Description
Morone saxatilis(female) X M. americana (male) (Virginia Bass) is an artificial hybrid first created in 1966 in North Carolina and occasionally produced and stocked thereafter. The reciprocal hybrid female M. americana X male M. saxatilis, called Maryland Bass, was reared only to the fingerling stage by Harrrell et al. (1990). Morone saxatilis X M. americana hybrids have not been reported from nature, probably because of differences in spawning habitat between the species.
Potentially Misidentified Species - Morone saxatilis X Morone chrysops (Palmetto Bass, Striped Bass X White Bass) is also an artificial hybrid, and more widely introduced; Morone saxatilis and Morone americana are both native; Morone saxatilis X Morone americana is an artificial hybrid. Morone chrysops has been introduced in some reservoirs in the watershed (Jenkins and Burkhead 1993). Other hybrids have been produced, including backcross combinations and hybrids with Morone mississippiensis (Yellow Bass), but rarely utilized (Harrell et al. 1990).
References- Harrrell et al. 1990; Harrell et al. 1993; Jenkins and Burkhead 1993
Taxonomy
Kingdom | Phylum | Class | Order | Family | Genus |
---|---|---|---|---|---|
Animalia | Chordata | Osteichthyes | Perciformes | Moronidae | Morone |
Synonyms
Invasion History
Chesapeake Bay Status
First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
---|---|---|---|---|---|---|---|
1980 | Unknown | Contracting | Introduced | Regular Resident | North America | North America | Fisheries(Fisheries Intentional) |
History of Spread
Morone saxatilis X Morone americana (Striped Bass X White Perch, Virginia Bass) hybrids have been stocked to a limited extent for recreational fishing in DE and MO (Fuller et al. 1999). This hybrid has also been stocked in Lake Jordan NC, with substantial numbers of fish escaping to the Cape Fear River estuary (Patrick and Moser 2001). However, slow and variable growth compared to the Morone saxatilis X M. chrysops (Palmetto Bass, Striped Bass X White Bass hybrid) limits utility for fisheries and aquaculture (Kerby and Joseph 1979; Kerby et al. 1990). Harrell (personal communication, 1996) mentioned that he knew of only 'one or two' operations utilizing this hybrid on the Eastern Shore of Chesapeake Bay, although it is hardier than either purebred M. saxatilis or M. saxatilis X M. chrysops. An early justification for research on the M. saxatilis X M. americana hybrid was that it would probably be non-migratory and provide year-round fishing (Kerby and Joseph 1979).
This hybrid is probably easily overlooked in Chesapeake Bay due to its morphological similarity with M. saxatilis and M. americana (Harrell et al. 1993). We have found no information on its fertility, but hybrids do appear to participate in spawning runs at the same time as Striped Bass (Patrick and Moser 2001).
Upper Bay- In 1980-84, small numbers of Morone saxatilis X americana were introduced in Chesapeake Bay tributaries by Maryland Department of Natural Resources as a 'marked population' for recruitment estimations, at the same time as M. saxatilis X M. chrysops introductions. One was collected in the Upper Bay in 1991 (Harrell et al. 1993).
Delaware Bay- Morone saxatilis x americana were stocked in 1985 in Moores Lake, Silver Lake, and St. Jones River, DE (Raasch and Altemus 1991).
History References - Fuller et al. 1999; Harrell 1996 personal communication; Harrell et al. 1990; Harrell et al. 1993; Jenkins and Burkhead 1993; Kerby and Joseph 1979; Patrick and Moser 2001; Raasch and Altemus 1991
Invasion Comments
Native Region - Morone americana (White Perch) is native to Chesapeake Bay and Atlantic drainages from SC to the St. Lawrence River. Morone saxatilis (Striped Bass) is native to Chesapeake Bay and Atlantic and Gulf drainages From Lake Ponchartrain to St. Lawrence River (Page and Burr 1991).
Vector(s) of Introduction- Morone saxatilis X Morone americana (Striped Bass X White Perch, Virginia Bass) was introduced in Chesapeake Bay tributaries by Maryland Department of Natural Resources as a 'marked population' for recruitment estimations (Harrell et al. 1993). It was introduced in DE as a sportfish (Raasch and Altemus 1991).
Ecology
Environmental Tolerances
For Survival | For Reproduction | |||
---|---|---|---|---|
Minimum | Maximum | Minimum | Maximum | |
Temperature (ºC) | ||||
Salinity (‰) | 0.0 | 35.0 | 0.0 | |
Oxygen | ||||
pH | ||||
Salinity Range | fresh-poly |
Age and Growth
Male | Female | |
---|---|---|
Minimum Adult Size (mm) | ||
Typical Adult Size (mm) | 227.0 | 227.0 |
Maximum Adult Size (mm) | ||
Maximum Longevity (yrs) | ||
Typical Longevity (yrs |
Reproduction
Start | Peak | End | |
---|---|---|---|
Reproductive Season | |||
Typical Number of Young Per Reproductive Event |
|||
Sexuality Mode(s) | |||
Mode(s) of Asexual Reproduction |
|||
Fertilization Type(s) | |||
More than One Reproduction Event per Year |
|||
Reproductive Startegy | |||
Egg/Seed Form |
Impacts
Economic Impacts in Chesapeake Bay
Impact of Morone saxatilis X M. americana (Virginia Bass) in the wild are unlikely at present because of the rarity of this hybrid. Stocking in MD tributaries has ceased (Harrell et al. 1993). However, this hybrid is being reared in the Bay watershed, though less widely than the M. saxatilis X M. chrysops (Striped Bass X White Bass) hybrid in aquaculture (Harrell 1996 personal communication; Kerby et al. 1990).
Fisheries- Given the high value of the Morone saxatilisfishery in Chesapeake Bay, protection of the M. saxatilis gene pool appears to be a priority. However, the M. saxatilis X M. americana hybrid has been stocked only in small numbers, and introgression of M. americana genes has not been demonstrated (Harrell et al. 1993). One early justification for developing this hybrid was as a non-migratory, year-round sport fish with many of the characteristics of M. saxatilis (Kerby and Joseph 1979). This hybrid is less popular for aquaculture than the M. saxatilis X M. chrysops cross, but it is hardier, and is being reared in several local aquaculture operations (Harrell 1996). Overall, the M. saxatilis X M. americana hybrid has probably had few impacts on Bay fish communities.
References - Fuller et al. 1999; Harrell et al. 1993; Harrell 1996 personal communication; Kerby and Joseph 1979; Raasch and Altemus 1991
Economic Impacts Outside of Chesapeake Bay
Morone saxatilis X M. americana (Virginia Bass) has been rarely stocked in the wild, and is much less frequently used n aquaculture than the M. saxatilis X M. chrysops (Striped Bass X White Bass)hybrid (Harrell et al. 1990; Harrell 1996 personal communication). Morone saxatilis X M. americana had no differences in growth during the first 30 days compared to M. saxatilis X M. chrysops (Houde and Lubbers 1986). Over a 17 month period, it demonstrated slower growth than purebred M. saxatilis (Kerby and Joseph 1979) and slower growth than M. saxatilis X M. chrysops hybrids (Harrell et al. 1990). However, it is hardier than the M. saxatilis X M. chrysops hybrid or purebred M. saxatilis (Harrell 1996 personal communication). It has been stocked in at least 4 states, MD, DE, NC, and MO (Fuller et al. 1999; Harrell et al. 1993; Raasch and Altemus 1991).
References- Fuller et al. 1999; Harrell et al. 1990; Harrell 1996; Houde and Lubbers 1986; Kerby and Joseph 1979; Raasch and Altemus 1991)
Ecological Impacts on Chesapeake Native Species
Impact of Morone saxatilis X M. americana (Virginia Bass) are unlikely at present because of the rarity of this hybrid. Stocking in MD tributaries has ceased (Harrell et al. 1993). This hybrid is less widely reared than the M. saxatilis X M. chrysops (Striped Bass X White Bass) hybrid in aquaculture, so that escapes of this form are less likely (Harrell 1996; Kerby et al. 1990).
Competition - Competion with Morone saxatilis and Morone americana would be likely if hybrids were present in large numbers, but has not been documented. Kerby and Joseph (1979) considered that hybrids would probably be outnumbered by the parent species; so that this effect would be small. They did recommend careful monitoring if extensive introductions of this hybrid were made. In the Cape Fear River NC, where a reservoir upstream is stocked, M. saxatilis X americana hybrids can outnumber purebred M. saxatilis. The hybrids appear to be adversely affecting M. saxatilis populations, since M. saxatilis are still declining in this estuary, while recovering in other NC estuaries. Food overlap between the two forms is substantial, but condition of the remaining adult M. saxatilis is good. The mechanism of the decline is unclear, but competition is strongly suspected (Patrick and Moser 2001).
Hybridization - Backcrossing with parent species has not been reported. However, in the Cape Fear River NC, Morone saxatilis X americana hybrids appear to participate in spawning migrations at the same time as M. saxatilis, so that backcrossing is possible (Patrick and Moser 2001).
Predation - Predaton by this hybrid would probably not be not distinguishable from that of parent species.
References - Harrell et al. 1993; Kerby et al. 1990; Kerby and Joseph 1979; Patrick and Moser 2001
Ecological Impacts on Other Chesapeake Non-Native Species
Impact of Morone saxatilis X M. americana (Virginia Bass) are unlikely at present because of the rarity of this hybrid. Stocking in MD tributaries has ceased (Harrell et al. 1993). M. saxatilis X M. chrysops (Striped Bass X White Bass) hybrid in aquaculture, so that escapes of this form are less likely ( Harrell 1996 personal communication; Kerby et al. 1990).
Predation- Predation on nonindigenous fishes and invertebrates would probably not be distinguishable from that of parent species or from M. chrysops hybrids.
Competition - Competition would be likely with Morone saxatilis X Morone chrysops hybrids, but has not been documented. The latter were much more widely stocked and are more abundant (Harrell et al. 1993).
References- Harrell 1996 personal communication; Harrell et al. 1993; Kerby et al. 1990
References
Fuller, Pam. L.; Nico, Leo; Williams, J. D. (1999) Nonindigenous fishes introduced into inland waters of the United States, , Bethesda MD. Pp.Harrell, R. M.; Strand, I. E. (1995) Differentiation of striped bass, Morone saxatilis (Walbaum) from a hybrid: effectiveness of training, Fisheries Management and Ecology 2: 53-60
Harrell, Reginal M.; Kerby, Jerome H.; Minton, Vernon R. (1990) Culture and propagation of Striped Bass and its hybrids, , Bethesda, MD. Pp.
Harrell, Reginal M.; Xu, Xiao Lan; Ely, Bert (1993) Evidence of introgressive hybridization in Chespeake Bay Morone., Molecular Marine Biology and Biotechnology 2: 291-299
Houde, Edward D.; Lubbers, Lawrence III (1986) Survival and growth of striped bass, Morone saxatilis, and Morone hybrid larvae: laboratory and pond enclosure experiments, Fishery Bulletin 84: 905-914
Jenkins, Robert E.; Burkhead, Noel M. (1993) Freshwater fishes of Virginia., , Bethesda, MD. Pp.
Kerby, J. Howard; Joseph, Edwin B. (1979) Growth and survival of striped bass and striped bass x white perch hybrids, Proceedings of the Annual Conference of the Southeast Association of Fish and Wildlife Agencies 32: 715-726
Page, Lawrence M.; Burr, Brooks M. (1991) Freshwater Fishes., , Boston. Pp.
Patrick, Wesley S.; Moser, Mary L. (2001) Potential competition between hybrid striped bass and striped bass in the Cape Fear River Estuary, North Carolina, Estuaries 24: 425-429
Raasch, Maynard S.; Altemus, Vaughn L., Sr. (1991) Delaware's freshwater and brackish water fishes: a popular account, , Wilmingotn, Delaware. Pp.