Nathalie Rose Le François took part in a mission at Palmer Station in the Antarctic until August 19, 2016. For five months she conducted research work devoted to bettering methods for the reproduction, incubation and larval rearing of Antarctic icefish species. This third mission to the South Pole in the company of different specialists allowed her to observe life and change on the frozen continent from close up.
My third visit to the Antarctic peninsula is over. It was the final season at Palmer Station (United States), in the context of the work being done by William Detrich (Northeastern University, Boston) and John Postlethwait (University of Oregon, Eugene). They were studying the effects of temperature on the embryonic development of two species of fish: the black rockcod (Notothenia corriiceps) and the blackfin icefish (Chaenocephalus aceratus), a proud icefish representative.
More sophisticated techniques
After a number of experimental seasons, we succeeded in greatly improving techniques for catching spawning stock of these species– and particularly the black rockcod – at sea, and for holding them in captivity. (An article describing the embryonic development in the black rockcod was recently published by our group in the scientific journal Developmental Dynamics: “Embryogenesis and early skeletogenesis in the Antarctic Bullhead notothen, Notothenia coriiceps,” Postlethwait et al., 2016.)
A tricky case
In the case of icefish, the capture and captivity of females ready to spawn are particularly challenging, and to this point not a single one had survived long enough to lay fertile eggs. An article submitted in October 2016 to the journal Polar Biology relates the techniques regarding capture and fitness in captivity for these females, and explores alternatives in animal husbandry, meaning all the sciences and techniques employed in the selection and reproduction of animals, to improve their chances of survival (“Characterization and husbandry of wild broodstock of blackfin icefish Chaenocephalus aceratus [Lönnberg 1906] from Palmer Archipelago [Antarctic Peninsula] for breeding purposes,” Le François et al. 2016).
Quick, a plan B!
Totally unexpectedly, in 2016, a female blackfin icefish produced about 25,000 viable eggs. Unlike the previous years, all the C. aceratus males we had in the basin were immature and incapable of fertilizing the precious eggs. Why? It often happens that, in a catch zone, one of the two sexes is absent, which upsets the male/female ratio and complicates fertilization activities. We therefore developed a plan B, which we’re very proud of: produce in extremis a hybrid by crossing two icefish species: male Chionodraco crossed with female Chaenocephalus. That hybrid presented a mix of the genetic features of both parents.
A major first
Against all expectations, the first cell divisions were observed after 48 hours: 2, 4, 8, 16, 32, 64… Two hundred and fifty days later, larvae are hatching at Palmer Station. And according to our sources, this would be a world first!
The possibility of the Montréal Biodôme being involved, in 2018, in another project connected with climate change and biodiversity conservation in the Antarctic is already being discussed. Great news!