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The Lake Tyers project is being led by Chris Setio, and working under Professor Iain Suthers and Dr James Smith. This project is the first for any waters in Victoria and has only been attempted in a few times in other states.

The Prawns released were in the post larval stage D, hence ready to descend from the planktonic floating stage to the benthic lake bottom to grow close to maturity feeding off detritus.

When they have reached the stage E they are ready to return to the sea and while still on the sea floor, mature to the reproductive stage F.

The stages D and especially E are well known and easy to imagine. However they only make up a small number of the overall changes. Notably though due to narrow exits from the lakes, this stage E is the most vulnerable to human's over fishing and natural predators.

Other pressures such as quality of the lake environment are also areas where humans can have a big impact on phase D.

Though, ironically the blue green algae blooms that we get periodically, call a halt to commercial prawn netting (at least inside the lakes) probably assists more "adolescents" making it out of the lake systems, going on to disperse in the ocean, and to mature as breeding adults.

There is one remaining Commercial Bait Fishing Licence still operating in the lake and as part of this experiment, it operations were on a two year fishing moratorium for the 2014 and 2015 seasons. However it is presumed the commercial bait harvesting of prawns will begin again this year, 2016.

It will be interesting to see if this significantly impacts on the good harvests amateurs have enjoyed in the last two years.

Prawn Life Cycle

Recently (2014) the University of New South Wales developed a plan to boost the stocks of King Prawns in Lake Tyers by releasing 300,000 post larval prawns (about 10 mm long at that stage, and look like miniature prawns) into the lake. Residents around the Lakes Entrance and Lake Tyers take a great interest in the prawns as they are both delectable eating and also excellent fish bait.

However the life cycle of the Prawns found in our lakes is much more of a mystery and does make interesting reading. An excellent document is produced by the NSW DPI called Biology and life cycles of prawns
This document is the source of the information below.

Above is a diagram of a generalised Prawn life cycle and should whet your appetite to look up the original document as each stage is well described in layman's terms and is quoted below.

A. The ‘mixed’ life cycle is picked up at this point here, where spawning has occurred and fertilized eggs are shed onto the bottom in oceanic waters where they remain for a short period until they hatch. The first larval stage called a nauplius emerges from the spherical egg and starts swimming up towards the surface. This naupliar stage goes through several moults, getting larger with each moult, and ultimately changes to a protozoea.	B. The prawn similarly moults and grows through several protozoea then mysis stages before developing into a postlarva. The mysis stage is the first stage that somewhat resembles the appearance of the adult prawn. The development time from spawning to postlarva for prawn species with ‘estuarine’ or ‘mixed’ life cycles is between two and three weeks. Hatching success and larval survival are affected by water temperature and salinity and are greatest in waters of the same temperature and salinity as that where spawning took place.
C. Up to the mysis stage the larvae are free swimming and form part of the zooplankton found in the open sea. Zooplankton together with phyto-plankton is eaten by a multitude of other animals, including larval prawns, and is a vital part of the ocean’s food system.	D. After the free swimming, planktonic mysis stage, postlarva adopt a bottom existence, reach the shore and enter the rivers and coastal lakes In the estuaries and lakes, the juvenile prawns have to adapt to wide fluctuations in, among other things, salinity and temperature. School prawns appear to be more tolerant of these fluctuations than eastern king prawns.
E. After over-wintering in the estuaries and lakes the juvenile prawns grow rapidly and upon some cue, start to migrate back to the ocean. These migrations rise to a peak in the ‘dark’ period of the summer, lunar cycles and are fished enthusiastically by both amateur and professional fishermen.	. Chris Setio, Dr James Smith and Tim Bull MLA releasing the very last bag of prawns at stage D.
F. The physiology of prawns with a ‘mixed’ life cycle is such that the prawns require the conditions found in the deeper ocean waters to reach maturity. Once they reach oceanic waters, the prawns rapidly mature, mate and spawn – thus completing the life cycle.	G. The life cycle of prawns is rather short with species such as school prawns living, for the most part, a little over a year while larger species such as eastern king prawns are probably up to two years old, with some individuals perhaps entering a third year of life. For more information on the East Australian Current

Like to know more about the Prawns try these websites: Australian Museum , Queensland Fisheries , Sydney Fishmarket, Queensland Museum, just mention a few.