38 — Anemones and amphipods at Piha

Gammaridean amphipods swarm around a
giant shore anemone, Lion Rock, Piha.

Gammaridean amphipods swarm around a
giant shore anemone, Lion Rock, Piha.

These videos are of the giant shore anemone (Oulactis magna) at Piha. Often these anemones are in rock pools teaming with small shrimp-like animals called amphipods. Most people encounter amphipods when they turn over seaweed on the beach; the jumping sandhoppers, which appear from under the seaweed are a kind of amphipod.

Amphipods are very diverse, but come in three main flavours: Gammaridea, Hyperiidea, and Senticaudata (there's also the Ingolfiellidea, but they are not as common as the the other three major suborders). At the moment there are thought to be about 9500 species, and this number is probably going to increase.

As a group, amphipods are very important in marine food webs, as nearly everything larger eats them, e.g., Jones (2008); Padovani et al., (2012). However, I'm not sure that these anemones actually eat these particular amphipods, but I did see some small ones get caught by the tentacles of one anemone, so maybe...


More info:

https://en.wikipedia.org/wiki/Amphipoda

Horton, T., Lowry, J., De Broyer, C., Bellan-Santini, D., Coleman, C. O., Daneliya, M., Dauvin, J-C., Fišer, C., et al., & Zeidler, W. (2016). World Amphipoda Database. Accessed at http://www.marinespecies.org/amphipoda on 2016-09-30