Habitats Used by Shortnose Sturgeon in Two Massachusetts Rivers, with Notes on Estuarine Atlantic Sturgeon: A Hierarchical Approach

Abstract

Biotelemetry of shortnose sturgeon Acipenser brevirostrum and Atlantic sturgeon A. oxyrinchus oxyrinchus was used to study fish uses of habitat in several hierarchical classes in the Connecticut and Merrimack rivers. Hierarchical classes were geomorphological region (straight river run, run with an island, and river curve), river cross section (channel or shoal), and microhabitat (water depth, bottom current, substrate, and illumination). Coastal wandering juvenile Atlantic sturgeon were summer visitors to the Merrimack River, where they used a narrow range of habitat on all spatial scales, e.g., run-with-island, the channel portion of the cross section, and sand substrate. Shortnose sturgeon, year-round residents in both rivers, showed great individual variation in habitat use, and all ages selected a broad range of habitats on all spatial scales. However, shortnose sturgeon in both rivers preferred curves with sand or cobble substrate and avoided runs regardless of substrate. Individuals used channel or shoal at rates ranging from 0 to 100% on a weekly time scale in an unpredictable manner. Connecticut River shortnose sturgeon increased their use of curves, channels (deep water), and sand substrate in the fall. This strategy may conserve energy because these conditions usually reflect slow water velocity. Winter habitat selection continued the fall pattern, but was less variable because habitat affinity was highest among wintering fish. Documenting individual fish use of large-scale habitat revealed habitat relationships that would not have been discovered if only fish use of microhabitat had been studied.

Behavior of early life intervals of Klamath River green sturgeon, Acipenser medirostris, with a note on body color

“…Because movement occurred during the late summer and fall, it likely reflects a movement of wild juveniles to wintering habitat. Shortnose sturgeon move to wintering areas during the same time period (Kynard et al 2000).…”

“…The 10 wintering juveniles spent 67% of the time on sand, not gravel habitat, but the preference was not significant, likely because only 10 fish were tested. Wintering juveniles of six North American sturgeons prefer sand (Parker et al unpublished data), and wintering juvenile (and adult) Connecticut River shortnose sturgeon, A. brevirostrum, use deep, sandy habitat (Kynard et al 2000). Thus, sandy deep-water habitat may be typical winter habitat of many sturgeons.…”

“…The occurrence of the black-tail phenotype on early larvae suggests this morphological character is linked to behavioral characteristics and is an adaptation for migration, early foraging, or both. The wigwag movement of the black tail is a good visual signal and is possibly used for social signaling, predator avoidance, or both (Kynard et al 2000). Green sturgeon were distributed randomly among the sections of the oval stream without rocks, a result suggesting they are not social and black-tail is not a social signal for green sturgeon.…”

Continuous acoustic studies of overwintering sprat Sprattus sprattus reveal flexible behavior

“…Research of overwintering environments has increased during the last 2 decades, and the habitat and behavior of a large number of freshwater fish have been investigated (Riehle & Griffith 1993, Kynard et al 2000, Huusko et al 2007). However, the overwintering microhabitats of marine and estuarine fishes are mainly unknown.…”

Evaluation of Adult White Sturgeon Swimming Capabilities and Applications to Fishway Design

“…To improve the safety and efficiency of fish ladders for use by larger species, such as sturgeon, the modification of fish ladders by incorporating orifices into the traditional pool and weir design has been reported and the study of swimming behavior for the gulf sturgeon (Chan et al 1997) and for the wild, shovelnose sturgeon (Hurley et al 1987;Adams et al 1997) have been reported. Identifying attraction speed of flow, passage time, sustained swim speed, hydraulic conditions, and locomotory activity are necessary to consider for the effective design of fishways and passage facilities (Auer 1996;Chan et al 1997;Schaffter 1997;Quist et al 1999;Kynard et al 2000;Bramblett and White 2001;Peak and Farrell 2004;Castro-Santos 2005). White and Mefford (2002) reported that passage was more successful in the rock fishway because a variety of flow velocities were available, and fish seemed to search for the best possible hydraulic conditions.…”