Direct and indirect estimates of the productive capacity of fish habitat under Canada’s Policy for the Management of Fish Habitat: where have we been, where are we now, and where are we going?

2011 ◽  
Vol 68 (12) ◽  
pp. 2204-2227 ◽  
Author(s):  
Charles K. Minns ◽  
Robert G. Randall ◽  
Karen E. Smokorowski ◽  
Keith D. Clarke ◽  
Antonio Vélez-Espino ◽  
...  

No net loss of productive capacity (PC) of fish habitat has been the central concept guiding Canadian fish habitat management policy since 1986. The purpose of this paper is to describe the concept of PC, to review the history and application of the fish habitat management policy in Canada, and to provide a critical review of the range of potential approaches to estimating PC. The approaches were grouped by their central focus: habitat, individual, population, and community–ecosystem. A set of case studies is used to illustrate the use of some approaches drawn from freshwater and marine contexts. Ten components to assessing no net loss of PC were developed and used in the review of approaches for evaluating potential limitations. The review also highlighted the likely future direction of method development, with increasing emphasis on dynamic models integrating population responses to habitat supply characteristics. More work needs to be done to turn research-based metrics of PC into practical operational management assessment tools and to better quantify the link between habitat structure and function and fisheries productivity. The evolving approaches to measure PC reinforce the ties that fish habitat management has to the emerging practices in ecosystem-based management.

2003 ◽  
Vol 60 (1) ◽  
pp. 100-116 ◽  
Author(s):  
Charles K Minns ◽  
James E Moore

Canada's fish habitat management is guided by the principle of "no net loss of the productive capacity of fish habitat" (NNL). Many development proposals are assessed using habitat information alone, rather than fish data. Because fish–habitat linkages are often obscured by uncertainty, uncertainty must be factored into NNL assessments. Using a quantitative framework for assessing NNL and lake habitats as a context, the implications of uncertainty for decision making are examined. The overall behaviour of a net change equation given uncertainty is explored using Monte Carlo simulation. Case studies from Great Lakes development projects are examined using interval analysis. The results indicate that uncertainty, even when large, can be incorporated into assessments. This has important implications for the habitat management based on NNL. First, schemas to specify relative levels of uncertainty using simple habitat classifications can support robust decision making. Second, attaining NNL requires greater emphasis on minimizing habitat loss and creating new areas to compensate for losses elsewhere and less on detailing small incremental changes in modified habitats where the fish response is difficult to demonstrate. Third, the moderate to high levels of uncertainty in fish–habitat linkages require that created compensation is at least twice the losses to reasonably ensure NNL.


1997 ◽  
Vol 54 (10) ◽  
pp. 2463-2473 ◽  
Author(s):  
C K Minns

A net change equation is derived for assessing no net loss of productivity of fish habitat (NNL). NNL is the guiding principle of the Canadian policy for the management of fish habitat. The equation provides a middle ground between the extremes of no conservation and no development. Projects affecting fish habitat are accountable for the productive capacity in loss areas and the difference between current and future productivities in modified areas. The equation implies quantitative conservation targets overall and loss-offsetting equivalencies in modified habitat areas. Generalization of the net change equation to heterogeneous habitats is illustrated with a development in a coastal wetland on the Great Lakes. The net change framework has implications for linkages between suitable habitat supply and fish population dynamics. Area fish habitat management plans envisioned in the policy and site-level net change assessments are connected. Quantitative ways are proposed for simultaneous assessment of NNL and ``harmful alteration, disruption, or destruction'' of fish habitat, as required in the Canadian Fisheries Act. Defensible methods for applying the net change equation are superior to earlier nonquantitative approaches. If the available science is insufficient, the precautionary principle is recommended. Future development steps for the quantitative net change framework are suggested.


2003 ◽  
Vol 60 (3) ◽  
pp. 286-300 ◽  
Author(s):  
Thomas C Pratt ◽  
Karen E Smokorowski

Compensation measures in response to Fisheries and Oceans Canada (DFO) Policy for the Management of Fish Habitat includes provisions for habitat creation and enhancement. Thus, an assessment of nearshore habitat utilization patterns by fishes is needed to put DFO compensation measures in the context of the "no net loss of the productive capacity of fish habitat" directive. Measures of abundance, richness, and diversity of fishes were compared across nine habitat types in a lake using rapid visual underwater assessment. Multivariate analyses separated habitats into three groups and identified two distinct species assemblages. Most species were associated with macrophytes, but a few were primarily associated with rocky substrate. Shallow mud (open) habitats contained significantly fewer species and had lower mean scores and diversity than all other habitat types. Rocky habitats had lower mean scores and diversity than some vegetated habitat types containing similar fish assemblages. Surprisingly, within-site fish assemblage heterogeneity was similar to among-site heterogeneity, and among-habitat heterogeneity was lower than within-habitat heterogeneity, further supporting our inability to distinguish among vegetated habitat types. Our results suggest that habitat heterogeneity is critical in maintaining diverse communities and that compensation measures should account for differences in fish–habitat associations among varied habitats.


2006 ◽  
Vol 63 (5) ◽  
pp. 1172-1182 ◽  
Author(s):  
Charles K Minns

Minns' (Can. J. Fish. Aquat. Sci. 54: 2463–2473 (1997)) framework for assessing net change of productive capacity of fish habitats in Canada is expanded to include the effect of timing of losses and gains on cumulative net change. The expansion requires establishment of a reference time frame for assessment. A time frame of twice the project's duration is recommended. Delaying compensation actions while incurring losses early in a project increases the levels of compensation required. The addition of future discounting had much less effect on compensation requirements than the effects resulting from timing differences between losses and compensation. As discounts apply equally to losses and gains, they likely balance out over time. Delays between when habitat alterations occur and when expected productive capacity is attained increase the required compensation. There are advantages to starting compensation efforts early in a development project. A case study of a hypothetical northern diamond mine shows how various components of compensation (replacement, uncertainty, and timing) can be integrated when assessing net change. Consideration of all components of compensation indicates the need for tougher precautionary compensation guidelines with ratios greater than the current 1:1. Values of 2:1 or higher may be necessary to ensure attainment of Canada's guiding policy principle of no net loss.


<em>Abstract.</em>—Efforts to achieve no net loss of productive capacity (PC) of fish habitat are failing in Canada and elsewhere. These growing losses, particularly in freshwaters, have a central role in ongoing global changes that threaten our future. Canada has a large share of global freshwater resources and hence a greater responsibility to help find solutions. For fish habitat, a preoccupation with habitat suitability, and other indices of that ilk, has diverted attention from self-sustaining fish populations, their productivity, and their fisheries. Symptoms of the problem are reviewed and a remedial approach is offered alongside analogies from comparable conservation and protection arenas such as fisheries, biodiversity, and human society. Many of the symptoms of failure arise from the primary focus of management efforts at the level of individual development activities while the remedies require a focus on more holistic ecosystem-level strategies. Implementation of these remedial approaches is considered.


<em>Abstract.—</em> The quality and quantity of habitats determine ecosystem productivity. Hence, they determine the potential fish productivity that sustains the fish harvests extractable from freshwaters and seas. Efforts to conserve and protect fish habitats are frustrated by key unanswered questions: which habitat types and how much must be protected to ensure natural self-sustaining fish stocks? Minns and Bakelaar presented a prototype method for assessing suitable habitat supply for fish stocks in Lake Erie, an analysis that can be used to address conservation issues. Here, the method is refined and extended, taking the assessment of habitat supply for pike <em>Esox lucius </em> in the Long Point region of Lake Erie as a case study. As with the previous study, much emphasis is placed on “learning by doing.” Because available inventories of habitat features are coarse and incomplete, improved guidelines for estimating habitat supply are expected from these prototype studies. The habitat supply method previously presented by Minns and Bakelaar is elaborated in three ways here: (1) the basic physical habitat assessment is derived from a remote-sensing inventory database; (2) methods of quantifying the thermal regime and integrating it with other habitat elements are examined; (3) habitat supply estimates are used in a pike population model, and pike biomass and production are simulated for the Long Point region of Lake Erie and then compared with available records. The roles of error and uncertainty are examined for all elements in the estimation and application of suitable habitat supply values. There is potential for supply measurement and analysis to guide fish habitat management.


<strong><em>Abstract. </em></strong>This paper summarizes the results of the National Research Council Study on the Effects of Bottom Trawling and Dredging on Seafloor Habitat (National Research Council 2002). The report concludes that integration of existing data on the effects of trawls and dredges, level of fishing effort, and distribution of seafloor habitats would facilitate development of habitat management plans. Current and new management measures should be assessed regularly to provide a better understanding of how various restrictions affect fish habitat and to determine the socioeconomic impacts on the fishing industry and local communities. Resolution of the different, and at times conflicting, ecological and socioeconomic goals will require not only a better understanding of the relevant ecosystems and fisheries but also more effective interaction among stakeholders.


<em>Abstract.</em>—The landscape for policy and management of fish habitat is changing. The historic focus on evaluating environmental impact assessments for large projects, and issuing (or not) permits for small projects is being supplanted by new expectations for habitat managers and policy makers. Many of these new expectations are rooted in the adoption of an ecosystem approach to management of diverse human activities, including fisheries, in aquatic ecosystems, combined with a growing emphasis on integrated management of those human activities, in turn aided by spatial planning and spatial management approaches in many fields. These new expectations placed on habitat managers and policy makers create the need for expanded support from a new blending of habitat and population sciences. Historically, it may have been sufficient to use science advice based on relative indices of habitat quality and carefully assembled expert opinion as the basis for many tasks in habitat policy and management. Such tools now must be augmented by much more quantitative science advice, to allow for setting operational objectives for managing habitats, assessing the quality and quantity of critical or essential habitat for protected or exploited fish populations, conducting risk assessments of projects and mitigation measures, making siting decisions about marine protected areas and other spatial zoning measures, and many other tasks in which habitat managers and policy makers must participate. Science advice now must be able to quantify the relationships between habitat features and population status and productivity, as well with community properties such as resilience and vulnerability. This advice has to capture the uncertainty in the relationships and data sources, in forms that fit comfortably into risk assessments. Tools for forward projection of the habitat consequences of management options are needed, as are tools for cost-benefit analyses of tradeoffs among different types of habitats for different groups of aquatic species. None of these analytical challenges is beyond the scope of modern statistical and modelling capabilities, and current ecological concepts. Few of them can be met by existing tools and data-bases however. Moreover, many of the conceptual approaches to aquatic habitat management have been imported from terrestrial habitat management. They may have served adequately for management of riverine and marine benthic habitats, but some of the fundamental conceptual starting points are being questioned for marine and lacustrine habitats more generally. The paper brings out both some promising opportunities and some difficult challenges for the science needed to support contemporary habitat management and policy.


Sign in / Sign up

Export Citation Format

Share Document