An evaluation of a proposed technology to prevent invasive species migration using a treatment chamber using chlorination.
On 24 February 2014, commercial fishers caught an unusually large Hypophthalmichthys nobilis (Bighead Carp) from an oxbow lake in northwestern Mississippi. We examined it to determine age, gonadal development, and fecundity. The specimen was 1316 mm total length, 49.7 kg, and 11 years old. It had asymmetric ovaries that collectively represented 15.7% of the body weight, with an estimated 1.9 to 2.7 million eggs, ∼40% of which were mature. The data we collected for size, age, and fecundity were all at or near maximum values known for the species. This specimen demonstrates that for life-history studies and demographic models to be representative of introduced populations, rare or hard-to-catch large specimens are required due to their influence on estimates of longevity, mortality, and fecundity.
Although the movement of invasive bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix) in the Upper Mississippi River system is dependent on their ability to swim through its numerous lock-and-dams, the swimming performance of adults of these species is at present unknown. Using a large (2,935-L) mobile swim tunnel, the swimming performance of adult bighead and adult silver carp was quantified at water velocities that challenged them to exhibit either prolonged and/or burst swimming (76–244 cm/s) with fatigue times of less than 10 min. Simple log-linear models best described the relative swim speed to fatigue relationships for both species. Under these conditions, the swimming performances of adult bighead and silver carp were similar to several species of adult fishes native to the Mississippi River system, but relatively low (<3 total body lengths per second, TL/s) compared to previously studied juveniles and sub-adult bigheaded carps (3–15 TL/s). The decline in endurance with water velocity was three times greater in bighead carp (slope = −2.98) than in silver carp (slope = −1.01) and the predictive ability of the bighead model was appreciably better than the silver carp model. The differences in adult swimming performance between the two species were coincident with behavioral differences (e.g. breaching in silver carp but not in bighead carp). The swimming performance data of adult bighead and silver carp can now be used to evaluate whether their passage through manmade river structures including the gates of lock-and-dams in the Upper Mississippi River might be reduced.
PURPOSE: Empirical swim speed data are needed to manage invasive bigheaded or " Asian " carps (Figure 1). However, such data are limited within the scientific literature. The large size and active temperament of the carp combined with current legislative restrictions concerning transport, make them difficult to acclimatize and test in traditional laboratory swim tunnels. Biologists from the Engineer Research and Development Center (ERDC) Environmental Laboratory (EL), with funding from the EL and the Aquatic Nuisance Species Research Program (ANSRP), designed and constructed a mobile swim tunnel for use along shorelines, minimizing transport, and eliminating the need for acclimitization. This enables immediate evaluation and on-site measurements of swimming performance in carp and other species. BACKGROUND: The swimming speeds of adult bigheaded carps (Hypophthalmichthys spp) are needed for management of these invasive species in North American waterways. Such data can be used to assess rates of movement (Konagaya and Cai 1987; 1989), the likelihood of hydraulic containment or displacement (Hoover et al. 2012), and the risk of establishment (Cooke and Hill 2010). Substantial obstacles to completing these studies are: their maximum size when mature (> 1 m and > 40 kg), their characteristic activity (powerful free-swimmers and leapers), and the Lacey Act restrictions concerning the interstate transport of the species (Kolar et al. 2005; USFWS 2007, 2011). These obstacles preclude traditional study approaches, including: collecting wild fish or using hatchery-produced fish; transport to and acclimatization in laboratory holding tanks; repeated testing of naïve individuals in controlled swim trials in laboratory swim tunnels (Brett, 1964; Hoover at al. 2012).