Macrobenthic prey and physical habitat characteristics in a western Gulf sturgeon population: differential estuarine habitat use patterns

Abstract

Gulf sturgeon Acipenser oxyrinchus desotoi is listed as 'threatened' under the US Endangered Species Act throughout its range in the northern Gulf of Mexico, with Mobile Bay, Alabama, USA, as the recognized break between eastern and western populations. Population recovery requires protection of the species and its critical habitat. We examined Gulf sturgeon physical habitat attributes and infaunal macrobenthic prey density and composition both spatially and seasonally relative to acoustically tagged Gulf sturgeon occurrence in the Pascagoula River estuary. Gulf sturgeon occupancy patterns indicated that adults move quickly through the system during fall and spring compared to longer but more spatially and temporally variable occupancy for juveniles and sub-adults in both seasons; sub-adults exhibited a less spatially and temporally variable occupancy pattern. We found significant differences in physical habitat and macrobenthic density characteristics that partially explained Gulf sturgeon spatial and temporal occupancy patterns. Direct comparisons of physical drivers (% silt, depth, particulate organic carbon) and macrobenthic density patterns (BEST procedures) were significantly correlated (p < 0.01) but weak (global R = 0.277) and suggest alternate hypotheses to better explain the differential estuarine habitat use patterns. The most parsimonious explanation with multiple weights-of-evidence suggests reduced use of the eastern distributary habitat by Gulf sturgeon based on synergistic effects of urbanization and industrialization such as bulkheading, channelization, dredging and related maintenance activities, and beach re-nourishment, all of which occur almost exclusively in the east zone of the estuary.

Subcutaneous injection of visible implant elastomer in sterlet (Acipenser ruthenus Linnaeus, 1758): a study on compatibility and retention

“…Internal PIT tags have been used e.g. in A. brevirostrum (Welsh et al, 2002), A. oxyrinchus (Laney et al, 2007), A. oxyrinchus desotoi (Peterson et al, 2013;Ross et al, 2008), pallid sturgeon Scaphyrinchus albus (Hamel, Steffensen, Hammen, & Pegg, 2013;Steffensen, Powell, & Koch, 2010), and Dabry's sturgeon Acipenser dabryanus (Wu, Wei, Du, Wang, & Zhang, 2014). Examples for the use of CWTs are A. dabryanus (Wu et al, 2014) and S. albus (Steffensen et al, 2010).…”

“…Acoustic and radio telemetry transmitters, both implanted as well as externally attached, are also often used to monitor movement and habitat use of various sturgeon species, e.g. A. brevirostrum (Welsh et al, 2002;Zydlewski, Kinnison, Dionne, Zydlewski, & Wippelhauser, 2011); Russian sturgeon Acipenser gueldenstaedtii, and stellate sturgeon, Acipenser stellatus (Kynard, Suciu, & Horgan, 2002); green sturgeon Acipenser medirostris (Erickson, North, Hightower, Weber, & Lauck, 2002;Erickson & Webb, 2007;Lindley et al, 2008); A. oxyrinchus desotoi (Peterson et al, 2013;Ross et al, 2008), and Chinese sturgeon Acipenser sinensis (Yang et al, 2006).…”

Growth Estimation of Western Population Segment Gulf Sturgeon Using Length‐at‐Age and Mark–Recapture Data

“…Captured Gulf Sturgeon individuals were measured in the field for TL (nearest 0.1 cm), FL (nearest 0.1 cm), and weight (W; nearest 0.01 kg for fish <25 kg, nearest 0.1 kg for fish >25 kg). Additionally, fish were marked with all or at least one of the following tags for recapture purposes: a PIT tag in the dorsal musculature, T-bar anchor tags in one or both of the pectoral fins, and a surgically implanted or externally attached (to the base of the dorsal fin) VEMCO acoustic tag (various portions of these sampling efforts have been reported by Ross et al 2002Ross et al , 2009Dugo et al 2004;Heise et al 2004Heise et al , 2005Havrylkoff et al 2012;Peterson et al 2013Peterson et al , 2016Grammer et al 2015;and Vick et al, in press). Gulf Sturgeon juvenile (<89 cm FL), subadult (89-125 cm FL), and adult (>125 cm FL) size-classes follow those specified by Parauka et al (2011).…”

Activity patterns of Gulf Sturgeon (Acipenser oxyrinchus desotoi) in the staging area of the Pascagoula River during fall outmigration

“…; Peterson et al. ). An effective sampling strategy would be adapted to correspond with periods when there is a high probability of increased Gulf Sturgeon activity.…”

“…Gaps in knowledge exist about the links of potential environmental cues and increased periods of activity of Gulf Sturgeon, as they pause their emigration from the lotic environment after leaving the summer holding area. Due to their rarity, sampling for Gulf Sturgeon is costly and time-consuming, especially in the Western portion of their range (Havrylkoff et al 2012;Peterson et al 2013). An effective sampling strategy would be adapted to correspond with periods when there is a high probability of increased Gulf Sturgeon activity.…”