Joe N. Fries

An Evaluation of Visible Implant Elastomer for Marking the Federally Listed Fountain Darter and the San Marcos Salamander

Abstract Visible marks can aid in population studies but, depending on the type of mark used, may result in poor retention and increased mortality. Visible implant elastomer (VIE) was evaluated as a marking technique for two species listed as endangered or threatened under the federal Endangered Species Act: The fountain darter Etheostoma fonticola and the San Marcos salamander Eurycea nana. We compared VIE with acrylic latex paint (ALP) marks in the fountain darter and found that VIE marks exhibited greater retention than ALP marks (88% versus 23% at 244 d). Fountain darter survival and growth were not affected by mark type. In the San Marcos salamander, the use of VIE marks did not affect survival or growth. For both species, mark placement (dorsally versus ventrally) did not affect retention. Visible implant elastomer marks would be the preferred method for population studies of these listed species.

Survey and Distribution of Invertebrates from Selected Springs of the Edwards Aquifer in Comal and Hays Counties, Texas

Abstract We surveyed four spring sites of the Edwards Aquifer to determine current distribution and abundance of spring and cave-adapted invertebrates, including three that are federally listed as endangered. We found 18 species from 12 families of endangered and stygobiontic fauna, similar to other surveys completed 10 years prior, and recorded new localities for Tethysbaena texana, Cirolanides texensis, Lirceolus hardeni, Lirceolus smithii, Stygobromus longipes, Stygobromus flagellatus, and Artesia subterranea. We also report discovery of new species of Bogidiellidae (near Parabogidiella), Ingolfiella, and Almuerzothyas.

Habitat and Substrate Use in Reproduction of Captive Devils River Minnows

Abstract The Devils River minnow Dionda diaboli is a threatened species once endemic to a portion of the Rio Grande drainage in western Texas and northern Mexico but now found only in the Devils River and San Felipe and Pinto creeks. Because little is known about the biology of this species, it is difficult to establish protocols for maintaining captive populations. We monitored the production of Devils River minnows in two laboratory culture systems containing four substrate types (rocks, gravel, sand, and Spawntex) within each of two habitat types (riffle and pool) that had two subhabitat types each (upper and lower riffle, covered and uncovered pool). A total of 38 adult fish (mean weight = 1.38 g; mean total length = 54 mm) were introduced into the two culture systems (19 fish each, approximately equal sex ratio) on 5 September 2001. From 18 September to 6 December, 2,269 young were removed. A significantly greater number (1,922; three-factor nested analysis of variance [ANOVA], Fishers least-signifi...

Apparent Sunburn of Juvenile Paddlefish

Abstract Juvenile paddlefish (Polyodon spathula) transferred to outdoor raceways at the National Fish Hatchery and Technology Center, San Marcos, Texas, exhibited dorsal skin lesions characteristic of sunburn within 1 week. These fish were assigned to one of three classifications: normal, burned, or curved (curved rostrum), depending upon the severity of the lesions. Approximately equal numbers of fish from each classification were stocked into a raceway in two compartments. One section remained uncovered and received full sunlight while the other was covered and received reduced sunlight for 51 d. Survival of the covered and uncovered fish was 87% and 55%, respectively. Many of the covered fish returned to the normal condition.

SENSORY CUES FOR CONSPECIFIC ASSOCIATIONS IN AQUATIC SAN MARCOS SALAMANDERS

The mode and effectiveness of signals greatly depends on habitat characteristics and the activity patterns of a species. Visual cues frequently are involved in social interactions, although their effectiveness can be reduced with nocturnal species or in habitats with limited visibility. The combination of multiple signals, such as chemical and visual cues, can increase the accuracy and efficacy of communication in these systems. Association preferences of male and female Eurycea nana were examined by allowing individuals to choose between members of both sexes based on (1) chemical signals, (2) visual signals, and (3) chemical and visual signals. Both sexes showed stronger associations with the chemical signals and combined chemical and visual signals of the opposite sex than with visual cues alone. The simultaneous inclusion of both chemical and visual signals did not increase male or female responses suggesting that chemosensory communication is sufficient for individuals of this aquatic species to distinguish between the sexes at close range. Additionally, the finding that females as well as males exhibit sexual discrimination suggests that both sexes seek out potential mates, a phenomenon rarely seen in salamanders.

Culture Studies of the Devils River Minnow

Abstract Requirements for indoor culture of the threatened Devils River minnow Dionda diaboli were developed and refined. Spawning over gravel previously occurred in experimental systems with a riffle area under a compressed seasonal cycle (temperature and photoperiod). Subsequently, spawning occurred without the riffle area and seasonal cycle. Given only gravel (15- 25 mm) and rock (40–80 mm) as spawning substrate, more eggs were found in the gravel (Mann-Whitney tests, P < 0.001). Additionally, pairwise breeding was achieved in both wild-stock and first-generation fish; average survival from egg to fry was improved from about 25% to 45%; a growth curve was developed, in which fish averaging 7 mm total length (TL) grew to an average of 35 mm TL in 192 d; growth rate was noted to decline as culture density increased (nonlinear regression, P < 0.001). Sexually dimorphic characteristics (yellow fins, blue body coloration, and nuptial tuberculation) and aspects of spawning behavior (substrate necessity, terr...

Retention of Coded Wire Tags in Four Locations in Juvenile Paddlefish

Abstract One hundred eighty juvenile paddlefish Polyodon spathula (mean total length, 240 mm) were tagged with coded wire tags in either the midrostrum, rostrum tip, dorsal fin, or opercular flap. Mean tagging times were significantly longer (P ≤ 0.05) for the dorsal fin (19.3 s) and opercular flap (18.4 s) than for the midrostrum (5.1 s) and rostrum tip (6.6 s). Tag retention was checked monthly for 3 months. Mean tag retention for the rostrum tip (94.8%) and midrostrum (92.9%) was significantly higher (P ≤ 0.05) than that for the opercular flap (86.1%) or dorsal fin (67.4%), and tag retention for the opercular flap was significantly higher (P ≤ 0.05) than that for the dorsal fin. My results corroborate rostrum tagging locations recommended by the Mississippi Interstate Cooperative Resource Association.

Agonistic and Courtship Behaviors in Dionda diaboli, the Devils River Minnow

Abstract Reproductively mature male Dionda diaboli, the Devils River minnow, exhibited agonistic and courtship behavior in presence of conspecifics under laboratory conditions. Dionda diaboli spawned over small trays of gravel and did not use a cavity or a crevice. Devils River minnows were non-communal, territorial, broadcast spawners and agonistic behavior consisted of chases, parallel swims, lateral displays, circle swims, and head butts. Courtship behavior consisted of a male approaching a female and pushing her down toward the substrate (male-female approach) prior to spawning. Spawning did not occur until a male had established dominance in the hierarchy.

Evaluation of an Aeration System in a Loaded Fish-Hauling Tank

Abstract An aeration system (three 12-V DC Fresh-Flo aerators and two Wilfley-Weber oxygen diffusers) was evaluated in a 2,650-L fish-hauling tank loaded with 908 kg (521 g fish/L) of 23-cm-long channel catfish (Ictalurus punctatus) in a static test. Water quality was monitored while fish were being loaded (21 min) and for 4 h thereafter. Dissolved oxygen (DO) dropped from above 20 to 2.2 mg/L during the first 50 min. By the end of the test, DO had risen to 8.5 mg/L (106% saturation). The pH dropped from 7.70 to 6.70 and the temperature rose from 21.5 to 23.5°C. Total ammonia nitrogen rose from 0.7 to 12.8 mg/L during the test but was primarily ionized; un-ionized ammonia rose from 0.015 to 0.032 mg!L. This poor performance emphasizes the need to monitor water quality in hauling systems for various loading conditions and aeration systems.

Spawning Behavior and Nest Association by Dionda diaboli in the Devils River, Texas

Abstract Spawning behaviors of the Devils River minnow (Dionda diaboli) were observed in the Devils River, Val Verde County, Texas. Spawning in the wild was observed over active and inactive nests of centrarchids near openings of a spring. Nests consisted of cleaned gravel ca. 2–3 cm in maximum dimension. Males defended territories and occasionally spawned with receptive females over the nests. All behaviors observed in the laboratory were observed in wild fish and percentages of time that those behaviors were observed were similar.