Validation of the use of Otoliths to determine the ate and growth of Murray Cod, Maccullochella peelii (Mitchell) (Percichthyidae), in Lake Charlegrark, Western Victoria

Abstract

The age and growth of Murray cod, Maccullochella peelii, in Lake Charlegrark, western Victoria, were determined by using otoliths from fish sampled by beach-seine and gill-net, or caught by anglers, between August 1978 and August 1982. Annulus formation was validated up to 11 + years by several methods. Otoliths were examined from hatchery-bred fish of known age (up to 4+ years) that had been stocked into local farm ponds. Analysis of incremental growth for all fish sampled from the lake indicated that the mean edge-growth ratio was lowest, and the percentage of otoliths with an annulus at the edge was highest, in October. A nominal birth date of 1 October was designated for the population to enable calculation of the absolute age for each fish. Age-composition data for those fish taken by gill-net and by anglers (up to 21 + years) revealed modal progression of strong year classes (1970 to 1973 inclusive) during the sampling period. Length-frequency data for those fish taken by beach-seine (up to 3 + years) revealed modal progression, on a seasonal basis, of two relatively strong year classes (1978 and 1979) during the sampling period. A von Bertalanffy growth curve was fitted to length and age data for all fish collected in the lake (no sex difference, P>O.05), and growth parameters were estimated for the population (L∞ = 695 mm). This curve did not adequately describe the growth of fish older than 11 + years because the majority of sampled fish (98.3%) were aged 11 + years or younger. The length-weight relationship for the population was determined by using data from all fish collected in the lake (no sex difference, P>0.05).

Age and growth of the largemouth perch Percichthys colhuapiensis in the Negro river, Argentine Patagonia

“…Unfortunately, data about the maximum age attained by largemouth perch in captivity, or results of monitoring studies in fish farming sites are not available. Longevity, notwithstanding, has been well documented in other percichthyids, as indicated by the maximum ages reported in several studies conducted on other genera and species of the family, namely, 9 years for Morone americana (Bath and O'Connor, 1982), 10 years for P. trucha (Dománico and Guerrero, 1990), 21 years for Maccullochella peelii (Gooley, 1992), 22 years for Macquaria novemaculeata (Harris, 1985), and 26 years for Macquaria ambigua (Mallen-Cooper and Stuart, 2003).…”

Variable stocking effect and endemic population genetic structure in Murray cod Maccullochella peelii

“…The approximate age of sampled fish based on total length ( L T ) measurements where available was estimated using data from the ageing studies of Gooley (1992), Anderson et al (1992) and Rowland (1998 b ). All three studies employed the same otolith ageing metrics to examine the relationship between L T and age of M. peelii in the southern MDB (Anderson et al , 1992; Gooley, 1992) and in the southern, central and northern MDB (Rowland, 1998 b ). There is no difference in the growth rate of males and females, or between M. peelii in different rivers, but fish in impoundments grow faster (Rowland, 1998 b ).…”

Spawning time and early life history of Murray cod, Maccullochella peelii (Mitchell) in an Australian river

“…Much of our knowledge of the biology of Murray cod has, therefore, relied on investigations carried out under aquaculture-type conditions 2 (Lake 1967a, b;Rowland 1983Rowland , 1988Rowland , 1998. Recent work on life history (Humphries et al 1999(Humphries et al , 2002, habitat use, 3 movement 4 and ageing (Anderson et al 1992;Gooley 1992) in the wild, however, is adding significantly to our knowledge base. Although Murray cod spawn each year -unlike, perhaps golden perch Macquaria ambigua (Richardson) -an inability to locate spawning individuals in the wild has meant that reliable identification of spawning times has been elusive, as have the environmental variables associated with them (although, see Langtry's mainly anecdotal accounts 5 .…”