Patterns in deep-sea coral (DSC) diversity and distribution are described for a range of benthic habitat features including offshore banks, continental shelf and slope, and submarine canyons in three national marine sanctuaries off the coast of North-central California. Sixteen visual datasets of DSC observations collected using underwater vehicles from 2010 to 2021 across a wide depth range of 35-3317 m were analyzed for zonation by depth and seafloor feature type. A total of 36,670 DSC from at least 20 families were documented in the study area. Taxa displayed patterns corresponding to depth and seafloor feature type, such as broad distribution across multiple depths and features or narrower depth range and fewer features. Significant divergence in DSC assemblage diversity and density occurred between banks and canyons, representing the shallowest and deepest depth extents in the study area. One species of Stylasteridae coral primarily inhabited banks and accounted for the highest density of all DSC taxa. Diversity of soft corals and gorgonians (Octocorallia) and black corals (Antipatharia) was greatest on the slope and canyons. Other octocorals such as sea pens (Pennatuloidea) collectively spanned the largest depth ranges throughout the study area on all features other than banks. Comprehensively describing DSC communities in relation to seafloor features throughout an extensive depth range may have applications to other regions globally where similar habitats and DSC families are found. Our growing understanding of taxonomic diversity and zonation adds to existing knowledge of depth and geographic distributions on the U.S. West Coast and provides a crucial foundation for effective management and conservation efforts for DSC communities.

The frequency and severity of marine heatwaves (MHWs), an emergent property of global warming, has led to large-scale disruptions to marine ecosystems. As upper trophic species, marine birds reflect shifts in trophic structure and stability; therefore, a sharp increase in marine bird mortality is a clear signal of ecosystem impact. In this study, we analyzed 29 yr (1993-2021) of beached bird monitoring data (~90000 surveys) to identify marine bird mortality events throughout the Northeast Pacific and Alaska, USA, and examined linkages to ocean-climate variability. Mortality events were documented throughout the study period, but massive events (>500 km in extent, >10 carcasses km -1 ) occurred infrequently (n = 5), with an unprecedented sequence from 2014-2019. Event characteristics, including encounter rate (carcasses km -1 ), duration, and spatial extent, were positively related to prior-year averaged sea surface temperature anomaly, with event magnitude (product of encounter rate, extent, and duration) displaying a step-like transition, increasing 5-fold between +0°C and +1°C above baseline (1981-2010) temperatures. Mortality events occurred more frequently following MHWs, and a common sequence of mortality events (at 1-6 and 10-16 mo after heatwave onset) was observed in the California Current large marine ecosystem following 3 prolonged MHW events. Following the second wave of mortality at 10-16 mo after MHW onset, a consistent 16 mo period of depressed carcass encounter rates ensued. Given continued global warming, our results point to more frequent large-scale mortality events and the potential for a new lower carrying capacity for marine birds in the Northeast Pacific.

Mass mortality events (MMEs) of seabirds are becoming more frequent as the global climate warms. Often documented via beached bird surveys, methods for estimating event-wide mortality are needed that can accommodate regional differences in carcass deposition and data quality/quantity. We develop a framework for estimating mortality from beached bird counts, extending existing approaches through the novel application of ocean circulation modeling to assess beaching likelihood. We applied our framework to the 2014/15 Cassin’s auklet (Ptychoramphus aleuticus) MME, which spread across three regions (central California, northern California-through-Washington, British Columbia) with varying data quality/quantity. Our best mortality estimate of ∼400 000 (estimates ranged from 265 000 to 700 000 depending on model uncertainty and extent) places this seabird MME as one of the largest on record. However, we caution that much uncertainty exists surrounding model parameterization and deposition in British Columbia where beached bird data were sparse. We suggest that the application of ocean circulation models, combined with process-based modeling of carcass persistence and detection, can improve estimates of MME magnitude.

About 62,000 dead or dying common murres (Uria aalge), the trophically dominant fish-eating seabird of the North Pacific, washed ashore between summer 2015 and spring 2016 on beaches from California to Alaska. Most birds were severely emaciated and, so far, no evidence for anything other than starvation was found to explain this mass mortality. Three-quarters of murres were found in the Gulf of Alaska and the remainder along the West Coast. Studies show that only a fraction of birds that die at sea typically wash ashore, and we estimate that total mortality approached 1 million birds. About two-thirds of murres killed were adults, a substantial blow to breeding populations. Additionally, 22 complete reproductive failures were observed at multiple colonies region-wide during (2015) and after (2016-2017) the mass mortality event. Die-offs and breeding failures occur sporadically in murres, but the magnitude, duration and spatial extent of this die-off, associated with multi-colony and multi-year reproductive failures, is unprecedented and astonishing. These events co-occurred with the most powerful marine heatwave on record that persisted through 2014-2016 and created an enormous volume of ocean water (the "Blob") from California to Alaska with temperatures that exceeded average by 2-3 standard deviations. Other studies indicate that this prolonged heatwave reduced phytoplankton biomass and restructured zooplankton communities in favor of lower-calorie species, while it simultaneously increased metabolically driven food demands of ectothermic forage fish. In response, forage fish quality and quantity diminished. Similarly, large ectothermic groundfish were thought to have increased their demand for forage fish, resulting in greater top-predator demands for diminished forage fish resources. We hypothesize that these bottom-up and top-down forces created an "ectothermic vise" on forage species leading to their system-wide scarcity and resulting in mass mortality of murres and many other fish, bird and mammal species in the region during 2014-2017.

Climate change has exacerbated the occurrence of large‐scale sea surface temperature anomalies, or marine heatwaves (MHWs)—extreme phenomena often associated with mass mortality events of marine organisms. Using a combination of citizen science and federal data sets, we investigated the causal mechanisms of the 2014/2015 die‐off of Cassin's Auklets (Ptychoramphus aleuticus), a small zooplanktivorous seabird, during the NE Pacific MHW of 2013–2015. Carcass deposition followed an effective reduction in the energy content of mesozooplankton, coincident with the loss of cold‐water foraging habitat caused by the intrusion of the NE Pacific MHW into the nearshore environment. Models examining interannual variability in effort‐controlled carcass abundance (2001–2014) identified the biomass of lipid‐poor zooplankton as the dominant predictor of increased carcass abundance. In 2014, Cassin's Auklets dispersing from colonies in British Columbia likely congregated into a nearshore band of cooler upwelled water and ultimately died from starvation following the shift in zooplankton composition associated with onshore transport of the NE Pacific MHW. For Cassin's Auklets, already in decline due to ocean warming, large‐scale and persistent MHWs might represent a global population precipice.

The Brandt's Cormorant of the California Current is a "boom-or-bust" species like its congeners in other eastern boundary, upwelling driven ecosystems, and like many of the prey upon which they depend. These birds produce many recruits when fish availability is high, leading to rapidly increasing populations, but few recruits, and may even exhibit die-offs, when the opposite is true. Unlike cormorants in the Peru and Benguela currents, however, Brandt's Cormorant population changes have yet to be correlated with those of its prey. Herein, using multi-decadal time series of cormorant colony size, diet, prey availability and mortality, in the context of changes in breeding site and fishery management, we provide insight into why central California colonies near San Francisco — a major portion of this species' global population — expanded from principally one offshore island in the 1960–70s to include a large mainland component by the 1990s. Involved were increases and decreases, respectively, of northern anchovy, a coastal forage species, and young-of-the year rockfish, more prevalent offshore. With protection of breeding sites and a shift towards ecosystem-based fisheries management by the 1990s, variations of the central California Brandt's Cormorant population are now driven naturally by forage fish availability, and perhaps inter- and intraspecific competition for prey and space when population sizes are high. This species, owing to its "boom-or-bust" natural history and the relative ease of assessing breeding population size and diet, may be ideal for monitoring the state of the central California Current food web.

From August through December 2015, beachcast bird survey programs reported increased deposition of Common Murres ( Uria aalge) on central and northern California beaches, but not on southern California beaches. Coastal wildlife rehabilitation centers received more than 1,000 live, stranded, and debilitated murres from Sonoma County to San Luis Obispo County during August-October. Approximately two-thirds of admitted birds were after-hatch-year birds in emaciated body condition and in various stages of molt, with extremely worn plumage. Necropsies were done on a sample ( n=35) of birds to determine the probable cause of death of beachcast carcasses. Most birds examined during necropsy were emaciated, with starvation the most likely cause of death. Birds were also tested for underlying infectious diseases at the US Geological Survey National Wildlife Health Center and harmful algal bloom toxins at the University of California at Santa Cruz and the National Oceanographic and Atmospheric Administration's Northwest Fisheries Science Center. Twenty-four out of 29 tested birds had detectable levels of domoic acid, and no indication of infectious disease was found. Emaciation is thought to be the cause of death for these birds, with a large warm water anomaly and harmful algal bloom playing a secondary detrimental role.

The Farallon Islands in the Gulf of the Farallones National Marine Sanctuary (GFNMS) is a 7-island chain located 48 km west of San Francisco, California. Since 1993, GFNMS biologists and associates have monitored algal and invertebrate species abundances on the intertidal shores of the 2 South Farallon Islands. The monitoring occurred 1–3 times yearly in 6 study areas. In each study area, 3–4 permanent, 0.15-m2 quadrats located between the upper and midintertidal zones were sampled for algal and sessile invertebrate cover and invertebrate counts. Taxonomic surveys were also completed to document other species in the vicinity of the sampling quadrats and to further characterize the sampling areas. Here we report monitoring results for the period 1993 to 2011. While species richness has remained relatively stable and high compared to the nearest mainland sites (Sonoma County through San Mateo County), there has been a slow, long-term net decline in the abundance of algal species and mussels at various sites on the islands. Causes for the declines remain unknown, but increased trampling from rising numbers of pinnipeds and increased waste from pinnipeds and seabirds are among the influences suspected to be important.

The impacts of climate change have been observed both globally and on regional scales, such as in the North-central California coast and ocean, a region that extends from Point Arena to Point Ano Nuevo and includes the Pacific coastline of the San Francisco Bay Area. Because of the high economic and ecological value of the region’s marine environment, Gulf of the Farallones National Marine Sanctuary (GFNMS) and other agencies and organizations have recognized the need to evaluate and plan for climate change impacts. Climate change indicators provide information about the presence and potential impacts of climate change. While climate change indicators exist for the nation and for the state of California as a whole, no system of ocean climate indicators exist that specifically consider the unique characteristics of the North-central California coast and ocean region. To that end, GFNMS collaborated with over 50 federal, state, and regional natural resource managers, research scientists, and other partners to develop a set of eight physical and four biological ocean climate indicators specific to this region. A smaller working group of regional experts developed overarching indicator monitoring recommendations, and specific metrics and monitoring goals, objectives, strategies, and activities for each of the twelve ocean climate indicators. Broadly speaking, these strategies are centered on maintaining existing indicator monitoring, and expanding or establishing new monitoring in critical habitats. To maximize the utility of these indicators for decision-makers, priority levels, current and potential future partners, funding requirements, and implementation timelines are provided for each indicator monitoring strategy.

Entanglement records for seabirds and marine mammals were investigated for the period 2001–2005. The entanglement records were extracted from databases maintained by seven organizations operating along the west coast of the United States of America. Their programmes included beach monitoring surveys, rescue and rehabilitation and regional pinniped censuses. Records of 454 entanglements were documented in live animals and in carcasses for 31 bird species and nine marine mammal species. The most frequently entangled species were Common Murres, Western Gulls and California sea lions. The entanglement materials identified were primarily fishing related. Entanglements were recorded every year suggesting that although the incidence level differs annually, entanglement is a persistent problem. It is recommended that each programme records details in standardized categories to determine entanglement material sources. Numbers of entanglements observed during these surveys are likely to be a conservative view of the actual entanglement rate taking place at sea.

Systematic shoreline surveys for beached birds have been conducted since the middle of the twentieth century (Bull & Boeson 1961, Veitch 1976, Page et al. 1982, Stenzel et al. 1988, Powelsland & Imber 1988, Carter & Page 1989, Bayer et al. 1991, Heubeck 1995, Benson et al. 1999, Camphuysen & Heubeck 2001). In 1993, the Gulf of the Farallones National Marine Sanctuary (GFNMS) began Beach Watch, a long-term shoreline monitoring program, in north-central California. The program records baseline data on beachcast and live marine organisms, assists sanctuary management in the early detection of natural and human-caused environmental perturbations such as epizootic outbreaks, El Nino-Southern Oscillation (ENSO) events and oil spills, and provides a network of skilled shoreline surveyors to respond during oil spills. Since 1996, the Beach Watch program has also counted tarballs (small patties of oil) found on survey beaches, as a secondary indicator of chronic oil pollution.

Marine Mammal ScienceVolume 17, Issue 2 p. 397-402 HISTORICAL AND RECENT COLONIZATION OF THE SOUTH FARALLON ISLANDS, CALIFORNIA, BY NORTHERN FUR SEALS (CALLORHINUS URSINUS) Peter Pyle, Peter Pyle Point Reyes Bird Observatory, 4990 Shoreline Hwy., Stinson Beach, California 94970, U. S. A.; e-mail: [email protected]Search for more papers by this authorDouglas J. Long, Douglas J. Long Department of Ornithology and Mammology, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118, U. S. A.Search for more papers by this authorJacqueline Schonewald, Jacqueline Schonewald Department of Ornithology and Mammology, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118, U. S. A.Search for more papers by this authorRobert E. Jones, Robert E. Jones Museum of Vertebrate Zoology, University of California, Berkeley, California 94720, U. S. A.Search for more papers by this authorJan Roletto, Jan Roletto Gulf of the Farallones National Marine Sanctuary, Fort Mason Building 201, San Francisco, California 94123, U. S. A.Search for more papers by this author Peter Pyle, Peter Pyle Point Reyes Bird Observatory, 4990 Shoreline Hwy., Stinson Beach, California 94970, U. S. A.; e-mail: [email protected]Search for more papers by this authorDouglas J. Long, Douglas J. Long Department of Ornithology and Mammology, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118, U. S. A.Search for more papers by this authorJacqueline Schonewald, Jacqueline Schonewald Department of Ornithology and Mammology, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118, U. S. A.Search for more papers by this authorRobert E. Jones, Robert E. Jones Museum of Vertebrate Zoology, University of California, Berkeley, California 94720, U. S. A.Search for more papers by this authorJan Roletto, Jan Roletto Gulf of the Farallones National Marine Sanctuary, Fort Mason Building 201, San Francisco, California 94123, U. S. A.Search for more papers by this author First published: 26 August 2006 https://doi.org/10.1111/j.1748-7692.2001.tb01282.xCitations: 11AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Literature Cited Ainley, D. G., and T. J. Lewis. 1974. History of Farallon Island marine bird populations, 1854–1972. Condor 76: 432– 446. Bancroft, H. H. 1886. History of California, Volume II. 1801– 1824. The History Company Publishers, San Francisco , CA . Busch, B. C. 1985. The war against the seals. McGill-Queens University Press, Montreal , Kingston . Delong, R. L., P. L. Walker, D. J. Kennett and T. L. Jones. 1999. Archeological investigations on San Miguel Island, California: A view of 3,000 years of pinniped community dynamics. Abstract. 13th Biennial Conference on the Biology of Marine Mammals, Wailea, Hawaii, 28 November-3 December 1999. Desante, D. F., and D. G. Ainley. 1980. The Avifauna of the South Farallon Islands, California. Studies in Avian Biology 4: 1– 104. Hanni, K. D., D. J. Long, R. E. Jones, P. Pyle and L. E. Morgan. 1997. Sightings and strandings of Guadalupe fur seals in central and northern California. Journal of Mammology 78: 684– 690. Hildebrandt, W. R.. 1984. Archeological presence of the northern fur seal (Callorhinus ursinus) along the coast of Northern California. Murrelet 65: 28– 29. Hildebrandt, W. R., and T. L. Jones. 1992. Evolution of marine mammal hunting: A view from the California and Oregon coasts. Journal of Anthropological Archeology 11: 360– 401. King, J. E. 1983. Seals of the world. Cornell University Press, Ithaca , NY . Lyman, R. L. 1988. Zoogeography of Oregon coast marine mammals: The last 3,000 years. Marine Mammal Science 4: 247– 264. Lyon, G. M. 1937. Pinnipeds and a sea otter from the Point Mugu shell mound of California. University of California Publications in Biological Science 1: 133– 168. Melin, S. R., and R. L. Delong. 1999. Observations of a Guadalupe Fur seal (Arctocephalus townsendi) female and pup at San Miguel Island, California. Marine Mammal Science 15: 885– 888. Orr, R. T., and R. C. Helm. 1989. Marine mammals of California. California Natural History Guides 29: 1– 93. University of California Press, Berkeley , CA . Peterson R. S., and B. J. Le Boeuf. 1969. Fur seals in California. Pacific Discovery 23(3): 12– 15. Peterson, R. S., B. J. Le Boeuf and R. L. Delong. 1968. Fur seals from the Bering Sea breeding in California. Nature 219: 899– 901. Repenning, C. A., R. S. Peterson and C. L. Hubbs. 1971. Contributions to the systematics of the southern fur seals, with particular reference to the Juan Fernandez and Guadalupe species. Pages 1– 34 in H. B. Burt, ed. Anarctic Pinni-pedia. Antarctic Research Series, v. 18. Riddell, F. A. 1955. Archeaological excavations on the Farallon Islands, California. Reports of the University of California Archaeological Survey 32: 1– 18. Scheffer, V. B. 1958. Seals, sea lions, and walruses. A review of Pinnipedia. Stanford University Press, Palo Alto , CA . Scheffer V. B., and B. S. Kraus. 1964. Dentition of the northern fur seal. Fishery Bulletin, U. S. 63: 293– 315. Starks, E. C. 1922. Records of the capture of fur seals on land in California. California Fish and Game 8: 155– 160. Sydeman, W. J., and S. G. Allen. 1999. Pinniped population dynamics in central California: Correlations with sea surface temperature and upwelling indices. Marine Mammal Science 15: 446– 461. Townsend, C. H. 1931. The fur seal of the California islands. New York Zoological Society 9: 443– 457. Walker, P. L., and S. Craig. 1979. Archeological evidence concerning the prehistoric occurrence of sea mammals at Point Bennett, San Miguel Island. California Fish and Game 65: 50– 54. Warheit, K. L., and D. R. Lindberg. 1988. Interactions between seabirds and marine mammals through time: Interference competition at breeding sites. Pages 292– 328 in J. Burger, ed. Seabirds and other marine vertebrates: Competition, pre-dation, and other interactions. Columbia University Press, New York , NY . York, A. E. 1987. Northern fur seal, Callorhinus ursinus, eastern Pacific population (Pribilof Islands, Alaska, and San Miguel Island, California). Pages 9– 22 in J. P. Croxall and R. L. Gentry, eds. Status, biology, and ecology of fur seals. NOAA Technical Report NMFS 51. Citing Literature Volume17, Issue2April 2001Pages 397-402 ReferencesRelatedInformation

Personnel at The Marine Mammal Center (The Center) treated 1,446 stranded marine mammals recovered from the central and northern California (USA) coast from 1984 through 1990, including California sea lions (Zalophus californianus), northern elephant seals (Mirounga angustirostris), Pacific harbor seals (Phoca vitulina richardsi), northern fur seals (Callorhinus ursinus), Steller sea lions (Eumetopias jubatus), and Guadalupe fur seals (Arctocephalus townsendi). The primary disease findings in stranded California sea lions were renal disease, renal disease complicated by severe verminous pneumonia, verminous pneumonia, seizures of unknown etiology, and renal disease complicated by severe pneumonia of unknown etiology. Stranded elephant seals included pups, yearlings with dermatological problems, and neonates. Most harbor seals admitted to The Center were underweight and premature pups. Stranded northern fur seals included animals with seizures of unknown etiology and emaciated pups. Stranded Steller sea lions included underweight pups and aged adult females with pneumonia. Two Guadalupe fur seals had hemorrhagic gastroenteritis. Incidental findings at the time of stranding among the six species included verminous pneumonia and pneumonia of unknown etiology, renal disease, internal parasitism, ophthalmologic problems, gastrointestinal disorders, otitis externa, and external wounds.