The National Marine Mammal Laboratories' California Current Ecosystem Program (AFSC/NOAA) initiated a long-term marking program of northern fur seals (Callorhinus ursinus) at San Miguel Island, California in 1975. A sample of up to 300 pups has been tagged in the foreflippers with various types and colors of tags each year between 1975 and the present. Resighting surveys for marked animals are conducted annually at summer breeding sites. Resightings are also obtained from the public when animals are observed on beaches or in fisheries. The data are used in mark-recapture models to estimate the age and sex specific vital parameters of the population and to describe age and sex specific reproductive behavior and seasonal movements of animals throughout their lives.

The Marine Mammal Laboratories' California Current Ecosystem Program (AFSC/NOAA) in collaboration with Point Blue Conservation Science initiated long-term studies to determine pup abundance of the California Stock of northern fur seals. The California Stock is comprised of northern fur seals inhabiting San Miguel Island (and Castle Rock, and islet ~1 km northwest) and the Farallon Islands (specifically, Southeast Island) off California. Pup production is the sum of the numbers of live pups and dead pups for a given pupping season. This in turn is used as index to estimate total population abundance. Population abundance is vital to knowing the status of a particular stock or the entire species, as well as knowing what factors are driving population trends. Metadata and datasets corresponding to these studies are reported in Stock Assessment Reports (SAR) for the U.S. Congress and other stakeholders.

This dataset provides counts of harbor seals from aerial surveys over Lake Iliamna, Alaska, USA. The data have been collated from three previously published sources (Mathisen and Kline 1992; Small 2001; ABR Inc. Environmental Research and Services 2011) and newly available data from the NOAA Alaska Fisheries Science Center and the Newhalen Tribal Council. The survey years range between 1984 and 2013. Counts are reported as summed totals across all identified waypoints in the lake for each survey date. The NOAA National Marine Mammal Laboratory (NMML) (Alaska Fisheries Science Center, Seattle, Washington, USA) conducted aerial surveys of Iliamna Lake between 2008 and 2013. Surveys were conducted as part of annual harbor seal survey effort and in collaboration with local community participants and researchers at the University of Alaska. Surveys were flown using high wing, twin engine aircraft (Aero Commander 680, 690 or a de Havilland Twin Otter). Survey altitude was generally 330 m and at an aircraft speed of 120 kts. Surveys were performed seasonally for most years between 2008 and 2013. Surveys were timed so that one survey was conducted while the lake was mostly frozen (Late March/early April), one during pupping (mid July), and often several during the August molt, when the greatest number of seals typically haul out on shore. Surveys were flown, weather allowing, in the mid- to late-afternoon, when the number of seals hauled out was expected to be highest. Aircraft flight track was recorded by GPS and all seals sighted were digitally photographed using a high resolution digital SLR camera with a telephoto zoom lens (up to 400mm). Time, date, latitude, longitude, and altitude were automatically saved into the image metadata or georeferenced post survey using the GPS track and software. The total number of seals hauled out were counted from the digital photographs and recorded for each identified site. Pups were determined by their smaller size, and close proximity (less than 1 body length; either nursing or laying right next) to a larger seal. Pups were no longer recorded beyond about mid-August when many have been weaned and cannot reliably be distinguished from other non-adult seals. In 2009, a collaborative effort between NMML and researchers from the Newhalen Tribal Council (Newhalen Tribal Council 2009) provided 10 additional surveys and similar techniques were used. The raw survey count data from these surveys was provided to NMML. Aerial surveys were authorized under a Marine Mammal Protection Act General Authorization (LOC No. 14590) issued to the NMML. Between 2005 and 2007, ABR, Inc. Environmental Research and Services conducted a series of aerial surveys for harbor seals in Iliamna Lake (ABR Inc. Environmental Research and Services 2011). In addition, earlier counts from surveys conducted by ADFG (Small 2001) and a 1991 census by Mathisen and Kline (Mathisen and Kline 1992) were incorporated into the dataset to expand the historical reach. Geographic coordinates were provided (or, when not provided, determined based on descriptions or physical maps) for each survey site and these sites were compared and merged with locations identified by NMML. In some cases, sites in very close geographic proximity were combined into a single site. The iliamna_totalcounts file provides counts (n=96) and observed weather conditions for each survey date. Both total number of adult seals (adulttotal) and total number of identified pups (puptotal) are provided when available. puptotal is recorded as NA when adults and pups were not distinguished. In these cases, the adulttotal value is presumed to include pups. In addition to the seal count information, each record includes observed weather variables (airtemp (in ranges of degrees F), windspeed (in ranges of miles per hour), winddirection (cardinal), and descriptive categories for skycondition and precip). The datetime values correspond to local Alaska time.

Scientists at NOAA's Northeast Fisheries Science Center (NEFSC) are using environmental DNA (eDNA) to identify fish communities and monitor ecosystems by collecting a water sample and analyzing the DNA found in it, identifying the species that left it behind without capturing a single animal. As animals swim, they shed scales, tissue, and waste, leaving traces of DNA in the water. A water sample is first collected from the ocean and filtered to concentrate DNA in it. NOAA scientists then make millions of copies of a target DNA region through polymerase chain reaction (PCR) to make enough genetic material for high throughput sequencing. The metabarcoding process described above for eDNA analysis allows scientists to look for many species in the same sample. The final step is like a matching game, in which the DNA sequences are compared with a reference library of known species to find a match. The eDNA method is particularly useful for detecting species that are not easily captured, including rare or migratory species. It can also help in areas that are difficult to sample because of challenging ocean conditions, sensitive habitats, or a rugged seafloor. An eDNA analysis provides a snapshot of the community of species at the time of sampling and over time. This can help us detect shifts in marine ecosystems. eDNA samples have been collected on NOAA Ecosystem Monitoring (EcoMon) surveys since 2019. These samples will help develop best eDNA practices using metabarcoding, an innovative way to determine what fish species live in what parts of the ocean without actually seeing any fish.