Alison M. Hutson

Quantitative trait loci map for growth and morphometric traits using a channel catfish × blue catfish interspecific hybrid system

Head length, head depth, head width, body depth, body width, caudal depth, and caudal width and total length and BW were measured for 71 backcross full sibs between the interspecific backcross F1 (female channel catfish [Ictalurus punctatus] × male blue catfish [Ictalurus furcatus]) female × blue catfish male. Body measurements were corrected for both size and the relationship between relative body shape and size, which is critical but usually ignored in fish research. Amplified fragment length polymorphism analysis was used for construction of a QTL map with 44 linkage groups. Eleven of 44 linkage groups had at least 1 significant QTL (P ≤ 0.05) and 11 of 44 at P = 0.10. Linkage group 19 was unique as it had multiple QTL for every trait measured, except for caudal width for which no QTL was identified on any linkage group. Approximately half of the markers measured were associated with positive effects (increase in size) on the traits and half had negative effects (decrease in size). Linkage groups 5, 9, 18, 20, 39, and 40 were significant for multiple traits and always had a trait negative effect. Total length is represented on the map by the most linkage groups and the most markers. The linkage relationships found among BW, total length, and the 7 morphometric traits indicated that multiple trait marker-assisted selection to simultaneously increase BW body depth, body width, and caudal depth while decreasing the head traits with the goal to increase body weight and carcass yield would be very difficult. Multiple genetic enhancement approaches would likely be needed to simultaneously improve BW and body conformation.

Effect of High Stocking Rates on Growth and Survival of the Endangered Rio Grande Silvery Minnow Hybognathus amarus

The endangered Rio Grande silvery minnow Hybognathus amarus was cultured in 2.44-m-diameter outdoor tanks in a 131-day yield trial to assess growth, survival, and percentage of taggable-sized fish ( >35 mm total length) when stocked at 500/tank (1.07 million/ha), 1,000/tank (2.14 million/ha), and 1,500/tank (3.21 million/ha). At harvest, fish averaged 45.6 mm and 0.94 g in the 500/tank treatment, 42.6 mm and 0.74 g in the 1,000/tank treatment, and 38.4 mm and 0.55 g in the 1,500/tank treatment; the differences were significant ( P = 0.05). Survival in the three treatments was 70%, 64%, and 52%, respectively, but the differences were not significant. Percent taggable-sized fish was 86%, 89%, and 65%, respectively, but the differences were not significant. Yield was 672.5 kg/ha, 1,026.6 kg/ha, and 887.8 kg/ha, respectively; yield in the 1,000/tank treatment was significantly greater than that in the 500/tank treatment, but was not significantly greater than that of the 1,500/tank treatment. This facility is a conservation facility and a major goal is to raise fish without formulated feed. Fertilization produced good growth for the first month, but little growth occurred during the second month so supplemental feed had to be used for the final 60 d of the yield trial.

Lower lethal temperature of the endangered Rio Grande silvery minnow and its implications for propagation and reintroduction

ABSTRACT The lower lethal temperature of the endangered Rio Grande silvery minnow, Hybognathus amarus, was estimated from survival rates of fish overwintered in above-ground tanks. Temperature went to 0.0°C both winters. In 2012–2013, survival of Age class 0 fish was 79.87%, and in 2013–2014, survival of Age class 1 fish was 97.1%, suggesting that if Rio Grande silvery minnow is subjected to seasonal temperature changes, lower lethal temperature is ≤0.0°C. Results show that heating hatchery water in the winter is unnecessary. Additionally, current management guidelines that preclude reintroduction of the species into river sections where winter temperatures are ≤1°C must be reevaluated.

Determining preferred spawning habitat of the endangered Rio Grande silvery minnow by hydrological manipulation of a conservation aquaculture facility and the implications for management: Spawning habitat of Rio Grande silvery minnow

Ecohydrology. 2018;11:e1964. https://doi.org/10.1002/eco.1964 Abstract The endangered Rio Grande silvery minnow (Hybognathus amarus) was induced to spawn in both 2012 and 2013, using hydrological manipulation of a conservation aquaculture facility to create floodplain habitat. Fish responded to the flood by leaving the stream and entered both deep (20–97 cm) and shallow (14–18 cm) low‐velocity off‐channel habitats, spawning in the deep ones; fish did not spawn in the stream. When water level was brought down from flood stage, fry actively moved into the stream 2.5 weeks postspawn. This study supports the hypothesis that this species is a floodplain spawner. The results show that habitat restoration of the Rio Grande to create floodplains is needed for recovery of this species as floodplains are both spawning and nursery habitats. The study provides guidelines about how deep floodplain inundation must inundate for spawning to occur and for the duration of inundation so fry can actively swim with the water when flood waters recede. This project also shows that a conservation facility can be used for all stages of fishs life history. Equally important, it shows that a conservation aquaculture facility can be used to conduct hydrological experiments to determine how an endangered fish will respond to changes in river management.

Behavioral observations of the endangered Rio Grande silvery minnow in a conservation aquaculture facility

Abstract A major reason why conservation aquaculture is needed to improve the success of aquaculture-assisted fisheries is that traditional production aquaculture produces fish with mal-adaptive behaviors. These behaviors can be produced via domestication and culture techniques, and preventing these mal-adaptive behaviors requires integrating improvements in genetic management and culture protocols. The genetic protocols needed to minimize hatchery-induced genetic changes have received considerable attention, but changing the way fish are raised has received less effort. Conservation aquaculture cultures fish in environments that resemble their native habitats so that when stocked, they behave like wild fish rather than hatchery fish. A purpose built-conservation aquaculture facility can also be used to learn about a species’ behavior and how it reacts to changes in the environment, something which can be difficult or expensive to study in the wild. These observations can then be used to help direct both propagation and recovery management. This paper provides the rationale for why genetic management, culture systems, and management practices need to be altered to produce fish that are behaviorally similar to wild fish for aquaculture-assisted fisheries programs. It then provides a description of some of the behaviors of the endangered Rio Grande silvery minnow Hybognathus amarus that were observed at the Los Lunas Silvery Minnow Refugium, a purpose-built conservation aquaculture facility, and explains how some of these behaviors can be used in culture and recovery management. Behaviors described are: schooling; predator avoidance; feeding behavior; use of vegetation for cover and predator avoidance; habitat use by bottom substrate; location in the water column; upstream movement via a fish ladder; movement upstream in a high-velocity channel; response to changes in water level; spawning behavior; seine avoidance; and Kaah-chee-nyee Srkaash, a behavior described for the first time.

Comparison of Body Composition and Fatty Acid Profiles between Wild and Cultured Rio Grande Silvery Minnows

Abstract Federally endangered Rio Grande Silvery Minnows (RGSM; Hybognathus amarus) were raised in one of three culture regimes: intensively, with only a hatchery diet; semi-intensively with access...