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The Presence and Distribution of Sturgeon in the Damariscotta River Estuary

The Presence and Distribution of Sturgeon in the Damariscotta River Estuary. Kimberly Picard Gayle Zydlewski. Goal. Document contemporary presence and distribution of tagged sturgeon in the Damariscotta River Estuary. Objectives. Locate habitat areas used by tagged sturgeon and

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The Presence and Distribution of Sturgeon in the Damariscotta River Estuary

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  1. The Presence and Distribution of Sturgeon in the Damariscotta River Estuary Kimberly Picard Gayle Zydlewski

  2. Goal • Document contemporary presence and distribution of tagged sturgeon in the Damariscotta River Estuary Objectives • Locate habitat areas used by tagged sturgeon and • Associate habitat use to: • Abiotic features (e.g., temperature, salinity, depth) • Biotic features (prey availability)

  3. Atlantic Vs. Shortnose sturgeon Photo courtesy: South Carolina DNR

  4. Background • Both sturgeon species’ have been documented in the Gulf of Maine • Kennebec River (Squiers and Smith 1979; Wippelhauser et al., unpublished) • Penobscot River Estuary and Bay (Fernandes 2008). • These tagged sturgeon moved to other river systems • Presence and distribution are influenced by suitable environmental conditions, foraging and prey availability Photo Courtesy: Cornell University Photo Courtesy: Cornell University

  5. SNS documented in multiple rivers… Zydlewski et al. 2011. Tara Trinko, NOAA

  6. Methods- Sturgeon in the Damariscotta • Acoustic telemetry • Receivers record acoustic signals from individual tags implanted in sturgeon • Three stationary receivers placed in the river from Apr 12-Dec 5, 2012 • Weekly mobile surveys at 10 different locations from Sept 11-Nov 14, 2012 Photo courtesy: Zydlewski Lab

  7. Methods- Environment • Weekly surveys • Sep 11-Nov 14, 2012 • At each of 10 locations: • Depth (m) • Surface and bottom temperature (°C) • Salinity (ppt) • Dissolved oxygen (mg/l) • A PONAR grab was used to collect • Substrate • Benthic prey Photo Courtesy: Matthew Dzaugis

  8. Approximate locations of collected data of each trip (circles) and of three stationary receivers (stars). DMC

  9. Results- Passive receivers • Sturgeon movements in Damariscotta River estuary observed in 2012 ‘D’ represents a fish detected on downstream receiver ‘U’ represents fish detected on upstream receiver

  10. Results- Environmental data Bottom water temperature Surface water temperature Warmer: Sept 11- Oct 2 Warmer: Sept 11- Oct 2 Colder: Oct 17- Nov 14 Colder: Oct 17- Nov 14 Upstream Downstream

  11. Average depth (m) and salinity (ppt) at each survey location. Downstream Upstream

  12. Results- Prey Availability Before and After the 3°C temperature drop in October and upstream versus downstream.

  13. Prey Species Capitellidae sp. Juvenile bivalve

  14. Conclusions • Higher number of sturgeon in the spring • related to warmer water conditions or prey diversity. • Atlantic sturgeon only visited in the spring • may prefer warm water in small coastal rivers • Sturgeon that stayed for >24hrs travelled further upriver, into shallower depths and warmer temperatures • Perhaps to find additional food sources.

  15. Conclusions Data suggest that: Prey diversity and richness is higher upstream • perhaps a motivation for sturgeon to move upstream More prey were available in the summer than fall • perhaps a reason we see more sturgeon in the Damariscotta in the spring.

  16. National Marine Fisheries Service

  17. Questions?

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