Legal Size Limit Research Articles

Age and Growth of the Walleye in Lake Erie, 1963-1968

Abstract Age and length distributions are given for 6,764 walleyes, Stizostedion v. vitreum (Mitchill), sampled during 1963-1968 from commercial landings of walleyes representing discrete populations in the eastern and western basins of Lake Erie. In the eastern basin, where all catches were made with gill nets, age-groups III and IV predominated in samples from large-mesh nets and age-group I in samples from small-mesh nets. In the western basin, where nearly all walleyes were taken in trap nets, age-groups I and II predominated in 1963-1965, and II and III in 1966-1968 (after the legal commercial size limit was raised from 330 to 394 mm). Study of 5,082 walleyes from the two basins showed that at any given age during the first 3 years of life, females were longer than males and, on the average, fish from the western basin were longer than those from the eastern basin. The greatest difference in growth of fish of the same sex for the two basins was apparent at the end of the first year of life, when fish...

Catch Composition of the Sand Crab Fishery in Moreton Bay

The sand crab industry of Moreton Bay is an expanding fishery. Nets are used in the south of the bay and pots in the north. Three principal grounds are fished within the bay and these yield catches of differing composition. A tendency to sexual schooling is apparent, large males predominating in catches from the southern bay, while the sexes are equally well represented in the north, where the mean size of the males is less. The crabbing grounds vary in productivity, the Scarborough ground producing almost twice as many marketable crabs as the Woody Pt. ground. The percentage of crabs taken that are marketable varied from 55 per cent, in the Cleveland area to 43 per cent. at Scarborough and 34 per cent. at Woody Pt. Female crabs in berry were taken at sizes from 4 to 7.1 in. (carapace width). Sacculina-infested crabs were far more numerous on the Woody Pt. grounds than elsewhere. It is recommended that the legal size limits and the restrictions on the take of female crabs be continued, but that Sacculina-infested crabs be accepted for market.

Legal Size Limits and their Effect upon Fisheries

IN California, more than twenty years ago, when the crab fishery was declining, an investigation carried out by F. W. Weymouth, of Stanford University, showed that the then minimum size limit of six inches was too low, since it permitted the destruction of male crabs before they had a chance to breed. On the evidence put before it, the Legislature decided to raise the limit at which the commercial crab might be taken, to seven inches. The result of so small a change has been remarkable. A few years after the passing of the new regulation, when the first crop of crabs under its protection had reached the seven-inch size, the production of the fishery suddenly doubled, and since then the catch has gone on increasing until now the fishery produces 75,000 dozen crabs more than it did before the law was changed, an increase worth 185,000 dollars to the fishermen (N. B. Scofield in California Fish and Game, 1932, p. 260). Yet originally they opposed the change, saying that already at six inches the size limit was too high, and that declining production could be stayed only by permitting the capture of smaller individuals through the reduction of the six-inch limit. Once more, scientifically ascertained facts have triumphed over opinion and so-called experience.