Taramaire torrentfish

[David Riddell]

Was netting for fish with Ian Southey at the mouth of the Taramaire Stream on Saturday, as part of the Miranda shorebird course (trying to illustrate the abundance of fish which some of the birds are feeding on), when, along with the regular yellow-eyed mullet, smelt and flounder, we caught the little fish in the pictures below. At first I thought it must be an estuarine cockabully or some kind of goby, but when I got it into a jar and could look at it side-on I realised it was a small torrentfish! It was a lot darker than usual for the species, but the distinctive banding pattern on the sides was still discernible, and the overall layout of the fins (pelvic fins forward of pectorals, one long dorsal fin) and the shark-like profile were diagnostic.
This is a primarily freshwater species (the only freshwater member of a family that also includes blue cod), but the larvae wash down into the sea after spawning by the adults in the lower reaches of the waterways in which they live. According to McDowall's Field Guide to NZ Freshwater Fishes the juveniles return from the sea in spring and summer, when 16-20mm long, but this one was more like 45mm. What it was doing in almost undiluted sea water (it was right at the stream mouth, with small waves washing in, just after high tide, low water flows with little rain in the past couple of weeks), I have no idea. It's normally a fish of swift-flowing waters, as you might guess from the name, although I've seen good numbers of them in the lower reaches of the Waitakaruru River (around Coxhead Rd) which has dense weed beds and a fairly gentle flow. I guess it was late migrating up from the sea for some reason.
Anyway, it was a remarkable thing to find, and probably a new species for the Miranda area. (Just checked the Niwa Freshwater Fish Database - there's a record of 18 torrentfish from the lower reaches of the Whakatiwai Stream, just north of Kaiaua, from 31 October 2003, which I suspect might have been migrating juveniles, though no details are given.)

[Hypno]

Cool find. I have seen them very close to the mouths of streams before. But never in the estuary