly everywhere. To avoid this, holding the fish by the tail, place it inside a plastic bag. Run a fish scaler, or the back of a butter knife, along the skin to dislodge the scales. Remove the fish from the bag and wipe any remaining scales off with a clean, damp cloth.

Purging ensures that bivalves that live in sand, such as pipis, have expelled all of the sand before they’re cooked, otherwise the resulting dish can taste gritty. Most are already purged when you buy them, but to get rid of any remaining sand place them in a solution of cool water and sea salt (30g salt to each litre of water) for several hours, or overnight, at room temperature (if you refrigerate them they’ll close up and won’t ‘spit out’ the sand).

Seafood should never be thawed at room temperature, or in water, as this may encourage the growth of harmful bacteria. The best way to thaw seafood is to place it in a colander with a shallow tray or bowl underneath to collect the water it gives off, cover and place in the refrigerator for several hours or overnight. Thawing slowly at a low temperature also helps maintain quality. Some seafood, such as prawns, can also be added to wet dishes (like soups or curries) without being thawed as the heat of the cooking will thaw them and any juices they give off will add flavour to the finished dish.

It is easy to buy good fresh fillets from most fishmongers … but some people prefer to fillet their own fish for several reasons. Whole fish are more economical than fillets, you aren’t paying for someone else’s labour, plus you can use the head and bones to make a quick stock to freeze for later use in soups, sauces or risotto. It’s easier to tell the freshness of whole fish as the brightness and lustre of the skin is a good indicator. This isn’t an issue if you’re shopping at SFM where there’s a very high turnover or from a fishmonger you know and trust, but it’s worth keeping in mind if you’re buying from a retailer you don’t know. For convenience, most fishmongers fillet under running water - at home you can dry fillet, a method preferred by chefs, so the flesh doesn’t come into contact with chlorine or become waterlogged and so retains maximum flavour. So grab a filleting knife and give it a go … there are step-by-step colour photos in the Sydney Seafood School Cookbook if you need guidance.

In many ways your nose is the best indicator of whether or not seafood is fresh. Only stale seafood smells ‘fishy’, fresh seafood has little aroma except for a slight fresh ‘sea’ smell. Other signs of freshness include bright shiny skin or shell, and in the case of fillets and steaks, bright lustrous flesh that doesn’t look dried out or discoloured. If there’s a bloodline, it should be bright red rather than dark or browning. Some people say bright eyes are a good indicator, but eyes can go cloudy if they come into contact with ice, so cloudy eyes alone do not indicate that the fish is stale. Most importantly ‘the nose knows’, if it smells ‘fishy’, it’s past its prime!