Annual production and drift of the stream amphipod Gammarus pseudolimnaeus in Valley Creek, Minnesota1

Abstract

Annual production and drift of Gammarus pseudolimnaeus were measured in a 100‐m section of Valley Creek for the 5‐year period 1968–1973. Production was estimated by the procedure previously termed the “Hynes method,” herein proposed to be termed the “size‐frequency method.” Annual production was 271 and 231 kg·ha−1 (dry wt) in the first 2 years but declined subsequently to a low of 64 kg·ha−1, apparently the result of a severe siltation. Annual mean daily drift corresponded, being high at 41 and 46 g·d−1·m−3 s−1 in the first 2 years, but only about 7 and 11 in the last 2 years. Mean annual standing stock was also high in the first 2 years (47 and 35 kg·ha−1) but substantially lower n the last 2 years (11 and 17); mean annual density was 7,176 and 6,849·m−2 in the first 2 years and 1,586 and 2,363·m−2 in the last 2 years. Annual P:B ratios were 5.7–6.6 over the 5‐year period, with an average of 6.0.

Drift of stream invertebrates below a cave source

“…Whereas a number of investigations have attempted to correlate drift with standing stock or production (Waters, 961;Dimond, I967;Pearson & Kramer, 1972;Hildebrand, 1974;Waters & Hokenstrom, 980), the functional relationship between the two concepts remains elusive. Involved is the distance of drift, but the few studies on this subject (Waters, 1965;McLay, 1970;Elliott, 197I) have not provided the kind of data that would elucidate the basic functional relationship.…”

Annual production by a stream brook charr population and by its principal invertebrate food

“…The siltation cleared noticeably in 1972, and by autumn of that year the condition of the stream substrate appeared to have returned to normal. During the time of the most severe siltation, production by G. pseudolimnaeus was significantly reduced, particularly in 1971 (Waters & Hokenstrom 1980). The long-range ongoing production studies thus provided a valuable opportunity for the present analysis of a possible relationship between predator and prey, particularly when drastic changes resulted from the fortuitous and unanticipated siltation.…”

“…During the five-year period, [1968][1969][1970][1971][1972], an intensive study of production by the charr's principal invertebrate food, the amphipod Gammarus pseudolimnaeus Bousfield, was conducted in Valley Creek (Waters & Hokenstrom 1980). The ongoing studies on fish production during the same years, in a nearly contiguous study section, made it possible to compare production by the charr to production by its principal invertebrate prey, for this continuous five-year period.…”

Production and biomass of Tenagomysis tasmaniae Fenton, Anisomysis mixta australis (Zimmer) and Paramesopodopsis rufa Fenton from south-eastern Tasmania (Crustacea: Mysidacea)

“…Two methods, firstly the size frequency method (Waters & Hokenstrom, 1980 ;Hynes, 1980) and secondly, the method develop ed by Petrovich et al (1964) and later modified by Winberg (1971) are both ap p licable for the calculation of mysid p roduction . The size frequency method calculates p roduction by summing the biomass lost between successive size classes (Menzie, 1980) .…”