Cultus pygmy sculpin (Cottus sp.) recovery strategy: chapter 7

Anticipated Conflicts or Challenges

Cultus pygmy sculpin are currently of little or no economic value, and this is unlikely to change.  By contrast there are other public, private and commercial interests in the Cultus watershed.  These interests include water extraction, roads, and recreation, residential and commercial property development.  It is possible that mitigating threats to Cultus pygmy sculpin will conflict with some development pressures.  Recovery of the species will therefore require continuous stewardship, effective decision-making, and specific research over the long-term.  It is important to understand that many of the threats to Cultus pygmy sculpin can be reduced but not eliminated.

10.1 Potential Management Impacts for Other Species

Although Cultus pygmy sculpin are found only in a single watershed, the introduction of this species into other watersheds has not been put forward as a recommendation.  It is also unclear whether introduction elsewhere is even possible, given that the specific habitat conditions for evolution of a pelagic sculpin appear to have occurred only twice (i.e., in Cultus Lake and Lake Washington).

It is unlikely that recovery efforts aimed at Cultus pygmy sculpin will have a negative effect on other fish or wildlife species indigenous to Cultus Lake.  For example, the impact of Cultus pygmy sculpin on the abundance of resident and anadromous fish species is not known, but is not believed to be substantial.  Numeric enhancement of the species is not being recommended, and protection of Cultus pygmy sculpin habitats will likely benefit other species too.

It has been noted that management of Cultus sockeye may have implications for Cultus pygmy sculpin and vice versa, since the species have similar prey and predators. Management of the two species should be coordinated and outcomes monitored to ensure that goals and actions for each species are not in opposition.

11. Recovery Feasibility

Cultus pygmy sculpin are found only in Cultus Lake and there is no plan to purposely transplant them elsewhere in BC.  Extreme endemism is a primary reason for current status as a threatened species, and Cultus pygmy sculpin is likely to remain at an elevated risk due to its small geographic range.  Recovery actions will be aimed at maintaining or improving current habitat conditions, monitoring the population, and undertaking specific research tasks.  With the support of local governments, local industry and the public, recovery is deemed to be technically and biologically feasible.

As part of the SARA process, the competent minister must determine the feasibility of recovery for each species at risk.  To help standardize these determinations current draft policy (Government of Canada 2005) poses four questions, which are to be addressed in each recovery strategy.  These questions are posed and answered here.

1.     Are individuals capable of reproduction currently available to improve the population growth rate or population abundance?

Yes.  Cultus pygmy sculpin naturally have a very restricted distribution.  The population is believed to be self-supporting at present, although population status is unknown.  Regardless of population abundance and trends the species will continue to be at risk due to limited geographic range. 

2.     Is sufficient suitable habitat available to support the species or could it be made available through habitat management or restoration?

Yes.  Sufficient suitable habitat exists in Cultus Lake.

3.     Can significant threats to the species or its habitat be avoided or mitigated through recovery actions?

Yes.  Controlling threats to Cultus pygmy sculpin is feasible, but rests more on social than technical considerations.  For example, the primary threats are urban expansion, water management and general land use.  Most threats, such as those from excessive water use and land development, can be managed with existing regulations, but may require consultation with stakeholders.

4.      Do the necessary recovery techniques exist and are they demonstrated to be effective?

Yes.  Special recovery techniques are not required for recovery of Cultus pygmy sculpin.  What is required is effective management of current and future threats, which is believed to be entirely feasible.  It should be stressed, however, that Cultus pygmy sculpin will likely always be very restricted in their distribution.  As a result, they are likely to remain at risk.  Recovery efforts are best concentrated on controlling threats.  There are no significant technical challenges in this regard. 

12. Recommended Approach / Scale for Recovery

This recovery strategy recommends the use of a single species approach (rather than an ecosystem approach) because it addresses a single taxonomic unit.  However, recovery efforts for Cultus pygmy sculpin should be coordinated with those for Cultus sockeye, a salmonid stock designated as endangered by COSEWIC (COSEWIC 2003).  Juvenile sockeye are planktivores and occupy the same habitat as Cultus pygmy sculpin, so protection of limnetic habitats is likely to benefit both species. 

Every effort should be made to provide input to management planning initiatives, actions, or policies, particularly land use planning for the local parks.  Development must be approached such that cumulative impacts do not lead to significant changes in the ecology of Cultus Lake, which requires planning at the watershed scale and compliance with existing regulations and best management practices.  It will be necessary to identify specific sites for protection or special management within the watershed. 

13. Knowledge Gaps

Little is known about the ecology of Cultus pygmy sculpin, the environmental factors that affect abundance and distribution, and the threats to this species.  Meeting conservation goals will require addressing several knowledge gaps.  The gaps fall into three main categories, as outlined below.

Basic Biology

  • Taxonomic status and phylogenetic relationships,
  • Habitat use and requirements by life stage (e.g., population distribution within the drainage; differential use of particular tributaries), and in particular spawning habitat and how it differs from C. aleuticus.
  • Which habitats are most likely to be limiting for different life stages,
  • Life history information,
  • Diets,
  • Causes of mortality (e.g., temperature, pollutants, predation, siltation of incubation habitat, etc.),
  • Factors limiting population growth.

Threat Clarification

  • Status of key habitats and potential threats to these habitats,
  • Effect of present and future human activities and prioritization of threats.

Population Abundance and Dynamics

  • Current population abundance of Cultus pygmy sculpin,
  • Natural population fluctuations of Cultus pygmy sculpin,
  • Current and historic trends in abundance.

Basic knowledge of the natural history of this species is severely limited.  Significant gaps exist with respect to taxonomic status relative to C. aleuticus, population demographics, critical habitat, and tolerance to changes in physical habitat.

14. Actions Already Completed and/or Underway

Some recovery-related actions have been completed or initiated, including taxonomic investigations and molecular genetics work.

15. Statement of When Action Plans Will be Completed

Within two years of posting the final version of this recovery strategy, one or more Action Plans will be developed.  The plans will include descriptions of programs, plus a timeline of programs with estimated budgets, and will encompass a timeframe of at least five years.

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