Search results

Title: Aquatic mating strategies of the male pacific harbor seal (Phoca vitulina richardii),
Description: Compared to the harem and resource defense systems of terrestrial mating pinnipeds, males of aquatic mating species appear unable to monopolize females or resources. We investigated movements, acoustics, and aquatic territorial behavior of male harbor seals, Phoca vitulina richardii, in Elkhorn Slough, California, using VHF telemetry, hydrophones, and acoustic playback experiments. During the mating season 22 males increased time spent in the water and away from haul-out locations, exhibiting activity patterns similar to Atlantic subspecies. Two acoustic display patterns were observed. At one location multiple males aggregated to display with acoustic activity peaking one month before peak estrus. At two other locations, lone males displayed primarily during peak estrus. Acoustic display areas were non-adjacent with a mean ± SE size of 4,228 ± 576 m2, similar to harbor seal display patterns in the Moray Firth, Scotland. Underwater playbacks of male vocalizations were used to define territorial boundaries by inducing responses from territory-holding males. Four solitary males defended adjacent territories (mean area 39,571 ± 18,818 m2) along a travel corridor, similar to observations of harbor seals at Miquelon, Newfoundland. Acoustic display stations appeared to be subcomponents of larger territories. Males exhibited site fidelity to territories for at least 2-A yr. Females moved through territories freely. The establishment of male-display territories along female-traffic corridors resembles terrestrial systems described as hotspot leks., Cited By (since 1996):15, Marine Mammals, Birds & Turtles, CODEN: MMSCE, ,
Author: Hayes, Costa, Harvey, Le Boeuf
Date: 2004-01-01T00:00:00Z

Title: A new attachement device for radio-tagging large whales,
Description: , , ,
Author: Mate, Harvey, Hobbs, Maiefeski
Date: 1983-01-01T00:00:00Z

Title: The acoustic identification and enumeration of scyphozoan jellyfish, prey for leatherback sea turtles (Dermochelys coriacea), off central California
Description: Acoustic-sampling techniques were developed to estimate the abundance and distribution of scyphozoan jellyfish, prey for leatherback turtles foraging off central California. Acoustic data were analysed from regions where jellyfish were present or absent from corresponding net tows. Empirical data on bell-diameter distribution (mean 26.2 cm; s.d. 10.6) were used to estimate target strength (TS; dB re 1 m 2) at 18, 38, 70, 120, and 200 kHz using a distorted-wave Born approximation scattering model. TS measurements of in situ animals at 38 and 200 kHz averaged -63.9 and -70.5 dB, compared with the model estimates of -54.9 and -64.0 dB, respectively. The model estimates of TS at 18, 70, and 120 kHz were -53.9, -59.9, and -61.8 dB, respectively. Using these TS estimates, an algorithm was developed to extract jellyfish echoes from total acoustic backscatter. Echo-integration methods applied to regions where net catches contained jellyfish resulted in an estimate of mean numerical abundance of 3217 jellyfish (s.d. 2276) with a mean density of 251 522 jellyfish nautical mile -2 (s.d. 57 504) and a mean concentration of 0.003 jellyfish m -3 (s.d. 0.002). The novel methods developed will help characterize prey resources for leatherback turtles off central California. © United States Government, National Oceanographic and Atmospheric Administration 2010., Cited By (since 1996):5, Invertebrates, Marine Mammals, Birds & Turtles, CODEN: ICESE
Author: Graham, Harvey, Benson, Renfree, Demer

$Nitrogen isotope fractionation in amino acids from harbor seals: Implications for compound-specific trophic position calculations$

Title: Nitrogen isotope fractionation in amino acids from harbor seals: Implications for compound-specific trophic position calculations
Description: Compound-specific isotope analysis of individual amino acids (AA) is a rapidly growing tool in ecological studies to assess diet and trophic position (TP) in both modern and ancient foodwebs. We conducted the first controlled feeding study examining δ15N values in AAs in a marine mammal (harbor seal Phoca vitulina). The pattern of δ15N variation among AAs in seals was similar to that observed in other heterotrophs, although exceptions were found with proline and threonine. However, many δ15N changes with trophic transfer were very different than those reported for zooplankton and other lower TP marine consumers. In particular the measured trophic enrichment factor (TEF) now broadly used for TP estimation (TEFGlu-Phe) was much lower in harbor seals (̃4.3%) than the current commonly applied value (̃7.5%). Recently published data on wild marine birds (penguins) and elasmobranchs (stingrays) suggests that similar, low TEF values may also be characteristic of these taxa. Together, these data imply that marine mammals and other higher animals have different, but also diagnostic, changes in δ15N-AA with trophic transfer vs. organisms examined in previous feeding studies (e.g. zooplankton, bony fish and mollusks), possibly due to dietary protein content, trophic position, and/or form of nitrogen excretion (urea vs. ammonia). Therefore, we propose that for marine mammals, a multi-TEF calculation is required to account for variations of TEF between animals within a food web, and we demonstrate that this approach can predict accurate TP estimates for harbor seals. These results also have significant implication for the application of compound-specific isotope analysis of AAs on terrestrial ecology and trophic structure. © Inter-Research 2013.
Author: Germain, Koch, Harvey, McCarthy
Date: 2013-01-01T00:00:00Z

Title: Genetic substructure of the pacific harbor seal (Phoca vitulina richardsi) off Washington, Oregon, and California
Description: Genetic substructure among groups of Pacific harbor seals, Phoca vitulina richardsi, along the western coast of the United States was investigated using mitochondrial DNA sequences. Blood and tissue samples were removed from 86 seals inhabiting Puget Sound and the Pacific coasts of Washington, Oregon, and California. A 320 base-pair segment of the control region was amplified using the polymerase chain reaction and directly sequenced. These data indicated a high level of diversity. Thirty variable sites were found that define 47 mitochondrial haplotypes. Among groups of P. v. richardsi sampled, 5 haplotypes were shared, but most (42) were unique to a locality. Haplotypic frequency and an Analysis of Molecular Variance (AMOVA) revealed significant differences (P = 0.001) among regions. Phylogenetic analysis indicated Puget Sound seals possess unique divergent lineages not found in seals from the coasts of Washington, Oregon, and California. These lineages may represent haplotypes from north of Washington, which is consistent with late reproductive timing of harbor seals from Puget Sound., Cited By (since 1996):19, CODEN: MMSCE, Marine Mammals, Birds & Turtles Harbor Seals
Author: Lamont, Vida, Harvey, Jeffries, Brown, Huber, Delong, Thomas
Date: 1996-01-01T00:00:00Z

Title: Determining a correction factor for aerial surveys of harbor seals in California
Description: Counts of pinnipeds provide a minimal estimate of population size because some unknown proportion of individuals is in the water during surveys. We determined a correction factor (CF) for Pacific harbor seals (Phoca vitulina richardii) by estimating the proportion ashore of 180 seals tagged with flipper-mounted radio tags throughout California. The mean proportions of tagged individuals ashore during four complete surveys in 2004 were not different between central and northern California (F= 1.85, P= 0.18) or between sexes (F= 0.57, P= 0.45), but a lesser proportion of weaners was ashore than subadults or adults (F= 7.97, P= 0.001), especially in northern California. The CF calculated for the statewide census of harbor seals was 1.65, using transmitters operating during the survey (n= 114). Using a mark-recapture estimator for tag survival (phi) and the four telemetry surveys the mean CF for central and northern California was 1.54 ± 0.38 (95% CI). A CF for southern California of 2.86 was based on a single survey. Using the mean CF of 1.54 and a statewide count in 2009 we estimated 30,196 (95% CI = 22,745-37,647) harbor seals in California., Cited By (since 1996):3, CODEN: MMSCE
Author: Harvey, Goley
Date: 2011-01-01T00:00:00Z

Title: Selenium and mercury concentrations in harbor seals (Phoca vitulina) from central California: Health implications in an urbanized estuary
Description: We measured total selenium and total mercury concentrations ([TSe] and [THg]) in hair (n = 138) and blood (n = 73) of harbor seals (Phoca vitulina) from California to assess variation by geography and sex, and inferred feeding relationships based on carbon, nitrogen, and sulfur stable isotopes. Harbor seals from Hg-contaminated sites had significantly greater [THg], and lesser [TSe] and TSe:THg molar ratios than seals from a relatively uncontaminated site. Males had significantly greater [THg] than females at all locations. Sulfur stable isotope values explained approximately 25% of the variability in [THg], indicating increased Hg exposure for seals with a greater use of estuarine prey species. Decreased [TSe] in harbor seals from Hg-contaminated regions may indicate a relative Se deficiency to mitigate the toxic effects of Hg. Further investigation into the Se status and the potential negative impact of Hg on harbor seals from Hg-contaminated sites is warranted. © 2014 Elsevier Ltd., Harbor Seals
Author: McHuron, Harvey, Castellini, Stricker, O'Hara

Title: Chronic oiling of marine birds in California by natural petroleum seeps, shipwrecks, and other sources
Description: We assessed temporal and spatial patterns of chronic oiling of seabirds in California during 2005-2010, using data on: (1) live oiled birds reported to the Oiled Wildlife Care Network (OWCN) from throughout the state, and (2) dead oiled birds found during systematic monthly beached-bird surveys in central California. A mean of 245 (±141 SD) live miscellaneous oiled birds (not associated with known oil spills) were reported to the OWCN per year, and 0.1 oiled dead birds km-1 per month were found on beach surveys in central California. Chemical fingerprinting of oiled feathers from a subset of these birds (n = 101) indicated that 89% of samples tested were likely from natural petroleum seeps off southern and central California. There was a pronounced peak during late winter in the number of oiled birds reported in southern California, which we theorize may be related to large storm waves disturbing underwater seeps. © 2013., Marine Mammals, Birds & Turtles, Article in Press
Author: Henkel, Nevins, Martin, Sugarman, Harvey, Ziccardi
Date: 2014-01-01T00:00:00Z

Title: Diving behavior of the Pacific harbor seal (Phoca vitulina richardii) in Monterey Bay, California
Description: Physical environment and physiological characteristics of marine mammals potentially affect the duration and depth of diving. Härkönen (1987b) proposed a hypothesis that the harbor seal would gain maximum energy by foraging at intermediate depths. To investigate this hypothesis, we studied diving behavior of the Pacific harbor seal (Phoca vitulina richardii) during 1995 through 1997 in Monterey Bay, California. Dive depths (n = 13,063 dives) were recorded via time-depth recorders. Approximately 80% of recorded dives were classified as square dives (type I), which typically were associated with foraging in pinnipeds. Approximately 11% of dives were V dives (type II; 1,402 dives), and the remainder (1,225 dives) were skewed dives (type III and IV). The deepest recorded dive was 481 m, while the greatest duration was 35.25 min. Body mass explained the variability of durations of long dives for females (95th percentile; D95,♀ = -5.47 + 0.18 × (mass ♀), r2 = 0.91, 95% CI for slope = [0.08, 0.28], n = 5) and for males (D95,♂ = -5.86 + 0.18 × (mass ♂), r2 = 0.83, 95% CI for slope = [0.12, 0.24], n = 11). The large proportion of variability in deep dives, however, was explained by body mass only for males (95th percentile; Z95,♂ = -363.9 + 6.05 × (mass♂), r2 = 0.83, 95% CI for slope = [3.93, 8.17], n = 11) and not for females (Z95,♀ = -148.1 + 3.11 × (mass♀), r2 = 0.58, 95% CI for slope = [-1.7, 7.9], n = 5, 95% CI for slope = [-1.7, 7.9]). Median depths of presumed foraging dives of harbor seals in the Monterey Bay area were between 5 and 100 m, which were within the range of the previously reported depths for other areas (<100 m). Our findings generally supported Härkönen's hypothesis that harbor seals forage in the intermediate depth in their environment. © 2005 by the Society for Marine Mammalogy., Cited By (since 1996):5, Marine Mammals, Birds & Turtles Harbor Seals, CODEN: MMSCE
Author: Eguchi, Harvey
Date: 2005-01-01T00:00:00Z

Title: Quantifying errors associated with using fecal samples to determine the diet of the California sea lion (Zalophus californianus),
Description: Cited By (since 1996):33, Export Date: 2 June 2014, We examined the digestion and passage times of bones and other hard parts from pollock, herring, salmon, and sandlance recovered from two juvenile captive Steller's sea lions (Eumetopias jubatus) subjected to varying activity levels. Key bones that could be identified to species were distributed over an average of 3.2 scats (range 1–6) following a single meal, with pollock remains occurring in significantly more scats than other species. Relying on otoliths alone to determine the presence of prey resulted in significantly fewer prey being identified than if other structures were also used (such as vertebrae, jaw bones, and teeth), particularly for salmon. Using either technique, there were significant differences in the likelihood that bones would be recovered from the series of scats produced following a meal, with pollock recovery exceeding herring (by three-fold) and sandlance (by eight-fold). Differences between species were reduced when recovery was calculated on a per scat basis rather than over multiple scats. Active animals passed greater numbers of bones, but the overall effect on prey recovery estimates was not significant. Defecation times of prey structures from a meal were variable and ranged from an initial 2–56 h to a final 28–148 h. The time interval to pass 95% of recovered structutes varied by a factor of two among prey species, and was highest for pollock due to retention beyond 65 h., ,
Author: Orr, Harvey
Date: 2001-01-01T00:00:00Z

Title: Foraging behavior of humpback whales: Kinematic and respiratory patterns suggest a high cost for a lunge,
Description: Lunge feeding in rorqual whales is a drag-based feeding mechanism that is thought to entail a high energetic cost and consequently limit the maximum dive time of these extraordinarily large predators. Although the kinematics of lunge feeding in fin whales supports this hypothesis, it is unclear whether respiratory compensation occurs as a consequence of lunge-feeding activity. We used high-resolution digital tags on foraging humpback whales (Megaptera novaengliae) to determine the number of lunges executed per dive as well as respiratory frequency between dives. Data from two whales are reported, which together performed 58 foraging dives and 451 lunges. During one study, we tracked one tagged whale for approximately 2h and examined the spatial distribution of prey using a digital echosounder. These data were integrated with the dive profile to reveal that lunges are directed toward the upper boundary of dense krill aggregations. Foraging dives were characterized by a gliding descent, up to 15 lunges at depth, and an ascent powered by steady swimming. Longer dives were required to perform more lunges at depth and these extended apneas were followed by an increase in the number of breaths taken after a dive. Maximum dive durations during foraging were approximately half of those previously reported for singing (i.e. non-feeding) humpback whales. At the highest lunge frequencies (10 to 15 lunges per dive), respiratory rate was at least threefold higher than that of singing humpback whales that underwent a similar degree of apnea. These data suggest that the high energetic cost associated with lunge feeding in blue and fin whales also occurs in intermediate sized rorquals., Cited By (since 1996):31, CODEN: JEBIA, ,
Author: Goldbogen, Calambokidis, Croll, Harvey, Newton, Oleson, Schorr, Shadwick
Date: 2008-01-01T00:00:00Z

Title: Diet of a piscivorous seabird reveals spatiotemporal variation in abundance of forage fishes in the Monterey Bay region
Description: Brandt's Cormorant (Phalacrocorax penicillatus) diet was investigated using regurgitated pellets (n = 285) collected on 19 sampling days at three locations during the 2006-07 and 2007-08 nonbreeding seasons in the Monterey Bay region. The efficacy of using nested sieves and the all-structure technique to facilitate prey detection in the pellets was evaluated, but this method did not increase prey enumeration and greatly decreased efficiency. Although 29 prey species were consumed, northern anchovy (Engraulis mordax) dominated and speckled sanddab (Citharichthys stigmaeus) also was important in the diet. Few rockfishes (Sebastes spp.) and market squid (Doryteuthis opalescens) were consumed compared with great prevalence in previous studies during the 1970s. El Niño and La Niña during the study provided a unique opportunity to examine predator response to variation in prey availability. Patterns of prey number and diversity were not consistent among locations. Greatest number and diversity of prey occurred at locations within Monterey Bay during La Niña, results not evident at the outer coast location. Short-term specialization occurred but mean prey diversity indicated a generalist feeding mode. This study demonstrated the importance of periodic sampling at multiple locations within a region to detect spatiotemporal variability in the diet of opportunistic generalists.
Author: Webb, Harvey

Title: Diet estimation in California sea lions, Zalophus californianus
Description: We performed a captive feeding experiment using California sea lions to assess biases associated with estimating pinniped diet using scats and spews. Sea lions were fed nine of their natural prey species: anchovy, sardine, Pacific mackerel, jack mackerel, hake, steelhead smolts, shortbelly rockfish, pink salmon, and market squid. Recovery percentages varied among prey species using otoliths and were improved for adult salmon and sardine using the all-structure method. Numerical and graded length correction factors provided better estimates of number and size of prey consumed. Four models used to determine the proportions of prey species consumed by a sea lion population were tested. The all-structure method and variable biomass reconstruction model, in conjunction with numerical and graded length correction factors, provided more accurate estimates than without. We provide numerical correction factors for all prey species, including correction factors for specific salmon bones: vertebrae, branchials, radials, teeth, gill rakers, and hypurals. © 2011 by the Society for Marine Mammalogy., Cited By (since 1996):2, Marine Mammals, Birds & Turtles, CODEN: MMSCE
Author: Sweeney, Harvey

Title: Seasonal occurrence of leatherback sea turtles (Dermochelys coriacea) in the Monterey Bay region, with notes on other sea turtles, 1986-1991,
Description: , , ,
Author: Starbird, Baldridge, Harvey
Date: 1993-01-01T00:00:00Z

Title: Distribution and abundance of and habitat use by harbor porpoise, Phocoena phocoena, off the northern San Juan Islands, Washington,
Description: Boat surveys along randomly placed line transects were conducted from June to August 1991 and June to October 1992 to determine distribution and abundance of and habitat use by harbor porpoise (Phocoena phocoena) off the northern San Juan Islands, Washington. There were 301 sightings (average 4.4 sightings/h) of 526 harbor porpoise during 73 random boat surveys, with group sizes of 1 to 8 individuals (mean=1.87, SE=0.06, n=278). An estimated 299 harbor porpoise (1.26 porpoise/km2, SE=0.20) were distributed in an aggregated pattern within a 237 km2 area (10% of Washington Sound), indicating that a large proportion (30%) of harbor porpoise in Washington Sound occur in the northern San Juan Islands. Harbor porpoise were distributed over a depth range from 20.1 to 235.0 m (mean= 141.6 m, SE=2.43, n=275) and were observed more than expected (P<0.05) in depths greater than 125 m and over shallow slopes (<10%) and observed less than expected (P<0.05) in depths less than 75 m. Porpoise occurred at sea surface temperatures of 10.1°to 16.3°C and were sighted more frequently than expected (P<0.05) in water temperatures of 11°to 12°C. Boat surveys along fixed location transects indicated distribution was similar between 1991 and 1992. The occurrence of harbor porpoise in deep water, at cooler sea surface temperatures, over shallow sloping seafloor, and in tidally mixed regions (owing to currents and tide rips) within our study area may, collectively, affect prey distribution and associated harbor porpoise distribution., Cited By (since 1996):12, Marine Mammals, Birds & Turtles, CODEN: FSYBA, ,
Author: Raum-Suryan, Harvey
Date: 1998-01-01T00:00:00Z

Title: Beached birds and physical forcing in the California Current System,
Description: Seabirds have often been proposed as environmental indicators. Beached bird data may provide an additional data source and such data is efficacious because it can reliably be collected by volunteers. In addition to anthropogenic factors, such as oil spills, changes in the ocean-atmosphere can affect carcass beaching rate in 3 non-exclusive ways: (1) direct mortality following storms, (2) mortality via bottom-up food web processes, and (3) increase in carcass delivery due to shifts in surface water movement. We used data from 3 volunteer-based beached bird data sets collected within the California Current System (CCS) to (1) examine the level of response to anomalous ocean conditions in 2005 and (2) explore the degree to which long-term beaching patterns could be explained by one or more of our proposed mechanisms. In 2005, anomalous die-offs of Cassin's auklet Ptychorhamphus aleuticus and the rhinoceros auklet Cerorhinca monocerata occurred in the winter in Monterey. By spring, anomalous die-offs of Brandt's cormorant Phalacrocorax pencillatus and the common murre Uria aalge occurred throughout the CCS. Over the longer term, increases in beaching were associated with changes in the timing and intensity of upwelling and, secondarily, with zonal winds aloft - a potential proxy of shifts in pelagic community composition. These results suggest that a bottom-up food web mechanism best explains seabird beaching, at least in the spring. Correlations of local measures of storminess to seabird beaching rates were weak to non-existent. Correlations were much stronger at the California site (8 yr) and weaker to non-existent at the Oregon site (26 yr). Collectively, these data suggest that relationships between ocean physics and beached bird response may be site specific and/or may reflect choices live birds make vis-à-vis non-breeding distribution. © Inter-Research 2007., Cited By (since 1996):9, Marine Mammals, Birds & Turtles, CODEN: MESED, ,
Author: Parrish, Bond, Nevins, Mantua, Loeffel, Peterson, Harvey
Date: 2007-01-01T00:00:00Z

Title: Abundance, distribution, and habitat of leatherback turtles (Dermochelys coriacea) off California, 1990-2003
Description: Leatherback turtles (Dermochelys coriacea) are regularly seen off the U.S. West Coast, where they forage on jellyfish (Scyphomedusae) during summer and fall. Aerial line-transect surveys were conducted in neritic waters (<92 m depth) off central and northern California during 1990-2003, providing the first foraging population estimates for Pacific leatherback turtles. Males and females of about 1.1 to 2.1 m length were observed. Estimated abundance was linked to the Northern Oscillation Index and ranged from 12 (coefficient of variation [CV] = 0.75) in 1995 to 379 (CV = 0.23) in 1990, averaging 178 (CV = 0.15). Greatest densities were found off central California, where oceanographic retention areas or upwelling shadows created favorable habitat for leatherback turtle prey. Results from independent telemetry studies have linked leatherback turtles off the U.S. West Coast to one of the two largest remaining Pacific breeding populations, at Jamursba Medi, Indonesia. Nearshore waters off California thus represent an important foraging region for the critically endangered Pacific leatherback turtle., Cited By (since 1996):16, CODEN: FSYBA, Marine Mammals, Birds & Turtles
Author: Benson, Forney, Harvey, Carretta, Dutton

Title: Cephalopod remains from stomachs of sperm whales (Physeter macrocephalus) that mass-stranded along the Oregon coast
Description: On 16 June 1979, a herd of 41 sperm whales stranded near the mouth of the Siuslaw River in Florence, Oregon. The stomach contents from 32 whales were collected, identified to the lowest taxonomic level possible, enumerated, and measured. A total of 20,247 cephalopod lower beaks that represented 24 species from 14 different families were recovered. The most numerous species were Histioteuthis hoylei (25.9%), Taonius borealis (12.9%), Galiteuthis phyllura (11.2%), Gonatopsis/Berryteuthis type (10.9%), and Moroteuthis robusta (10.7%). Reconstructed estimates of mass indicated that M. robusta contributed almost 50% of the total mass of cephalopods consumed, followed by H. hoylei (19.3%), and T. borealis (7.0%). The most important species in the diet of stranded whales were M. robusta, H. hoylei, T. borealis, G. phyllura, Octopoteuthis deletron, and Gonatopsis/Berryteuthis type. There were significant differences in the diet of males and females, but no differences between sperm whales of different age groups. Overall, sperm whales primarily consumed small cephalopods that were likely eaten south of 45oN in or near the California Current System. This study provides new estimates of the food habits of sperm whales in the northeast Pacific from one of the largest strandings of this species. © 2013 Society for Marine Mammalogy., Marine Mammals, Birds & Turtles, Article in Press, CODEN: MMSCE
Author: Harvey, Friend, McHuron

Title: Assessment of errors associated with harbour seal (Phoca vitulina) faecal sampling,
Description: , , , Six harbour seals, ages 4-8 years, were held as pairs in a 10 x 20 x 2 m tank filled with sea water, and on 60 occasions were fed a meal of a specific species of fish or cephalopod of known size. The tank was drained periodically, and harbour seal faeces were collected on a 0.5 mm sieve. Number and size of otoliths and beaks found in faeces were determined. Fifty-eight percent of 670 fish and 37% of 36 cephalopods fed to harbour seals were represented by their otoliths or beaks in faeces. Estimated number of prey consumed was determined from the greatest number of left or right otoliths or upper or lower beaks collected in faeces. Estimated length ofprey was determined from measurements of otoliths and beaks recovered in the tank and relationships of otolith and beak measurements to prey length. Estimated number of fish eaten was not significantly different among pairs of harbour seals, but was different among species of fishes. Only 24-35% of fish species with small otoliths were represented in faeces, whereas more robust otoliths from other species were less apt to be completely dissolved. Estimated length of fishes was significantly less than lengths of fishes fed to harbour seals in 39 (76.5%) of 51 trials. Cephalopod beaks were not affected by passage through the harbour seal digestive tract. Amount of otolith dissolution was not related to species of fish; estimated fish length was underestimated by an average 27.5%. Although some (7.4%) of the otoliths were collected within 100 h after the fish were ingested, more than 90% were recovered within 24 h after the fish was eaten. Correction factors were developed which will allow researchers to estimate more reliably number and size of fish and cephalopod prey eaten by harbour seals., ,
Author: Harvey
Date: 1989-01-01T00:00:00Z

Title: Survival and behavior of previously captive harbor seals after release into the wild
Description: Downloaded from: www.nmfs.noaa.gov (4 August 2014). Harbor Seals
Author: Harvey, Reynolds, Odell
Date: 1991-01-01T00:00:00Z

Title: An application of underwater imaging for marine vertebrate ecology,
Description: Moss Landing Marine Laboratories (MLML) and the National Marine Fisheries Service have conducted leatherback (Dermochelys coriacea) sea turtle research for the last eight years. Leatherbacks come to the central California coast to forage on concentrations of jellyfish that accumulate in the nutrient rich waters over the coastal shelf. The research includes tracking leatherbacks across the Pacific Ocean with satellite transmitters, suction-cup attachment of time-depth-recorders (TDR) tags, and collection of morphological data. The TDRs are used to record the dive profiles of the leatherbacks foraging for jellyfish near shore. The TDR data provide graphical representation of the dive profile, showing decent and ascent rates, along with variations or deviations in the ascent pattern. This paper describes an application of a modest, but unique underwater imagining system designed and constructed at MLML to answer some of the questions inspired by the dive profiles. MLML's Turtle Cam synchronizes dive profiles with video images, providing researchers with a tool that is giving new insights to leatherback foraging ecology. ©2010 IEEE., Marine Mammals, Birds & Turtles, Art. No.: 5664044, ,
Author: Watson, Benson, Harvey
Date: 2010-01-01T00:00:00Z

Title: Development of body oxygen stores in harbor seals: Effects of age, mass, and body composition,
Description: Harbor seal pups are highly precocial and can swim and dive at birth. Such behavioral maturity suggests that they may be born with mature body oxygen stores or that stores develop quickly during the nursing period. To test this hypothesis, we compared the blood and muscle oxygen stores of harbor seal pups, yearlings, and adults. We found that pups had smaller oxygen stores than adults (neonates 57%, weaned pups 75%, and yearlings 90% those of adults), largely because neonatal myoglobin concentrations were low (1.6 ± 0.2 g% vs. 3.8 ± 0.3 g% for adults) and changed little during the nursing period. In contrast, blood oxygen stores were relatively mature, with nursing pups having hematocrit (55% ± 0.2%), hemoglobin (21.7 ± 0.4 g%), and blood volume (12.3 ± 0.5 mL/kg) only slightly lower than the corresponding values for adults (57% ± 0.2%, 23.8 ± 0.3 g %, and 15.0 ± 0.5 mL/kg). Because neonatal pups had relatively high metabolic rates (11.0 mL O 2/ kg min), their calculated aerobic dive limit was less than 50% that of adults. These results suggest that harbor seals' early aquatic activity is primarily supported by rapid development of blood, with immature muscle oxygen stores and elevated use rates limiting aerobic diving ability. © 2005 by The University of Chicago. All rights reserved., Cited By (since 1996):36, Marine Mammals, Birds & Turtles, CODEN: PBZOF, ,
Author: Burns, Costa, Frost, Harvey
Date: 2005-01-01T00:00:00Z

Title: Methods of capturing, handling, and tagging harbor seals,
Description: , , ,
Author: Jeffries, Brown, Harvey
Date: 1993-01-01T00:00:00Z

Title: Abundance, distribution, and habitat of Leatherback turtles (Dermochelys coriacea) off California, 1990-2003,
Description: Leatherback turtles (Dermochelys coriacea) are regularly seen off the U.S. West Coast, where they forage on jellyfish (Scyphomedusae) during summer and fall. Aerial line transect surveys were conducted in neritic waters (<92 m depth) off central and northern California during 1990-2003, providing the first foraging population estimates for Pacific leatherback turtles. Males and females of about 1.1 to 2.1 m length were observed. Estimated abundance was linked to the Northern Oscillation Index and ranged from 12 (coefficient of variation [CV]=0.75) in 1995 to 379 (CV=0.23) in 1990, averaging 178 (CV=0.15). Greatest densities were found off central California, where oceanographic retention areas or upwelling shadows created favorable habitat for leatherback turtle prey. Results from independent telemetry studies have linked leatherback turtles off the U.S. West Coast to one of the two largest remaining Pacific breeding populations, at Jamursba Medi, Indonesia. Nearshore waters off California thus represent an important foraging region for the critically endangered Pacific leatherback turtle., , ,
Author: Benson, Forney, Harvey, Carretta, Dutton
Date: 2006-01-01T00:00:00Z

Title: Blastogenesis and interleukin-2 receptor expression assays in the harbor seal (Phoca vitulina),
Description: Cited By (since 1996):12, , , ,
Author: DiMolfetto-Landon, Erickson, Blanchard-Channell, Jeffries, Harvey, Jessup, Ferrick, Stott
Date: 1995-01-01T00:00:00Z

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