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Recovery strategy for the Northern Abalone

1.6 Threats

1.6.1 Threat classification

Table 1. Threat Classification Table
1Illegal harvestThreat Information
Threat CategoryConsumptive UseExtentWidespread
General ThreatHarvestingOccurrence Historic and current
Frequency Continuous/recurrent
Specific ThreatIllegal HarvestingCausal Certainty High
Severity High
StressReduced population size Level of ConcernHigh
2Low recruitmentThreat Information
Threat CategoryChanges in Ecological Dynamics or Natural ProcessesExtentWidespread
General ThreatLow (or no) recruitmentOccurrence Historic and current
Frequency Unknown
Specific ThreatInsufficient spawner densities and natural causesCausal CertaintyHighMedium
StressReduced population size Level of ConcernHigh
3Works or developments on, in and under waterThreat Information
Threat CategoryHabitat Loss or DegradationExtentLocalized
General ThreatWorks or developments on, in and under water OccurrenceAnticipated 
Specific ThreatAlteration of habitat characteristics (e.g., siltation), or loss of habitat (e.g., obstruction, burying)Causal CertaintyHigh to unknown 
StressReduced population sizeLevel of ConcernLow
4Sea otter predationThreat Information
Threat CategoryChanges in Ecological Dynamics or Natural ProcessesExtentOverlapping portion of range
General ThreatSea otter predationOccurrenceCurrent and ImminentAnticipated
FrequencyContinuous or RecurrentUnknown
Specific ThreatAltered predator-prey dynamics (predation)Causal CertaintyMediumUnknown
StressIncreased mortality and unknown effects on population dynamicsLevel of ConcernMedium

1.6.2 Description of threats

Continued illegal harvest and low recruitment levels have had predominant and widespread impacts and are considered to be the most significant threats to northern abalone recovery.    

Illegal Harvest

Mature northern abalone, which tend to accumulate in shallow water, are easily accessible to harvesters.  The market value of abalone, and the difficulty in enforcing the fisheries closures in a large, mostly uninhabited coastal area, has encouraged illegal harvesting.  Illegal harvesting not only depletes the already depressed northern abalone population, but also reduces their reproductive potential by removing large mature abalone and leaving the remaining mates too far apart to successfully spawn.  Samples from northern abalone illegally harvested during 1995-98 suggested that harvesters indiscriminately removed mostly large mature abalone (Campbell 2000b). Recent mortality rates estimated by Lessard et al. (2006) indicated that the mortality rate (all sources) for northern abalone were too high to be sustainable.

In 2006, three separate abalone poaching events culminated in February when Fisheries Officers seized the largest single haul of illegally harvested northern abalone in Canada’s history; 1,120 kg or an estimated 11,000 animals were seized.  Illegal harvesters have generally come from coastal communities, and the abalone have been destined for sale or personal consumption.  Convictions for buying or selling northern abalone have been made in recent years against seafood wholesalers in Vancouver and a Chinese restaurateur in Victoria, B.C.  The Courts have taken illegal harvesting seriously; heavy fines, forfeiture of vessels, vehicles and gear, and prohibitions on fishing are now standard sentences.

Without reductions in illegal harvest, protection of mature abalone, a continued closure of the fisheries, and other effective rehabilitation methods, northern abalone population abundance will remain low or continue to decline in many areas.

Low Recruitment

Low recruitment in an area, over a protracted period of several years, may contribute to further declines in the northern abalone population by not replenishing the reproductive adults that have died from natural causes or illegal harvest.  Generally, high densities of adult northern abalone are required to ensure sufficient recruitment (refer to Section 1.4.1 Habitat and biological needs). 

Low recruitment caused by unfavourable environmental and biotic factors usually can not be predicted nor controlled.  Ensuring that there are sufficient adult northern abalone to reproduce each year will allow high recruitment to occur when environmental conditions are favourable.

Habitat Loss or Degradation

Works and developments on, in, and under the water (e.g., marinas, loading facilities, aquaculture farms) may have negative impacts on northern abalone habitat and numbers in localized areas, and will need to continue to be monitored and regulated in order to maintain habitat in which the northern abalone can be recovered and to prevent losses to important spawning aggregations.  Protocols for authorizing and monitoring works and developments around abalone habitat have been developed (Lessard et al. 2006).

Sea Otter Predation

Historically, sea otters were common in coastal regions of the North Pacific.  They were hunted to near extinction from the mid-1700s until protected in 1911, and were reintroduced to B.C. by the Federal and Provincial governments in a series of three translocations of 89 sea otters in 1969, 1970, and 1972 (Watson 2000).  The sea otter population is also listed as threatened under SARA (2003).  In areas off the west and north coasts of Vancouver Island and in the Goose Group on the central coast of B.C., where sea otters are now established, sea otters prey on northern abalone, reducing the density, size, and distribution of northern abalone compared to areas without sea otters (Breen et al. 1982; Watson 1993).  While sea otters are clearly not responsible for the observed decline in the northern abalone population over the last few decades, as the range of sea otters expands, northern abalone may only be sustained at low levels. 

Northern abalone and sea otters have co-existed in the past before the extirpation of sea otters.  However, the levels at which they co-existed or whether populations may have fluctuated in the past is unknown.  The majority of knowledge on the northern abalone population has been in the absence of sea otters. 

Sea otter expansion may be a concern in areas where the abalone population is already depleted and may make meeting abalone recovery objectives, as currently defined from areas without sea otters, impossible.  Provided sufficient densities of northern abalone remain to be able to reproduce successfully, sea otters may in the longer-term help northern abalone recover by increasing kelp and algae biomass and thereby increasing the food supply available to abalone.  This interaction has been highlighted as a knowledge gap (refer to Section 1.8).  Refinements to the abalone population and distribution objectives for areas with sea otters may be necessary with improved knowledge of species interactions.

1.7 Actions Already Completed or Underway

Surveys of Key Index Sites (1978-present)have been conducted every 1-5 years to monitor population abundance and evaluate recovery.  These broad scale surveys are considered representative by providing time-series trends of the northern abalone population.

Closures to Commercial Fishing (1971-1990).  The Lower Johnstone Strait, Georgia Basin and Strait of Juan de Fuca were closed in 1971 to commercial fishing to provide for recreational fishing opportunities.  In addition, there were a number of closures to the commercial fishery to provide for First Nations and recreational harvest (Farlinger, 1990).

Total Fisheries Closures December (1990-present).   All B.C. fisheries, including commercial, recreational and First Nations’ food, social and ceremonial fisheries, were closed to abalone harvest in 1990.  There are currently no commercial fisheries for northern abalone anywhere.

Threatened Status (1999) and Legal Listing (2003-present).  Northern abalone were designated by COSEWIC as threatened in 1999 and legally listed under SARA in 2003 (with the Act’s proclamation).  A re-assessment of northern abalone’s status by COSEWIC is in preparation and anticipated to be made in 2009.

Enforcement measures have been undertaken by regular patrols in support of the harvest prohibition and in response to reports of illegal activity.  Covert operations and investigations target specific poaching operations. Penalties and court imposed fines have become significant in recent years. 

An international Workshop on Rebuilding Abalone Populations in British Columbia (1999) was held in February 1999, and convened individuals from local communities, First Nations, international research institutes and government organizations to focus on developing solutions to rehabilitate northern abalone populations (approximate cost $100K).  Thirteen peer-reviewed papers were presented (Campbell 2000a) and a Strategy for Rebuilding Abalone Populations in British Columbia was prepared by Dovetail Consulting Inc.  The broad approaches and strategies of this Abalone Recovery Strategy were drawn from this workshop.

Pilot Projects in support of rebuilding the wild abalone population (2000-present).  In 2000, Fisheries & Oceans Canada in co-operation with several First Nations, coastal communities, and the aquaculture industry, initiated several pilot projects in support of rebuilding wild abalone populations. 

Rebuilding Sites:  The Haida Fisheries Program and Kitasoo Fisheries Program have established long-term rebuilding sites to improve recruitment by aggregating reproductively mature adults.  The Haida Fisheries Program and Pacific Urchin Harvesters Association initiated a joint research project in 2004 to study interactions between northern abalone and red sea urchins, a potential competitor of abalone.  The Heiltsuk Abalone and Sea Otter Stewardship Project established rebuilding sites in 2004 and will include studies on the effects of sea otters on the abalone population.  These activities are supported also by habitat and population assessment (surveys), community education and awareness and Abalone Coast Watch to protect the abalone population.  Fisheries & Oceans Canada and Parks Canada Agency established research sites in 2002 in and around Pacific Rim National Park to investigate local habitat requirements for recruitment and to test the rebuilding technique of aggregating reproductively mature northern abalone.  Current modeling and night surveys by Parks Canada Agency were used to predict and assess juvenile recruitment from the aggregation sites.  Preliminary results indicate that aggregation increases localized recruitment.  Aggregation studies are authorized under the Fisheries Act and section 73 of SARA.

Development of Culture Technology and out-planting:  The Bamfield Huu-ay-aht Community Abalone Project was established in 2001 and made the first out-planting to the wild of hatchery-raised northern abalone in 2003.  Since then, 2 million abalone larvae and 75,000 young juveniles have been out-planted to the wild.  BHCAP made the first sales of cultured northern abalone in 2006.  Hatchery-raised abalone are available to research studies (e.g., disease, feeding, effect of finfish farms, interactions with red urchins) that could not previously be conducted with wild abalone.  The BHCAP’s activities are authorized under the Fisheries Act and section 73 of SARA.

An Abalone Recovery Team (2001) was formed in November 2001, with representatives from the federal departments of Fisheries and Oceans Canada and Parks Canada Agency, and the Provincial Ministries of Environment (formerly Water, Land and Air Protection) and Agriculture and Lands (formerly Agriculture, Food and Fisheries). 

Eight Workshops (2002) for coastal B.C. communities (Bella Bella, Port McNeil, Powell River, Port Alberni, Victoria, Nanaimo, Prince Rupert, and Skidegate) were held in February 2002 as forums to receive input on the recovery strategy from all interested parties.  Concurrently, the recovery strategy was reviewed by seven external reviewers representing academia, government, and non-government organizations from Canada, U.S.A., Australia and New Zealand.

A National Recovery Strategy for the Northern Abalone in Canada (2002) was adopted under the Accord for the Protection of Species at Risk in November, 2002.  This was one of the first marine recovery strategies, and the first in the Pacific Region.

Index Sites in southern B.C. (2003-2004)have been established to monitor population abundance and evaluate recovery in Queen Charlotte and Johnstone Straits and the West Coast of Vancouver Island.  Limited surveys were conducted also in Georgia Basin in 2005. 

Scientific documents and publications produced to increase the knowledge base regarding northern abalone (see References and Additional Reading).

Anti-illegal harvest communications campaign consisted of multiple activities and the production of communications products by Fisheries & Oceans Canada and abalone stewardship projects to raise public awareness of the current status of northern abalone and the harms of continued illegal harvest.  Materials produced include an abalone web site, news releases, education curriculums and presentations in local schools, translated articles in the Asian press, posters, stickers, tattoos, t-shirts, water bottles and community brochures, websites, ‘Observe-Record-Report’ reporting forms, newsletters, and workshops.  Numerous newspaper stories, particularly in recent years, and have also supported the campaign.

Abalone Genetics Research (2001). The population structure of northern abalone has been determined in B.C. and a forensic DNA technique has been developed to identify confiscated abalone to species to support enforcement against illegal harvest.

1.8 Knowledge Gaps

Larval Dispersal, Patch Size and Recruitment

Currently very little is known about the relationship between northern abalone adult concentrations, breeding success and subsequent dispersal of larvae and settlement of juveniles.  Juvenile northern abalone are cryptic (i.e., hiding in cracks and crevices and unobservable to survey) and difficult to survey effectively until they reach maturity.  Low abundance and fragmentation of the population are considered to be impairing the potential reproductive success of northern abalone.  The frequency and size of patches of northern abalone required to maintain sufficient recruitment for a healthy population requires further investigation.  While a stock-recruitment model was recently developed for the first time for northern abalone (Lessard et al. 2006), a better measure for cryptic animals to assess recruitment is still required.

Species Interactions

A better understanding of the ecological interactions between northern abalone and abalone predators (e.g., sea otters) and competitors (e.g., sea urchins) is required.  The sea otter, a significant predator of northern abalone, is expanding its range in B.C. following extirpation and re-introduction.  Most of the studies on the northern abalone population have been in the absence of sea otters and abalone recovery objectives are based on life history parameters that have been determined without the influence of sea otters.  Sea otters affect the size and density of northern abalone, and may also influence factors such as size at maturity and the portion of the population that remains cryptic.  Sea otters will also affect the abundance and distribution of other abalone predators, including Dungeness and other crabs, and abalone competitors, particularly red sea urchins.  Currently, the factors that facilitate co-existence of sea otters and northern abalone are unknown, and further research on these factors is needed.  Recovery objectives in the presence of sea otters need to be determined.  In some areas, increased predation from the expanding sea otter population on an already reduced and fragmented northern abalone population poses a concern for northern abalone recovery. 

Rebuilding Techniques

Tagged abalone remain relatively close to their transplant site in the first year (B. DeFreitas, Haida Fishery Program, Massett, BC , pers. comm.; J. Lessard, pers. comm.), which is likely sufficient time to allow for spawning.  A preliminary study by Parks Canada Agency and Fisheries & Oceans Canada indicates that aggregating reproductive adults may contribute significantly to local recruitment (Parks Canada Agency, in preparation).  Out-planting juvenile abalone has had some limited success with other species in other jurisdictions (Seki and Taniguchi 2000; Shepherd et al. 2000; Tegner 2000).  The recent work in B.C. indicates that shelter from predation and, possibly, selection of sites with lower abundances of predators are important considerations for out-planting, particularly for juvenile northern abalone <12mm SL (Griffiths 2006).  Further evaluation of the rebuilding techniques for northern abalone in B.C. is required.


Abalone disease has severely impacted wild abalone stocks in California (e.g., foot withering syndrome), however it is unknown if the causative agent (a rickettsia-like organism that infects the epithelium of the digestive tract) or other parasites reported in California (e.g., kidney coccidia) occur in northern abalone in B.C.  As random sampling of wild northern abalone in B.C. for a disease survey is not a feasible approach due to low population levels, abalone in culture are being sampled.  Broodstock obtained from the wild population will harbour parasites enzootic to the area of collection and these organisms may become evident under culture conditions.  Also, hatchery-raised abalone produced in culture will reflect the agents of disease occurring in the vicinity of the culture facility (given the current restrictions with transplanting abalone between different regions of the province, cultured abalone should not develop "exotic" diseases).  As well, in the event cultured abalone are used in rebuilding (out-planting) experiments, these animals should have prior disease screening to ensure that only healthy abalone are introduced into the wild population.

Extent of Illegal Harvest

Known quantities of illegally harvested B.C. northern abalone have ranged from <45 to 4500 kg (Jubinville 2000).  Prior to the closure of the commercial, recreational, and First Nations fisheries in 1990, and continuing afterwards, there has been illegal harvesting at unknown exploitation rates, and despite the closure, northern abalone has not shown signs of natural recovery.   The density of large mature abalone (>100mm SL) has continued to decline at survey index sites, and is reported to be declining at other locations.  Anecdotal information suggests that illegal harvesting occurs on a scale significant enough to cause a severe conservation risk to this species. 

Clarification of Habitat Concerns

The extent to which works or developments on, in or under the water (e.g., finfish farms, floating camps) may pose a threat to northern abalone by direct and indirect impact(s) in localized areas is unknown.  To date, only one study (Lessard et al. 2006) has specifically examined the indirect impact from finfish farms on northern abalone, using hatchery-raised abalone.  Although the study had some difficulty due to poor survival overall, growth was decreased in proximity to the farm sites in comparison to the controls.  A protocol for authorizing works and developments on, in and under the water where abalone are present (Lessard et al. (2006)), therefore, adopts a precautionary approach to the authorization of sites in abalone habitat.  The protocol includes provisions for monitoring and collection of additional data.  

Identification of critical habitat

Although abalone habitat (Section 1.4.1) is not considered to be limiting, there may be certain habitats where juvenile survival is better, or where the reproducing adults contribute to a larger portion of the total recruitment.  Identification of this key habitat is included as part of the abalone research and rebuilding plans.