Saturday, April 20, 2019

Rosyside Dace, in nuptial colors

From L to R, Phil Melillo, Kelly Capuzzi, John Howard, and your narrator inspect a mess of fish hauled from a small stream in southern Ohio's Scioto County.

Last Tuesday was an epic ichthyological day, at least as far as I was concerned. Fish-hunting is something I'm lucky to get in on once or twice a year, and these aquatic forays are always fruitful, and highly educational. And when I say fish-hunting, this isn't bluegills with doughballs or bass with rod and reel. We're nearly always after far more obscure species than that, and the target this day is a fish known to very few.

Our guides were aquatic biologists Kelly Capuzzi and Laura Hughes. You've seen Laura's name in posts here many times, if you are a regular reader. Kelly works with stream surveys and fish routinely as part of her job with the Ohio EPA. And man, does she know the scaly crowd. Back in my early days with the Ohio Department of Natural Resources, I was fortunate to have the opportunity to spend untold hours afield conducting fish surveys with Dan Rice (who wrote this NEW BOOK) and Ted Cavender. Both of those guys are ichthyological legends, and I never failed to be awed at how they could glance through a seine full of similar minnows and shiners and quickly call out the different species. Deja vu set in after watching Kelly and Laura do the same.

The stream in the first image is a big one, considering the habitat of our primary quarry on this day. We didn't find it in there, but did produce some interesting species including this rainbow darter, Etheostoma caeruleum. It is a male resplendent in its nuptial colors - a gaudy dress it'll only hold for a brief few weeks during the courtship and mating period. Hard as it may be to believe that such an exotic looking creature occupies Ohio streams, rainbow darters are pretty common statewide. It epitomizes the wonders of conducting subsurface aquatic explorations. Streams are full of fascinating creatures, but one must dive in to observe them.

We also hauled up several central stoneroller minnows, Campostoma anomalum. This is a male in breeding condition, flushed with peachy-orange and head beset with pointy tubercles. Apparently this "fish acne" helps male stonerollers win the girl. This fish has big lips. The lower lip is modified into a stiff cartilaginous ridge that it uses to rasp algae from rocks. Stonerollers are very common throughout Ohio, and one of relatively few fish species that tolerates heavy phosphorus loading. This common agricultural pollutant promotes the growth of algae - not good news for most things - but the hardy stonerollers capitalize and make lemonade from lemons.

Ah! This much smaller headwater stream holds today's primary target, which we'll soon get to. One could easily bound across this stream in places, and it's so small that the flow dries to a trickle in the heat of summer. Deeper pools like the one at the bend of the stream in this photo are critical in providing refugia for fish during low water flow. Dense forests along the stream's course ensure a lack of siltation and high water quality.

We were understandably pleased to find several orangethroat darters, Etheostoma spectabile. Here we have a pair - male above, female partially concealed in the rock cobble. The male is in its nuptial finery and we can see the namesake orange throat. Orangethroats are headwater stream specialists and normally occupy tiny streamlets such as this one.

Darters are icing on the cake, but today was principally a dace safari. Dace are small members of the cyprinid family, which includes carp, chubs, dace, minnows and shiners. The five Ohio dace species all inhabit small headwaters streams such as the one in the previous photo. Three species occur in the stream section in the image, or very nearby. This one is a female southern redbelly dace, Chrosomus erythrogaster.

This is a male western blacknose dace, Rhinichthys obtusus, its lateral band infused with rusty orange as it is during breeding season.

Finally, the main target, a long-coveted "life fish" for your narrator, and a stunning creature, the rosyside dace, Clinostomus funduloides. Rosyside dace have a very limited distribution in a handful of stream systems in just four southern counties: Adams, Jackson, Pike and Scioto. They were once thought to be much rarer, but heavy sampling of their (at the time) understudied habitat by the aforementioned Dan Rice and colleagues revealed the rosysides to be more plentiful than thought.

Kelly noted their resemblance to salmon, and I couldn't agree more. Elfin salmonlets. A big one is only a few inches long. These two males are still in breeding condition and it isn't hard to see where their common name is derived.

There are about 62,000 river miles in Ohio. Big rivers like the Maumee, Muskingum, and Scioto get more than their fair share of attention due to their size and conspicuousness. But it's the little headwater streams that do much of the heavy aquatic lifting. They make up nearly 80% of Ohio's river miles, and form and feed the big streams. As we've seen - and this is just a tiny sampler - headwater creeks support an interesting diversity of specialized fishes and other aquatic life. But they are vulnerable to destruction and detrimental impacts. One of the largest rosyside dace populations was wiped out by a highway construction project. Just a week or so ago, in the area that generated this article, I came across an excavator smack in the middle of a headwater stream, dredging rocks which were being hauled out by big dump trucks. Permits? Nah, probably not. Stuff like this goes on all the time, and it's not to the benefit of the streams' rightful occupants.

Major thanks to Kelly, Laura, John and Phil for creating a fascinating natural history foray.

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