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Anadromous sea lampreys ( P etromyzon marinus ) are ecosystem engineers in a spawning tributary
Author(s) -
Hogg Robert S.,
Coghlan Stephen M.,
Zydlewski Joseph,
Simon Kevin S.
Publication year - 2014
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/fwb.12349
Subject(s) - habitat , benthic zone , nest (protein structural motif) , ecology , invertebrate , tributary , fish migration , nekton , ecosystem , fishery , spawn (biology) , biology , hydrobiology , environmental science , geography , biochemistry , cartography , aquatic environment
SummarySea lampreys ( P etromyzon marinus ) disturb the substratum during nest construction and alter the physical habitat, potentially affecting other stream organisms. We quantified differences in depth, velocity, fine‐sediment coverage, embeddedness, intragravel permeability and benthic invertebrate assemblages (density and diversity) among nest mounds, nest pits and undisturbed reference locations over a 4‐month period after June spawning. In 2010 and 2011, immediate and persistent effects of nest construction were assessed in summer ( J uly) and in autumn (late S eptember to early O ctober), respectively. Randomly selected nests were sampled annually (25 each in summer and autumn). Nest construction increased stream‐bed complexity by creating and juxtaposing shallow, swift, rocky habitat patches with deep, slow, sandy habitat patches. Mounds had a 50–143% less cover of fine sediment, and a 30–62% reduction in embeddedness, compared to pits and reference locations. These physical changes persisted into the autumn (almost 4 months). Five insect families contributed 74% of the benthic invertebrate abundance: C hironomidae (27%), H ydropsychidae (26%), H eptageniidae (8%), P hilopotamidae (7%) and E phemerellidae (6%). Densities of H ydropsychidae, P hilopotamidae and H eptageniidae were up to 10 times greater in mounds than in pits and adjacent reference habitat. In summer, mounds had twice the density of C hironomidae than did pits, and 1.5 times more than reference habitats, but densities were similar among the habitats in autumn. These results suggest that spawning sea lampreys are ecosystem engineers. The physical disturbance caused by nest‐building activity was significant and persistent, increasing habitat heterogeneity and favouring pollution‐sensitive benthic invertebrates and, possibly, drift‐feeding fish.