Otolith microchemistry is a commonly used tool for stock discrimination in fisheries management. Two key questions remain with respect to its effectiveness in discriminating among river-spawning populations. First, do larvae remain in their natal river long enough for their otoliths to pick up that system’s characteristic chemical signature? Second, are larval otolith microchemical differences between natal rivers sufficiently large to overcome spatiotemporal variation in water chemistry? We quantified how larval age, the ratio of ambient strontium to calcium concentrations (Sr:Ca), and water temperature influence otolith Sr in both lab-reared and wild-collected Lake Erie walleye (Sander vitreus). Otolith microchemistry shows promise as a spawning stock discrimination tool, given that otolith Sr in larval walleye (i) is more strongly influenced by ambient Sr:Ca than by temperature; (ii) reflects Sr:Ca levels in the natal environment, even in larvae as young as 2 days old; and (iii) can effectively discriminate between larvae captured in two key Lake Erie spawning tributaries, even in the face of short larval river residence times and within-year and across-year variation in ambient Sr:Ca.

Southern Flounder Paralichthys lethostigma is the most commonly harvested flatfish in the north‐central Gulf of Mexico (GOM), yet knowledge of this species’ growth and reproduction is limited for the Mississippi region. Given the offshore spawning migrations and likely mixing between state‐managed units of the GOM Southern Flounder stock, small‐scale environmental influences may constitute a major driver of life history dynamics during early life residency in nearshore estuaries. Therefore, estimates of local demographic characteristics are needed for effective fishery management. Here, we describe critical life history traits of Southern Flounder, including estimation of growth rates and maturity. The three‐parameter von Bertalanffy growth function best described female‐specific growth: mean asymptotic length L∞ was 514 mm TL, mean growth coefficient k was 0.67 year–1, and mean theoretical age at zero length t0 was –0.50 years. The estimated female‐specific mean length at 50% maturity (L50) was 303 mm TL, and the female‐specific mean age at maturity was 0.96 years. Although we observed significant differences between L50 estimates in the GOM, length‐at‐age parameter estimates were similar to those reported for other areas of the GOM. Both individual growth and length‐at‐maturity estimates were significantly different from those reported for the Atlantic, suggesting basin‐level differences in population characteristics, with faster growth and earlier maturation in the GOM. Histological indicators and gonadosomatic index data indicated that the spawning season in the north‐central GOM occurs from November to January and that Southern Flounder are batch spawners with asynchronous oocyte development. Our study provides a description of growth and spawning dynamics that will contribute to future stock assessment efforts focused on the Southern Flounder fishery in Mississippi and the GOM.