Date of Award

2002

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Zoology

Advisor

John R. Moring

Second Committee Member

Malcolm L. Hunter

Third Committee Member

Robert L. Vadas

Abstract

Tidepool fishes are an interesting and commercially valuable guild of fishes that reside in tidepools at low tide. Tidepool fishes of the North Atlantic Coast reside in tidepools only during the late spring to Ml months, and are typically juveniles of subtidal adult species. Tidepool fishes on the Pacific Coast of North America have been studied extensively, but species of the North Atlantic Coast have rarely been studied. An important area of study is the use of different tidepool microhabitats by fishes, specifically the use of rockweed (AscophyZZum nodosum) fringe, which is present in many tidepools. Rockweed is an algal species that grows extensively on the North Atlantic Coast, and it is important due to the current commercial harvest of rockweed along many shores, including the coast of Maine. The objectives of this study were to document the presence of fish species within the rockweed fringe, and to assess the short-term effects of experimental removal of rockweed fringe. The study took place along the coast of Maine during the summer of 2001 at three sites: Schoodic Point, Great Wass Island, and Quoddy Head. Fishes and invertebrates were sampled in nine tidepools at each site on three occasions before treatment. Previously assigned experimental treatments (no removal, half removal (fringe length of 15 cm), or full removal of the rockweed fringe) were then performed. Four sampling periods followed treatment to assess short-term effects on fishes, invertebrates, and physical characteristics of the pool. At least 5 species of fishes, Cyclopterus lumpus, Myoxocephalus scorpius, Myoxocephalus aenaeusl Pholis gunnellus, and Liparis atlanticus, utilize rockweed fringe habitat. Experimental results are unclear due to high variation within treatments because of the high variability between individual tidepools. However, rockweed was found to host high numbers of invertebrates commonly preyed upon by tidepool fishes, and thus we assume that the removal of rockweed can have impacts on the food base available to fishes. Physical and behavioral characteristics of these fishes, specifically camouflage and modes of attachment, indicate that these species are well adapted to utilizing the habitat, perhaps as a refuge from predators. Rockweed is a species of algae that is vitally important to marine life, and this study has implications for the regulation of commercial rockweed harvesting.

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