Compensation ratios needed to offset timing effects of losses and gains and achieve no net loss of productive capacity of fish habitat

2006 ◽  
Vol 63 (5) ◽  
pp. 1172-1182 ◽  
Author(s):  
Charles K Minns
Keyword(s):  
Fish Habitat ◽  
Time Frame ◽  
Development Project ◽  
Productive Capacity ◽  
Habitat Alterations ◽  
No Net Loss ◽  
Future Discounting ◽  
Timing Effects ◽  
Fish Habitats

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.

Assessment of net change of productive capacity of fish habitats: the role of uncertainty and complexity in decision making

2003 ◽  
Vol 60 (1) ◽  
pp. 100-116 ◽  
Author(s):  
Charles K Minns ◽  
James E Moore
Keyword(s):  
Decision Making ◽  
Habitat Management ◽  
Fish Habitat ◽  
Productive Capacity ◽  
No Net Loss ◽  
Habitat Linkages ◽  
Fish Habitats ◽  
Fish Response ◽  
Lake Habitats

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.

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
Lake Erie ◽  
Habitat Management ◽  
Fish Habitat ◽  
Learning By Doing ◽  
Suitable Habitat ◽  
Physical Habitat ◽  
Fish Stocks ◽  
Habitat Features ◽  
Fish Habitats

<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.

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 ◽  
...  
Keyword(s):  
Habitat Management ◽  
Method Development ◽  
Dynamic Models ◽  
Fish Habitat ◽  
Assessment Tools ◽  
Management Policy ◽  
Productive Capacity ◽  
No Net Loss ◽  
Future Direction ◽  
And Function

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.

Stream modifications to enhance system connectivity for fish habitat compensation: a case study in the Barrenlands region of Canada

2014 ◽  
Vol 41 (7) ◽  
pp. 650-659 ◽  
Author(s):  
Gregory Courtice ◽  
Abul Basar M. Baki ◽  
David Z. Zhu ◽  
Christopher Cahill ◽  
William M. Tonn
Keyword(s):  
Catchment Area ◽  
Rectangular Cross Section ◽  
Fish Habitat ◽  
Fish Passage ◽  
First Year ◽  
Productive Capacity ◽  
Flow Depth ◽  
Lake Catchment ◽  
Habitat Compensation

This study examines stream modification efforts to increase the productive capacity of an isolated system of three small lakes in the Barrenlands region of Arctic Canada by enhancing system connectivity. The lakes’ outlet streams were modified to create conditions favourable for fish passage and thereby promote migration among the lakes and the large lake into which they drain. Gabion step pools (in two streams) and a nature-like choke-and-pool structure (in one stream) were installed. Two years of post-construction hydraulics data were compared to data collected for two years prior to construction to determine the efficacy of the various stream modifications. Initial evaluations indicated unsuccessful performance of gabion step pools, so after the first year, they were retrofitted with boulders to increase flow depth, restrict discharge, improve flow duration, and create unimpeded connections rather than sudden drops. Variation of lake levels and duration, variability, and depth of stream flow indicated that outlet geometry and lake catchment area should be important considerations when enhancing connectivity for fish migration in ephemeral systems. A narrow, rectangular cross-section was deemed effective for increasing flow depth while decreasing discharge, resulting in increased duration of flows. Catchment area was an effective indicator of a headwater lake’s potential response to connectivity enhancements. Smaller catchments may provide inadequate runoff to sustain minimum storage requirements for enhanced connectivity. Our findings should advance the knowledge of headwater system hydraulics in the Barrenlands and assist in designing future fish habitat compensation projects on similar systems.

Quantifying “no net loss” of productivity of fish habitats

1997 ◽  
Vol 54 (10) ◽  
pp. 2463-2473 ◽  
Author(s):  
C K Minns
Keyword(s):  
Habitat Management ◽  
Coastal Wetland ◽  
Fish Habitat ◽  
Fish Population ◽  
Suitable Habitat ◽  
Productive Capacity ◽  
No Net Loss ◽  
Heterogeneous Habitats ◽  
The Difference ◽  
Change Framework

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.

Managing the Impacts of Human Activities on Fish Habitat: The Governance, Practices, and Science

2015 ◽  
Keyword(s):  
Habitat Suitability ◽  
Fish Habitat ◽  
Individual Development ◽  
Global Changes ◽  
Human Society ◽  
Productive Capacity ◽  
No Net Loss ◽  
Governance Practices ◽  
Ecosystem Level ◽  
Primary Focus

<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.

scholarly journals Modeling nearshore fish habitats using Alaska as a regional case study

2021 ◽  
Vol 238 ◽  
pp. 105905
Author(s):  
Arnaud Grüss ◽  
Jodi L. Pirtle ◽  
James T. Thorson ◽  
Mandy R. Lindeberg ◽  
A. Darcie Neff ◽  
...  
Keyword(s):  
Fish Habitats
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