Developing the techniques and learning at the laboratory scale: 1970-1980. Part 2: Exchanging with other scientist groups.

To stay in touch with other scientists working in shrimp aquaculture, Aquacop team regularly participated to the the World Mariculture Society meetings which became later the World Aquaculture Society. The spirit and the interest of all the WMS participants were very high, as everybody was conscious of so much unknown aspects about shrimp reproduction, and were discussing openly their findings and their ongoing research. Each year, Aquacop members participated, sharing their findings and learning a lot from others.

After the results of the reproduction in captivity presented at the Charleston WMS meeting, Harvey Persyn, working for Ralston Purina in Crystal River, asked to visit COP in Tahiti. Alain answered Yes, as long as there was reciprocity through a visit in Crystal River and Panama. Harvey came and brought with him some P. merguiensis from his facility where he also got the reproduction. Then, Alain went to Crystal River where he saw for the first time tanks operated as floc system. They were covered of 50 cm of foam; shrimp were growing like hell in “dirty” water and were perfectly healthy with long antennae and without any black necrosis. He visited, with Ron Staha, the first commercial hatchery at Vera Cruz in Panama at a time they were capturing at night newly fecundated females of L. stylirostris. They called that "sourcing for the blues". The hatchery, operating large tanks, was quite successful. Alain also visited the Ralson Purina farm in Aguadulce where he met for the first time Yosuke Hirono a famous name in shrimp pioneering.

Back to Tahiti, Alain received this letter from Harvey: “I will gladly supply you post-larvae of L. vannamei and L. stylirostris. It will be of major interest to me if you can mature and spawn these species in the lab”. Strains of unicellular algae were also exchanged. Those shrimps grew so well that after 6 months the first reproduction was achieved using the eyestalk ablation technique. A few months later, Aquacop team obtained also 18 spawnings from 8 P. monodon females in 2 months. Harvey wrote then to Alain: “I believe your CNEXO (which will become IFREMER in 1982) team is doing some of the best work in the world today”. Harvey sent to Alain a handmade illustrated explanation about how to proceed for an “artificial fecundation”, i.e., insemination (see right picture in the title) which was tested and soon successful. Since 1976, this method has been successfully applied… becoming until today, in 2022, the standard for so many shrimp hatcheries worldwide! It has been the real starting point of French captive broodstocks of L stylirostris still going on now in 2013 in Tahiti and in New Caledonia and of L. vannamei kept in Tahiti till 2000.

The initial constraint of no existing species of shrimp in Tahiti has been in fact Alain’s team luck as the work on the reproduction in captivity was an essential prerequisite and they achieved it when the industry was looking for it. Regularly, members of the team were participating to aquaculture meetings, maintaining permanent links with other teams: the Galveston laboratory with Cornelius Mock in the US, the Tungkang laboratory of Dr Liao in Taiwan, the ICLARM in the Philippines with a strong cooperation with Jurgenne Primavera a pioneer in P. monodon, among others.

The control of reproduction through keeping captive breeders from generation to generation has been Aquacop first major achievement with shrimp and has been used further on everywhere. In Tahiti water conditions (pristine water, oceanic salinity, and high temperature all year round), using a photoperiod of 14 hours of light, the various shrimp species were able to mature and to spawn all year round, after eyestalk ablation, provided they received the right food which was a mixture of high-quality pellets with some fresh squids and mussels. Under these conditions some P. monodon females were spawning as many as 6 times during an intermolt period!

In the meantime, Aquacop was developing the technique of mass production of post larvae using the Galveston technique. To feed the larvae one Isochrysis strain was isolated by Jean-Louis Martin and Gérard Joncquières. It was later used in many laboratories under the name Tahitian Isochrysis.?

Quite rapidly, some diseases showed up: the fungus Lagedinium was finally controlled by Dr. Jean-Fran?ois Le Bitoux by using Treflan, drop by drop, 24 hours on a row. For bacterial proliferation in digestive gut, first management was to treat with a “preventive antibiotic” like Gallimycin and others. Very small quantities were delivered every two days in the water during the larval stages. Alain had to acknowledge that the mechanism of action was never elucidated, even after detailed studies about the evolution of the bacterial fauna, but it was working. The necessity of a complete dry-out after two or three production cycles was also found as an efficient method to avoid diseases outbreaks in the hatchery.

In parallel, Gérard Cuzon was developing adequate feed formulations, incorporating different local ingredients, including some specifically developed microparticulated feed for postlarvae derived from the ones used for the freshwater prawn larval rearing. Water quality was also a main concern to produce postlarvae consistently. Jacques Calvas, then Jean-Paul Blancheton began to operate some recirculating systems.

This was when Aquacop had reached a significant level of control of each step of a full domesticated process to close the shrimp cycle, repetitively. They had no idea that those findings were about to be applied at industrial scale on 3 continents, contributing to the first boom of the modern shrimp aquaculture.

To be continued…