From the Chagrin River Basin, Northeastern Ohio1
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OhioJ. Sci. A II IN HEMORRHAGIC HYPOTENSION 181 Copyright© 1982 Ohio Acad. Sci. 0030-0950/82/0004-0181 $2.00/0 LIFE-HISTORY NOTES AND DISTRIBUTIONS OF CRAYFISHES (DECAPODA:CAMBARIDAE) FROM THE CHAGRIN RIVER BASIN, NORTHEASTERN OHIO1 RAYMOND F. JEZERINAC, The Ohio State University, Newark, OH 43055 ABSTRACT. Stream crayfishes were collected from the Chagrin River watershed during 1963-65 to determine their distributional patterns and to gather life-history information. Orconectes rusticus (Girard 1852), probably introduced into the basin in the early 1930s, was the dominant pool-dwelling species in the Chagrin River and Aurora Branch. Orconectespropinquus (Girard 1852), was restricted to the head-water portions of the main stream, the East, the Aurora Branches, and their tributaries; amplexus of this species was observed in September and March. Orconectes sanbornii sanbornii (Faxon 1884), was caught at one locality; this is the first record of its presence in the watershed. Orconectes virilis (Hagen 1870), inhabited pools of the middle and upper portions of the East Branch and its tributaries; its presence in the basin may be a remnant of a more expansive distribution. Orconectes immunis (Hagen 1870), probably a prairie relict, was captured at 2 disjunct localities in the watershed and at 3 other sites in northeastern Ohio. These are the first records of this species in these areas. Cambarus (Puncticambarus) robustus (Girard 1852), was widely distributed and abundant in the pools and riffles of the smaller tributaries and in riffles of the larger streams. An undescribed species, related to Cambarus {Cambarus) bartonii (Fabricius 1798), was captured at 8 localities. Equal sex ratios occurred in populations of 0. virilis and C. (P.) robustus, but 0. rusticus and 0. propinquus had unequal ratios of 1.30:1 and 1.49:1 (male:female), respectively. OHIOJ. SCI. 82(4): 181, 1982 INTRODUCTION from the Chagrin River in 1920. Turner Ortmann (1924) captured Orconectes (1926) cited Ortmann's records, but ap- propinquus (Girard 1852) and Cambarus parently did not investigate the river {Puncticambarus) robustus (Girard 1852) system himself. When Rhoades (1944b) published a supplement to Turner's paper, Manuscript received 26 January 1981 and in re- he mentioned the presence of Orconectes vised form 17 February 1982 (#81-5). rusticus (Girard 1852) in Geauga County. 182 R. F. JEZERINAC Vol. 82 Before 1963, 3 species of crayfish had been recorded from the river system. During 1963 and 1964, I collected 2 additional species from the drainage: Orconectes virilis (Hagen 1870) and Orconectes immunis (Hagen 1870). It became apparent that the Chagrin River system had one of the highest diversity indices of crayfishes of any Ohio stream. This investigation was initiated to determine (1) if additional species might be present, (2) the current spatial distribution of crayfishes in the ba- sin, (3) what physical and/or biotic factors might affect their distributional patterns, and (4) to collect information on habitats, sex ratios, breeding, and crayfish associates for each species. STUDY SITE C UY« H OCA CO. | ' The Chagrin River watershed is located PORT AGE CO. in northeastern Ohio, approximately 24 km east of Cleveland. It drains 692 ha of land (Frost et al. 1959) in parts of Cuyahoga, Geauga, Lake, and Portage counties. The main stream is approximate- FIGURE 1. Localities investigated in the Chagrin ly 77 km long (Frost et al. 1959) and has River basin, northeastern Ohio. 1965 field col- lection numbers are given unless preceded by a pre- an average gradient of 7.9 m/km. The fix indicating 1963 (63-) or 1964 (64-). Political lowest 8.9 km of the river transverses boundaries: dot-dashes, a county line; dashes, a the Lake Plain, part of the Central Low- township line; dots, a city limit. land physiographic province, whereas the remainder flows upon the Glaciated Allegheny Plateau (Fenneman 1938). Ad- specimens could not be found. Each locality was ditional information on the bedrock geo- sampled for at least one hour. Immediately there- logy (Pedry 1961), Pleistocene geology after, the locality was marked on a 7.5 min topo- graphic map of the United States Geological Survey (Baker 1957), forest communities (Ohio (1961 series) and habitat data were recorded on a Division of Water 1959, Gordon 1969), field sheet similar to Trautman's (1957). and physical and chemical properties of the A total of 4,260 crayfishes was collected and iden- surface waters (Ohio Division of Water tified, using both the taxonomic keys of Turner 1953) is available for this watershed. (1926) and the reference collection at the Ohio State University Museum of Zoology. The nomenclature of Hobbs (1974) was followed. All specimens were METHODS AND MATERIALS catalogued and deposited in the crayfish collections Incidental collections of crayfishes were made of The Ohio State University Museum of Zoology during 1963 (6 sites) and 1964 (5 sites). A system- (OSUMZ), and all field notes and maps associated atic investigation of 118 additional localities was with the study were deposited in the museum's ar- made between 29 August and 20 September 1965. chives. The method of Freund et al. (I960) was used This time was chosen because most males would to determine if differences in sex ratios were statisti- be first form, or breeding, individuals. Such indi- cally significant at the 0.05 level (Z0.05 = 1-96). viduals are essential for unambiguous species The given ratios are the proportion of males to fe- identification. males. Sample sizes of less than 50 individuals could A total of 129 localities were investigated (fig. 1). not be validly analyzed because a maximum permis- Habitat data and specimens were collected at 121 sible error of 0.10 was arbitrarily chosen to deter- localities and habitat data only at 8 localities because mine the statistical significance of the proportion. OhioJ. Sci. CHAGRIN RIVER CRAYFISHES 183 Orconectes rusticus (Girard 1852) HABITAT. The 16 collections contain- ing more than 50 individuals each came from permanently flowing streams that were between 4.6 m and 18.3 m wide, had pools 0.5 m—1.2 m deep, and had moderate to low gradients (see Trautman 1957 for a discussion of stream gradient). The pools ranged from well defined to poorly defined, all with current. They con- tained substrates primarily of silt, sand, and some gravel and cobbles. Algae (pri- marily Spirogyra and Cladopbora) was usu- ally abundant and pollution, determined by smell and the appearance of the water, was generally absent. The microhabitat of 0. rusticus was pools CUYAHOSACO. \ containing substrates of silt, sand, gravels, POKTAOI CO. and some cobbles. Specimens with a total carapace length of 2.5 cm or greater were commonly captured in the deepest parts of pools among cobbles, whereas the smallest individuals were most often taken from the FIGURE 2. Chagrin River distribution of 0. rusti- shallowest waters of the pools where gravel cus, 0. propinquus, O.s. sanbornii, and 0. immunis during 1963-65. Half-shaded circles indicate that formed the substrate. Individuals of inter- both 0. rusticus and 0. propinquus were captured mediate size were the most randomly dis- at the site. Political boundaries are the same as in tributed members of the population. fig. 1. Elsewhere in its range, 0. rusticus is common in flowing streams with lime- stone bottoms. Rhoades (1944b) reported SEX RATIO. A total of 2,117 specimens that it has a "preference for limestone of 0. rusticus was captured and preserved habitats" and might be successfully intro- during this study. Except for 17 in- duced into non-limestone streams, such as dividuals whose sex could not be deter- the Chagrin River, provided that there mined because of their small size, 1,188 exist '"islands' of limestone in an area of (56.6%) of the specimens were males. The silicious rock." Pedry (1951) found iron result of a statistical testing indicates that carbonate concretions in the shales out- an equal sex ratio should be rejected cropping in the Chagrin River basin, but (Z = 6.02). The ratio was 1.30:1. Why these carbonates are probably quickly neu- males were more often captured than fe- tralized by the acidic shales. The abun- males is unknown. dance of 0. rusticus in the Chagrin River BREEDING. Of the 1,188 males, 524 system is unexpected if limestone is a nec- (50.0%) were first form individuals. These essary part of its habitat. Lime is present in data, suggest that the molt producing first the glacial till overlying most of the water- form males begins in the late summer shed and these deposits may provide the and that 0. rusticus has a breeding cycle calcium carbonate that this species seems similar to that of 0. obscurus (Hagen 1970), to require (J. L. Forsyth, pers. comm.). 0. limosus (Rafinesque 1817), and 0. pro- 184 R. F. JEZERINAC Vol. 82 pinquus (Girard 1852), (Ortmann 1906, Orconectes propinquus Crocker 1957, Van Deventer 1937). (Girard 1852) CRAYFISH ASSOCIATES. Orconectes rusti- HABITAT. At localities from which 30 cus was most often captured alone (31 or more individuals were captured, the sites), with 0. propinquus (24 sites), with stream was 1.8 m— 10.7 m wide, usually 0. immunis (one site) with C. (P.) robustus 15 cm—0.9 m deep, and had moderate to (21 sites), and with C. (C.) sp. A (12 high gradients. The pools were chiefly well sites). The species and 0. propinquus inhib- defined, with moderate current, and had it similar types of pools and, numerically, substrates of sand, gravel, and cobbles. 0. rustkus appears to be replacing 0. pro- Algae (primarily Spirogyra) was abundant pinquus. When 0. rustkus, Cambarus (C.) and pollutants were non-evident. sp. A, and 0. immunis occurred at the same The primary microhabitat of the species site, 0.