The Value of Rockweed (Ascophyllum nodosum) as Habitat for Tidepool Fishes

Gullo, Amy

FIELD WORK: 2001 '...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, Cylclopterus lumpus, Myoxocephalus scorpius, Myoxocephalus aenaeus, Pholis gunnellus, and Liparis atlanticus, utilize rockweed fringe habitat. Experimental results are unclear due to high variation within treatments becuase 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 camaflage 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.' Coordinates for all of the tidepool sampling locations are avaialble in the appendices. All raw data are of specis of fish and invertebrates are provided in the appendices as well. /STUDY LOCATIONS:/ /SCHOODIC POINT/ GIS category 1: Coordiantes for all tide pool sampling sites are provided in appendices.