Resource use by stream-dwelling rock bass and smallmouth bass

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bass, food, habitat, water depth

Journal or Book Title

Transactions of the American Fisheries Society


We examined food and habitat use of sympatric smallmouth bass (Micropterusdolomieui) and rock bass (Ambloplites rupestris) in the Current and Jacks Fork rivers, Missouri.Use of food resources was similar between species and within a species. On a total caloric basis,the importance of prey ranked crayfish > fish > insects. The similarities of both prey types and thesize selection of prey indicated that food resources were not a mechanism of ecologicalsegregation between rock and smallmouth bass. Habitat use was evaluated by underwaterobservation. Location of both species was highly correlated with some aspect of cover, especiallywoody structure. Although cover use overlapped among size classes and species, rock basswere more often associated with rootwads and smallmouth bass with log complexes (aggregatesof logs and branches). Cover use was independent of rock bass size, but smallmouth bassshorter than 350 mm long more often used vegetation and boulders and were more often found inopen water than were smallmouth bass larger than 350 mm. Smallmouth bass used woodystructure associated with higher current velocities more often than did rock bass. A positiverelation between water depth and fish size was evident for each species, but water depthappeared unimportant in interspecific segregation.





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