||02-19-2008 11:04 AM
Hey WaterAye, can you or anyone else here elaborate more on this two stock theory for fluke
I read about it some years back in a periodical called: Marine Fisheries Review, the issue was dated 6/22/2001. You can read it on the web:
Here is an except, but the article is good you should read it:
The potential existence of independent spawning aggregations of summer flounder in the management area has prompted many studies that compare phenotypic traits among groups determined a priori. While environmental factors affect expression of the traits and can confound interpretations, some have made efforts to control for environmental effects, and geographically distinct phenotypes have been described as evidence of multiple stocks. Latitudinal variation in growth rates has been observed through holding experiments, length frequency analysis, and through back-calculation of size-at-age from hard parts (Dery, 1981; Powell, 1982; Szedlmayer et al., 1992; Malloy and Targett, 1994; Burke et al., 2000). Morphometric and meristic analyses were able to discriminate differences among individuals from north and south of Cape Hatteras (Ginsburg, 1952; Smith and Daiber, 1977; Wilk et al., 1980; Fogarty et al., 1983, Delaney, 1986). Gel-electrophoresis isozyme analysis further suggests that Cape Hatteras acts as a zoogeographic barrier to the mixing of populations from the north and south (Van Housen, 1984). The variation in growth rates provides a justification for managing multiple stocks (Burke et al., 2000), and the morphological, meristic, and biochemical results could be applied to identify landings from separate stocks. These phenotypic delineations of stock structure have not motivated managers to consider multiple stocks, and lack of a genetic basis for stock structure (Jones and Quattro, 1999) has been used to justify managing summer flounder as a single stock (NEFSC (1)).