Threatened and Endangered Species Issues on the Kennebec River, Maine
Acipenser brevirostrum Photo: Nancy Haley, NOAA Atlantic sturgeon photo courtesy of Robert Michelson Threatened and Endangered Species Issues on the Kennebec River, Maine Obstacles to Dredging due to the Presence of Shortnose Sturgeon, Atlantic Salmon and Atlantic Sturgeon Kenneth M. Levitt Valerie A. Cappola Ph.D. USACE New England District Troy R. Bennett / The Times RecordBangor Daily News, September 1, 2011 Kennebec River Federal Navigation Channel
Phippsburg to Bath (approximately 13 miles) Maintained by the U.S. Army Corps of Engineers Bath Iron Works depends on channel to move Navy vessels Extremely dynamic and subject to unpredictable shoaling Authorized to Depth of 27 Feet M.L.L.W. Active from Phippsburg to approximately 13 miles upstream to Bath Maintained by the U.S. Army Corps of Engineers Bath Iron Works depends on channel to move Navy vessels Area is extremely dynamic and subject to unpredictable shoaling Doubling Point, approximately 12 miles upstream from mouth of river
Two reaches where shoaling has historically occurred: Doubling Point, approximately 12 miles upstream from mouth ofriver Popham Beach, where river joinsAtlantic Ocean Two reaches where shoaling has historically occurred: Doubling Point, approximately 12 miles upstream from mouth ofriver Popham Beach, where river joinsAtlantic Ocean Kennebec River Provides Habitat for Three
Federally Listed Fish Species 1.Shortnose Sturgeon (Acipenser brevirostrum) a.Originally Listed as Federally Endangered in March 1967 by the U.S. Dept of Interior b.Anadromous/ freshwater amphidromous in Kennebec River Spawns upstream in freshwater in Kennebec River.Adults inhabit lower esturarine regions of river and have been shown to migrate along the coast to Penobscot River. Adults spawn in freshwater but regularly enter saltwater habitats during their life (Kieffer and Kynard 1993 as cited in NOAA, 1998) although will spend time in freshwater. b. Over-winters in areas of Kennebec River upstream from Doubling point (Merrymeeting Bay, shown by red arrow). Recent Kennebec River population estimates indicate that population has increased since the 1990s. Spawning areas have been found in the Androscoggin River below the Brunswick Dam (not shown on map), and in the Kennebec River near Gardiner (marked by red arrow), and now upstream below Lockwood Dam in Waterville (since the removal of the Edwards Dam in Augusta). Gulf of Maine DPS of Atlantic Salmon (Salmo salar)
(Salmo salar) Photo: William Hartley, USFWS a.Gulf of Maine Distinct Population Segment (DPS). First Listed as Endangered in 2000, with the addition of the upper Kennebec River and Penobscot River stocks in 2009. b.Anadromous Spawns upstream in freshwater in Kennebec River.Young will live in the river for several years before smolting (a physiological change where the fish becomes able to live in salt water) and migrating downstream to mature in marine environment Adults migrate out towards Greenland before returning to spawn in freshwater natal streams (often migrating upstream over one hundred miles, not including their oceanic migrations). Lower Kennebec River has fish that spawn in both the Androscogin River and Kennebec River.Will begin to migrate upstream in May through Julyand spawn in the fall.Smolts will migrate downstream in the spring.Post spawning adults will down-migrate in the later fall. Spawning areas located upstream near Augusta, and with the removal of the Edwards Dam have been able to move further upstream. Gulf of Maine DPS of Atlantic Sturgeon
(Acipenser oxyrinchus oxyrinchus) Atlantic sturgeon photo courtesy of Robert Michelson Photo: USFWS a.Gulf of Maine DPS proposed for listingas Threatened in October 2010, with final listing in February Also New York Bight and Chesapeake Bay DPS listed as Endangered.Although not listed at the time of dredging, it still needed to be addressed in the Section 7 Consultation because it was proposed. b.Anadromous Spawns upstream in freshwater reaches of the Kennebec River but spendmost of their adult life in the marine environment. After hatching larvae move downstream to estuary where they transition to juveniles, and will remain formonths or years before moving to open ocean as sub-adults.At sea, adults make long range migrations but will return to their natal rivers to spawn (ASSRT, 2007). Have been shown to move between the Kennebec River and the Penobscot River. Have also been found in Saco River, south of the Kennebec (not shown on map). Spawning migrations occur from May July in more northern areas (Maine/Canada).Kennebec River is one of the few rivers in Maine where spawning has historically occurred and still believed to occur for this species. d.Spawning areas believed to have been near Gardiner, and since the removal of the Edwards Dam in Augusta fish have been found further upstream on Kennebec River (ASSRT, 2007). November 1 to April 30 of any year
All three species will move throughout the Kennebec River to access various habitats during their life cycles, passing through theareas that are periodically dredged Consultation with the National Marine Fisheries Service (NMFS) under Section 7 of the EndangeredSpecies Act (required) Biological Opinion (BO) established dredge windows, reasonable and prudent measures and incidental take statements (for SNS) November 1 to April 30 of any year Dredging outside the windows -In 2003 dredged in October to move the Navy destroyer the U.S.S. Chafee Resulted in 5 Incidental takes of SNS 1.Numerous Studies conducted by and for the federal and state resource agencies have shown that all three of these species will seasonally move throughout theKennebec river to access various habitats(i.e. spawning, overwintering, or foraging) 2.All three species will be required to pass through the areas that are periodically shoaled and dredged at some point during their life cycles 3. Consultation with the National Marine Fisheries Service (NMFS) under Section 7 of the EndangeredSpecies Act has been required for past dredging events.Resulted in their issuance of aBiological Opinion (BO) establishing dredge windows, reasonable and prudent measures and incidental take statements to avoid jeopardy (for shortnose sturgeon) 4. The most recent dredging window established for shortnose sturgeon ranged from November 1, to April30 of any year 5.The dynamic and unpredictable nature of the shoaling in the Kennebec River has necessitated dredging of the river outside of these dredging windows (at times) in order to ensure the passage ofNavy vessels through the channel to meet critical deployment schedules. In 2003 the channel was dredged during October (outside of the window) in order to move the Navy destroyer the U.S.S.Chafee. 6. This dredging resulted in the incidental take of 5 endangered shortnose sturgeon. A BO prepared as a result of an expedited Section 7 Consultation determined that these takes did not jeopardize the continued existence of the species. Biological Opinion Determined that 5 incidental takes of shortnose sturgeon did not jeopardize their continued existence in the Kennebec River 1.A total of5 takes from hopper dredge Padre Island,3 lethal.Less injuries occurred when inflow screens were removed.Take number 1above was first lethal take.Most injuries appeared to be from retention at inflow screen. Shoaling in late 2010 and early 2011
Dredging would need to occur to move the U.S.S. Spruance Scheduled for departure on September 1, 2011 Would need to be dredged in August (outside of window) Shoaling occurred again during late 2010 and early It was determined that dredging would need to occur prior to the departure of a newlyconstructed Navy destroyer, the U.S.S. Spruance Scheduled for departure from Bath Iron Works on September 1, 2011 Due to the time required to secure funding and permits, the dredging would need to occur in August, 2011 (outside of the previously established dredging window for shortnose sturgeon) Shortnose and Atlantic sturgeon acoustic telemetry data
Shortnose and Atlantic sturgeon sampling and acoustic tracking data (collected and compiled by the State of Maine) indicated that both of these species concentrated just downstream from the proposed dredging area to forage during the late summer, with movement of individual fish through the area of active dredging expected during that time (upstream and downstream). Fish were collected and surgically implanted with sonic tags that transmit high frequency sound waves specific to that tag/fish. Acoustic receivers are set-up at designated locations along the study reach of the river Location of fish is determined relative to where and when the signal is received Map on left is study area of Kennebec River showing river kilometers and locations of acoustic receivers Graphs on right show locations of acoustically tagged Atlantic sturgeon (top) and shortnose sturgeon (bottom), as detected at specific receivers.Y axis is location (river kilometer) andX axis is time of year (month). Red mark on Y axis is river kilometer 16 (below Doubling Point).Yellow highlights on X axis are months July, August and September Data points indicate signal at specific acoustic receiver.Receiver at river kilometer 16 (shown on map as lower red line) is downstream from Doubling Point and receiver at river kilometer 21 (shown on map as upper red line) is upstream from Doubling Point (Bath).(Doubling point is blue line on map) Can see from top graph (Atlantic sturgeon) that there is movement between river kilometer 16 (below Doubling Point) to river kilometer 48 (above Doubling Point)and then back down again between August and September. Can also see at least one shortnose sturgeon (bottom graph) moved from river kilometer 16 to river kilometer 21 between June and October (orange line), as well as movement of another fish between these two areas during late July/early August (light blue line). Also, sampling net data showed concentration of both shortnose and Atlantic sturgeon in area just downstream from Doubling Point during late August and September time frame (just downstream of Doubling Point) Map and data compiled by: Gail Wippelhauser Marine Resources Scientist Maine Department of Marine Resources #172 State House Station Augusta, ME 04333 Phone: Fax: (Used with permission) 1. Turtle deflectors on the dragarm
A total 27 takes of shortnose sturgeon could occur without jeopardy (NMFS BO) Assumption that sturgeon would be in the area of active dredging and likely be entrained in the dragarms. Also very low probability of contacting Atlantic salmon Provided reasonable and prudent measures and equipmentspecifications to avoid/minimize contact with endangeredspecies that included: 1.Turtle deflectors on the dragarm 2.Methods to maintain the dragarm in contact with the substrate during dredging 3.Removing the grates and screens from the dragarms and outflow pipe(s) 4.Endangered Species Observers NMFS provided a BO determining that a total 27 takes of shortnose sturgeon could occur without jeopardizing the continued existence of the species. 2.This was based upon the assumption that sturgeon would be in the area of active dredging and likely be entrained in the dragarms of the dredge.They also determined that there would be very low probability of contacting Atlantic salmon. 3. Provided reasonable and prudent measures as well as equipment specifications to avoid or minimize contact with endangered species that included: 1.Turtle deflectors on the dragarm 2.Methods to maintain the dragarm in contact with the substrate during dredging(to avoid contact with the species) 3.Removing the grates and screens from the dragarms and inflow pipe(s) to reduce trauma from entrainment 4.Endangered Species Observer to monitor for sturgeon and other species 4.Dragarms were to be in contact with the substrate and suction would be throttled down prior to moving dragarm off of substrate, and would not be restarted until dragarm was back in contact with the substrate. Developed by the U.S. Army Corps of Engineers
Turtle Deflectors Developed by the U.S. Army Corps of Engineers Prevents turtles from becoming entrained.Can also be used for sturgeon Were installed on the dredge, Atchafalaya in 2011 Turtle Deflectors Developedby the U.S. Army Corps of Engineers Allows the dragarm to move forward while preventing the turtles from becomingentrained by moving them out of the way Can also be used for sturgeon Were installed on the dredge, Atchafalaya for dredging Kennebec River in 2011 Grates and screens initially removed from dragarms and
Grates and screens initially removed from dragarms and inflows of dredge Atchafalaya Later replaced Grates and screens initially removed from dragarms and inflows of dredge Atchafalayatominimize potential trauma to sturgeon Later replacedto ensure that sturgeon were not being missed Dredging began on August 1, 2011
Public opposition lead to legal action against the USACE, the State of Maine Department of Environmental Protection, and NMFS Injunction against the USACE denied in federal court Also revised BO was issued by NMFS (due to legal challenge) Dredging began on August 1, 2011 No evidence of shortnose or Atlantic sturgeon takes observed after 12 days with minimal entrainment of any other fish (i.e. several flounder were observed) Grates were re-installed. No indication of sturgeon entrainment after approximately 2 more days of dredging Public opposition to the dredging project occurred during this time based upon theperceived potential adverse impacts of the dredging and the disposal of dredged material on water quality, fish and shellfish and their habitat, including endangered species, leading to legal action against the USACE, the State of Maine Department of Environmental Protection, and NMFS An injunction against the USACE requesting that the dredging be modified was denied in Federal Court.In addition, a revised BO was issued by NMFS (in response to a legal challenge) Dredging began on August 1, 2011 After nearly 12 days of dredging, no evidence of shortnose or Atlantic sturgeon takes wereobserved; with only minimal entrainment of any other fish species (i.e. several flounderwere observed) In order to determine if entrainment of sturgeon was being missed, the grates were re-installed on the inflow, with subsequent re-installation of the grating on the drag arms However continued dredging for approximately 2 more days showed no indication of anysturgeon entrainment, with very little evidence of any fish entrainment They were reasonably expected to be in the dredging areas
Assumed that the implementation of the reasonable and prudent measures may have helped to avoid contact with the endangered shortnose and threatened Atlantic sturgeon They were reasonably expected to be in the dredging areas Dredging completed successfully(with no takes) TheU.S.S.Spruance departed on schedule on September 1, 2011 1. Therefore, it is assumed that the effective implementation of the reasonable and prudent measures for theoperation of the dredge may have helped to avoid contact with the endangered shortnoseand threatened Atlantic sturgeon. 2.They were reasonably expected to be in the dredging areas (although also possible that they were not in the area) 3. Could also be due to them not actually being in the area of active dredging even though theywere reasonably expected to be there Dredging was completed successfully with no observed endangered species takes TheU.S.S.Spruance departed on schedule on September 1, 2011 Troy R. Bennett / The Times RecordBangor Daily News, September 1, 2011