The diet of harbor porpoises (<i>Phocoena phocoena</i> (L.)) in coastal waters of Eastern Canada, with special reference to the Bay of Fundy

Smith, G. J. D.; Gaskin, D. E.

doi:10.1139/z74-102

Cited by 57 publications

(43 citation statements)

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“…Harbor porpoises are a coastal species, and the population analyzed here is not known to leave the Gulf of Maine during the summer months (Read et al 1993). Here, harbor porpoises were seen in the coolest, shallowest, and most productive waters; this is consistent with both their life history strategy (Read & Hohn 1995) and their diet, which is primarily comprised of herring and cod (Smith & Gaskin 1974, Smith & Read 1992. Although they are planktivores, Five groups resulted from lumping sightings across taxonomic levels, i.e.…”

Section: North Of Hatterassupporting

confidence: 67%

Community structure in pelagic marine mammals at large spatial scales

Schick¹,

Halpin²,

Read³

et al. 2011

Mar. Ecol. Prog. Ser.

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The understanding of a species' niche is fundamental to the concept of ecology, yet relatively little work has been done on niches in pelagic marine mammal communities. Data collection on the distribution and abundance of marine mammals is costly, time consuming and complicated by logistical difficulties. Here we take advantage of a data archive comprising many different datasets on the distribution and abundance of cetaceans from Nova Scotia through the Gulf of Mexico in an effort to uncover community structure at large spatial scales (1000s of km). We constructed a multivariate ordination of the species data, tested for group structure that might exist within the ordination space, and determined how these groups might differ in environmental space. We examined 3 biogeographic regions: the oceanic waters north and south of Cape Hatteras, NC, and the Gulf of Mexico. North of Hatteras, we found 2 main groups split along a temperature and chlorophyll gradient, with most piscivores being found in cooler, more productive waters of the continental shelf, and most teuthivores being found farther offshore in warmer, less productive waters at the shelf break (200 m isobath). South of Hatteras, we found 3 groups, with the largest group being in warmer, lower chlorophyll waters that are closest to shore. In the Gulf of Mexico, we found 7 groups arrayed along a bottom depth gradient. We also tested the effect of taxonomically lumping different beaked whale species on ordination results. Results showed that when beaked whales were identified to the species level, they clustered out into distinct niches that are separate from those of other Odontocete groups. These results add to an increasing understanding of wildlife habitat associations and niche partitionings in the community structure of pelagic species, and provide important baseline information for future population monitoring efforts. KEY WORDS: Cetaceans · Group contrast Mantel test · Nonmetric dimensional scaling · Multivariate ordination · Northwest Atlantic OceanResale or republication not permitted without written consent of the publisher

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Section: North Of Hatterassupporting

confidence: 67%

Community structure in pelagic marine mammals at large spatial scales

Schick¹,

Halpin²,

Read³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…Assuming similar patterns for Pacific white-sided dolphin behavior and click activity, the variability in recorded click rates and occurrence can be used to differentiate periods of activity and rest. In addition, echolocation clicks, produced during daily foraging (Smith & Gaskin 1974, Lockyer 1981, Au 1993, are an ideal call type for examining seasonal occurrence throughout an area; comparisons of echolocation clicks across sites allow investigation of seasonal movement patterns.…”

Section: Introductionmentioning

confidence: 99%

Spatio-temporal comparison of Pacific white-sided dolphin echolocation click types

Soldevilla¹,

Wiggins²,

Hildebrand³

2010

Aquat. Biol.

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A comparison of temporal and geographical trends in different echolocation click types produced by Pacific white-sided dolphin Lagenorhynchus obliquidens can lead to insights into the significance of their usage by the dolphins. Using autonomous seafloor recording packages, the spatial, diel and seasonal patterns of Pacific white-sided dolphin echolocation click activity are described for 6 locations in the Southern California Bight. Click bouts of the 2 types of Pacific white-sided dolphin echolocation clicks are identified based on their unique spectral characteristics in long-term spectral averages. Type A clicks were detected on 317 of 1959 recording days and were heard at all 6 sites, with the majority of detections occurring at San Clemente Island and Point Conception. Type B clicks were detected on 130 recording days and were only heard at the 2 southern inshore sites. Significant diel patterns were evident for both click types: Type A click bouts were detected during more hours and with higher click rates at night than during the day, while Type B click bouts exhibited the opposite behavior, with greater activity during the day. At the southern sites, both click types exhibited a fall-winter peak in seasonal occurrence. At Point Conception, where only Type A was detected, peak occurrence was during spring. The described spatial and seasonal patterns support the hypothesis that click types are population-specific, while diel patterns suggest differences in prey preferences.

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“…In the 1970s, porpoises were hunted for research purposes by the late Professor D. E. Gaskin (e.g. Smith & Gaskin 1974). In the 1980s, many specimens were obtained from a commercial gill net ¢shery (Read & Gaskin 1988).…”

Section: Methodsmentioning

confidence: 99%

“…Harbour porpoises feed primarily on juvenile herring (Smith & Gaskin 1974;Recchia & Read 1989;Gannon et al 1998) so I examined trends in the biomass of ¢sh in age classes 2^4 years. In order to obtain annual estimates of biomass, I multiplied the number of ¢sh in each age class by the mean weight of that class and then summed the three age classes for each calendar year.…”

Section: Methodsmentioning

confidence: 99%

“…The diet of porpoises in the Bay of Fundy and Gulf of Maine is dominated by Atlantic herring (Clupea harengus), which comprises up to 80% of their total calori¢c intake (Smith & Gaskin 1974;Recchia & Read 1989;Gannon et al 1998). Due to their small size, females are unable to store extensive energy supplies (Koopman 1998) and instead rely on supplementing their diet in order to obtain the extra energy required for their o¡spring.…”

Section: Introductionmentioning

confidence: 99%

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Trends in the maternal investment of harbour porpoises are uncoupled from the dynamics of their primary prey

Read

2001

Proc. R. Soc. Lond. B

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Harbour porpoises in the Bay of Fundy and Gulf of Maine feed primarily on Atlantic herring. Herring stocks have undergone dramatic £uctuations in abundance over the past three decades due to changes in ¢shing intensity. In order to understand the e¡ects of these changes in prey abundance on the patterns of maternal investment, I examined interdecadal variation in the size of porpoise calves measured in August prior to weaning. Female harbour porpoises exhibited signi¢cant variation in maternal investment between 1970 and 1999. During the 1980s, females consumed more herring and produced larger calves. Surprisingly, however, this increased maternal investment occurred during the period of lowest prey abundance, perhaps because the herring stock assessment does not re£ect the availability or quality of prey to female porpoises.

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The diet of harbor porpoises (Phocoena phocoena (L.)) in coastal waters of Eastern Canada, with special reference to the Bay of Fundy

Cited by 57 publications

References 0 publications

Community structure in pelagic marine mammals at large spatial scales

Community structure in pelagic marine mammals at large spatial scales

Spatio-temporal comparison of Pacific white-sided dolphin echolocation click types

Trends in the maternal investment of harbour porpoises are uncoupled from the dynamics of their primary prey

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