Pinto abalone ( Haliotis kamtschatkana kamtschatkana ) index stations in the San Juan Archipelago were systematically monitored by the Washington Department of Fish and Wildlife from 1992 through 2006. During this period, abalone abundance declined by 77% and the mean shell length (SL) increased 10.4 mm. Abalone densities at all index stations are currently well below the threshold of 0.15 abalone·m–2 required for successful fertilization. From 1992 to 1996, 16% of individuals encountered measured <90 mm SL, while only 6% of the individuals from 2003 to 2006 were in this small size class. Similarly, the number of those >114 mm SL was greater in the 2000s than in the 1990s. The mean SL of all live abalone observed in the 1990s (107.62 ± 0.87 mm) was significantly different from the mean SL of empty shells (114.21 ± 2.1 mm), but no difference was detected between the mean SLs of empty shells and live abalone in the 2000s (114.97 ± 1.42 mm). Taken together, these data suggest recruitment failure from an Allee response to low population densities.

ABSTRACT1. Northern abalone (Haliotis kamtschatkana kamtschatkana) is a federally listed species of concern. 2. The status of northern abalone and the characteristics of the habitats they associate with were determined showing that northern abalone have declined dramatically in Washington State with present day abundances <10% of those found in 1979.3. Northern abalone inhabited kelp beds (Nereocystis luetkeana), more than red sea urchin beds (Strongylocentrotus franciscanus) (X 2 = 16, d.f. = 1, P < 0.01) or habitats with both kelp and sea urchins (X 2 = 13.2, d.f. = 1, P < 0.01). Sites with Nereocystis kelp canopy had twice the percentage cover of encrusting coralline algae compared with sea urchin sites.4. No juvenile abalone (<75 mm) were found in any of the habitat types raising concerns about recruitment failure.5. Abalone co-occurred with other molluscs including limpets and scallops. Kelp holdfast microhabitats had significantly higher species richness (t = 2.2, d.f. = 6, P < 0.05), twice the effective number of species and 5x more individuals than sea urchin spine microhabitats.6. In laboratory choice experiments, juvenile abalone (20 mm) preferred coralline rocks to kelp holdfasts or sea urchin spine canopy. The small snail, Amphissa spp. (5-15 mm) was more abundant inside kelp holdfasts than under sea urchins or in rock cobble, suggesting this may be an important microhabitat.7. It is recommended that kelp beds with abundant coralline substrate be used for restoration including stocking juveniles and adult aggregations as this biogenic habitat may enhance northern abalone restoration actions.

To investigate contemporary pinto abalone Haliotis kamtschatkana kamtschatkana recruitment events and juvenile abundance, 66 abalone recruitment modules (ARMs) were deployed at two depths and three sites in the San Juan Archipelago (Washington State) that were historically inhabited by substantial abalone populations. Based on published studies from California and British Columbia, ARMs are proven tools for surveying juvenile pinto abalone abundance. Abalone recruitment modules provide complex habitat and protection from predation. The ARMs were surveyed in situ for juvenile abalone abundance six times over the course of 26 months. Only eight abalones were observed, including three juveniles that were less than 50 mm (shell length). The mean density of juvenile abalones inhabiting the ARMs across all three sites during the 2006 surveys was 0.012/m 2 . The absence of juvenile abalones within the ARMs, combined with sharp regional declines in adult pinto abalone abundance, suggests limited local recruitment of this species, which is currently designated as threatened in Canada and as a species of concern in the USA.Pinto (northern) abalone Haliotis kamtschatkana kamtschatkana are the northernmost haliotid species and range from Sitka, Alaska, to Point Conception, California (Geiger 2000). Haliotis kamtschatkana is the predominant abalone species found in the San Juan Archipelago (SJA) and the coastal waters of Washington State, British Columbia, and

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