DREDGING SUMMIT & EXPO ’18 PROCEEDINGS ESSENTIAL FISH HABITAT CONSIDERATIONS FOR DREDGE OPERATIONS: MITIGATION MEASURES AND CASE STUDIES FROM ALASKA S. Kelly1 and L. Ames2 ABSTRACT Dredging operations and the placement of dredge 'spoils' in Alaska typically occur within habitats identified as Essential Fish Habitat (EFH). EFH is defined as those waters and substrates necessary for roughly 60 species of shellfish, crab, salmon, and groundfish to complete their life cycles. EFH conservation and management is required under the Magnuson-Stevens Fishery Conservation and Management Act (MSA). Dredging can adversely affect EFH by reducing the quality and/or quantity of EFH. If adverse effects are determined to be likely, EFH Consultations are required. NOAA Fisheries is required to provide conservation recommendations to Federal and state agencies regarding any action that would adversely affect EFH. Mitigation measures are recommended actions that minimize adverse effects or encourage the conservation and enhancement of EFH. This talk will focus on two important fishery resources, Red King Crab and Pacific salmon. Each species has a unique life history and their use of different habitat types vary greatly throughout development and recruitment. The adverse effects of dredging vary by life stage, and the vulnerable life stages must especially be considered when dredging or disposing of dredge spoils within EFH. Many factors should be considered when planning a dredging project that could affect EFH, including type of dredging equipment, current strength, temperature, substrate type, timing, and other factors in order to develop appropriate mitigation measures. A full description of potential adverse impacts and recommended conservation measures for EFH during dredging activities can be found in the NOAA Technical Memorandum Impacts to Essential Fish Habitat from Non-Fishing Activities in Alaska, May 2017. KEYWORDS Dredging, beneficial uses, Essential Fish Habitat, dredged material disposal, contaminated sediment, conservation, management, mining INTRODUCTION Management of Essential Fish Habitat (EFH) is required by the Magnuson-Stevens Act (16 U.S.C. 1801 et seq) as first authorized by the Sustainable Fisheries Act, signed into law on October 11, 1996. It mandates that the Secretary of Commerce (Secretary) shall establish guidelines by regulation to assist the Regional Fishery Management Councils (Councils) and the National Marine Fisheries Service (NMFS) to describe and identify EFH in each Fishery Management Plan (FMP). These descriptions must include adverse impacts on such habitat and proposed actions to conserve and enhance such habitat. EFH regulations (67 FR 2343, January 17, 2002) established a process for Councils to identify and describe EFH, including adverse impacts to that habitat, per the requirements of the Magnuson-Stevens Act. The Magnuson-Stevens Act also requires that the Secretary, in consultation with stakeholders, provide each Council with recommendations and information regarding each fishery under that Council’s authority to assist it to identify EFH, the adverse impacts on that habitat, and actions that should be considered to conserve and enhance that habitat. These regulations established procedures to carry out this mandate. In addition, the Magnuson-Stevens Act requires that Federal action agencies consult with the Secretary on any activity authorized, funded, or undertaken, or proposed to be authorized, funded, or undertaken, that may adversely affect EFH. The Secretary must respond with recommendations for measures to conserve EFH. Dredging is 1 Fishery Management Specialist, National Marine Fisheries Service Alaska Region, 222 West 7th Ave, Anchorage, Alaska, 99513, USA, T: 907-271-5195, Email: [email protected]. 2 Resource Specialist, National Marine Fisheries Service Alaska Region, 222 West 7th Ave, Anchorage, Alaska, 99513, USA, T: 907-271-5002, Email: [email protected]. 222 DREDGING SUMMIT & EXPO ’18 PROCEEDINGS one such activity that requires consultation; the Federal action agency on most Federal dredging projects is the US Army Corps of Engineers (USACE). The Magnuson-Stevens Act expands requirements for habitat sections of FMPs and requires consultation between the Secretary and Federal and state agencies on activities that may adversely impact EFH for those species managed under the Act. It also requires the Federal action agency (e.g. USACE) to respond to comments and recommendations made by the Secretary and Councils. For the purpose of consultation on activities that may adversely affect EFH, the description of EFH included in the FMP is determinative of the limits of EFH; however, mapping of EFH is required by the regulations to assist the public and affected parties to learn where EFH is generally located. EFH descriptions and maps must be revisited every 5 years as part of an EFH Review to incorporate the best available science, due to data gaps and the dynamic nature of physical and biological habitat characteristics. More information on EFH descriptions and maps in Alaska can be found at https://alaskafisheries.noaa.gov/habitat/efh. The Fish and Wildlife Coordination Act (FWCA) provides a mechanism for the Secretary to comment to other Federal agencies on activities affecting any living marine resources. Under the FWCA, Federal agencies are required to consult with the Secretary on habitat impacts from water development projects. The Secretary is not, however, required to consult with Federal agencies on all activities that may adversely affect habitat of managed species, nor are agencies required to respond to Secretarial comments under the FWCA. The FWCA allows the Secretary to comment and make recommendations on Federal activities that may adversely affect living marine resources and their habitat, even if such habitat is not identified as EFH. The Endangered Species Act (ESA) definition of ‘‘critical habitat’’ to describe habitats under its authority includes areas occupied by the species at the time of listing, as well as those unoccupied areas that are deemed ‘‘essential for the conservation of a species.’’ The EFH regulations specify that, for species listed under ESA, EFH will always include critical habitat. EFH may be broader than critical habitat if restoration of historic habitat areas is feasible, and more habitat is necessary to support a sustainable fishery. Because the statutory definition of EFH includes the full life cycle of a species, including growth to maturity, EFH is broader than critical habitat where marine habitats have not been included in the identification of critical habitat (e.g., for anadromous salmonids listed under the ESA). No fish species listed as threatened or endangered under ESA originate in Alaska. A complete list of ESA-listed species can be found at http://www.nmfs.noaa.gov/pr/species/esa/listed.htm. ESSENTIAL FISH HABITAT The Magnuson-Stevens Act defines EFH as ‘those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity.’ This includes associated physical, chemical, and biological properties of the aquatic areas that fish use as well as the sediment, hard bottom, structures, and associated biological communities. ‘Adverse effect’ means any impact that reduces quality and/or quantity of EFH. Adverse effects may include direct or indirect physical, chemical, or biological alterations of the waters or substrate and loss of, or injury to, benthic organisms, prey species and their habitat, and other ecosystem components. Adverse effects to EFH may result from actions occurring within EFH or outside EFH and may include site-specific or habitat-wide impacts, including individual, cumulative, or synergistic consequences of actions (NMFS 2017). Many species managed under the Magnuson-Stevens Act spend some part of their life cycle in state waters (in most states 0–3 miles offshore) as well as Federal waters (generally 3–200 miles offshore). Because the statutory definition of EFH covers the entire life cycle of a species, EFH is often identified within both Federal and state waters. Therefore, the consultation provisions for activities that may adversely affect EFH may require the Secretary to consult on activities in both Federal and state waters. NMFS may comment on activities in both Federal and state waters. Dredging and Habitat There are many mechanisms by which marine dredging can have the potential for adverse effects on EFH. Dredging can cause direct mortality of fish and damage or removal of crucial ecosystem components. Dredging-related stressors like suspended sediment, contaminated sediment, hydraulic entrainment, and 223 DREDGING SUMMIT & EXPO ’18 PROCEEDINGS underwater noise can directly elicit responses and affect growth and behavior of fish across all aquatic ecosystems and all life-history stages (Wenger et. al 2016). Suspended Sediment Suspended sediment can have direct impacts on fish survival, the severity of which depends on species, life stage, concentration, and duration of exposure. Experiments with eggs and larvae of anadromous and estuarine fish in Chesapeake Bay showed that suspended sediment reduced the hatching success and survival of some species at concentrations higher than 1000 mg/l for 48-96 hours, while some species were less tolerant, exhibiting significantly reduced survival at concentrations of 100 mg/l continuously for 96 hours. (Auld et. al 1978). Other similar experiments with marine species resulted in 50% mortality rates at concentrations of 1000 mg/l