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<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>David H. Bennett</dc:contributor>
  <dc:creator>Steven R. Chipps</dc:creator>
  <dc:date>2000</dc:date>
  <dc:description>&lt;p&gt;We investigated zooplanktivory and nutrient regeneration by the opossum shrimp&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis relicta&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and kokanee&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Oncorhynchus nerka&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to assess the relative roles of these planktivores in oligotrophic food webs. Using bioenergetic models and clearance rate estimates, we quantified phosphorus (P) excretion rates and consumption of cladoceran prey by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and kokanees in Lake Pend Oreille, Idaho, from 1995 to 1996. Consumption of cladoceran prey by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;was 186 kg·ha&lt;sup&gt;−1&lt;/sup&gt;·year&lt;sup&gt;−1&lt;/sup&gt;, whereas consumption by kokanees was less than one quarter as much, at 45 kg·ha&lt;sup&gt;−1&lt;/sup&gt;·year&lt;sup&gt;−1&lt;/sup&gt;. Similarly,&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;excreted approximately 0.250 kg P·ha&lt;sup&gt;−1&lt;/sup&gt;·year&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;during nighttime migrations into the upper water column, whereas P excretion by kokanees was less than one third as much, at approximately 0.070 kg P·ha&lt;sup&gt;−1&lt;/sup&gt;·year&lt;sup&gt;−1&lt;/sup&gt;. On a volumetric basis, nocturnal excretion by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;ranged from 0.002 to 0.007 μg P·L&lt;sup&gt;−1&lt;/sup&gt;·d&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;and accounted for less than 1% of the soluble reactive P typically measured in the upper water column of the lake. Hence, nutrient recycling by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;may be limited in the upper water column because of the nocturnal feeding habitats that constrain&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to deeper strata for much of the day. In spring and autumn months, low abundance of cladoceran prey coincided with high seasonal energy requirements of the&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;population that were linked to timing of annual&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;brood release and abundance of age-0&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis.&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;Predation by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;accounted for 5–70% of daily cladoceran standing stock, supporting the notion that seasonal availability of cladocerans may be regulated by&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;predation. In lakes where&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;experience little predation mortality, they likely play a dominant role in food web interactions (e.g., trophic cascades) relative to planktivorous fishes. Biotic mechanisms, such as successful predator-avoidance behavior, omnivorous feeding habits, and seasonal variation in&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;biomass, enhance the ability of&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;i&gt;Mysis&lt;/i&gt;&lt;span&gt;&amp;nbsp;&lt;/span&gt;to influence food web interactions from an intermediate trophic level.&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1577/1548-8659(2000)129&lt;0569:ZANRBI&gt;2.0.CO;2</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Wiley</dc:publisher>
  <dc:title>Zooplanktivory and nutrient regeneration by invertebrate (Mysis relicta) and vertebrate (Oncorhynchus nerka) planktivores: Implications for trophic interactions in oligotrophic lakes</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>