Slender Sunfish stranding

It must have been sad to watch but wow, what a story.
The photos above, plus another two (see links below), were taken by hylacola. They record a mass stranding of Slender Sunfish, Ranzania laevis, on 16 May 2014.
Interestingly, the southern coastline of Western Australia around Albany (Peaceful Bay to Bremer Bay) seems to be a hot spot for mass strandings of Slender Sunfish, with strandings documented in 1928 (Gomon et al., 2008), 1941, 2008 (with map), this record in 2014 and another in 2016 (view video).
One of my colleagues wondered if the fish were aggregating in shallow water to spawn. Smith, et al. (2010), however, stated that "Gonad development indicated spawning was not imminent. The cause of the strandings was unclear, although advection of fish to the south coast by the tropical Leeuwin Current was strongly implicated." In other words, the strong Leeuwin Current that flows down the coast of Western Australia may have swept the fish 'around the corner' of the State, then onto the southern coast.
The Slender Sunfish occurs globally in tropical and temperate seas. In Australian waters, it is known from tropical northern Queensland, right around the temperate south of the country and north to North West Cape, Western Australia.
Perhaps surprisingly, given its unusual shape, the Slender Sunfish is a strong swimmer. (View video)
  1. Gomon, M.F., Bray, D. & R.H. Kuiter (Eds). 2008. The Fishes of Australia's Southern Coast. Reed New Holland. Pp. 928.
  2. Smith, K.A., Hammond, M. & P G. Close, 2010. Aggregation and stranding of elongate sunfish (Ranzania laevis) (Pisces:Molidae) (Pennant, 1776) on the southern coast of Western Australia. Journal of the Royal Society of Western Australia, 93: 181–188.
Publicado el 20 de septiembre de 2017 a las 11:19 PM por markmcg markmcg


Intriguing article Mark, they certainly don't look like strong swimmers, but then again neither do boxfish ;D They dart off like little bullets when scared. I've only ever witnessed the mass die-off of some globefish...

Anotado por henrick hace mas de 6 años

Thanks @henrick. I found the observations of @hylacola fascinating, hence looking into the subject a bit further and finding out that Slender Sunfish have a 'habit' of stranding in that stretch of coast. It would be neat to look at what the Leeuwin Current was doing at the time of each stranding.

Anotado por markmcg hace mas de 6 años

Ah yes, another understanding of another current and all the intricacies and movements associated with it would come in handy in regards to our EAC.

Anotado por henrick hace mas de 6 años

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