band transects which are visually searched for all individuals. Since 1994 the abundance of newly recruiting abalone (<20 mm) in size has progressively decreased.
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Figure 1. Patterns of abundance in adult intertidal black abalone (Haliotis cracherodii) on Santa Cruz Island between 1987-1999. |
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Figure 2. Patterns of abundance in adult intertidal black abalone on Santa Cruz Island between 1990-1999. |
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Figure 3. Percent change in abundance in adult intertidal black abalone 1987-1999. |
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Figure 4. Size frequency of adult black abalone in intertidal surge channels on Santa Cruz Island from 1990-1999. Abalone are surveyed using eight-1 m wide band transects which are visually searched for all individuals. |
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Figure 5. Density of juvenile abalone in intertidal boulder fields. |
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Figure 6. Size frequency of juvenile black abalone in intertidal boulder fields on
Santa Cruz Island from 1990-1997. Juveniles are surveyed using two-6 m wide band transects which are visually searched for all individuals. Since 1994 the abundance of newly recruiting abalone (<20 mm) in size has progressively decreased. |
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Figure 7. Changes in the density of small recruiting abalone in intertidal boulder fields relative to adult density on nearby surge channels at Santa Cruz Island. Abalone were identified as recruits if their shell length was < 20 mm |
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Figure 8. Changes in recapture rate and shell growth rates 1987-1999 in relation to warm and El Niņo years. |