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| Creek and Pool back in business |
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| Logperch (Percina caprodes) |
Within the Creek upstream of the Pool, we sat on cool stones and watched as several logperch fed along the sandy bed of the stream. They turn the pieces of gravel, feeding on such small animals as rotifers and waterfleas. The stone-turning behavior is one of the best ways to identify this species. As they grow older, the logperch will feed on such things as leeches, fish eggs, snails, and insect larvae. Like other darters, this non-schooling fish lives alone or in the presence of only a few others.
As for breeding, the female will lay eggs within the gravel bed after the male and her have briefly joined up. But the fertilized and hatched young ones will be left to themselves. One source sums up the family-values of the logperch: "Beyond laying and fertilizing eggs, logperch exhibit no parental investment."
As for breeding, the female will lay eggs within the gravel bed after the male and her have briefly joined up. But the fertilized and hatched young ones will be left to themselves. One source sums up the family-values of the logperch: "Beyond laying and fertilizing eggs, logperch exhibit no parental investment."
In the accompanying video below, we hear observers commenting on some nearby dragonflies' sex-life. Below are comments regarding the sex-life of logperch:
"Spawning season: In Central Texas , mid-December or early January to mid-May (Hubbs 1985); average seasonal temperature in Central Texas at the time females are known to be ripe varies from 9-23 degrees C (Hubbs and Strawn 1963). Spawning habitat: Over sand or gravel-bottomed areas of streams or in sand shoal areas of lakes (Winn 1985a); brood hiders that release eggs just below the surface of the substrate; lithophils, rock and gravel spawners that do not guard their eggs (Simon 1999).
Spawning behavior: In lakes, breeding males are non-territorial and weakly so in streams, defending only the immediate area around a female (referred to as moving territory; Ross 2001). Male mounts female just prior to spawning, placing his pelvic fins in ahead of hers, bending his tail down alongside her tail. Both fish quiver, raising a cloud of sand as they partially bury themselves. During this time, eggs laid and fertilized. Exposed eggs are usually eaten by other males. On occasion, female may vibrate and partially bury herself before being mounted by male (Winn 1958a).
Fecundity: Egg counts varies from 1,060-3,085 for mature females of sizes ranging 55-84 mm SL (ova count averaged about 2,000 in two-year-olds); however only 10-20 eggs are laid at each spawning. Larger females produce more eggs than do smaller females (Winn 1958a). Average diameter of mature, ovarian eggs is 1.31 mm; eggs colorless and transparent (Winn 1958b). Cooper (1978) recorded eggs, each with granular yolk, numerous small oil droplets, and one large oil droplet, that averaged 1.1-1.3 mm in diameter, and hatched in about 200 hours after fertilization at an average water temperature of 16.5 degrees C. Grizzle and Curd (1978) reported egg hatching occurring in 5-7 days at water temperatures of 21-23 degrees C."
Their name Percina means “a small perch,” and caprodes is Greek for “resembling a pig,” in reference to the snout.
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| Focusing on the shale bed underlying the Creek. |
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| Still focusing on the underlying bed of shale beneath a scene of dragonfly intimacy. |
Dimple-shadows rhythmically passing over creek-stones.
Curved stream-ripples
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| Rain-Lily (Cooperia drummondii) |
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| June 2007 debris |
Fluvial geomorphologists study how processes associated with rivers and streams change the shape of the earth. So one of the things they study is debris. I could do that. In the photo above we see fairly large pieces of debris caught in a big tree on the lower south end of the property. But it's not technically big enough to be called "large woody debris (LWB)." There's actually a term for that (skeptics may be referred to the 2003 article in the journal Geomorphology, volume 51, pages 61-80 for an example). LWB must be at least 10cm in diameter, and our piece in the center of the photo is but half that. But the piece does show interesting evidence of having been chewed on by nutria or beaver.
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| Diggings of armadillo or feral pig? |
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| We've looked at this sort of (acidic?) erosion on the limestone up among boulders on Whitman's Rough, but I can't get enough of the beautiful forms. |
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| Harlin excogitating creekside. |
