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The Fate of a Marine Octopus Species in Our "Brave New World"

Paper Reviewed
Ramos, J.E., Pecl, G.T., Semmens, J.M., Strugnell, J.M., Leon, R.I. and Moltschaniwskyj, N.A. 2015. Reproductive capacity of a marine species (Octopus tetricus) within a recent range extension area. Marine and Freshwater Research:

Introducing their publication, Ramos et al. (2015) write that "to persist in the face of environmental change, species must adjust to the new conditions or change their geographical distribution, e.g. by range extension." And they note, in this regard, that "success for individuals within a zone of range extension requires the new environment to support their capacity to produce viable gametes and survival of the offspring." Thus, they examined the reproductive characteristics of the poleward range-shifting Octopus tetricus within its newly inhabited range off north-eastern Tasmania, Australia, in order to assess whether it is likely to successfully establish itself in this extended area of its range. And what did they thereby learn?

The six Australian scientists report that (1,2) "approximately 44% of captured males and 14% of captured females were mature," that (3) "mature females with developing eggs were found throughout the year," although (4) "greater numbers of mature females were observed during the austral summer and spring, whereas [5] mature males were observed all year round." In addition, they note that (6) "fecundity was high" and (7) "developing embryos appeared to be viable."

As for the significance of these findings, Ramos et al. conclude that (8) the reproductive cycle of Octopus tetricus "is timed to favorable environment conditions," and that (9) "the population has the potential to be self-sustainable." In fact, they write that (10) "the reproductive capacity of O. tetricus is not compromised in the range-extension area, and [11] it may actually facilitate the establishment and prevalence of the population beyond its historical distribution zone."

And so it is that another of the many species of marine animals inhabiting Earth's oceans appears to be quite capable of successfully dealing with whatever nature -- or man -- throws at it.

Posted 13 September 2016