 |
|
|
|
|
The Striper A Publication of the Striped Bass Growers Association
July 1999 President's Message ... With the ‘99 growing season well under way, it may seem difficult to step from the thick of things to look ahead. Yet "now" is usually the best time for such plans to be laid. This year’s annual meeting in Tampa, FL was well attended and informative covering such topics as HCG, generic marketing, quinine potential, and a web-based Suppliers Directory. Attendance and participation in these events is critical to our industry for both information and direction, so I strongly encourage you to register for next years meeting now. It will be held in conjunction with Aquaculture America 2000, February 2 - 5 at the New Orleans Marriott. For more information call 425-485-6682. As you’ll read in the enclosed Association minutes, the possible use of quinine as an anti-parasitic feed additive had not been fully addressed. Association member, Brent Blauch has picked up the torch and is currently attempting the protocol towards INAD status for quinine. He is working with Julie Bebak of the Freshwater Institute in West Virginia and NADA Coordinator Roz Schnick. Roz’s inquiries with the theraputant supplier sparked questions of industry interest and potential markets. The result was the Quinine Survey many of you received. If you have not done so already, please return this survey as soon as possible. Every interested grower counts! Of the 12 surveys received so far: Growers that would use quinine if approved: YES - 11; NO - 1. Growers that would participate in an INAD: YES - 7; NO - 5. In order to step up industry participation, a similar survey will be sent to the Florida Tropical Fish Farms Association and the Arkansas Bait and Ornamental Fish Growers Association. A total of 20 Suppliers Directory surveys were returned from: Growers - 16; Feed Mills - 2; Farm Supply - 1; and Support Services (extension) - 1. The following statistics were derived from those polled:
The new Suppliers Directory is currently being formatted and should be available by the end of July on the SBGA website at http://ag.ansc.purdue.edu/aquanic. The membership is invited to contact the board at any time with issues, questions, or suggestions. Many thanks to past-president, Steve Mitchell and the board for their continuing service to the industry. In closing, my best wishes for a successful and profitable 1999! The following summarizes major points of the Noninsured Crop Disaster Assistance Program (NAP), as excerpted from "Federal Aquaculture Briefs", published 2/1/99 by USDA/CSREES. To get ALL the details, contact your local FSA office. Producer Eligibility - Producers must "register" with FSA, and keep that office informed of the farmÆs status. Fish farmers must: - Report acres and production for crops eligible for NAP on or before September 30. - Report losses within 15 days of the disaster or the date that damage becomes apparent. - Certify production history and report current crop year production; - Earn less than $2 million in annual gross revenue - Meet other administrative requirements Determining Crop Loss - Producers establish an expected yield by averaging actual yields over a 4 to10 year period. Area Defined - In the 50 States, a NAP area must include at least five producers on separate and distinct farms with eligible NAP crops that have each suffered more than a 35 percent crop loss. Farm Production Records - After an approved yield is established, the producer must annually report acreage and production. If records are not provided, a yield will be assigned for only one year, usually a low value. If the producer fails to report production again, a zero yield is entered in the database, severely lowering expected yield figures. Payment - If your area loses 35% of the crop, NAP payments will be based on 1) individual crop losses in excess of 50% of the approved expected yield, and 2) 55% of the crop's average market price as determined by the USDA Farm Service Agency. Payments cannot exceed $100,000 for any given crop year. The bottom line is this, if you have a 100% wipeout, you could be entitled to about 25% of the cropÆs value, up to a maximum of $100,000. With all of the caveats and conditions and judgements to be made by the FSA, it is important to address your eligibility for this assistance well before you actually need it! Call your FSA office soon to get the details for your area. Let them know you exist and make sure that your average annual yield is a reasonable expectation of what you can/hope to produce. May you never need to take advantage of this program! Valderrama Recipient of Walter Landry Memorial Award Diego Valderrama was selected as the recipient of the 1999 Walter Landry Memorial Award for his research on predation of cyclopoid copepods on sunshine bass fry, see insert for submitted summary. The award is presented to a student for outstanding achievements in research on any of the species in the Morone genus and/or Morone hybrids. Valderrama is a student at Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff. He was presented with an award certificate and a travel assistance of $250 during the 1999 Striped Bass Growers Association Annual Meeting in Tampa, Florida. Students interested in submitting entries for the 2000 Walter Landry Memorial Award are invited to submit identification of their academic affiliation and a summary (maximum of four pages) detailing their research accomplishments to the Striped Bass Growers Association, PO Box 11280, Columbia, SC, 2921l. Deadline for entries is October 1, 1999. The Striper The Striper is published by the Striped Bass Growers Association, a non-profit, membership corporation. Membership information is available by contacting: Striped Bass Growers Association President: Sam Plottel Nature’s Catch Inc New Market - Supplying the Sportfish "Put and Take" Niche by Brent Blauch Odds are probably good that every striped bass grower at one time or another liked to go fishing. Even though at this time of year the thought of going fishing and relaxing (while the fish farm is in the height of excitement) seems as remote as Mars, the thought of someone else going fishing - to catch your fish - doesn’t seem that far fetched. In fact, hybrid striped bass are one of the hardest-fighting, most aggressive fish one can angle for in fresh water. Last month’s issue of Pennsylvania Game and Fish Magazine (one of several State focused sportsman magazines published by Game and Fish Publications, Inc. of Marietta, GA) highlighted hybrids as a fish that "...fills a niche for anglers looking for big, aggressive, hard-fighting fish." The article went on the talk about the State’s best hybrid striper hotspots - stocked by the Fish and Boat Commission - and the great angling opportunities afforded by these special fish. Hybrids are known across the US as a formidable gamefish, but the word hasn’t quite leaked out that ANYONE can have great hybrid fishing by simply stocking catchable sized hybrids in their private lakes and ponds, just like they can do with trout or catfish. They don’t realize that there are excellent sources of full-grown hybrids available from established growers (like yourself) that can turn their fishing into catching, with immediate and gratifying results. "You gotta hook ‘em to cook ‘em," could be a slogan we hear over and over. Granted, food market sales for hybrid striped bass must be expanded to meet our new anticipated production, if we are to keep farmgate pricing from deteriorating. However, with directed marketing of our fish to sportsmen groups, private landowners, clubs, and generally avid anglers, we should be able to uncover new market opportunities with customers who have interests close to our own - spending some relaxing time fishing. Perhaps with some coordinated advertising in fishing publications, recreational sportsmen shows and expositions, and sponsorship of events like tournaments, we can bring an awareness of our growers’ capabilities to a new market of anglers. The trout industry enjoys large food market sales as well as large angling sales. We can do the same - we just need a little refocusing. Striped Bass Growers Association PO Box 11280 Predation of cyclopoid copepods on sunshine bass fry. Abstract Low and variable survival rates have been observed for sunshine bass fry in rearing ponds despite following the standard procedures used to stock striped bass and palmetto bass fry. A mismatch between sunshine bass fry and forage of suitable size is regarded as the primary cause of mortality among the fry. Mortality could also be due to direct predation on the fry by carnivorous copepods. To test this hypothesis, recently hatched sunshine bass fry were exposed to a concentration gradient of cyclopoid copepods (0, 5, 50, and 500 copepods/L) during a 24-hour period. No significant differences in survival rates were found among the first three treatments, but fry suffered high mortality in the 500-copepod/L treatment. Adult copepods are observed at such high densities in culture ponds. Results were also used to test a model that predicts predation rates on fish larvae by a variety of predators. This study indicates that stocking sunshine bass fry in ponds containing only rotifers and copepod nauplii will reduce the risk of predation and ensure suitable forage. Introduction Striped bass (Morone saxatilis) and its hybrids with white bass (M. chrysops) have been routinely cultured to fingerling size in earthen ponds since the mid-1960’s (Stevens 1966, Bishop 1968, Kerby et al. 1983). Good survival rates for striped bass and palmetto bass (original-cross hybrid striped bass: female striped bass x male white bass) fry have been attained following the nursery pond management strategies recommended by Geiger et al. (1985) and Geiger and Turner (1990). However, these methods are not adequate for sunshine bass (reciprocal-cross hybrid striped bass: female white bass x male striped bass) fry, which are smaller and have lower and more variable survival rates than striped bass and palmetto bass fry (Ludwig 1993). The most apparent cause of the low and variable survival rates of sunshine bass fry in ponds is the inadequate size of zooplankton being present as forage. Previous investigations (Ludwig 1994, Denson and Smith 1997) have demonstrated that rotifers (0.06-0.8 mm) and smaller protozoans are suitable first foods for sunshine bass fry. These organisms dominate the zooplankton community during the early stages of succession in fertilized rearing ponds (Geiger et al. 1985, Parmley and Geiger 1985, Fitzmayer et al. 1986), but their dominance usually ends abruptly (Harrell and Bukowsky 1990). Other factors, ordinarily overlooked, may have a detrimental effect on the survival of sunshine bass fry. Ludwig (1993) reported low fry survival in ponds even though rotifers were abundant and available as forage for sunshine bass fry. He hypothesized that predation by cyclopoid copepods, present at concentrations of 439 ± 256/L, was the most likely cause of the low survival of sunshine bass fry in his study. Attacks on fish larvae by cyclopoid copepods have been documented both in natural water bodies (Davis 1959, Fabian 1960, Hartig et al. 1982, Garcia and Alejandre 1995, Cooper 1996), and artificial enclosures (Lillelund and Lasker 1971, Smith and Kernehan 1981, Hokanson and Lien 1986, McGovern and Olney 1988). This study examined the consequences of exposing recently hatched sunshine bass fry to a concentration gradient of cyclopoid copepods. Methods The experiment was carried out in April 1998. It consisted of three treatments and a control with four replicates each. Treatments were prepared in sixteen 3.7-L glass jars, each one containing two liters of well water obtained from the facilities of the University of Arkansas at Pine Bluff Aquaculture Research Station in Pine Bluff, Arkansas. Each jar was stocked with five-day-old sunshine bass fry at a rate of 20 fry/L. Water from a 0.1-hectare catfish fingerling pond was pumped with a 1.87-kW gas pump through a 150-mm mesh sieve. Samples of zooplankton retained by the sieve were placed in a Sedgewick-Rafter counting cell and quantified under an Olympus CH-2 light microscope. Over 99% of the individuals in the sample were adult cyclopoid copepods. Adult cyclopoids were stocked in the experimental glass jars at concentrations of 5, 50, and 500 cyclopoids/L. For the first treatment (5 cyclopoids/L), copepods were counted individually. Based on the concentration of cyclopoids in the sample, subsamples of a known volume were added to the 3.7-L glass jars to prepare the 50- and 500-cyclopoid/L treatments. Four jars containing only fry were designated as the control treatment. After 24 hours fry were removed from each jar, examined to verify life, and enumerated. Direct observations of attacks were made following enumeration by placing surviving fry and copepods in a watch glass. Observations were recorded with 35-mm still and video cameras. Twenty fry and twenty cyclopoid copepods were preserved in ethanol. These fry and copepods were subsequently videotaped under an Olympus SZ-40 stereoscope coupled with an Olympus SZ-PT video camera connected to a Sony SLV-771 HF VCR. Images from the videotape were digitalized by means of a Matrox video capture board. Body-length measurements were taken from the digitilized images using Image Tool software (University of Texas Health Science Center at San Antonio). Survival data from the trials were analyzed by one-way ANOVA and Duncan’s multiple range test. Statements of significance refer to P<0.05. Results and Discussion Survival of sunshine bass fry was significantly lower in the high-density treatment (500/L) while no significant differences were found among the other treatments and the control (Table 1). Only two fry survived out of the 160 originally stocked in the four replicates of the high-density treatment. A counting error was detected in one replicate of the 50-cyclopoid/L treatment. Forty-four surviving fry were counted after the trial when only 40 were supposedly stocked. Average survival was the highest in this treatment (91.9%), but this is due in part to the aforementioned counting error. Even if this replicate was removed, the mean number of surviving fry and percent survival would still be the highest (34 and 85.8%, respectively) of all treatments. Thus, the statistical analysis is considered to be affected minimally by the introduction of this error. Studies of cyclopoid predation on fish larvae have repeatedly shown that predation occurs when temporal and spatial proximity between adult cyclopoids and susceptible fish larvae occurs (Hartig et al. 1982, Hokanson and Lien 1986, McGovern and Olney 1988, Cooper 1996). Hartig et al. (1982) studied cyclopoid predation in Lake Michigan and found that small alewife (Alosa pseudoharengus) larvae were preferred as prey over larvae of other species (rainbow smelt, Osmerus mordax; yellow perch, Perca flavescens; common carp, Cyprinus carpio). Lack of predation on the other species was mainly due to their more robust nature, rather than spatial and temporal asynchrony. Alewife larvae are smaller at hatching (about 3 mm) than the other fry, soft-bodied, and slower swimmers. Sunshine bass fry exhibit characteristics similar to alewives. They are considerably smaller than striped and palmetto bass fry. The five-day-old fry used in this experiment averaged 3.6 ± 0.23 mm TL, which is a size range particularly susceptible to predation by cyclopoids according to previous reports. Copepod densities as low as 100/L have proved to be detrimental to fish larvae (Hokanson and Lien 1986). Results from this experiment indicate that cyclopoid concentrations lower than 50/L did not affect 24-h survival rates of sunshine bass fry, while ten times that concentration (500/L) completely eliminated a fry population. To further examine the relationship between cyclopoid concentration and fry predation we adapted an empirical model developed by Paradis et al. (1996). This model predicts predation by crustaceans on fish eggs and larvae based on the relative sizes of prey and predator as follows: (1) ln (P)crustaceans = -5.2 – 0.97 ln(R) – 0.42 ln(V) where P = standardized predation rate where the numerator is the number of prey eaten and the denominator is the initial number of prey offered times the number of predators per experimental trial times the duration of the trial in hours (Note: if multiplied by 100, this rate represents the percentage of the prey population consumed by an individual predator per unit of time), R = prey/predator size ratio expressed as prey length divided by predator length, and V = container volume in liters. (Note: ln (V) is included in the equation as a correction factor to account for over-estimation of predation rates when trials are run in small containers). With data from this study (V = 2 L; R = 3.6 mm/1.1 mm), the model predicts a predation rate of 0.13% of fry eaten per copepod per hour. The observed predation rate in the 500-copepod/L treatment was only 0.004% of fry eaten per copepod per hour. This rate was calculated assuming that predation took place uniformly throughout the entire trial, even though the fry could have been entirely consumed during the first hours. Thus, the observed predation rate could be an underestimation of the actual predation rate. It is also possible that a lower concentration of cyclopoids (<500 individuals/L) could have caused a mortality of 100% (i.e. not all cyclopoids were eating during the 24-h period). We used the theoretical predation rate (P) predicted by equation 1 (0.13%.cop-1.h-1), an initial number of prey (ni) of 40, a number of prey eaten (ne) of 40, and a duration (D) of 24 h to solve for the number of predators per experimental trial (m) in the following equation: (2) P = (ne.ni-1.m-1.D-1)*100 Such a calculation indicates that a concentration of 16 copepods/L would be enough to kill a fish population of 20 fry/L in 24 hours. This study did not find any significant difference in mortality rates between the control and the treatment with 50 copepods/L. It appears that the model developed by Paradis et al. (1996) does not describe predation on sunshine bass fry by freshwater cyclopoids. Data on cyclopoid copepods for the Paradis et al. (1996) model were obtained for the most part from the Lillelund and Lasker (1971) study of predation on fish larvae by marine copepods. Those copepods were considerably larger (over 3 mm) than the freshwater species (less than 1 mm) used in this study. This could help explain the failure of the model when using data from this study. This work has important management implications for the culture of sunshine bass fry. Densities as high as 500 copepods/L in striped bass rearing ponds are not unusual. High mortality of sunshine bass fry (85%) was observed in fertilized culture ponds where adult copepods averaged 439 individuals/L (Ludwig 1993). Geiger et al. (1985) reported an average of 710 copepods/L in striped bass fingerling ponds. Survival in one of the ponds was as low as 10% after 28 days. Thus, results of this and previous studies suggest that sunshine bass fingerling producers should not only ensure adequate forage of appropriate size, but also avoid high numbers of cyclopoid copepods during the first weeks that fry are present in rearing ponds. Authors: Striped Bass Growers Association Directors in Attendance: Steve Mitchell,Delbert Gatlin, Sam Plottel, Jackson Curry, Chris Nelson, Ron Slay President Mitchell called the meeting to order 11:00 AM and asked for a showing of hands by SBGA members. A quorum was present. Minutes of the February 17, 1998 Annual Membership Meeting were presented by Secretary-Treasurer Betsy Sheehan. Curry Woods made a motion to accept the minutes as published in the SBGA association newsletter, The Striper. Seconded by Ron Slay, the motion carried. The financial report was presented by Betsy Sheehan. The 1998 Year-End Financial Report showed income of $11,562 and expenses of $8,174.71, giving a year-end balance of $26,051.28. Sheehan noted that part of the shown 1998 income were 1999 membership dues. She also stated that the 1999 National Aquaculture Association dues in the amount of $1,170.00 had been paid and were included in 1998 expenses. President Mitchell asked for committee reports, beginning with Membership. Committee Chairman Sheehan distributed a Membership Analysis of 1989 through 1998 and reported that there was an increase of five new members in 1998. In the 1998 total of 78, there were 7 Sustaining members, 45 Producer members, 23 Affiliate members and 3 student memberships The INAD Committee report was presented by Curry Woods, Chairman, who stated that HCG was still not legal, however, it was allowed under special labeling and that the prognosis for getting new drugs approved was very slow. He further stated approval of the FDA MUMS document could allow for speedier and increased drug approval and that it was very important for SBGA to support any efforts on getting the document passed in Congress. Woods also asked for SBGA consideration to increase the association donation towards the request for funding of the NADA Coordinator position. Bob Goetz, chairman of the Fish Health Committee, was not present. No report given. There was no Old Business. Under New Business, Sam Plottel stated that a Poster had been presented in Aquaculture America ’97 in Seattle on the use of quinine as a therapeutic feed additive effective against protozoan parasites. He has since approached Roz Schnick about an INAD and other potentially interested parties. Schnick informed Plottel that she had not heard from any one else on this issue and would like to know the level of SBGA’s interest. Plottel will provide copies of the article to any interested parties. After some discussion, Brent Blauch made a motion that the SBGA Fish Health INAD Committee coordinate with members to pursue the development of quinine as INAD status. Seconded by Chris Nelson, the motion carried. During discussion on the proposed SBGA Website, Jim Ekstrom made a motion that a Supplier Listing be included on the SBGA homepage. Seconded by Curry Woods, the motion carried. A survey application is to be sent to the membership requesting their approval and pertinent information for the directory listing. Applications are to be returned to Sam Plottel. Jim Carlberg suggested that consideration be given to allocating a portion of the SBGA funds towards a generic marketing campaign. Brent Blauch suggested that a portion of the focus be made on the recreational market. President Mitchell stated the Board would take the request under advisement. There being no further New Business, President Mitchell introduced Diego Valderrama as the recipient of the 1998 Walter Landry Award for Outstanding Research on Predation of Cyclopoid Copepods on Sunshine Bass Fry. Mitchell presented Valderrama with a $250 check towards travel expenses to Aquaculture America ’99 and a plaque. Valderrama then presented a synopsis of his research accomplishments. President Mitchell reported that the following had been elected by written ballot for 1999-2001 terms as directors: David Burnside, Jim Ekstrom and Jackson Currie. President Mitchell expressed his appreciation to the 1998 committee chairmen and the board of directors for their efforts and involvement during his term as president and asked that President-Elect Sam Plottel come forward for the passing of the gavel. Plottel presented Mitchell with a plaque of appreciation from the membership. Plottel asked that all board members remain for a board meeting to immediately follow adjournment of the annual meeting. There being no further business, a motion was made by Jim Ekstrom to adjourn. Seconded by Chris Nelson, the meeting was adjourned at 12:10 PM. Respectfully submitted: Betsy Sheehan,
|