EXECUTIVE SUMMARY

Seven shipments of hickory shad eggs (28.7 million eggs) were received at Van Dyke in 2005. Egg viability was 61.4% and 17.6 million hickory shad larvae were stocked in Conowingo Reservoir and in the Delaware River and its tributaries, Pennypack Creek and Ridley Creek.

A total of 42 shipments of American shad eggs (17.1 million eggs) was received at Van Dyke in 2005. Total egg viability was 37% and survival of viable eggs to stocking was 87%, resulting in production of 5.2 million larvae. Larvae were stocked in the Juniata River (2.2 million), Susquehanna River near Montgomery Ferry (1.0 million), the West Branch Susquehanna River (335 thousand), the Lehigh River (669 thousand), the Schuylkill River (799 thousand) and the Delaware River (170 thousand). Scheduled releases in the North Branch Susquehanna River, the Chemung River, and the four lower river tributaries were cancelled due to lack of eggs.

Overall survival of larvae was 87%. No episodes of major mortality occurred as a result of larvae lying on the bottom of the tank or any other cause. Van Dyke jars with foam bottom jars were used only twice with no mortality problems.

All American and hickory shad larvae cultured at Van Dyke were marked by 4-hour immersion in oxytetracycline. Marks for American shad were assigned based on release site and/or egg source river. Mark retention for American shad was 100% for all groups analyzed. Hickory shad were marked at 512 ppm on day three. Mark retention for hickory shad was 100%. A single tank of larvae (A32) was given an experimental mark at 3, 6, 9 and 12 days of age. The day 6 and 12 marks utilized generic Oxytetracycline hydrochloride from Am Tech at 171-ppm and 342-ppm, respectively. Mark retention was 61% for the 171-ppm concentration and 83% for the 342-ppm concentration. Marks produced by this product were not as bright at those produced by Pfizer Terramycin 343.

INTRODUCTION

The Pennsylvania Fish and Boat Commission has operated the Van Dyke Research Station for Anadromous Fishes since 1976 as part of an effort to restore diadromous fishes to the Susquehanna River Basin. The objectives of the Van Dyke Station were to research culture techniques for American shad and to rear juveniles for release into the Juniata and Susquehanna Rivers. The program goal was to develop a stock of shad imprinted to the Susquehanna drainage, which will subsequently return to the river as spawning adults. With the completion of York Haven Dam fish passage facilities in 2000, upstream hydroelectric project owners were no longer responsible for funding the hatchery effort. Funding was provided by the Pennsylvania Fish and Boat Commission.

In 2003, a new effort in migratory fish restoration was undertaken. Adult hickory shad (Alosa mediocris) were collected and tank-spawned as part of the initial efforts to culture, release and restore runs of hickory shad to the Susquehanna and Delaware River basins.

As in previous years, production goals for American shad for 2005 were to stock 10-20 million American shad larvae. All Van Dyke hatchery-reared American and hickory shad larvae were marked by immersion in tetracycline bath treatments in order to distinguish hatchery-reared shad from those produced by natural spawning of wild adults. All eggs received at Van Dyke were disinfected to prevent the spread of infectious diseases from out-of-basin sources.

EGG SHIPMENTS

Hickory shad

A total of 28.7 million hickory shad eggs (73.5 L) were received in seven shipments from tank-spawning operations at Conowingo Dam (Table 1). Some 17.6 million (61.4%) of the hickory shad eggs were viable.

American shad

A total of 17.1 million American shad eggs (372 L) were received in 42 shipments in 2005 (Table 1). This was the second lowest quantity of eggs received since 1982 (Table 2). Egg collections were reduced as a result of a late start on the Hudson River. Egg collection was delayed 7 to 10 days while the contractor resolved permit reporting issues from 2004. Overall American shad egg viability (which we define as the percentage which ultimately hatches) was 36.6%.

Thirteen Hudson River egg shipments (2.9 million eggs) were received from May 19 to June 5, 2005. Overall viability was 72.4%. By comparison, in 2003, 23 shipments were received from the Hudson River for a total of 17.1 million eggs. Hudson River eggs were collected from sites at Coxsackie and Lower Schodack Island.

Delaware River egg shipments were received from May 9 to June 2. A total of 18 shipments were received (6.2 million eggs) with a viability of 31.80%. By comparison, in 2004, the Delaware River produced 2.4 million eggs.

The U.S. Fish and Wildlife Service attempted to obtain eggs by strip-spawning ripe adult shad collected by gill net in the lower Susquehanna River near Lapidum, MD. This effort resulted in insufficient eggs to justify a shipment to the hatchery.

Normandeau Associates, under contract with the PFBC, attempted to obtain eggs by strip-spawning ripe adult shad collected by gill net in the upper portion of Conowingo Reservoir. Few ripe shad were collected and no eggs were shipped.

American shad eggs were also obtained from a tank-spawning effort at Conowingo Dam, operated by Normandeau Associates. Pre-spawn adult American shad were obtained from the West Fish Lift at Conowingo Dam, injected with hormones and allowed to spawn naturally. Some 8.0 million eggs, in 11 shipments, were delivered to the Van Dyke Hatchery, with a viability of 23.9%. By comparison, 4.7 million eggs, in 7 shipments, were received from this source in 2004.

SURVIVAL

Overall survival of American shad larvae was 87% compared to a range of 19% to 94% for the period 1984 through 2004. The 27% increase in survival from 2004 (60%) was due, in part, to stocking larvae earlier. In 2004, we reared the larvae longer, while waiting for river flows and turbidity to decrease. Average age at stocking was 15.2 days in 2005, compared to 23.4 days in 2004.

Survival of individual tanks followed patterns similar to those observed in the past. Four tanks, reared from 20 to 26 days of age, exhibited 20-d survival of 83.6% (Figure 1). Nine tanks, reared from 14 to 17 days of age, exhibited 14-d survival of 88.9%. Eleven tanks, reared from 10 to 13 days of age, exhibited 10-d survival of 94.1%. High mortality episodes occurred only in low density tanks (15,000 to 57,000 larvae), with the lowest survival in the lowest density tanks. The cause of the low survival in low density tanks is unknown. Feed rates were adjusted to feed as if 100,000 larvae were in each tank to ensure that the larvae could find the feed. Tank I41 was a result of pair spawning Delaware River brood fish for a genetics study conducted by the Northeast Fishery Center at Lamar. These fish were not tagged with tetracycline and were not stocked.

LARVAL PRODUCTION

Hickory shad larvae (5.4 million) were stocked in the lower Susquehanna River at Muddy Creek Access in the Conowingo Reservoir. Some 11.8 million hickory shad were also stocked in the Delaware River (3.2 million) and two of its tributaries Pennypack Creek (8.0 million) and Ridley Creek (600 thousand).

Production and stocking of American shad larvae, summarized in Tables 2, 3 and 4, totaled 5.21 million. A total of 2.2 million was released in the Juniata River, 1.0 million in the Susquehanna River near Montgomery Ferry, and 335 thousand in the West Branch Susquehanna River. Due to the poor egg production, no larvae were stocked in the North Branch Susquehanna River (PA or NY), the Chemung River, the Raritan River, or the four lower river tributaries. Delaware River egg collections were sufficient to nearly meet the goals for the Delaware River Basin. Larvae were stocked in the Lehigh River (669 thousand), the Schuylkill River (799 thousand), and the Delaware River (170 thousand). Larvae stocked in the Delaware River were allocated to replenish the Delaware for the brood stock taken there. Larvae stocked during the second of two trips to the Delaware (6/28/05) were observed to be heavily preyed upon by indigenous shad, 1 to 1 ½ inches in length.

TETRACYCLINE MARKING

All American and hickory shad larvae stocked received marks produced by immersion in tetracycline (Table 5). Immersion marks for American shad were administered by bath treatments in 256-ppm oxytetracycline hydrochloride for 4h duration. All American shad larvae were marked according to stocking site and/or egg source. All hickory shad larvae were marked with 512-ppm and given a single mark on day 3. American shad larvae from the Susquehanna River egg source, and stocked in the Juniata River or Susquehanna River near Montgomery Ferry were given a triple mark at 3, 6, and 9 days of age. Larvae from the Hudson River egg source and stocked in the Juniata River or Susquehanna River near Montgomery Ferry were marked at 3, 6 and 12 days of age. Larvae stocked in the West Branch Susquehanna River were given a quintuple mark at 3, 6, 9, 12, and 15 days of age. Larvae stocked in the Lehigh River were given a triple mark at 9, 12, and 15 days of age. Larvae stocked in the Schuylkill River were given a quadruple mark at 3, 6, 9, and 12 days of age. Larvae stocked in the Delaware River were given a quintuple mark at 3, 9, 12, 15, and 18 days of age.

A single tank of larvae (A32) was given an experimental mark at 3, 6, 9 and 12 days of age and stocked in the Schuylkill River. Marks on days 3 and 9 were standard marks at 256-ppm OTC, using Terramycin 343 from Pfizer under INAD 8512. The day 6 and 12 marks utilized generic Oxytetracycline hydrochloride from Am Tech at 171-ppm and 342-ppm, respectively. This product is approved by FDA for marking skeletal tissue of fish and has fewer record-keeping and reporting requirements.

Verification of mark retention was accomplished by stocking groups of marked fry in raceways and examining otolith samples collected later. Otoliths were extracted and mounted in Permount on microscope slides. A thin section was produced by grinding the otolith on both sides. Otolith sections were examined for marks with an epi-fluorescent microscope with a UV light source. Retention of tetracycline marks for American shad was 100% for all groups analyzed (Table 5).

Mark retention was 100% for all American shad production marks sampled (Table 5). Mark retention could not be evaluated for the day 9,12,15 mark (larvae stocked in the Lehigh River) because none of the larvae stocked in the raceway survived. The experimental mark (Tank A32) using Amtech oxytetracycline HCL was not successful. Marks produced by immersion in 256-ppm Terramycin 343 on days 3 and 9 exhibited 100% retention with good or excellent mark ratings on all 18 specimens examined. Marks produced by immersion in 171-ppm Amtech Oxytetracycline hydrochloride on day 6 exhibited 61% retention with a single good mark, ten poor marks, and 7 unmarked specimens, of the 18 examined. Marks produced by immersion in 342-ppm Amtech Oxytetracycline hydrochloride on day 12 exhibited 83% retention with eight excellent marks, six good marks, one poor mark, and 3 unmarked specimens, of the 18 examined.

Fingerlings grown out in raceways and marked with 88g Amtech oxytetracycline HCL per kg of food exhibited mark retention of five percent. In previous years, feed marks using the same concentration of Terramycin 343 exhibited mark retention of 100% (Hendricks 1998, 1999, 2002). The cause of the poor performance of Amtech Oxytetracycline hydrochloride as an immersion and feed marking agent is not known.

ACKNOWLEDGMENTS

The Pennsylvania Fish and Boat Commission began culturing hickory shad for the first time in 2003. We thank biologists Brian Richardson and Rick Morin from the Maryland Fisheries Service for their assistance in this new initiative. PFBC fisheries biologist Dave Arnold and his crew collected American shad eggs from the Delaware River. American shad eggs from the Hudson River were collected under contract with The Wyatt Group from Lancaster, PA. Collection of American shad for eggs and otolith analysis, from the Susquehanna River below Conowingo Dam, was done by Richard St. Pierre, Mike Mangold, Tina McCrobie, Steve Minkkinen, Sheila Eyler, and Clif Tipton of the U.S Fish Wildlife Service, and Gary “Rooster” Potter of Perryville, Md. Shad eggs from the Susquehanna River above Conowingo Dam were collected under contract with Normandeau Associates, of Drumore, PA. Normandeau Associates also conducted the tank spawning operation for both hickory shad and American shad at Conowingo Dam. PECO Energy provided broodstock, space and technical assistance in the tank spawning operations.

REFERENCES

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Gauldie, R. W. and D. G. A. Nelson. 1990. Otolith growth in fishes. Comparative Biochemistry and Physiology 97A (2): 119-135.

Hendricks, M. L., T. R. Bender, Jr. and V. A. Mudrak. 1991. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1990. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L., T. R. Bender, Jr. and V. A. Mudrak. 1992. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1991. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. and T. R. Bender, Jr. 1993. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1992. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. and T. R. Bender, Jr. 1994. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1993. Susquehanna River Anadromous Fish Restoration Committee.

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Hendricks, M. L. 2004. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 2003. Susquehanna River Anadromous Fish Restoration Committee.

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Ott, L. 1977. An introduction to statistical methods and data analysis. Duxberry Press, Belmont, California 730 p.

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