We tested the potential of a selective flatfish trawl to reduce bycatch of slope rockfish in the upper continental slope bottom-trawl fishery (250–500 m) on the U.S. West Coast. The trawl we tested differed from typical slope trawls in that it was a low-rise, two-seam trawl with a severely cut...
Submersible belt-transect surveys along a rocky bottom were combined with acoustic surveys of the water column to estimate depth distribution and density of fishes at Stonewall Bank, Oregon in the northeastern Pacific Ocean from September through October 1991. The objectives of the study were to determine the proportion of fish...
We quantified both in situ predation on Pacific herring (Clupea haregus pallasi ) larvae by soft-bodied zooplankton, and microzooplankton prey of herring larvae in Kulleet Bay, Vancouver Island, British Columbia. Samples were collected at 0 to 5 m depth daily at peak larval hatching from 14 to 21 April 1985....
Blooms of jellyfish around the world have been correlated with climatic variables related to environmental causes. Sizeable populations of large medusae, primarily Chrysaora fuscescens and Aequorea sp., appear annually in shelf waters of the Northeast Pacific Ocean. Previous research has shown that C. fuscescens is abundant seasonally in the inner...
Most marine fishes experience high rates of mortality during their early life history stages with far reaching consequences for adult population dynamics. Within a few weeks of hatching, relatively small changes in larval growth and mortality rates can lead to orders of magnitude variability in year-class strength. Growth and survival...
This study presents the first target strength measurements of Dosidicus gigas, a large squid that is a key predator, a significant prey, and the target of an important fishery. Target strength of live, tethered squid was related to mantle length with values standardized to the length squared of −62.0, −67.4,...
Skin condition assessment of wildlife can provide insight into individual and population health. Yet, logistics can limit skin condition assessment of large whales. We developed a standardized, quantitative protocol using photographs to assess skin condition of blue whales in New Zealand, and demonstrate the value gained by testing hypotheses, documenting...
Species conservation depends on robust population assessment. Data on population abundance, distribution, and connectivity are critical for effective management, especially as baseline information for newly documented populations. I describe a pygmy blue whale (Balaenoptera musculus brevicauda) population in New Zealand waters with year-round presence that overlaps with industrial activities. This...
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