Event Title

Averting the "Data-gap Trap" for poorly studied marine species in the Salish Sea

Presentation Abstract

Unlike southern resident killer whales, there is low statistical power to detect declines in many cetacean populations in the Salish Sea. This is particularly true for highly social odontocetes, including Pacific white-sided dolphins and common dolphins, and to a lesser extent, Dall’s porpoise. Commonness can be conflated with favorable conservation status, but abundant species may be undergoing undetected declines, especially when large and variable group sizes decrease power to detect trends. When funding is linked to conservation status, this can create a situation we call the “data-gap trap.” Declines can go undetected until a catastrophe causes a population to be listed, raising it to a priority needed to trigger funding to reassess risks and guide mitigation. We propose a proactive, generalizable modelling approach that uses best available information on demography and predictions of demographic responses to anthropogenic threats to rank species’ vulnerability to stressors, and prioritize them for research and conservation efforts. We illustrate our approach using four pelagic dolphins that are abundant in the northeast Pacific, but for which trend data are unavailable. Given no additional data, we found that population consequences of three sublethal stressors (i.e., prey limitation, ocean noise, and contaminants) could easily outweigh the impact of a single lethal stressor (i.e., fisheries bycatch). Long-beaked common dolphins were least resilient to anthropogenic stressors of the four case studies. Given the recent return of Pacific white-sided dolphins to the Salish Sea and the appearance of long-beaked common dolphins in Puget Sound, we consider them a priority for research. Mitigation of sublethal stressors, singly or in combination, may cause greater improvements in growth rate than mitigation of bycatch alone. Common species represent large biomass in marine ecosystems, making them ecologically important to conserve. We see value in predicting vulnerability of abundant species to threats to inform early intervention.

Session Title

Species and Habitats of Emerging Concern

Conference Track

SSE11: Species and Food Webs

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE11-632

Start Date

6-4-2018 10:45 AM

End Date

6-4-2018 11:00 AM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 6th, 10:45 AM Apr 6th, 11:00 AM

Averting the "Data-gap Trap" for poorly studied marine species in the Salish Sea

Unlike southern resident killer whales, there is low statistical power to detect declines in many cetacean populations in the Salish Sea. This is particularly true for highly social odontocetes, including Pacific white-sided dolphins and common dolphins, and to a lesser extent, Dall’s porpoise. Commonness can be conflated with favorable conservation status, but abundant species may be undergoing undetected declines, especially when large and variable group sizes decrease power to detect trends. When funding is linked to conservation status, this can create a situation we call the “data-gap trap.” Declines can go undetected until a catastrophe causes a population to be listed, raising it to a priority needed to trigger funding to reassess risks and guide mitigation. We propose a proactive, generalizable modelling approach that uses best available information on demography and predictions of demographic responses to anthropogenic threats to rank species’ vulnerability to stressors, and prioritize them for research and conservation efforts. We illustrate our approach using four pelagic dolphins that are abundant in the northeast Pacific, but for which trend data are unavailable. Given no additional data, we found that population consequences of three sublethal stressors (i.e., prey limitation, ocean noise, and contaminants) could easily outweigh the impact of a single lethal stressor (i.e., fisheries bycatch). Long-beaked common dolphins were least resilient to anthropogenic stressors of the four case studies. Given the recent return of Pacific white-sided dolphins to the Salish Sea and the appearance of long-beaked common dolphins in Puget Sound, we consider them a priority for research. Mitigation of sublethal stressors, singly or in combination, may cause greater improvements in growth rate than mitigation of bycatch alone. Common species represent large biomass in marine ecosystems, making them ecologically important to conserve. We see value in predicting vulnerability of abundant species to threats to inform early intervention.