Table 3.
Abundance of nudibranchs recorded in timed counts at Duxbury Reef, before (n = 7) and after (n = 5) arrival of Phidiana hiltoni
| Species | Taxon | Vulnerable to P. hiltoni | Mean (±SD) no. inds. h−1 obs.−1 | Δ | P | Geog. range | |
|---|---|---|---|---|---|---|---|
| 1969–1975 | 2007–2009 | ||||||
| Triopha catalinae (Cooper, 1863) | Dor | No | 3.59 ± 2.32 | 7.98 ± 12.39 | + | 0.87 | N |
| Triopha maculata MacFarland, 1905 | Dor | No | 2.32 ± 2.40 | 2.59 ± 2.90 | + | 0.97 | S |
| Rostanga pulchra MacFarland, 1905 | Dor | No | 2.20 ± 2.94 | 0.00 ± 0.00 | − | 0.02 | W |
| Cadlina modesta MacFarland, 1966 | Dor | No | 2.03 ± 2.66 | 0.00 ± 0.00 | − | 0.02 | W |
| Aegires albopunctatus MacFarland, 1905 | Dor | No | 1.58 ± 3.09 | 0.25 ± 0.35 | − | 0.28 | W |
| Diaulula sandiegensis (Cooper, 1863) | Dor | No | 1.55 ± 1.44 | 1.07 ± 1.23 | − | 0.52 | W |
| Dirona picta MacFarland in Cockerell and Eliot, 1905 | Arm | No | 1.24 ± 2.88 | 0.00 ± 0.00 | − | 0.22 | S |
| Doris montereyensis Cooper, 1863 | Dor | No | 0.73 ± 1.00 | 1.16 ± 1.90 | + | 0.79 | N |
| Diaphorodoris lirulatocauda Millen, 1985 | Dor | No | 0.70 ± 1.08 | 1.75 ± 3.50 | + | 0.71 | W |
| Cuthona lagunae (O’Donoghue, 1926) | Aeo | No | 0.51 ± 0.35 | 0.27 ± 0.60 | − | 0.30 | S |
| Ancula gibbosa (Risso, 1818) | Dor | No | 0.50 ± 0.51 | 0.42 ± 0.55 | − | 0.79 | N |
| Cadlina luteomarginata MacFarland, 1966 | Dor | No | 0.39 ± 0.34 | 0.05 ± 0.12 | − | 0.04 | N |
| Acanthodoris lutea MacFarland, 1925 | Dor | No | 0.35 ± 0.29 | 0.00 ± 0.00 | − | 0.02 | S |
| Doriopsilla albopunctatus (Cooper, 1863) | Dor | No | 0.33 ± 0.48 | 0.00 ± 0.00 | − | 0.10 | S |
| Acanthodoris nanaimoensis O’Donoghue, 1921 | Dor | No | 0.21 ± 0.24 | 0.10 ± 0.22 | − | 0.40 | N |
| Janolus fuscus O’Donoghue, 1924 | Arm | No | 0.17 ± 0.25 | 0.13 ± 0.30 | − | 0.78 | N |
| Limacia cockerelli (MacFarland, 1905) | Dor | No | 0.14 ± 0.20 | 0.00 ± 0.00 | − | 0.10 | W |
| Peltodoris nobilis (MacFarland, 1905) | Dor | No | 0.12 ± 0.22 | 0.35 ± 0.65 | + | 0.51 | N |
| Geitodoris heathi (MacFarland, 1905) | Dor | No | 0.10 ± 0.12 | 0.20 ± 0.45 | + | 0.73 | N |
| Acanthodoris rhodoceras Cockerell and Eliot, 1905 | Dor | No | 0.08 ± 0.11 | 0.00 ± 0.00 | − | 0.09 | S |
| Hallaxa chani Gosliner and Williams, 1975 | Dor | No | 0.05 ± 0.10 | 0.10 ± 0.22 | + | 0.73 | N |
| Onchidoris muricata (Linnaeus, 1767) | Dor | No | 0.02 ± 0.06 | 0.00 ± 0.00 | − | 0.36 | N |
| Dendronotus albus Robilliard, 1970 | Den | No | 0.01 ± 0.02 | 0.00 ± 0.00 | − | 0.36 | N |
| Dendronotus subramosus MacFarland, 1966 | Den | No | 0.01 ± 0.02 | 0.15 ± 0.34 | + | 0.41 | N |
| Tritonia festiva Stearns, 1873 | Den | No | 0.01 ± 0.02 | 0.00 ± 0.00 | − | 0.36 | N |
| Hermissenda crassicornis (Eschscholtz, 1831) | Aeo | Yes | 7.24 ± 4.60 | 1.25 ± 1.56 | − | 0.002 | W |
| Doto amyra Marcus, 1961 | Den | Yes | 3.11 ± 6.12 | 0.42 ± 0.55 | − | 0.12 | N |
| Flabellina trilineata O’Donoghue, 1921 | Aeo | Yes | 1.84 ± 1.16 | 1.29 ± 0.91 | − | 0.19 | N |
| Cuthona flavovulta (MacFarland, 1966) | Aeo | Yes | 0.77 ± 0.91 | 0.77 ± 1.44 | 0 | 0.42 | S |
| Cuthona divae (Marcus, 1961) | Aeo | Yes | 0.39 ± 0.44 | 0.15 ± 0.23 | − | 0.13 | N |
| Doto kya Marcus, 1961 | Den | Yes | 0.30 ± 0.62 | 0.00 ± 0.00 | − | 0.10 | N |
| Cuthona albocrusta (MacFarland, 1966) | Aeo | Yes | 0.27 ± 0.34 | 0.00 ± 0.00 | − | 0.04 | W |
| Aeolidiella oliviae MacFarland, 1966 | Aeo | Yes | 0.11 ± 0.20 | 0.00 ± 0.00 | − | 0.10 | S |
| Cuthona abronia (MacFarland, 1966) | Aeo | Yes | 0.10 ± 0.21 | 0.43 ± 0.66 | + | 0.82 | N |
| Aeolidia papillosa (Linnaeus, 1761) | Aeo | Yes | 0.08 ± 0.19 | 0.11 ± 0.24 | + | 0.57 | N |
| Doto columbiana O’Donoghue, 1921 | Den | Yes | 0.04 ± 0.09 | 0.25 ± 0.56 | + | 0.76 | N |
| Dendronotus venustus MacFarland, 1966 | Den | Yes | 0.03 ± 0.08 | 0.00 ± 0.00 | − | 0.18 | N |
| Eubranchus rustyus (Marcus, 1961) | Aeo | Yes | 0.02 ± 0.05 | 0.00 ± 0.00 | − | 0.18 | W |
| Cuthona fulgens (MacFarland, 1966) | Aeo | Yes | 0.00 ± 0.00 | 0.10 ± 0.22 | + | 0.81 | N |
| Phidiana hiltoni (O’Donoghue, 1927) | Aeo | Yes | 0.00 ± 0.00 | 10.44 ± 5.71 | + | <0.001 | S |
Species are grouped by vulnerability to P. hiltoni as outlined in “Materials and methods” and ranked by mean abundance during 1969–1975. Δ = change in abundance. Probabilities (P) are for t-tests (assuming unequal variances) of log-transformed abundances for the two time periods, two-tailed for P. hiltoni and species considered not vulnerable to P. hiltoni, and one-tailed for species deemed vulnerable. Nomenclature follows Behrens and Hermosillo (2005) and Stout et al. (2010). Taxon codes: Dor Doridina, Arm Arminina, Aeo Aeolidina, Den Dendronotina. Geographic range categories: N northern, S southern, W widespread (see “Materials and methods”)