Geraldton Fishermen's Co-operative Rock Lobster Exporters

Quality Articles

Get ready to make the most out of the whites-October 2017

This month is the time to ensure your holding tanks, cakka box, water pumps and aeration are running properly for the coming whites.

With most boats now catching more lobsters over shorter periods, live holding tanks on many boats may not be providing the best conditions for lobsters.  This has a direct effect on both your landed quality, export survival and, in the longer term, beach price.

There are several key things to check out before the whites:

Baskets: Ensure that all your baskets are fully lined with oyster mesh.  Oyster mesh is essential to prevent leg and feeler damage.  While one leg missing from a lobster might not affect your quality statistics, it dramatically affects the health of a lobster.  This can easily result in that lobster becoming weak or dying after consignment.

If you need to buy oyster mesh for your baskets, the GFC Marine Store has a special on at the moment (see last page of this Catcher edition).

Legs protruding from an unlined basket – what a waste!

Basket lids: Every GFC lobster is kept under chilled seawater sprays at some stage.  This system provides optimal conditions for lobsters and works best when there is maximum water flowing through the basket lids.  Check that the holes in your basket lids will allow adequate spray water onto your lobsters.

Pictures of various crate lids, (from L to R) GFC transfer crate lid; a prawn crate lid poorly suited to sprays and 2 lids well suited to sprays (both available from the Marine Store) 

Water pumps: Constant flow pumps are the only way of ensuring enough fresh seawater is getting to lobsters in your day and live tanks.  To calculate the size of water pumps necessary, a good rule of thumb is 1 litre of water / kg of lobster / minute.  For example, a live tank that holds 30 prawn crates (each holding 27 kg of lobsters) will need to be supplied 30 x 27 = 810 litres of seawater per minute.

If you need to upgrade or replace your water pumps, the GFC Marine Store has a special on at the moment (see last page of this Catcher edition).

Water intake and distribution: Check that sea chests / seawater intake strainers are clean and in good working order.  Likewise, ensure hoses and pipe work from intakes to pumps and from pumps to tanks are free of debris, marine growth, kinks etc.  Replace hoses (and hose clamps) if you are in doubt.  A small investment in hoses and hose clamps now can you save you a lot of heartache (and money) if your water supply fails when your tanks are full of lobster.

Cakka Box: With higher CPUE rates and some boats fishing larger or double gear, many existing cakka boxes are just too small for the number of lobsters coming up in each pot.  If you ever have lobsters fall out of the cakka box and onto the deck it is a sure sign you need to upsize your cakka box.  Lobsters that have fallen on the deck are damaged, are not in premium condition and deckies should be told not to put them in the catch.

Day tank: Water in day tanks is frequently unaerated and poorly circulated.  This dramatically affects lobster quality – before the crates even make it to the live tank.  To remedy this, ensure there is plenty of fresh seawater flowing continuously into the day tank – don’t rely on someone remembering to top up the day tank with the deck hose.  Plumb up day tanks as you would any other live tank and add proper aeration as well!

Finally, every lobster boat in GFC’s fleet should have tank aeration as a minimum, and we are keen to support our members to achieve this.  Every home aquarium has a bubbler for a few ten dollar fish: shouldn’t you look after your valuable catch in the same way?

Live tanks with good aeration

If you would like any assistance with a new system design, or even tips for your existing setup, contact GFC Continuous Improvement Manager,  Brad Armstrong (0437 513 837)  or GFC Research and Development Officer, Joel Durell (0407 135 712).