Invasive Asian Carps in North America

Abstract

<em>Abstract</em>.—Our book <em>The Black Carp: Biological Synopsis and Risk Assessment of an Introduced Fish </em>was published in 2005. The present chapter provides a brief overview of new events and re-examines pieces of earlier information on this molluskeating species. Effective November 19, 2007, black carp <em>Mylopharyngodon piceus </em>was placed on the Lacey Act list of injurious wildlife. Listing pertains to all forms of live black carp, including diploids (reproductively fertile), triploids (thought to be sterile), hybrids, and gametes and viable eggs, prohibiting their import into the United States and banning interstate transport. States retain rights to regulate black carp already within their jurisdiction. Although many states now ban black carp, a few states in the lower Mississippi basin still permit breeding programs and allow use of black carp for snail control in ponds. In North America, black carp are present in open waters of the lower Mississippi River basin. Likely the result of escape from aquaculture, some captures reportedly date to the early 1990s. Most (10 of 11) wild captures tested have been found to be diploids. During the mid-1990s, an estimated 400,000 black carp were in aquaculture. The number fluctuates and present total is uncertain but includes diploids. Currently, it is not possible to adequately assess the risk of additional escape because the numbers and distribution of diploid and triploid black carp held in aquaculture and the frequency and intensity of farm-pond flooding are not fully documented. Much also remains unknown about wild black carp populations in the Mississippi basin, especially with regard to their distribution, abundance, reproduction status, and types of mollusk prey consumed. The paucity of data is largely attributed to the difficulty of capturing wild black carp and the near absence of field research targeting this species.