Raymond Clarke

• Ph.D.
• Professor Emeritus at Sarah Lawrence College

A population of Fowler's toad (Bufo woodhousei fowleri) living on a golf course in New Haven, Connecticut, was studied for 3 years by the capture–mark–recapture method. Individual growth rates were determined using tibia length, which is isometric with body length, as the measure of size. Growth was rapid, with an average 6.58-fold length increase...

The interaction of flowing water with reef topography creates a continuum of flow microhabitats that can alter species distributions directly via transport of organisms or propagules, or indirectly by modulating the availability of critical resources. To examine how water flow affects the distribution and feeding performance of two species of plank...

The chaenopsid blenny Acanthemblemaria spinosa occupies topographically high locations on coral reefs where flow speeds and turbulence are frequently greater than those experienced by its congener, A. aspera, which occupies locations close to the reef surface. To investigate the adaptive mechanisms resulting in this microhabitat differentiation, th...

Water motion is an important factor affecting planktivory on coral reefs. The feeding behavior of two species of tube-dwelling coral reef fish (Chaenopsidae) was studied in still and turbulent water. One species of blenny, Acanthemblemaria spinosa , lives in holes higher above the reef surface and feeds mainly on calanoid copepods, while a second,...

To assess the ways in which different selection pressures on male and female spinyhead blennies (Acanthemblemaria spinosa) influence their use of space, we measured a number of features of their shelter sites. Both sexes occurred primarily on dead surfaces of elkhorn coral (Acropora palmata), but significantly more males than females were found on...

In order to determine the extent to which tube blennies depend on food derived from within or outside of the reef system, the diets of Acanthemblemaria spinosa, A. aspera, A. greenfieldi and A. paula were compared with food availability using plankton, benthic and gut sampling. All species fed primarily on copepods, but A. spinosa consumed calanoid...

I monitored the population~ of 2 fishes on a coral reef in St. Croix, U. S. Virgin Islands, from 1980 to 1995 to determine if they could track changes in their habitat. Starting in the mid-1970s. white band disease killed all the elkhorn corals Acropora palmata, providing access to a variety of boring organisms that create the cavities inhabited by...

Belt transect censusing was used to establish the habitat distributions of seven species of obligate hole-dwelling chaenopsid blennies on a coral reef in Belize (one Emblemaria and five Acanthemblemaria) and a rocky slope in the Virgin Islands (one Emblemaria and two Acanthemblemaria). There was clear habitat separation between most species, but on...

Spinyhead blennies (Acanthemblemaria spinosa) and roughhead blennies (A. aspera) are planktivorous hole-dwelling fishes that live in dead coral skeletons. Both species are known to choose shelters high above the reef surface (although spinyheads displace roughheads downwards). To test the hypothesis that this preference is due to greater plankton a...

Two species of hole-dwelling blenny, Acanthemblemaria spinosa and A. aspera, were studied on a coral reef in St. Croix, U.S. Virgin Islands, during two field periods 6 years apart (1980 and 1986) to determine degree of population stability, habitat saturation, and interspecific competition. A. spinosa increased from 1.18 to 1.78 fish · m−2 and A. a...

On four occasions at 3-month intervals, all fishes were collected from seven patches (0.6–1.6 m long) of the branching coral Acropora prolifera (Lamarck). The combined collection consisted of 868 individuals from 62 species in 27 families. There were small seasonal fluctuations in numbers of species and individuals, but the abundant species were pr...

The relative abundance of chaetodontid and pomacentrid fishes in 8 habitats, ranging in depth from 0.5 to 17 m, was determined by visual counting of free-swimming fish in the field. Habitat widths and overlaps were determined using weighting factors, developed by Colwell and Futuyma (1971), which account for the different degree of uniqueness of ea...

A population of Fowler's toad (Bufo woodhousei fowleri) living on a golf course in New Haven, Connecticut, was studied for 3 summers by the capture-mark-recapture method; the population was dormant for 7 months of the year. The adults were strictly nocturnal, with a maximum activity shortly after sunset and a decrease until none were active at dawn...

Examination of the contents of 108 stomachs of juvenile and adult Bufo woodhousei fowleri showed that ants and beetles comprised 81% of all the food items eaten. Ants and beetles are also the two most frequent prey in 26 out of 29 cases in the literature. The ability to utilize these ubiquitous taxa, and other available arthropods, partially accoun...

An experiment was designed to investigate the influence of spiders, as predator, upon other organisms in a maple forest litter community. A large number of spiders was removed from an enclosed (experimental) area; spiders were allowed to remain in 1 enclosed and 2 open areas (controls). Following spider removal, centipedes and collembola, known pre...