Effects of commercial harvest on shovelnose sturgeon populations in the upper Mississippi River

Abstract Due to the high amounts of harvest of natural fish populations, overexploitation can occur and subsequently lead to depleted fisheries. This is especially true for commercially exploited roe-bearing species that exhibit late age at maturation and intermittent spawning. Overexploitation can create an imbalance in natural ecosystem function and in turn jeopardize the livelihood of commercial fishers. Despite the problems created by overexploitation, trends of commercial harvest on large inland river roe-bearing populations have received minimal attention. As such, we evaluated trends in commercial fishing data from 1945-2010 for two roe-bearing species (paddlefish Polyodon spathula and shovelnose sturgeon Scaphirhynchus platorynchus) from two of the largest inland rivers in North America (Mississippi River and Missouri River) adjacent to Missouri. Commercial sturgeon and paddlefish catch has varied from ∼160 to 35,150 kg over the course of the 55-year duration. Abnormally high catches corresponded to initiation of worldwide caviar markets, onset of extensive regulations on the Missouri and Mississippi rivers, and the Caspian Sea fishery collapse; respectively. Further, our results suggest that the harvest of sturgeon and paddlefish have increased since 1945 and may be influenced by local, regional, and international events. Despite the increase in harvest and the possibility of overharvest, commercial fishing regulations have not been thoroughly evaluated for effectiveness. Further evaluation of current management and regulations of these paddlefish and sturgeon fisheries is suggested, especially considering these fisheries may be influenced by local, regional, and international events. Taking potentially influential events into consideration when evaluating and implementing regulations and authorizing commercial harvest permits are vital in sustaining a long term commercial fishery and protecting the livelihood of commercial fishers.

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Habitat use by shovelnose sturgeon in Pool 13, upper Mississippi River, Iowa

10.31274/rtd-180813-7315 ◽

1990 ◽

Cited By ~ 1

Author(s):

Gary L. Curtis

Keyword(s):

Habitat Use ◽

Mississippi River ◽

Upper Mississippi River ◽

Shovelnose Sturgeon

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Range-wide age and growth characteristics of shovelnose sturgeon from mark–recapture data: implications for conservation and management

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2014-0238 ◽

2015 ◽

Vol 72 (1) ◽

pp. 71-82 ◽

Cited By ~ 14

Author(s):

Martin J. Hamel ◽

Mark A. Pegg ◽

Reuben R. Goforth ◽

Quinton E. Phelps ◽

Kirk D. Steffensen ◽

...

Keyword(s):

River Basin ◽

Mississippi River ◽

Missouri River ◽

Large River ◽

Population Connectivity ◽

Growth Characteristics ◽

Age And Growth ◽

Mark Recapture ◽

Shovelnose Sturgeon ◽

Commercial Harvest

We used mark–recapture data from shovelnose sturgeon (Scaphirhynchus platorynchus) to describe range-wide growth characteristics and developed a model to estimate ages. Data were solicited throughout much of the current distribution of shovelnose sturgeon, specifically from the mainstem Missouri and Mississippi rivers and their tributaries. Shovelnose sturgeon exhibited variable growth among locations; however, adult fish exhibited almost no growth after they reached a particular size, presumably the size at sexual maturity. Shovelnose sturgeon from the Mississippi River basin attained greater maximum sizes and ages compared with the Missouri River basin. However, two populations from the Mississippi River that received high exploitation from commercial harvest had truncated age distributions with smaller asymptotic lengths. Lower Missouri River populations were characteristic of exploited populations (i.e., smaller fish and reduced longevity), presumably a result of anthropogenic effects. Wide discrepancies in maximum age and size suggest shovelnose sturgeon are capable of displaying phenotypic plasticity in response to exploitation or environmental influences. Determining metapopulation dynamics is a priority because it is unknown how population connectivity may influence dynamic rate functions and persistence of large-river fishes. Identifying potential source–sink connections in terms of population dynamics may provide a template for direction of future restoration and recovery efforts.

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