Estimates of daily activity and consequent demand for food during winter are scarce for many polar seabirds, yet essential for assessing constraints on foraging effort, demand for food, and potential competition with local fisheries. We affixed archival temperature tags to gentoo penguins (Pygoscelis papua) from two colonies in the South Shetland Islands to measure the frequency, timing, and duration of foraging trips and to estimate minimum food requirements during winter. Foraging trip frequencies ranged from 0.85 to 1.0 trips day-1 and were positively correlated with day length. Early winter foraging trips more closely matched day length than late winter foraging trips. The data suggest that individuals maximize foraging time during the early winter period, likely to recover body mass following the breeding season and molt. The more attenuated response of foraging trip durations to increasing day length in late winter may be related to differences in local resource availability or individual behaviors prior to the upcoming breeding season. Minimum food requirements also exhibited a seasonal cycle with a mid-winter minimum. On average, minimum food requirements were estimated at 0.70 ± 0.12 kg day-1. Extrapolated to the regional population of gentoo penguins, winter food requirements by gentoo penguins were equivalent to roughly 33% of annual krill catches by commercial fisheries in the South Shetland Island region over the past decade. Current expansion of the gentoo population and the krill fishery in the southern Scotia Sea warrants continued monitoring of gentoo penguins during winter.
Fish larvae counts and standardized counts for eggs captured in CalCOFI icthyoplankton nets (primarily vertical [Calvet or Pairovet], oblique [bongo or ring nets], and surface tows [Manta nets]) . Surface tows are normally standardized to count per 1,000 m3 strained. Oblique tows are normally standardized to count per 10 m2 of surface sampled. This table includes only tows where one or more larvae were captured for the species selected by the user, i.e., no "zero" tows. The "Larvae Counts" table includes all tows by species, i.e., both positive and negative tows.
In 1997, the Southwest Fisheries Science Center (SWFSC) conducted a survey designed to estimate the abundance of vaquita, the Gulf of California harbor porpoise (Phocoena sinus). This was a joint project between the fisheries agencies of the United States and Mexico.
An archive of multi-frequency and multi-beam echosounder data (Simrad .raw format), collected as part of SWFSC-FRD surveys of the U.S. west coast between San Diego, CA and Vancouver Island, BC. The archive contains echo power and inerferometric-phase-angle data that describe acoustic backscatter from marine organisms ranging in size from zooplankton to fish.
SWFSC FED Mid Water Trawl Juvenile Rockfish Survey: Station Information and Surface Data.
Surveys have been conducted along the central California coast in May/June
every year since 1983. In 2004 the survey area was expanded to cover the
entire coast from San Diego to Cape Mendocino. The survey samples a series
of fixed trawl stations using a midwater trawl. The midwater trawl survey
gear captures significant numbers of approximately 10 rockfish species during
their pelagic juvenile stage (i.e., 50-150 days old), by which time annual
reproductive success has been established. Catch-per-unit-effort data from
the survey are analyzed and serve as the basis for predicting future
recruitment to rockfish fisheries. Results for several species (e.g.,
bocaccio, chilipepper [S. goodei], and widow rockfish [S. entomelas]) have
shown that the survey data can be useful in predicting year-class strength
in age-based stock assessments.
At-sea distribution and density of marine mammals and seabirds. Seabird and marine mammal observations were collected from research vessels during transits between stations, to and from port of calls, etc.
Individual specimens measured (weight in grams and length in mm) and sexed from mainly targeted species caught during SWFSC-FRD fishery independent trawl surveys of coastal pelagic species. Individuals are categorized as random or non-random samples. Does not include species with length bins recorded in the CPS Trawl Life History Length Frequency dataset.
Weight in kilograms for all species (identified to lowest taxonomic criteria) caught during SWFSC-FRD fishery independent surveys (including DEPM, ATM, SaKe) of coastal pelagic species using mid-water trawls (with most tows performed near the surface) at position and times listed. Additional information for a subset of individuals from some species can be found in either CPS Trawl Life History Length Frequency or the CPS Trawl Life History Specimen datasets.
An aerial monitoring program was conducted during the period 1962 - 2007 in cooperation with aerial spotters working for the commercial purse seine fleet. Flights were conducted throughout the year to estimate abundance of pelagic fishes off California and Baja California, Mexico. Measurements were recorded for each identifiable species in 10'-longitude by 10'-latitude blocks. This data file provides each pilot's name with their assigned pilot code used in the effort and sighting files.