Flathead Catfish Pylodictis olivaris in the lower Wabash River, Illinois and Indiana, are currently exploited by anglers and commercial fishers under the same fishing regulation; however, the regulations differed between the states prior to 2015. We assessed demographics of Flathead Catfish in this interstate river to gain baseline information to create models to test for sustainable exploitation rates under the new regulation and several hypothetical scenarios. During 2010–2012, we sampled 951 Flathead Catfish (length = 343 ± 5.6 mm [mean ± SE], weight = 914.5 ± 55.6 g, age = 3.5 ± 0.07 years) using pulsed‐DC electrofishing, AC electrofishing, commercial harvest, and hoop nets. Mean relative weight of Flathead Catfish was greater than 100%, and proportional size distribution indices (electrofishing = 35, hoop netting = 54) suggested a quality fishery. Total annual mortality (electrofishing = 0.48, hoop netting = 0.54) was similar to estimates in other Midwestern rivers. Yield‐per‐recruit models predicted that growth overfishing may occur over time under the current regulation; however, demographic metrics relate to recreational and commercial creel assessments. Our results suggest that the current minimum length limit could be raised to increase yield and reduce exploitation. Our findings also demonstrate several useful field and modeling techniques to assess catfish (family Ictaluridae) populations in environments that are difficult to sample and that lack fishery‐independent information. Received January 11, 2017; accepted August 31, 2017 Published online October 20, 2017

With the closure of commercial fishing for Shovelnose Sturgeon Scaphirhynchus platorynchus in most reaches of the Mississippi and Missouri rivers, harvest may increase in other rivers. We studied the demographics of a commercially exploited Shovelnose Sturgeon population in the lower 322 km of the Wabash River, Illinois. During 2000–2013, 10,734 Shovelnose Sturgeon were captured by using DC and AC electrofishing, gill nets, hoop nets, trotlines, and benthic trawls. Of the captured individuals, 399 fish were recaptured. Electrofishing CPUE was the highest reported in any study on Shovelnose Sturgeon. Captured fish ranged between 61 and 909 mm FL (mean = 662 mm; median = 671 mm), but few fish were smaller than 500 mm. Although the fish were in good condition (mean relative weight = 89.9), there was a decreasing trend in mean condition over time. Shovelnose Sturgeon ranged in age from 0 to 25 years; 90% of the fish were between age 8 and age 19. Fish were fully recruited to the sampling gear at age 10; total annual mortality for fish older than 10 years was 20.6%. An empirical growth rate of 2.67 mm/year was observed for fish larger than 635 mm, with several individuals showing negative growth. The sex ratio was slightly skewed toward males (2.18 males : 1 female). The Shovelnose Sturgeon population in the lower Wabash River was generally healthy and stable and had characteristics comparable to those of the upper Wabash River population, with slow growth, large sizes, good condition, and low mortality. Received December 19, 2014; acceptedMay 11, 2015

Little information exists on the stock characteristics and dynamics of longnose gar (Lepisosteus osseus) and shortnose gar (Lepisosteus platostomus). We examined the size and age structure, mortality, growth, and condition of both species from the Wabash River, Indiana-Illinois, from June through August 2006. Longnose gar ranged from 492 to 1,224 mm in total length (TL) and from 250 to 5,600 g in wet weight (WW), while shortnose gar ranged from 498 to 776 mm in TL and from 350 to 1,900 g in WW Longnose gar and shortnose gar ranged in age from 2 to16 and 2 to12 years, respectively. Total annual mortality ranged from 13 to 17% for longnose gar and from 25 to 29% for shortnose gar. Annual growth in length was most rapid through age 6 for longnose gar (range, 18 to 100 W y r ) and age 4 for shortnose gar (range, 9 to 48 mndyr). Variation in relative condition of longnose gar and shortnose gar was heterscedastic over the size range of fish collected, but there was no significant relationship between relative condition and total length.

Shovelnose sturgeon (Scaphirhynchus platorynchus, Rafinesque, 1820) in the Wabash River, Illinois/Indiana, USA, provide an important recreational sport and commercial caviar fishery. In fact, it is one of the last commercially viable populations for sturgeon roe harvest. Due to increased demand in the caviar trade and endangered species legislation that protect shovelnose sturgeon in only a portion of their range, efforts of the roe harvest market may continue to divert toward unprotected populations like the shovelnose sturgeon in the Wabash River. Previous studies have shown that increased harvest pressure in this species can affect the age‐at‐maturation and result in recruitment overfishing. Therefore, it is important to closely and continuously monitor commercially exploited populations. Over the past decade (2007–2016), 13,170 shovelnose sturgeon were sampled with boat electroshocking, hoop nets, drift nets, trotlines, and benthic electrified trawls. Captured fish ranged from 61 to 910 mm fork length (FL; mean = 668 mm), with very few fish less than 550 mm FL. Although fish were found to be in a healthy condition (mean relative weight = 87), there was a decrease in the mean condition over time. In addition, we saw declines in mean FL, weight of roe‐per‐fish, and size‐at‐maturity for female fish directly impacted by harvest. The decline of these population parameters, coupled with an increase in total annual mortality and a truncated age frequency distribution, suggest that harvest is negatively impacting the demographics and recruitment of shovelnose sturgeon in the Wabash River. Considering the downward trajectory of population dynamics and high estimates of mortality, their resiliency to continued harvest and environmental changes will be limited.