Sicyases Sanguineus: a Unique Trophic Generalist from the Chilean Intertidal Zone Author(S): R
Total Page:16
File Type:pdf, Size:1020Kb
Sicyases sanguineus: A Unique Trophic Generalist from the Chilean Intertidal Zone Author(s): R. T. Paine and A. R. Palmer Source: Copeia, Vol. 1978, No. 1 (Feb. 10, 1978), pp. 75-81 Published by: American Society of Ichthyologists and Herpetologists Stable URL: http://www.jstor.org/stable/1443824 Accessed: 01/04/2009 15:42 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=asih. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit organization founded in 1995 to build trusted digital archives for scholarship. We work with the scholarly community to preserve their work and the materials they rely upon, and to build a common research platform that promotes the discovery and use of these resources. For more information about JSTOR, please contact [email protected]. American Society of Ichthyologists and Herpetologists is collaborating with JSTOR to digitize, preserve and extend access to Copeia. http://www.jstor.org POUGH-ENDURANCE IN WATER SNAKES 75 RUBEN, J. A. 1976a. Aerobicand anaerobicmetab- WHITE, F. N. 1959. Circulation in the reptilian olism during activity in snakes. J. comp. Physiol. heart (Squamata). Anat. Rec. 135:129-131. 109:147-157. WILSON, K. J. 1974. The relationship of oxygen . 1976b. Correlation of enzymatic activity, supply for activity to body temperature in four muscle myoglobin concentration and lung mor- species of lizards. Copeia 1974:920-934. phology with activity metabolism in snakes. J. WOOD,S. C., ANDC. J. M. LENFANT. 1976. Respira- Exp. Zool. 197:313-320. tion: mechanics, control, and gas exchange, p. SNYDER,G. K. 1971. Influence of temperatureand 225-274. In: Biology of the Reptilia, Vol. 5. C. hematocrit on blood viscosity. Amer. J. Physiol. Gans and W. R. Dawson (eds.). Academic Press, 220(6):1667-1672. New York. TUCKER,V. A. 1966. the Oxygen transport by SECTION OF ECOLOGY AND circulatory system of the green iguana (Iguana SYSTEMATICS, LANGMUIR iguana) at different body temperatures. J. Exp. LABORATORY, CORNELL UNIVERSITY, ITHACA, Biol. 44:77-92. NEW YORK 14853. Accepted 4 March 1977. Sicyases sanguineus: a Unique Trophic Generalist from the Chilean Intertidal Zone R. T. PAINE AND A. R. PALMER Stomach analyses of Sicyases, an amphibious marine clingfish, collected at Iquique and the Montemar region, Chile, indicate an extremely broad diet. Individual fish usually had been eating one prey type immediately prior to capture. However, there was wide within-sample variation: major prey categories include 3 plant and 3 animal phyla. Analyses indicate that the prey are obtained throughout the intertidal zone. Intertidal and shallow-subtidal prey are digested in middle to upper intertidal areas. The fish is characteristic of vertical rock walls in areas of great surf action. Its niche is unique, with no known parallel development in other rocky intertidal communities. fish are significant functional an amphibious clingfish, Sicyases sanguineus, elements ALTHOUGHin many tropical or sub-tropical known locally as the "pejesapo" (literally, frog- shallow water systems (Bakus, 1969; Randall, fish). It is a characteristic and apparently domi- it for 1961), appears unprecedented them to nant organism of the middle and upper rocky exert a potentially important influence on intertidal community along the exposed coasts temperate zone intertidal communities. The of western South America, ranging from south- evidence for this seems clear. Paine (1966), ern Peru to southern Chile (Buen, 1960). Its Paine and Vadas Connell (1969), (1970), Dayton niche, even in the Eltonian sense, seems unique, and Estes and (1971) Palmisano (1974) have for we can find no evidence of ecological or examined communities along the northeastern morphological convergence towards it in geo- Pacific rim and found no evidence for fish graphically distinct communities. Because it is effects. Rather, starfish, snails, sea urchins or one of the larger amphibious fish, there have sea otters seem be the to major determinants been examinations of its submerged and emerged of the and distribution abundance of the associ- oxygen metabolism and other physiological traits ated General literature or species. descriptions associated with its tolerance of aerial exposure reviews of temperate zone intertidal commu- (Vargas et al., 1957; Gordon et al., 1970; Ebeling nities also fail to reveal fish as major compo- et al., 1970). However, except for rudimentary nents, if they are mentioned at all (Ricketts, or anecdotal observations, little is known of its Calvin and Hedgpeth, 1968; Morton and Miller, ecology and behavior. 1968; Lewis, 1964; Dakin, 1953; Stephenson and We have observed the pejesapo at a number of Stephenson, 1972). Chilean localities: *Iquique (20115.5'S, 70008' We report here a series of observations on W), *Pozo Toyo (20'25'S, 70010'W), Punta 76 COPEIA, 1978, NO. 1 The fish are gregarious and often congregate on walls which they seem to prefer to other possible rock habitats, though we did observe them occasionally in boulderfields (Pozo Toyo, :? liraai: Antofagasta Bay). When exposed they are alert, and can detect moving objects over distances from 10-15 m. Their capture with long-handled nets requires careful and persistent stalking. Ebeling et al. (1970) and Viviani (1975) provide further observations on their overall responses to desiccating habitats. • . •:: ..... ? ....~--ti . DIET There are few data on the feeding and diet of Sicyases. Viviani (1975) gives a brief prey species : : : ii! ? • list, accompanied by the comment that they prefer barnacles. They have a typical buck tooth with a series of 4 incisor-like ?:, : appearance, long, teeth protruding beyond the "lips" of the upper jaw, complemented by four shorter chisel-like teeth on the lower jaw (Fig. 1, Ebeling et al., These are used in at least two The view of 1970). ways. Fig. 1. Frontal Sicyasessanguineus illus- most common mode is for an trating the elongate, rodentiform teeth used in feeding exposed substrate scraping. fish to anchor itself with its ventral sucker on a flat, usually smooth vertical surface, and then to swing its head in a small arc (perhaps in its teeth down- Patache (20148'S, 700 12'W), Antofagasta (23042' 30' total), repeatedly raking ward in 2-4 cm strokes the Minor S, 70027'W), Los Molles (32014'S, 71032'W), along way. be the *Islote Concon (32052'S, 71033'W), *Montemar repositioning may necessary during pro- cess. The resultant left on an (32057'S, 71032'W) and Guabun (41050'S, 74002' impression algal covered surface is of a series of W). Although the latitude is low at some of fan-shaped strokes. our stations, the annual water temperatures are parallel In we an view of comparable to more temperate zone environ- Fig. 2, present enlarged with ments. For example, at Antofogasta they range presumed pejesapo scrapings (2A) compared those an invertebrate most from 14.9 to 20.7 C (Guiler, 1959). Observation generated by grazer, a The are intervals were: Aug.-Sept. 1974; Oct.-Nov. 1975; likely limpet (2B). patterns readily in the field. Also note that the and June-July 1976. Stomach analyses of freshly distinguished in 2A to be sub-divided into netted or pole-hooked individuals were per- pattern appears formed at the asterixed areas. series of scrapes of about the same width, com- posed of either 2 or sometimes 4 distinct but bands. The mean width of of GENERAL OBSERVATIONS narrower, pairs scrapes is about 2 mm; the width across the The pejesapo is characteristic of exposed 2 central front teeth of a 15 cm (standard rocky shorelines and is commonly encountered length) pejesapo is about 3 mm. Hence, though where ocean swells break against vertical rock not observed directly, the size and peculiar walls. We did not find it in either the protected shape of these marks, and the unlikelihood that waters around Punta Arenas, the south end of this particular pattern (2A) could be attributed the island of Chiloe, or any of the islands be- to an herbivorous mollusc, all provide strong tween Chiloe and continental Chile. The miss- circumstantial evidence suggesting they were ing factor is predictable wave action and the as- caused by Sicyases grazing. sociated surge. The other two most likely local A second mode, which we infer from shells of determinants of Sicyases distribution, vertical the gastropod Fissurella taken from pejesapo walls and ample benthic prey (mainly barnacles, stomachs, is for the fish to insert its teeth under mussels and certain ubiquitous algae), were the limpet's shell and then twist. The action present and even abundant. produces a characteristic break in the shell's PAINE AND PALMER-INTERTIDAL TROPHIC GENERALIST 77 44 AO? al, ?I* - AlIV Fig. 2. A. PresumedSicyases grazing marks in a thin layer of encrusting algae. B. Radular marks of an herbivorous gastropod in the same encrusting algae. C. A heavily grazed rock surface, presumably by pejesapo. Scale Bars: A and B, 0.5 cm, C, 5.0 cm. anterior or posterior end. These prey are un- brate predators, especially the starfish Heliaster likely to be taken by generalized scraping and helianthus, reveal both a pronounced and effec- are probably attacked individually. Shells of tive Fissurella escape response and a very low Fissurella spp.