Shoreline works include any unnatural alteration or human intervention to nearshore areas such as infilling, armouring, aquatic vegetation removal or planting, or other actions that may alter nearshore or coastal processes. Fish and fish habitat could be affected by the alteration of their existing habitat and may include changes in the quality and quantity of fish habitats, habitat availability, water depth, velocity, water temperature, sedimentation, water quality, food resources, and competition for food and habitat. These changes could have serious implications for fish health and survival including species diversity; fish population distribution, fish population relative abundance, fish population biomass, sedimentation, stranding, and fish entrainment. Depending on the type of alteration, changes in fish movement and fish species population may be affected in the form of movement patterns and general life history parameters or fish productivity. Randall et al. [1] defined fish productivity as “the sustained yield of all component populations and species and their habitat which support and contribute to a fishery”. It should be noted that this definition is best for large projects, while for smaller projects surrogates of productivity may be more appropriate. To address this issue, Bradford et al. [2] developed a framework for assessing productivity via its “components”; aspects of fish population productivity that may be altered by a change in conditions caused by a proposed project. In this framework, impacts on fish productivity are separated into five components: growth, individual performance, survival, migration, and reproduction. In addition, twenty-one Pathways of Effects (PoEs) link activities on the water or shoreline with a probable response of the environmental variables. Based on this framework, linkages can be made between the environmental impacts following an activity and their effects on fish and fish population production (known as state-productivity relationships). Some potential measures and surrogates of ongoing productivity of temperate fish species and their habitats include abundance, biodiversity, quantity of available habitat, and abundance [1, 3]. Bradford et al. [2] define a component of productivity as “an aspect of fish population productivity that may be altered by a change in conditions caused by a proposed project”. Understanding how shoreline changes will impact fish productivity is essential for decision support of shoreline works in nearshore areas.
In June 2012, the Government of Canada introduced amendments to the Fisheries Act that included substantive changes to the protection of Canadian fishes and fish habitats. Scientific advice is needed to support and inform the implementation of these policies through the Fisheries Protection Program (FPP) of Fisheries and Oceans Canada (DFO). FPP serves as a decision-making body for the sustainability and ongoing productivity of commercial, recreational and Aboriginal (CRA) fisheries with the goal to prevent serious harm to fish that included the destruction or permanent alteration to fish (Fisheries Act [4]). In this review, CRA fish are limited to “temperate” fish species to restrict the scope of the study. The amended Fisheries Act defines serious harm to fish as “the death of fish or any permanent alteration to, or destruction of, fish habitat”, and allows the Minister of Fisheries and Oceans Canada to authorize a work, undertaking, or activity that causes serious harm to fish, if proposals are accepted after taking specified factors into account. Factors for Ministerial consideration in decision-making include: (a) the contribution of the relevant fish to the ongoing productivity of CRA fisheries; (b) fisheries management objectives; (c) whether there are measures and standards to avoid, mitigate or offset serious harm to fish that are part of a commercial, recreational or Aboriginal fishery, or that support such a fishery; and (d) the public interest. The new Fisheries Act introduces the need for metrics of productivity and methods to assess how a project may affect productivity. Projects that affect fish habitat can be classified into three types as those that: (1) reduce habitat quantity and carrying capacity; (2) affect habitat quality and fish vital rates and (3) impact at scales large enough to result in ecosystem transformation [2, 5, 6].
Shifting from a habitat-based policy [7] to a fisheries-based approach has led to using productivity as a measure for assessing serious harm to fish [1, 2]. Fish productivity is an appropriate measure for assessing impacts of projects, works or activities on CRA fisheries, as ongoing productivity implies maintenance of ecosystem function and structure [1]. A change in a component of productivity is expected to have some effect on fish productivity in general depending on the interactions between components, and the magnitude and scale of the change [2]. Bradford et al. [2] also provide possible surrogates of productivity for each project type as defined by Randall et al. [1].
New amendments of Fisheries Act (2012) also put responsibility on developers to avoid and mitigate any “serious harm to fish” resulting from projects affecting aquatic habitat. In the event that serious harm cannot be completely avoided or mitigated during all stages of development, proponents must request authorization and develop a plan to counterbalance this harm using offsetting measures. It is therefore important to determine if coastal shoreline projects are a limiting factor of fish productivity and its components. In this review, the coastal area will not be defined by depth or distance from shore, but by the maximum extent of the project or alteration type itself.
Existing literature reviews on the impacts of shoreline alteration projects and their reported impacts on fish populations and communities have limited their scope to specific geographic areas, or specific alteration types, e.g. seawalls [8] or aquatic systems (e.g. north temperate lakes [9]). This review hopes to complement an existing systematic review protocol that was developed to assess impact of anthropogenic physical and structural habitat changes in nearshore areas on fish recruitment in temperate regions, but focused in Baltic relevant regions [10]. The review largely focused on marine and brackish systems or large lakes and focused on abundance of juveniles in nearshore fish communities before and after disturbance. To our knowledge, no synthesis of literature has examined impacts of shoreline projects of several components of fish health features across all life histories in estuarine and freshwater systems assessing a range of shoreline alteration types. Furthermore, none of these reviews provides quantitative measures of how physical and ecological characteristics, and project features influences fish productivity in nearshore areas. A quantitative evaluation of the impacts of shoreline alteration on fish productivity is necessary to identify future information and research needs, develop standards for evaluating potential serious harm and provide a knowledge base for DFO’s future decision-making.
This systematic review aims to assess how shoreline works or alteration projects will affect the productivity of temperate fish. In this review, the types of shoreline alteration projects may include but are not necessarily limited to: hardening of shorelines, aquatic vegetation removal, change in depth through infilling, channel modification, riparian alteration, embayment creation vegetation planting/enhancement, artificial reefs, or other shoreline alterations designed to improve habitat through remediation, restoration or enhancement. When productivity is not defined or used within the literature, surrogates or components of productivity will be used in the evaluation [3]. During this review, the effects of impacts from more than one stressor from a single project as well as multiple projects in a localized area will need to be considered. Examples of potential measures and surrogates of productivity for CRA fishery species [3] include: production, catch, yield, biomass, abundance, density, recruitment, body size, biodiversity, species richness, mortality or survival, and somatic growth.
Topic identification and stakeholder input
Canada’s Fisheries Act (2012) put renewed responsibility on developers to avoid and mitigate any “serious harm to fish” resulting from projects affecting aquatic habitats. Proponents must request authorization by submitting development plans to the Fisheries Protection Program and to demonstrate how offsetting measures will compensate for any serious harm. However, it is important that before and after development these impacts and offsets be monitored or assessed in order to understand the real and resultant effects on fish. This systematic review aims to gather the current evidence to understand what kinds of design options and shoreline alteration works most affect fish productivity either positively or negatively. Identifying if shoreline projects are affecting habitats and their productivity directly or indirectly will help inform the referral process and desired outcomes.
The topic and the scope of this systematic review were developed from consultations with an Advisory Team consisting of FPP, DFO Science, and the Ministry of Natural Resources and Forestry (OMNRF) staff. The Advisory Team also guided the focus of this review to ensure the primary and secondary questions were both answerable and relevant. The Advisory Team also reviewed the key search terms and aided in compiling a list of relevant terms related to productivity surrogates.
Objectives
This systematic review aims to assess the effect of shoreline alteration projects on fish productivity. However, we will restrict our review to studies assessing productivity [3, 11] of temperate fish; hereby referred to as “relevant species”. Our objective is to identify the type, and strength of shoreline alteration effects on the productivity of relevant species. This review will cover existing studies conducted in all temperate aquatic ecosystems, largely estuarine and freshwater regions of the world because this study will be used to inform FPP policy.
Primary question
What are the effects of different types of shoreline alteration projects, works or activities on temperate fish productivity?
Components of the primary question
The primary study question can be broken down into the sub-components:
Subject (population) Fish species will be confined to those that are temperate species.
Exposure Shoreline alteration or shoreline works.
Comparator No exposure or alternative levels of exposure.
Outcomes Changes in fish productivity or surrogates of productivity such as abundance, biomass, growth, and others [3].
Secondary questions
Secondary questions were developed to support the overall goals and direct the potential analyses that may be performed from this review. The secondary questions related to shoreline alteration effects on productivity are:
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1.
Do fish productivity changes from shoreline alterations affect large lakes, small lakes, or lotic systems differently, and if so, how?
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2.
What are the major impacts from shoreline alterations to fish productivity?
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3.
How does fish utilization of shorelines change when comparing various shoreline protection designs versus the original natural shoreline?