The overall goal of this study was to include the 2018 survey data in the previous 1991–2014 modeling dataset in order to improve SMDs for the CCE study area. Specific objectives included: Generating multi-year average density surfaces for the Navy and others to use in their long-term (2–7 year) environmental planning efforts; and Providing updated abundance and “minimum population size (Nmin)” estimates as defined in the Guidelines for Assessing Marine Mammal Stocks (National Oceanic and Atmospheric Administration 2016).

The objectives of our study were two-fold: (1) develop spatially-explicit density estimates for winter/spring to support management applications, and (2) compare model-predicted density and distribution patterns to previously developed summer/fall model results in the context of species ecology. We used a well-established Generalized Additive Modeling framework to develop cetacean SDMs based on 20 California Cooperative Oceanic Fisheries Investigations (CalCOFI) shipboard surveys conducted during winter and spring between 2005 and 2015.

In this study, winter and spring density estimates for the entire CCE study area were made from SWFSC summer and fall model predictions (temporal extrapolation) and CalCOFI winter and spring model predictions (spatial extrapolation) for short-beaked common dolphin ( Delphinus delphis delphis ), Pacific white-sided dolphin ( Lagenorhynchus obliquidens ), Dall's porpoise ( Phocoenoides dalli ), and fin whale ( Balaenoptera physalus ).

The National Oceanic and Atmospheric Administration (NOAA) Alaska Fisheries Science Center has maintained passive acoustic recorder moorings in areas of interest to the US Navy in the Gulf of Alaska (GOA). Archival data from three of these sites were analyzed for the timing and occurrence of key cetacean species. In addition, three subsurface passive acoustic moorings were deployed for a year (fall 2023 to fall 2024) in areas of mutual interest to NOAA and the Navy. Two of these new moorings, located along the western GOA slope, were redeployed in 2024.

The present study provides new and current estimates of cetacean density for the six most commonly encountered cetacean species off southern California based on sighting data collected during 37 quarterly CalCOFI cruises from 2004 to 2013. The current study resulted from a high survey repetition rate that allowed for the examination of inter-annual and seasonal trends in density as well as temporal and spatial patterns of distribution for six common cetacean species off southern California: blue whales, fin whales, humpback whales, short-beaked common dolphins, Pacific white-sided dolphins, and Dall’s porpoise.

Cetacean distribution, density and abundance in the Southern California Bight were assessed through visual and acoustic surveys during five California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises from August 2012-November 2013. Visual monitoring incorporated standard line-transect protocol during all daylight transits while acoustic monitoring employed a towed hydrophone array during transits and sonobuoys at oceanographic sampling stations. Visual effort included 584 observation hours covering 10,900 kilometers yielding 565 sightings of 15 identified cetacean species.

Spatial and temporal distribution patterns, density and abundance of cetaceans in the southern California Bight were assessed through visual and acoustic surveys during five California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises from August 2011 – July 2012. Visual monitoring incorporated standard line-transect protocol during all daylight transits while acoustic monitoring employed a towed hydrophone array during transits and sonobuoys at oceanographic sampling stations.

Trends in cetacean density and distribution off southern California were assessed through visual line-transect surveys during thirty-seven California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises from July 2004–November 2013. From sightings of the six most commonly encountered cetacean species, seasonal, annual and overall density estimates were calculated. Blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) were the most frequently sighted baleen whales with overall densities of 0.91/1000km2 (CV=0.27), 2.73/1000km2 (CV=0.19), and 1.17/1000km2 (CV=0.21) respectively. Species specific density estimates, stratified by cruise, were analyzed using a generalized additive model to estimate long-term trends and correct for seasonal imbalances. Variances were estimated using a non-parametric bootstrap with one day of effort as the sampling unit. Blue whales were primarily observed during summer and fall while fin and humpback whales were observed year-round with peaks in density during summer and spring respectively. Short-beaked common dolphins (Delphinus delphis), Pacific white-sided dolphins (Lagenorhynchus obliquidens) and Dall’s porpoise (Phocoenoidesdalli) were the most frequently encountered small cetaceans with overall densities of 705.83/1000km2 (CV=0.22), 51.98/1000km2 (CV=0.27), and 21.37/1000km2 (CV=0.19) respectively. Seasonally, short-beaked common dolphins were most abundant in winter whereas Pacific white-sided dolphins and Dall’s porpoise were most abundant during spring. There were no significant long-term changes in blue whale, fin whale, humpback whale, short-beaked common dolphin or Dall’s porpoise densities while Pacific white-sided dolphins exhibited a significant decrease in density across the ten-year study. The results from this study were fundamentally consistent with earlier studies, but provide greater temporal and seasonal resolution. Keywords: Cetaceans; Line transect; Density; Abundance; Distribution; Trends; Southern California; CalCOFI

This survey implemented visual line transect and passive acoustic methods to assess the presence and distribution and to estimate density and abundance of cetaceans in Behm Canal and central Clarence Strait.

The Pacific Marine Assessment Program for Protected Species (PacMAPPS) survey occurred from 1 August to 26 August 2021, beginning and ending in Kodiak, AK. Over the course of the survey, a total of 2,330 km of on-effort tracklines were surveyed in suitable weather conditions, and a total of 687 sightings of marine mammals were documented (including duplicates and resights).

Cetacean distribution, density and abundance in the Southern California Bight were assessed through visual and acoustic surveys during eighteen California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises from February 2012-April 2016. Visual monitoring incorporated standard line-transect protocol during all daylight transits while acoustic monitoring employed a towed hydrophone array during transits and sonobuoys deployed at oceanographic sampling stations. Visual effort included 2,031 observation hours covering 31,807 kilometers. A total of 1,914 sightings were made, which included 18 different cetacean species. Acoustic effort included 1m027 sonobuoy deployments and 478 towed array deployments.

This document contains amplifying technical data and information for the United States Department of the Navy’s Southern California Range Complex Comprehensive Monitoring Report.

Navy Research Funded Year Three Project Reports

Documenting year-round diversity and distribution of marine mammals off Southern California is important for assessment of effects of potentially harmful anthropogenic activities. Although the waters off Southern California have been surveyed extensively for marine mammals over the past 18 years, such surveys have been periodic and were conducted primarily from summer to fall, thereby missing potential seasonal shifts. We examined seasonal abundance and population density of cetaceans off Southern California from 16 shipboard line-transect surveys conducted quarterly during 2004–08. The study area consisted of 238,494 km² of coastal, shelf, and pelagic oceanic habitat from near-shore waters to 700 km offshore.

Marine mammal surveys, initiated as part of the CalCOFI cruises in 2004, were continued during 2016-2017. Visual monitoring incorporated standard line-transect survey protocol which includes two experienced observers scanning for marine mammals during transits between CalCOFI stations.

During FY2012, with funding provided by the Chief of Naval Operations (CNO) N45 Energy and Environmental Readiness Division, the Marine Mammal Monitoring on Navy Ranges (M3R) program carried out several acoustic monitoring efforts to determine the spatial and temporal distribution of cetacean species on the Southern California Anti-Submarine Warfare (ASW) Range (SOAR) , to document the reaction of these species to sonar with a focus on beaked whales, and to provide a means of longterm passive acoustic monitoring. Specifically, M3R participated in a number of marine mammal species visual verification and tagging tests, ONR-sponsored glider tests, the SOCAL 2011-12 Behavioral Response Study (BRS), and for the first time conducted low-frequency acoustic monitoring of baleen whales.

Passive acoustic monitoring was conducted in the Navy’s Southern California Range Complex from April 2020 to 2021 to detect marine mammal and anthropogenic sounds. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at four locations: two west of San Clemente Island (1,300 m depth, site E and 1,100 m depth, site H) and two southwest of San Clemente Island (1,300 m depth, site N and 1,200 m depth, site U). With the offshore expansion of the SOCAL range, future noise monitoring will be improved by the deployment of a recorder west of San Nicolas Island (site SN). This new site will replace site U, which is located in the Mexican Exclusive Economic Zone where instrument deployment is difficult.

To effectively protect and manage marine mammals, contemporary information on their abundance and distribution is essential. Several factors influence presentday insight including the accessibility of the study area and the degree of difficulty in locating and studying target species.

During this project, the visual survey covered a total of 760 kilometers (410 nautical miles) on-effort while transit and fog effort legs accounted for 553 km (298 nm). There were a total of 96 sightings (453 individuals) of 11 confirmed marine mammal species; these included fin, humpback, gray, and minke whales as well as killer whales, Dall’s and harbor porpoise, Pacific white-sided dolphins and Steller sea lions, harbor seals and sea otters. Additionally, there were 36 sightings (46 individuals) of unidentified large whales, dolphins and pinnipeds. Acoustically, operations were conducted 24-hours/day surveying a total of 3,519 km (1,900 nm) and recording 49 acoustic detections of sperm whales and killer whales. Photographs of nineteen individual killer whales and four fin whales were obtained on this cruise and compared to existing catalogs.

During this survey, the visual team surveyed 4,504 kilometers (km) of ‘full-effort,’ which included 349 km of ‘transit-effort.’ There was an additional 375 km of ‘fog-effort’ (transect and transit). Based on total effort, there were 802 sightings (1,998 individuals) of 13 confirmed marine mammal species, with an additional 162 sightings (228 individuals) of unidentified cetaceans and pinnipeds (including those recorded on transit and during off-effort mode).

To effectively protect and manage marine mammals, contemporary information on their abundance and distribution is essential. Several factors influence present-day insight including the accessibility of the study area and the degree of difficulty in locating and studying target species. The offshore waters of the Gulf of Alaska are important habitat to a variety of cetaceans yet have remained largely unsurveyed due to its remote location, vast geographic area, and challenging environmental conditions. Between 2009 and 2015, three vessel surveys were conducted using line-transect sampling methods to estimate cetacean abundance and density. Here, we present results on the distribution for all species encountered and density and abundance for six species, including humpback whales (Megaptera novaeangliae), fin whales (Balaenoptera physalus), sperm whales (Physeter macrocephalus), blue whales (B. musculus), killer whales (Orcinus orca), and Dall’s porpoise (Phocoenoides dalli). Fin whales, humpback whales, and Dall’s porpoise were the most abundant species. Beaked whales were documented only in 2015. Prior to this study, recent sightings of blue whales were rare, likely related to the lack of offshore survey coverage. No North Pacific right whales (Eubalaena japonica) were sighted, underscoring the critically endangered status of this species in a formerly populous habitat. Although these results provide the first estimates from offshore waters, additional effort is necessary to assess trends and to obtain baseline data for the rare and cryptic species in order to better inform conservation and management actions.

This document represents a brief annual summary on work completed between January 1st, 2024 to December 15th, 2024, under award N66604-22-D-F200, which is part of a broad project to monitor the populations of goose-beaked whales (Ziphius cavirostris) and fin whales (Balaenoptera physalus) in the Southern California Testing and Training Range (SCTTR).

The Southern California (SOCAL) portion of the Hawaii-Southern California Training and Testing (HSTT) area (SOCAL TR) is one of the United States Navy’s most active training areas, particularly for mid-frequency active sonar (MFAS). Much of SOCAL lies within the Southern California Bight, a productive oceanographic region that hosts a wide variety of marine species. As part of an ongoing study of the distribution and demographics of several marine mammal species within SOCAL, we conducted 32 days of survey effort from 6 January 2022 to 26 November 2022, specifically focusing on the Southern California Anti-submarine Warfare Range (SOAR).

Here we present analyses of the DASBR deployments from the CCES 2018 project. We provide information on the times and locations of drift deployments and retrievals. Each drift is also illustrated on maps of the study area. We present analyses of cetacean echolocation detections 2 from DASBR recordings including those from beaked whales, sperm whales, and NBHF species. As in the previous 2016 study, beaked whale detections were dominated by Cuvier’s beaked whale. All the beaked whale species detected in 2016 were also detected in this 2018 study, plus the addition of a signal, designated BWC that had been previously detected in the central and western Pacific, but not previously in the eastern Pacific. Sperm whales and NBHF species were detected throughout the study area.

From 2013 to 2016, we conducted systematic line-transect aerial surveys in 8 sub-regions of Puget Sound encompassing inland waters of Washington State. U.S.-funded surveys were conducted year-round and focused on estimating seasonal in-water density and abundance of marine mammals, particularly harbor porpoises and harbor seals

From 2013 to 2015, researchers conducted systematic line-transect aerial surveys for marine mammals in eight subregions of Puget Sound encompassing inland waters of Washington State. Effort consisted of five separate survey periods spanning four seasons (winter, spring, summer and fall) and was funded by the United States Navy (Navy). Surveys focused on estimating seasonal in-water density and abundance of cetaceans, particularly harbor porpoise (Phocoena phocoena).

This report summarizes three aerial surveys conducted between 31 August 2011 and 31 July 2012 on the Navy’s Southern California Range Complex (SOCAL), and includes results from the first year of deploying sonobuoys from the aircraft to simultaneously monitor both acoustic and visually observed behaviors.

The Alaska Fisheries Science Center (AFSC), NOAA Fisheries, with support from the U.S. Navy, conducted line transect surveys in Behm Canal and adjacent areas in the spring of 2023 and fall of 2024 to obtain estimates of density and abundance of cetaceans and information on marine mammal distribution and occurrence.