Food habits of the endangered Alabama Sturgeon, Scaphirhynchus suttkusi Williams and Clemmer, 1991 (Acipenseridae)

Abstract

Summary The gut contents of 12 museum specimens of the federally (USA) endangered Alabama sturgeon were analyzed. This collective series represents 32% of the known museum specimens. Gut contents were dominated by aquatic insects and fishes. At the taxonomic level of insect orders, Dipterans (174.3/fish) were the most numerically abundant food item consumed, followed by Ephemeroptera (19.0/fish), Trichoptera (4.0/fish), Coleoptera (2.4/fish), and Odonata (2.0/fish). Weight, which better reflects the caloric value of food items consumed, showed a similar consumption pattern. Dipterans (12.5%) made up the largest percentage of the total weight of insect prey, followed by Ephemeroptera (8.9%), Trichoptera (6.0%), Odonata, (4.5%) and Coleoptera (0.9%). Volumetric values were substantially higher than weights for Odonata (13.4%) and Ephemeroptera (14.3%), but were comparable for Diptera (10.6%), Trichoptera (4.7%), and Coleoptera (2.2%). The diet of the Alabama sturgeon is similar to the pallid and shovelnose sturgeon, eating both aquatic invertebrates and fish. In terms of piscivory, the volume of fish in the diet of the Alabama sturgeon (34.5%) is intermediate between that of the shovelnose (0% fish) and the pallid sturgeon (60% fish). Based upon the habitat preference of the prey family assemblages present from the 12 guts examined, probable feeding habitats of this sturgeon include sandy to rocky bottoms, slow to swift water velocities, and the water column. Conservation of fish prey may be important to the survival and recovery of the Alabama sturgeon.

Freshwater biodiversity conservation: recent progress and future challenges

“…The conservation status of other freshwater insects was not assessed. Grobler et al 2006, Keevin et al 2007, and many others) have been published on these subjects over the past 25 y, and have added greatly to our knowledge of the biology of many imperiled species. The ultimate importance of many of these studies is difficult to assess because much of the information that they generated probably has not been used to inform conservation action or management interventions.…”

An Evaluation of the Relative Quality of Dike Pools for Benthic Macroinvertebrates in the Lower Missouri River, Usa

“…Fish and Wildlife Service, 2003;US Army Corps of Engineers, 2006). However, these efforts have not incorporated measures of water or sediment quality, and they also have not considered the effects these activities might have on macroinvertebrates, in spite of their documented importance as food for benthic feeding fishes (Berry, 1996;Galat et al, 2001;Braaten et al, 2007;Hoover et al, 2007;Keevin et al, 2007), shorebirds (Helmers, 1992;Skagan and Omen, 1996;Sherfy et al, 2000) and a variety of other wildlife, including endangered species (Wanner et al, 2007;Delonay et al, 2009;Grohs et al, 2009). Some water-quality data generated in dike pools of great rivers are available from past studies (Beckett and Pennington, 1986;Barnum and Bachmann, 1988;Baker et al, 1991); however, most previous Lower Missouri River studies that have included waterquality measurements have targeted water column sampling in the main channel (Berner, 1951;Walter, 1971;Munger et al, 1974;Petty et al, 1995Petty et al, , 1998Blevins and Fairchild, 2001).…”

Status of the imperiled Alabama Sturgeon (Scaphirhynchus suttkusiWilliams and Clemmer, 1991)

“…Other items included ephemeropterans, trichopterans, odonates, and coleopterans. Small fishes, including cyprinids (minnows) and percids (darters) made up 34.5% of the diet by weight, with small mussels and oligochaetes making up the remainder (Burke and Ramsey, ; Williams and Clemmer, ; Mayden and Kuhajda, ; Keevin et al., ). Fishers reported catching ALS on trotlines with a variety of baits, including live cyprinids (minnows), crayfishes, earthworms, and cutbait from Gizzard Shad ( Dorosoma cepedianum ) and chicken parts (Burke and Ramsey, ; Williams and Clemmer, ).…”

“…Overall the diet of the ALS is similar to other Scaphirhynchus . However, in terms of piscivory, the volume of fishes consumed is intermediate between SVS, which consume no fishes, and Pallid Sturgeon (PS) S. albus in which fishes comprise 60% of the diet (Keevin et al., ). Unfortunately, alterations of large‐river habitats in the Mobile Basin have reduced the abundance of, and in some cases eliminated, large‐river species from the Alabama River proper, especially percids (darters), cyprinid chubs, and shiners (Freeman et al., ), the primary fish food source for the ALS (Keevin et al., ).…”

“…Based on the aquatic insect taxa ingested, ALS feed in a broad range of habitats, including shallow depositional areas with soft sand bottoms and slow to moderate current, shallow water in swift current over firm bottoms, and perhaps in the water column based on the consumption of ceratopogonids (Burke and Ramsey, ; Mayden and Kuhajda, ; Keevin et al., ). The use by ALS of sand bars in swift currents is supported by specimens being caught on baited trotlines predominately set on mid‐river sand bars (Burke and Ramsey, ).…”