Fig 1.
Total number of confirmed humpback (solid black), blue (dotted pattern) and gray whale (diagonal stripes) entanglements in fishing gear from 1993 to 2017 off the coast of California [32, Lauren Saez, pers. comm.].
Fig 2.
Map of the study area located off the coast of central California showing the location of Southeast Farallon Island and the 30km sight range.
The Greater Farallones, Cordell Bank, and Monterey Bay National Marine Sanctuaries (NMS), which border the central California coast are outlined. The 200m isobath is depicted by the dashed line.
Table 1.
Oceanographic and climate data used as environmental covariates.
Fig 3.
Interannual trends in average weekly predicted counts of (A) humpback, (B) blue, (C) south-bound gray, and (D) north-bound gray whales. The 95% confidence intervals are shown in gray shading.
Fig 4.
Interannual trends in the timing of day of arrival and departure.
Shown are the arrival (blue) and departure (orange) trends for humpback (A), blue (B), gray-south (C), and gray-north (D). Blue whale departure, gray-north arrival, and gray-south arrival and departure, trends were significant (P>0.05); in this case we depict the linear trend. The other four trends shown were significant. The 95% confidence intervals are depicted in gray shading.
Table 2.
Changes in timing for humpback, blue, and gray whale arrival and departure times.
Table 3.
Results from the multivariable timing model for humpback, blue, and gray whales.
Fig 5.
Visual depiction of the environmental multivariable timing models for humpback, blue, and gray whales.
For each timing model shown in Table 3, the model predictions for each environmental variable is graphed while controlling for all the other significant variables in the model. Humpback arrival: SOI previous spring (A), NPGO-summer (B); Humpback departure: UI summer (C), SOI previous winter (D) NPGO summer (E); Blue arrival: annual SST (F), UI fall (G), SOI previous-winter (H); Gray-north departure SST summer (I), SSS previous winter (J). Shading indicates 95% CIs.
Table 4.
Coefficient of determination and model significance comparison between the full, forecast, and year-removal validation models.
Table 5.
Results from the multivariable model for confirmed entangled humpback whales.
Fig 6.
Residency time of humpback whales within 30 km of the Southeast Farallon Islands.
The bottom of the box plot corresponds to the arrival time (date of 10th percentile for the year’s sightings). The top of the box plot corresponds to the departure time (date of 90th percentile of the year’s sightings). The whiskers are the earliest arrival date (bottom) and the last departure date (top). The red line corresponds to the typical closure of the previous year fishing season on June 30th (Day 181) and the green line is the typical opening of the new fishing season on November 15th (Day 319). Years marked with a * correspond to years where there was early arrival.