Morris, Joseph

Work began on the research ponds at the Horticulture Station in the second week of October (2003) and was completed in May 2004. The project consisted of constructing 6, 0.2 acre research ponds, an access road, wetland, well, and a staging area. The Iowa State University Aquatic Research Facility has a total of 1.2 surface acres of water. The total project area covers 3.58 acres; approximately 20,000 cubic yards of dirt will be moved and reshaped for pond construction.

Sunfish have been identified as potential aquaculture taxa in the North Central Region (NCR). The North Central Regional Aquaculture Center (NCRAC) has funded projects to address the research needs of developing sunfish as a viable aquaculture commodity in the NCR. Because the NCRAC Board of Directors (Board) and the Industry Advisory Council (IAC) memberships change over time, the Board directed that white papers be developed on the NCR potential aquaculture species. These white papers are designed to outline the current status of aquaculture technology, the critical factors limiting economical and sustainable commercial production, and the recommendations for research and extension that should be considered in future work plans for each species considered. In addition, the white papers are considered as “living documents” that can be updated based on advancements and new developments within the industry.

A substantial need exists to reduce costs and develop more nutritionally adequate diets for established as well as emerging aquaculture species in the North Central Region (NCR). The study evaluated a diet for juvenile northern bluegill (Lepomis macrochirus) that is significantly less costly than currently available diets for sunfish, while yielding a growth rate that is at least equal to an industry standard sunfish diet. Such a diet formulation is now available to the NCR as the result of a recently funded North Central Regional Aquaculture Center (NCRAC) project.

The Sunfish Culture Guide, which focuses on Lepomis spp., is organized so that each chapter can stand alone. Culturists with different interests and levels of expertise can use all or any part of the guide. Consequently, some repetition of information was unavoidable; however, we believe that repetition will not cause readers undue distraction.

Fish culture ponds are commonly fertilized to increase fish production through enhancement of the plankton forage base. Many fish culture facilities rely on natural production of zooplankton and aquatic insects as food sources for larval fish. Literature on pond fertilization regimes varies; recommendations range from no fertilization to a combination of inorganic and organic fertilizers. More research on the interactions among water quality, nutrients, plankton (phytoplankton and zooplankton) and fertilizers of the appropriate nutrient ratios is needed to move fertilization from an art to a science.

The species commonly referred to as "sunfish" or "panfish" belong to the Centrarchidae family (Pflieger 1975). This family inhabits North America and is loosely divided among three groups: black bass Micropterus spp., sunfish Lepomis spp., and crappie Pomoxis spp. Although Centrarchidae includes several genera with culture potential, this chapter will focus on members of Lepomis; the term "sunfish" will be used hereafter.

Striped bass (Morone saxatilis) have been commercially harvested for many years, however wild stocks have declined due to environmental degradation, habitat loss and overfishing. The U.S. wild fishery of striped bass was 6.8 million kg (15 million lbs.) in 1973, but declined to less than 0.2 million kg (0.5 million lbs.) in 1990. In the past few years striped bass populations have started to rebound due to restrictions on their harvest, but are unlikely to approach the 1973 levels. In response to decreased commercial catches, the striped bass and its hybrids have been commercially produced in ponds, raceways, and tanks to fulfill the established commercial markets. The 1995 aquaculture production was 4 million kg (9 million lbs.).

The channel catfish, Ictalurus punctatus, is the principal warm water species grown in the southeastern United States. In 1991 there were 390 million lb. of channel catfish (live weight) produced in this country, with the majority produced in Mississippi. The price of channel catfish decreased in 1991 compared to 1990 when the production was 30 million lb. less. In December 1991 the price of channel catfish delivered to processing plants was $0.53/lb. compared to $0.72/lb. in December 1990 (live weight). In wholesale terms, dressed whole fish were $1.23/lb. in 1991 and $1.61/lb. in 1990 for the same time period. At the 1991 prices many of the aquaculturists were either losing money or just breaking even. However, both prices and production increased by December 1992. For fish delivered to processing plants, the price increased to $0.63/lb. with 457 million lb. processed (live weight).

Many of the world’s natural fisheries have been decimated. To meet future seafood demands, aquaculture must continue to grow. However, aquatic resources are limited, and aquaculture development must address the serious concerns of resource allocation, environmental impact, and sustainability. Current aquaculture activities in the United States vary by region. Although the North Central Region (NCR) is rich in freshwater resources, traditional aquaculture activities (both public and private) have been principally driven toward satisfying the demands for recreational fishing and tourism. Other regions of the United States have specialized in the production of fish and seafood for human food markets (e.g., catfish in the south and salmonids in Idaho).

Six 0.04-ha plastic-lined ponds were used at the Iowa Department of Natural Resources’ Rathbun Fish Culture and Research Facility to evaluate the use of supplemental fish food on walleye (Sander vitreus) fingerling growth and survival, and on the benthic invertebrate community. Walleye were stocked 3-4 days post hatch on 2 May 2003, and harvested 5-6 June 2003. Organic fertilizer (alfalfa pellets, 112kg/ha/week) was used to increase primary production and inorganic fertilizers were added periodically to maintain a target nutrient ratio of 7:1 nitratenitrogen to total phosphorus (NO3-N: TP). Additional nutrients in the form of Lansy CW fish feed were added to three of the six ponds. The objective of this project was to determine the effect of a commercial fish diet on water quality. At the end of the culture season, there were significant differences between water chemistry parameters in the ponds; the feed treatments had higher levels of nitrogenous compounds and total phosphorus.