Swimming performances of some native freshwater fishes

Abstract

Observations were made of the response to water velocity for upstream migrating juveniles of 5 diadromous native fishes (Anguilla auslralis, Galaxiasmaculatus,Galaxiasfasciatus,Retropinna relropinna, Gobiomorphus colidianus). Swimming performance within a hydraulic flume was measured and observations made of the behavioural adaptions of some species to swim through high water velocities. Timed swimming at known water velocities allowed estimation of critical velocities for fish passage. For juvenile fishes (30-80 mm total length), velocities below 0.3 m s -1 should allow unrestricted passage over obstacles less than 15 m in length. Water velocities below 0.25 m s -1 may be necessary for obstacles over 15m. Field observations otMugil cephalus corresponded with limited flume data, suggesting this species is a less vigorous swimmer: water velocities below 0.15 m s -1 would allow its passage over obstacles less than 5 m in length whereas longer obstacles, without resting areas of static water, may require velocities as low as 0.05 m s -1 for M. cephalus.

Effects of Slotted Water Control Structures on Nekton Movement within Salt Marshes

“…Water velocities at the WCS slots were too low (<0.2 m/s) to limit the migration of most nekton and only exceeded the swimming capabilities of larvae and small (e.g., <3 cm) juveniles (e.g., Mitchell 1989;Luckenbach and Orth 1992;Faria et al 2009). Individuals migrating out of managed marshes have been reported to be larger than those leaving unmanaged marshes (e.g., penaeid shrimps; Knudsen et al 1989Knudsen et al , 1996, ostensibly due to emigration impedance (resulting in long retention times), reduced predation, or decreased competition in managed marshes (Hoese and Konikoff 1995).…”

Quantification of the maximal swimming performance of Australasian glass eels,Anguilla australisandAnguilla reinhardtii, using a hydraulic flume swimming chamber

“…34 (MTL) elvers of the American eel (Davidson 1949). Although Mitchell (1989) Although data from successful negotiations of fishways by juvenile eels in Australia does provide some indication of their swimming ability, this data alone is insufficient. A study by Kowarsky & Ross (1981) found that small numbers of 47-60 mm A. reinhardtii glass eels and elvers were able to ascend particular cells of the Fitzroy River fishway (a vertical slot fishway) where velocities did not exceed 69-90 cm s -'.…”

“…The relative effort expended by swimming animals was categorised into four groups based on both the observed inflection points within the data (corresponding to distinct changes in the level of effort), and arbitrary categories modified from Beamish (1978) and Mitchell (1989). These different levels of effort were designated as sustained, steady prolonged, rapid prolonged, and burst.…”

“…1975;McCleave 1980), ,4. australis (Mitchell 1989), and A. rostrata (Davidson 1949;Barbin & Krueger 1993) (Table 1). Of these, Mitchell (1989) and Barbin & Krueger (1993) are the only published studies that have measured the swimming performance of any juvenile anguillid with a total length (TL) of less than 60 mm.…”

“…australis (Mitchell 1989), and A. rostrata (Davidson 1949;Barbin & Krueger 1993) (Table 1). Of these, Mitchell (1989) and Barbin & Krueger (1993) are the only published studies that have measured the swimming performance of any juvenile anguillid with a total length (TL) of less than 60 mm. These studies reported burst swimming speeds (maximum attainable speeds) of 57 cm s~' for pigmented New Zealand short-finned eels (A. australis) and 40 cm s~' for elvers of the American eel {A. rostrata) with mean total lengths (MTL) of 55-80 and 56 mm respectively.…”