effects of giant kelp (macrocystis) on the density and abundance of fishes in a cobble-bottom kelp...

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Page 1: Effects of giant kelp (Macrocystis) on the density and abundance of fishes in a cobble-bottom kelp forest

1120 E. Biological Oceanography OLR (1990) 37 (12)

slope form the only substantial shell accumulation below storm wave base. Four biofacies dominated respectively by mussels, lucinid clams, vesicomyid clams, and tubeworms are present. Each seep site is composed of a series of autochthonous beds domi- nated by one biofacies. Taphonomic parameters differ significantly within topographically and sed- imentologically equivalent areas. Despite essentially undisturbed accumulation below storm wave base, concavity ratios rarely differ from 1:1 and frequency of articulation may be low. Assemblages forming below storm wave base in low-energy environments may comprise a wide variety of taphofacies de- pending upon whether formation occurs beneath or upon the sediment surface. Dept. of Geol., Texas A&M Univ., College Station, TX 77843, USA.

90:7146 DeMartini, E.E. and D.A. Roberts, 1990. Effects of

giant kelp (Macrocystls) on the density and abundance of fishes in a cobble-bottom kelp forest. Bull. mar. Sci, 46(2):287-300.

Fish density was significantly related to the density of giant kelp for 18 of 30 life stages of the 14 major species tested at San Onofre kelp bed (San Diego County, California); in all cases the relation was positive. Kelp-by-year interactions were significant for 15 life stages of II species. Year effects were apparent for 13 cases involving 8 species. Bedwide fish density was twice as great during the second versus first fall season. Bedwide abundances of fish were 75% greater (numbers) and 100% greater Coiommass) during the second fall season, when both the density and abundance of giant kelp were about half the respective fall 1985 value. Thus, more fish were concentrated within less kelp in the second year. The implications of these observations for describing fish-kelp relations are discussed. NMFS, SWFC, 2570 Dole St., llonolulu, HI 96822-2396, USA.

90:7147 Edgar, G.J., 1990. The use of the size structure of

benthic macrofaunal communities to estimate faunal biomass and secondary production. J. expl mar. Biol. Ecol, 137(3): 195-214.

A general allometfic equation relating daily mac- robenthic production to ash-free dry weight and water temperature was calculated from published production rates of 41 invertebrate species. Equa- tions were also calculated for adult and juvenile animals. The biomass exponent of the general equation differed significantly from the value pre- dicted by Banse and Mosher's (1980) equation. A new method of estimating the secondary production of benthic macrofaunal communities is outlined.

Dept. of Zool., Univ. of Melbourne, Parkville, Vic. 3052, Australia.

90:7148 Edgar, G.J., 1990. The influence of plant structure on

the species richness, biomass and secondary production of macrofaunal assemblages associated with Western Australian seagrass beds. J. expl mar. Biol. Ecol, 137(3):215-240.

Considerable differences were found in the mac- rofauna at Cliff Head and Seven Mile Beach, two seagrass-dominated sites with differing wave expo- sure. Between-site differences were generally much greater than differences between habitats within each site. The species richness of faunal assemblages in different seagrass habitats nevertheless followed consistent patterns at both sites. Only one envi- ronmental factor, the diversity of food resources, corresponded with observed faunal species richness patterns. Macrofaunal abundance, biomass, and production were all much greater in vegetated than unvegetated habitats, but varied greatly between habitats and between sites. Between-site differences are explained by the distribution of plant debris bound at the sediment surface. Dept. of Zool., Univ. of Melbourne, Parkville, Vic. 3052, Australia.

90:7149 Eggleston, D.B., 1990. Behavioural mechanisms

underlying variable functional responses of blue crabs, OIlinectes sapldns feeding on juvenile oysters, Crnssostrea rlvginlca. J. Anita. Ecol~ 59(2):615-630. Virginia Inst. of Mar. Sci., Gloucester Point, VA 23062, USA.

90:7150 Guelorget, Olivier et al., 1990. Macrobentbofauna of

lagoons in Guadeioupean mangroves (Lesser Antilles): role and expressions of the confine- merit. J. coast. Res, 6(3):611-626. Lab. d'Ilydro- biol. mar, Univ. des Sci. et Tech. de Langnedoc, Place E. Bataillon, F-34000 Montpellier, France.

90:7151 Houri-Davignon, C., J.C. Relexans and J. Castel,

1989. Oxygen consumption and electron-trans- port-system (ETS) activity of meiobenthic nem- atodes and copepods: methodology, size-depend- ence, contribution to total benthic metabolism. Oceanis, 15(4):499-510.

Both specific oxygen consumption rate (R) and metabolic intensity were high in intertidal nema- todes and copepods. Electron transport system (ETS) activity is directly proportional to the body weight expressed in the individual protein content (P). Conversely, R/ETS varies in relation to body