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Sicyopterus lagocephalus; a sucker for extreme flow

By James Donaldson

 

Not the most colourful or rare of north Queensland’s suite of amphidromous cling gobies but I do have a soft spot for the ‘Sicky’. The rabbit-headed cling goby (Sicyopterus lagocephalus) is a relatively large representative of the cling goby group found in the Wet Tropics of north Queensland and other places around the Pacific. It is relatively abundant in streams of the Wet Tropics and is a sucker for extreme high flow environments.

This species was the star of the show from a few years back when I was looking at flow performance in a bunch of sympatric Gobioids for my honours research. Amongst other things, this involved documenting microhabitat preferences for each species in terms of flow velocity, substratum composition, depth etc. During flume tank trials they could not be moved, even with the motor maxed out and producing flows of over 1.4 ms-1. The key to this ability is a suction cup-like appendage formed from their two fused pelvic fins [a trait common to all gobies but refined in many Sicydiine species (see Maie et al., 2012)].

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A male ‘Sicky’ in wet season attire; typically when they are looking their best.

This neat attribute also allows them to colonise novel habitats that very few other fishes can access (e.g. chutes, above waterfalls), giving them the key to a huge diversity of habitats across a range of elevational and flow velocity gradients. However, it never ceases to amaze me just how specific this species is with its habitat preferences. In fact, the habitat selection of this species is akin to obnoxious Queenslanders watching a state of origin match and carrying on if the referee doesn’t award every penalty in their favour– very predictable.

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Myself with an obnoxious Queenslander taking flow readings at Oliver Creek (Photo: Chris Fulton)

This predictability (of Sickys) means you can turn up to a site, scout around for their preferred habitat, put a mask and snorkel on, and more often than not, stick your head in the water to find them going about their business. I’ll never forget the first time I went to Emmagen Creek with Ebb and he pointed to a fast flowing run and told me I would find a ‘Sicky’ in the midst of it. Sure enough, there was a large, brightly coloured male goby parading around in front of me in water that I could hardly hold position in.

Editors note:  Despite working with the guy and being aware of his hatred for Queensland Origin success, I have decided this article should still be uploaded to the Lair.

Further reading

Donaldson, J. A., Ebner, B. C. & Fulton, C. J. (2013). Flow velocity underpins microhabitat selectivity in amphidromous gobies of the Australian Wet Tropics. Freshwater Biology 58, 1038–1051.

Maie, T., Schoenfuss, H. L., & Blob, R. W. (2012). Performance and scaling of a novel locomotor structure: adhesive capacity of climbing gobiid fishes. The Journal of Experimental Biology215(22), 392–3936.