Search for: All records

Decadal variations of ocean soundscapes are intricately linked to large-scale climatic and economic fluctuations. This study draws on over 15 years of acoustic recordings at six sites within the Southern California Bight, investigating interannual, seasonal, and diel variations. By examining acoustic energy from fin and blue whales along with sounds from ships and wind, we identified changes in soundscape over time and space. This study reveals that sound levels associated with both biological and non-biological sound sources varied seasonally and correlated with large-scale climatic patterns and long-term oceanographic fluctuations. Baleen whale sound levels before, during, and after a marine heatwave were assessed; sound levels decreased in southern sites and increased in northern sites adjacent to the California Current, underscoring the potential for range shifts and habitat compression during warm years for these species. Ship-generated sound levels at high-traffic sites reflected economic events such as recessions, labor shortages and negotiations, and changes to port activities. Marine soundscapes offer an approach to assess the ocean's condition amid ongoing climatic and economic fluctuations. 

2022 marked the third consecutive La Niña and extended the longest consecutive stretch of negative Oceanic Niño Index since 1998-2001. While physical and biological conditions in winter and spring largely adhered to prior La Niña conditions, summer and fall were very different. Similar to past La Niña events, in winter and spring coastal upwelling was either average or above average, temperature average or below average, salinity generally above average. In summer and fall, however, upwelling and temperature were generally average or slightly below average, salinity was close to average and chlorophyllawas close to average. Again, as during prior La Niña events, biomass of northern/southern copepods was above/below average off Oregon in winter, and body size of North Pacific krill in northern California was above average in winter. By contrast, later in the year the abundance of northern krill dropped off Oregon while southern copepods increased and body sizes of North Pacific krill fell in northern California. Off Oregon and Washington abundances of market squid and Pacific pompano (indicators of warm, non-typical La Niña conditions) were high. In the 20^thcentury, Northern anchovy recruitment tended to be high during cold conditions, but despite mostly warm conditions from 2015-2021 anchovy populations boomed and remained high in 2022. Resident seabird reproductive success, which tended in the past to increase during productive La Niña conditions was highly variable throughout the system as common murre and pelagic cormorant, experienced complete reproductive failure at Yaquina Head, Oregon while Brandt’s cormorant reproduction was average. At three sampling locations off central California, however, common murre reproduction was close to or above average while both pelagic and Brandt’s cormorant were above average. California sealion reproduction has been above average each year since 2016, and pup weight was also above average in 2022, likely in response not to La Niña or El Niño but continuous high abundance of anchovy. The highly variable and often unpredictable physical and biological conditions in 2022 highlight a growing recognition of disconnects between basin-scale indices and local conditions in the CCE. “July-December 2022 is the biggest outlier from individual “strong” La Niña (events) ever going back to the 50s.” – Nate Mantua