Cordell Bank National Marine Sanctuary: Summary of Resource Conditions

The various resource status and trend evaluations presented in this report are summarized below. Each question used to rate the condition of and trends in sanctuary resources is listed, followed by:

A set of rating symbols that display key information. The first symbol includes a color and term to indicate status. The next symbol indicates trend. A shaded scale adjacent to both symbols indicates confidence (see key for example and definitions).
The status description, which is a statement that best characterizes resource status and corresponds to the assigned color rating and definition as described in Appendix A. The status description statements are customized for all possible ratings for each question.
The rationale, which is a short statement or list of criteria used to justify the rating.

Key:

Drivers and Pressures

Question 1: What are the states of influential human drivers and how are they changing?

Not Rated

Rationale: ONMS and CBNMS staff decided not to rate the status and trend of influential human drivers at CBNMS. The primary purposes for rating the status and trends of resources are to use condition reports to assess program effectiveness and to influence management of human activities and certain natural resource actions. For the most part, drivers are not manageable, at least not under the authority of the National Marine Sanctuaries Act, nor do most of them originate at scales relevant to national marine sanctuary management. While understanding them is important, rating them is not necessary to achieve the goals of the condition report.

Question 2: What are the levels of human activities that may adversely influence water quality and how are they changing?

Good/Fair

Status Description: Some potentially harmful activities exist, but they have not been shown to degrade water quality.

Rationale: There are fairly high levels of human activity, mainly vessel traffic, that pose risks to water quality. Varying patterns make it difficult to discern a trend, but fuel carried per vessel is increasing, though spill volumes have decreased. In addition, although there has been increased vessel traffic over several decades, recent air quality regulations have resulted in a change to low-sulfur fuel and improved emissions. Overall, the levels of large commercial vessel traffic have remained the same during the study period. There were no reported oil spill incidents inside CBNMS, but incidents that occurred nearby had the potential to affect the sanctuary. Vessel discharges were recorded in the sanctuary, yet are likely underreported. New regulations on sulfur oxide emissions resulted in an increase in exhaust gas cleaning systems and a downward trend in emissions over the study period.

Question 3. What are the levels of human activities that may adversely influence habitats and how are they changing?

Fair

Status Description: Selected activities have caused measurable resource impacts, but effects are localized and not widespread or persistent.

Rationale: Vessels in and around CBNMS generate noise that can degrade habitat quality for marine species. The soundscape of CBNMS is dominated by ships and baleen whales and is at the threshold of good environmental health, according to European Union standards. Trend data on the CBNMS soundscape are not yet available, but ocean noise has increased globally since the 1950s due to larger vessels and more vessel traffic. Bottom trawling occurs in CBNMS, mainly on soft sediment, and marine debris is present in all sanctuary habitats. It is possible that conditions are improving because bottom trawling has decreased during the study period, but it is also likely that debris and noise in the sanctuary are increasing.

Question 4. What are the levels of human activities that may adversely influence living resources and how are they changing?

Fair

Status Description: Selected activities have caused measurable living resource impacts, but effects are localized and not widespread or persistent.

Rationale: Impacts of concern for living resources in CBNMS include vessel traffic, fishing, and entanglement. Vessel traffic poses a risk of ship strikes to whales in the sanctuary, especially in high-use habitat that includes a heavily trafficked shipping lane. In addition, whales are at risk of entanglements in the region, but the occurrence of entanglements in CBNMS is thought to be low. The trend for entanglement and strandings could not be determined due a lack of temporal data from the sanctuary. Generally, however, vessel speed decreased over the study period. A recent, slight increase in vessels and records from VMS suggest that fishing activity has increased from a low in 2018, but there was not a strong long-term trend.

Experts assigned a trend rating of undetermined at the workshop. However, following the workshop, a new trend, “mixed,” was introduced to the condition report rating scheme as a result of discussions with experts. ONMS staff determined that this new rating was more appropriate to apply to this question based on the combination of trends from available data.

Question 5: What are the levels of human activities that may adversely affect maritime heritage resources and how are they changing?

Good

Status Description: Few or no activities occur at maritime heritage resource sites that are likely to adversely affect their condition.

Rationale: The rating is good because the levels of human activities that may adversely affect the one maritime heritage resource documented to be in the sanctuary, the ex-USS Stewart (DD-224), are thought to be minimal. This is due to its isolated location at a depth of 6,000 feet. For example, commercial fishing bottom trawls do not reach to that depth. There may be deposition of marine debris on the shipwreck and the corrosion rate may be changed by increasingly acidic ocean waters. Natural processes of degradation are likely to pose a larger threat. The trend is undetermined due to a lack of information about changes in human activities that may impact the shipwreck. Note that a confidence score was not assigned to the status or trend rating for this question, because subject matter external experts were not consulted on these ratings.this question, because subject matter external experts were not consulted on these ratings.

A workshop was not convened for question 5. Archaeological experts with the ONMS Maritime Heritage Program and CBNMS evaluated this question internally. These subject matter experts have been monitoring existing archaeological sites along the West Coast since the 1980s. Note that confidence scores were not assigned to the status or trend ratings for these questions, because subject matter external experts were not consulted on these ratings.

Water Quality

Question 6: What is the eutrophic condition of sanctuary waters and how is it changing?

Good

Status Description: Eutrophication has not been documented, or does not appear to have the potential to negatively affect ecological integrity.

Rationale: Although data are limited and only provide proxy information, there is no clear evidence of eutrophication resulting from anthropogenic sources occurring in the sanctuary. Some data suggest that climate change may influence nutrients; this issue is discussed further in Question 8.

Question 7: Do sanctuary waters pose risks to human health and how are they changing?

Good/Fair

Status Description: One or more water quality indicators suggest the potential for human health impacts but human health impacts have not been reported.

Rationale: Phytoplankton species that produce harmful algal blooms and biotoxins were present in CBNMS between 2010 and 2019. A harmful algal bloom event occurred in 2015 that was unprecedented in scope and impact. California sea lions and coastal bivalves, which were used as proxies for environmental biotoxins, indicated toxins were present throughout the region and appeared to worsen over time. Biotoxins were monitored in Dungeness and rock crabs by the California Department of Public Health, and levels often triggered fishery closures, which likely prevented human health impacts. The low confidence in the trend was due to the limited data availability for harmful algal bloom levels throughout the time period.

Question 8: Have recent, accelerated changes in climate-altered water conditions and how are they changing?

Fair

Status Description: Climate-related changes have caused measurable but not severe degradation in some attributes of ecological integrity.

Rationale: Climate-related changes in some water quality indicators have been observed. Notably, a marine heatwave in 2014–2016 resulted in the highest sea surface temperature on record for the area. This marine heatwave was present for an extended duration, with modeling showing the heat extended into the water column to at least 100 meters. In addition, the record warmest and coolest conditions were observed during the assessment period, indicating high variability in the system. Periods of anomalous conditions, both warm and cool, appear to be more extreme and longer in duration than in the past. Increased variability is one potential outcome of climate change and can indicate worsening conditions. At times, localized upwelling appears to buffer CBNMS from anomalous heating events observed in the surrounding region. Low-pH water and low dissolved oxygen levels extend onto the bank and shelf periodically during the year, but trend data were not available. These climate-related changes are notable because they have been linked to changes in some ecosystem components, including abundance and distribution of pelagic prey and predator species, condition of krill, and the presence and intensity of harmful algal blooms and domoic acid. The low confidence in the trend was due to low agreement among the experts in how to interpret the high variability in the data and the lack of evidence of a clear trend during the time period that was evaluated.

Question 9: Are other stressors, individually or in combination, affecting water quality, and how are they changing?

Good/Fair

Status Description: Selected stressors are suspected and may degrade some attributes of ecological integrity, but have not yet caused measurable degradation.

Rationale: Microplastics are present in the sanctuary, but at levels within the range of other open ocean marine settings and much lower than San Francisco Bay. There were no reported oil spill incidents inside CBNMS, but incidents that occurred nearby had the potential to affect the sanctuary. Vessel discharges were recorded in the sanctuary and are likely underreported. Changes to ocean temperature and chemistry caused by global greenhouse gases have also affected CBNMS. The undetermined trend was based on the limited time-series data available for most indicators.

Habitat Resources

Question 10: What is the integrity of major habitat types and how are they changing?

Fair

Status Description: Selected habitat loss or alteration has caused measurable but not severe degradation in some attributes of ecological integrity.

Rationale:Direct measures of impacts to CBNMS benthic habitats are limited, but data show that trawling activities, Dungeness crab fishing, and marine debris are present in the sanctuary, albeit at lower levels than some other areas along the U.S. West Coast. Monitoring is required to establish trend data in recently opened and closed Essential Fish Habitat Conservation Areas. Chronic noise from shipping is approaching a threshold level that could cause stress to marine mammals, particularly whales.

Question 11: What are contaminant concentrations in sanctuary habitats and how are they changing?

Undetermined

Status Description: N/A

Rationale: This rating is based on the lack of data on contaminants in the water column, sediments, and animal tissues within the CBNMS region. Based on other ocean areas, stressors of concern for CBNMS include persistent contaminants and microplastics in the water column, sediments, and resident species; these are data gaps that should be considered as targets for future research efforts. Very little information was available on trends for any of the indicators

Experts assigned a trend rating of undetermined at the workshop. However, following the workshop, a new trend, “mixed,” was introduced to the condition report rating scheme as a result of discussions with experts. ONMS staff determined that this new rating was more appropriate to apply to this question, based on the combination of trends from available data.

Living Resources

Question 12: What is the status of keystone and foundation species and how is it changing?

Good/Fair

Status Description: The status of keystone or foundation species may preclude full community development and function, but has not yet led to measurable degradation

Rationale:Foundation species at CBNMS include benthic macroinvertebrates (deep-sea corals and sponges), krill, and calanoid copepods. The abundance and health of corals and sponges appears to be good; however, long-term trends are not known due to a lack of historic baseline data. Krill and copepod abundance and composition fluctuated during the assessment period, particularly in association with marine heatwaves.

Question 13: What is the status of other focal species and how is it changing?

Fair

Status Description: Selected focal species are at reduced levels, but recovery is possible.

Rationale:Some indicator species are variable, while others are stable and some are declining. Blue and humpback whales are still recovering from past impacts, remain endangered or threatened, and are vulnerable to impacts such as ship strikes and entanglements. Commercially harvested rockfish have improved since the last assessment and are at management targets, but are far below near-pristine levels in the absence of fishing pressure. Seabirds are variable, but there is no evidence of long-term declining trends. Fish and invertebrates on Cordell Bank and the shelf appear stable. However, leatherback sea turtles are at very low abundance throughout their range, and their population has been declining. Because some species appear to be stable, some are variable, and some are declining, the trend was determined to be mixed.

Question 14: What is the status of non-indigenous species and how is it changing?

Good

Status Description: Non-indigenous species are not suspected to be present or do not appear to affect ecological integrity (full community development and function).

Rationale: Limited data from CBNMS have documented no mature or reproductive populations of non-indigenous taxa, and there is no evidence of detrimental impact. Some species of concern exist in the region, but none have become invasive or exhibited significant growth or expansion in the sanctuary. Adequate data do not exist to assess a trend for non-indigenous species, and there was low confidence due to data limitations.

Question 15: What is the status of biodiversity and how is it changing?

Good/Fair

Status Description: Selected biodiversity loss or change is suspected and may preclude full community development and function, but has not yet caused measurable degradation.

Rationale: Pelagic indicators such as zooplankton appear to have recovered; krill and copepod biodiversity returned to average following marine heatwave-induced changes. Groundfish diversity varied, but was stable and consistent across the region. Biodiversity of macroinvertebrates and fish communities on the bank appeared to be stable, yet the ability to detect trends was limited by the lack of long-term data. Knowledge of new species and range extensions in deep-water benthic communities has greatly improved with advancements in survey technologies and the increasing number of exploration missions. Seabird diversity appeared to be stable and changes in species composition reflected natural seasonal variation.

Maritime Heritage Resources

Question 16: What is the condition of known maritime heritage resources and how is it changing?

Undetermined

Status Description: The status is undetermined.

Rationale: The status rating is undetermined. The one maritime heritage resource documented to be sunk within the sanctuary, the ex-USS Stewart (DD-224), has not been specifically located or assessed since it sank in 1946 within what is now the sanctuary (see Sanctuary Setting for more information). It is assumed that the ship has deteriorated to some degree as a result of being submerged in the Pacific Ocean; accordingly, the trend for the condition of the shipwreck is thought to be worsening, most likely due to natural processes, though it is possible the condition may be somewhat influenced by human activities (see question 5 in this report). Note that a confidence score was not assigned to status and trend rating for this question because an actual assessment has not yet been conducted; also, subject matter external experts were not consulted on these ratings.

A workshop was not convened for question 16. Archaeological experts with the ONMS Maritime Heritage Program and CBNMS evaluated this question internally. These subject matter experts have been monitoring existing archaeological sites along the West Coast since the 1980s. Note that confidence scores were not assigned to the status or trend ratings for these questions, because subject matter external experts were not consulted on these ratings.