Hybrid Striped Bass (farmed)

Striped Bass

cross between Striped bass (Morone saxatilis); and White bass (Morone chrysops)

Sometimes known as Palmetto Bass or Sunshine Bass.

These species are farm-raised.

Summary

Hybrid striped bass are a cross between striped bass and white bass. The predominant farming methods for this species are inland ponds and tanks, which lead to less water pollution and disease than other aquaculture methods for finfish (e.g. netpens).

Criterion	Points
Inherent Operational Risks	1.75
Feed	0.75
Pollution	3.25
Risk to Other Species	2.75
Ecological Effects	3.25
Final Score (average of criteria)	2.35
Color

Final Score	Color
2.60 - 4.00
2.20 - 2.59
1.80 - 2.19
1.40 - 1.79
0.00 - 1.39

Last updated September 27, 2007.

Inherent Operational Risks

Core Points (only one selection allowed)

General System Design:

An aquaculture system's design is a good overall proxy measure for the likely effect of the operation on the environment. For example, open systems (e.g., net pens and net cages) are more likely to have pollution, disease, and escape issues than closed systems (e.g., recirculating tanks). With shellfish, which don’t require supplemental food input, the more important question is whether they are harvested on or off of the bottom.

1.00	This species is raised in a high risk system (e.g., net pens; net cages).
2.00	This species is raised in a moderate risk system (e.g., most ponds; raceways; bottom culture of mollusks). In 2003, the United States produced 11.5 million pounds of hybrid Striped Bass. Sightly more than half (57%) of this production occurred using pond systems. The remainder was produced produced in tanks (42%), with a small amount in net pens and cages (0.1%) (Carlberg and Van Olst 2003).
3.00	This species is raised in a low risk system (e.g., re-circulating closed system; suspended culture of mollusks; zero-discharge ponds).

Points of Adjustment (multiple selections allowed)

-0.25	Species is raised at a high stocking density; OR there is a high density of sites in the geographic region, with evidence of environmental impact. Hybrid striped bass farms are increasingly intensive operations. Fingerlings (200-300 fish per pound) are initially stocked at densities of 15,000-20,000 fish per acre, and are later culled to 4,000 fingerlings per acre. Resulting annual harvests are approximately 5,000 lb/acre (Carlberg et al., 2000). This is up from initial stocking densities of 8,000-12,000 fish per acre in 1989 (Hodson and Hayes, 1999). Hybrid striped bass farms are spread across the nation. In 2003 there were only 68 farms, and these are parsed over more than a dozen states (Carlberg and Van Olst 2003). Because stocking density is high and the density of sites is low, we do not add or subract points here.
-0.25	Operations do not incorporate best-available, cost-effective technology to reduce environmental impact.
-0.25	There are no effective zoning or permitting practices for siting of facilities.
-0.25	Government programs encourage expansion of high-impact systems.

+0.25	Species is raised at a low stocking density OR there is a low density of sites in the geographic region, which results in minimal impact to the natural ecosystem.
+0.25	Operations incorporate innovative culture methods that limit environmental impacts (e.g., polyculture).
+0.25	There are effective zoning or permitting practices for siting and operation of facilities (e.g., mandatory consideration of hydrographic characteristics; requirements for site rotation).
+0.25	Government programs preferentially encourage the expansion of low-impact systems over high impact systems.

1.75	Points for Inherent Operational Risks

Feed

Core Points (only one selection allowed)

Ecological Footprint of Feed:

"Trash" fish, frequently used in developing countries, is an industry term used to refer to whole fish or fish parts fed to farmed fish without being processed into fish meal and fish oil.

Twenty percent was selected as a cut-off because carnivorous species (e.g., salmon; eel; tuna; cobia; etc.) generally consume greater than twenty percent fish products (fishmeal, fish oil, or trash fish), while omnivorous or herbivorous species (e.g., catfish; tilapia; carps; etc.) consume less than twenty percent fish products.

1.00	Typical aquaculture feed includes high levels of fishmeal, fish oil, or "trash" fish (i.e., >20% of the feed; e.g., salmonid feeds). Hybrid Striped Bass are carnivores so feeds require fish meal and fish oil. Fishmeal content in Hybrid Striped Bass diets ranges between 18 and 35 percent (NOSB). Hybrid striped bass are optimally fed a forty percent protein diet. In trout, a similar forty percent protein diet is around 20 percent fishmeal and 14 percent fish oil (Tacon, 2000). Consequently, an estimated fishmeal inclusion rate of 30 percent would be conservative.
2.00	Typical aquaculture feed includes moderate levels of fishmeal, fish oil, or "trash" fish (i.e., <20% of the feed; e.g., tilapia and catfish feeds).
3.00	No feed is used (e.g., mollusks and seaweeds) or typical aquaculture feed includes no fishmeal, fish oil, or "trash" fish (e.g., paddlefish; filter-feeding carps).

Points of Adjustment (multiple selections allowed)

-0.25	When fish products are used, the major sources score low on the Wild-Caught Fisheries Ranking System.
-0.25	Feed contains greater than 10% of fish products and public or private sectors are not working to reduce fish content in feed. A study from Kentucky State University determined that juvenile hybrid striped bass could be fed diets containing as little as 15% fishmeal without adversely affecting growth or body composition as long as crude protein was maintained at 40% (by using soybean and meat/bone meal) (Hodson and Hayes, 1998). There is a movement to reduce the amount of fish products, as this is the most expensive component of aquaculture feeds. However, this is something that has not been adopted by industry.
-0.25	Feed conversion ratio (FCR) is high (i.e., >2.0; e.g., eel). FCR is likely approximately 2.0.
-0.25	Government policy promotes research, development and commercialization of carnivorous or other highly fishmeal-dependent species.

+0.25	When fish products are used, the major sources score high on the Wild-Caught Fisheries Ranking System; OR the source is innovative and ecologically sound (e.g., fisheries byproducts); OR no feed is used.
+0.25	Feed contains less than 10% of fish products OR public and private sectors are working to reduce the fish content in feed; OR no feed is used.
+0.25	Feed conversion ratio (FCR) is low (i.e., <1.3; e.g., salmon); OR no feed is used.
+0.25	Government policy promotes research, development and commercialization of herbivorous species or other species not highly dependent on fishmeal.

0.75	Points for Feed

Pollution

Core Points (only one selection allowed)

Typical effluent treatment procedures:

1.00	Effluent is not treated before discharge (e.g., salmon net pens).
2.00	Effluent is partially treated before discharge (e.g., infrequently discharged effluent from catfish ponds).
3.00	Effluent is substantially treated before discharge (e.g., recirculating shrimp systems; settling ponds; reconstructed wetlands); OR treatment is not necessary because supplemental feed is not used (e.g., molluscs or seaweeds). Almost half of hybrid striped bass farms use tank systems with some degree of recirculation. In addition, some of the pond systems treat their effluent. Generally, effluent from hybrid striped bass are more likely to be actively treated than any other finfish in the United States outside of sturgeon.

Points of Adjustment (multiple selections allowed)

-0.25	Operations have demonstrated negative impacts on water quality or sediment/benthic characteristics (e.g., elevated nutrient levels; algal blooms; altered benthic communities).
-0.25	Pollutants (e.g., pesticides; parasiticides; antibiotics; plastic; nets; dead fish) are frequently discharged into the environment or otherwise not appropriately discarded.
-0.25	Effluent regulations do not exist, are lax, or are poorly enforced, which allows for degradation of the aquatic environment.
-0.25	Available technologies and practices to reduce or recycle waste (e.g., feed sensors; low-pollution feeds) are not used.

+0.25	Operations generally improve water quality or sediment/benthic characteristics (e.g., oyster farms).
+0.25	Chemicals (e.g., pesticides; parasiticides; antibiotics) are rarely or never used. Antibiotic use is prohibited without a veterinarian's prescription. Other chemicals are rarely if ever used.
+0.25	Robust water quality regulations exist (e.g., permits required; discharge caps; strong enforcement), and regular monitoring occurs. Effluent controls vary by state and region. In some states, control of effluent from pond production systems is minimal or lacking entirely. No major concerns have been voiced about effluent from hybrid striped bass farms, particularly as almost half of operations are tank operations, while production from the remaining half is dwarfed by catfish pond systems.
+0.25	Innovative methods and practices to reduce or recycle wastes are used (e.g., integrated systems; effluent and solid wastes used as terrestrial fertilizer); OR innovative methods and practices are not needed because raising this species does not create waste. In some instances, effluent is applied to crops (e.g. Kent Sea Tech Corporation in California) (http://kentseatech.com). However, those instances are exceptions and not the general rule.

3.25	Points for Pollution

Risk to Other Species

Core Points (only one selection allowed)

Frequency and Impact of Escapes:

1.00	Farmed species regularly or intermittently escape into the wild AND escapes are non-native to the area or otherwise pose a risk to native populations or ecosystems (e.g., most non-native fish raised in outdoor facilities).
2.00	Escape frequency is not known OR farmed species is native to the area where it is raised and poses minimal risk to native populations or ecosystems (e.g., channel catfish in the US; most native mollusks). Hybrid striped bass are not native to the areas they are raised, because there are no native hybrid striped bass. However, both striped bass and white bass are native in large sections of the United States and have been introduced for sportsfishing purposes into many other areas. As a consequence, hybrid striped bass may be best considered as an established species – particularly given the fact the hybrids do not reproduce well in the wild.
3.00	Farmed species never (or virtually never) escape to the wild (e.g., species is raised in bio-secure facilities).

Points of Adjustment (multiple selections allowed)

-0.25	This farmed species has been known to survive in the surrounding ecosystem if it escapes; OR would likely survive given its physiological requirements.
-0.25	This farmed species is known or is likely to compete with wild species for food or habitat if it escapes; OR this species is known or is likely to compromise the genetic integrity of the wild species (e.g., through spawning disruption, genetic introgression or establishment of feral stocks) if it escapes.
-0.25	This farmed species is known or is likely to amplify and transmit disease or parasites to wild populations (e.g., infectious salmon anemia or sea lice infestations) if it escapes.
-0.25	Regulatory authorities are not adequately addressing the risks of escape or spread of disease associated with farming this species.

+0.25	This farmed species has not been known to survive in the surrounding ecosystem if it escapes; OR would not likely survive given its physiological requirements; OR farmed species is a native mollusc. There are no wild populations of hybrid striped bass. Moreover, while these hybrids are fertile, there have only been a few reports of successful reproduction (Hodson 1989).
+0.25	Operations employ management protocols and techniques to limit the ecological impacts of escaped farmed fish (e.g., triploidy; sterilization); OR it’s unlikely that escaped individuals will either compete with wild species for resources, or compromise the genetic integrity of wild species. Hybrid striped bass are not known to jeopardize the viability of other populations.
+0.25	Operations employ effective disease and parasite management protocols (e.g., fallowing of pens; retaining water when disease outbreak occurs); OR incidence of disease or risk of retransmitting disease is low. Hybrid striped bass are disease prone, but have not posed a known disease risk to wild populations (Carlberg et al. 2000). Bacterial diseases include columnaris, aeromonas, and pseudomonas. In addition, the viral disease vibriosis and the protozoan parasite Ich have been problematic. All of these diseases are widespread in distribution and effect multiple species.
+0.25	Regulatory authorities are addressing the risks of escape and spread of disease associated with farming this species.

2.75	Points for Risk to Other Species

Ecological Effects

Core Points (only one selection allowed)

Ecological sensitivity of site used for operations:

1.00	Operations are generally located in areas of high ecological sensitivity (e.g., coastal wetlands; mangroves).
2.00	Operations are generally located in areas of moderate ecological sensitivity (e.g., coastal and nearshore waters; rocky intertidal or subtidal zones; river or stream shorelines).
3.00	Operations are generally located in areas of low ecological sensitivity (e.g., land that is less susceptible to degradation such as land formerly used for agriculture or land previously developed). Although some coastal operations exist, most hybrid striped bass farms are located inland, either using tank or pond systems.

Points of Adjustment (multiple selections allowed)

-0.25	Farming this species causes substantial damage to surrounding habitat, ecosystem or other resources (e.g., groundwater depletion; stream diversion; saltwater intrusion; soil salinization; loss of habitat for juvenile fish; loss of flood control; dredging hard bottoms; etc.).
-0.25	Harmful or lethal predator deterrents are used (e.g., bird/seal shootings; acoustic deterrent devices); OR operation otherwise harms wildlife (e.g., dolphin/seal entanglement; disrupting migration routes; bird/animal shooting).
-0.25	If seed is collected from wild sources, the intensity of collection is high enough to result in depletion of brood stock, wild juveniles, or associated non-target organisms (e.g., collection of postlarvae shrimp).
-0.25	Government policy encourages aquaculture operations to locate or expand in areas of high ecological sensitivity.

+0.25	Operations enhance habitat structure or function (e.g., constructed wetlands).
+0.25	Predator deterrents are not used OR predator deterrents are used but are not harmful or lethal (e.g., predator exclusion nets), AND operation does not otherwise harm wildlife.
+0.25	Seed comes predominantly from hatcheries or on-farm sites (e.g., seed for trout); OR if seed is collected from the wild, it does not deplete brood stock, wild juveniles, or associated non-target organisms (e.g., collection of oyster or mussel spat). Hatchery operations provide fingerlings to grow-out operations using broodstock taken from the wild (Carlberg et al. 2000). Wild striped bass populations are at record high levels of abundance.
+0.25	Government policy encourages the growth of aquaculture operations in areas of low ecological sensitivity; OR protects sensitive habitats from aquaculture operations (e.g., prohibitions on cutting mangroves).

3.25	Points for Ecological Effects

References

*We would like to thank Environmental Defense for their research and ranking contribution toward this Score Card.

Carlberg, JM and J.C. Van Olst. 2003. U.S. production and sales of hybrid striped bass (1987-2002). http://aquanic.org/sbga/HSBversion5.ppt.

Carlberg, JM, J.C. Van Olst, and M.J. Massingill. 2000. Hybrid striped bass: an important fish in US aquaculture. Aquaculture Magazine 26 (6).

Hodson, RG and M. Hayes. 1999. Hybrid striped bass: pond production of foodfish. Southern Regional Aquaculture Center, SRAC Publication No. 303, July 1999.

Hodson, RG and M. Hayes. 1998. Improving feeds for hybrid striped bass. Southern Regional Aquaculture Center, SRAC Publication No. 304, April 1998.

Hodson, RG. 1989. Hybrid striped bass: biology and life history. Southern Regional Aquaculture Center, SRAC Publication No. 200, July 1989.

http://www.kentseatech.com/technology/conservation.htm

USGS. Aquatic Nuisance Species, Nonindigenous fish distribution information. http://nas.er.usgs.gov/fishes/fisheslist.htm

National Organics Standard Board (NOSB), Aquaculture Working Group. Aquaculture Working Group Report. http://www.ams.usda.gov/nop/nop2000/nosb%20recommedations/Aquaculture/workgroup1100.htm

Tacon, Albert. 2000.