The Presence and Distribution of Sturgeon in the Damariscotta River Estuary

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

5. 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species’ have been documented in the Gulf of Maine • Kennebec River (Squiers and Smith 1979; Wippelhauser et al., unpublished) • Penobscot River Estuary and Bay (Fernandes 2008).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

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

7. 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

8. 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

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

10. 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

11. 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

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

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

14. Prey Species Capitellidae sp. Juvenile bivalve

15. 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.

16. 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.

18. National Marine Fisheries Service

19. Questions?