EXECUTIVE SUMMARY

Four shipments of hickory shad eggs (13.6 million eggs) were received at Van Dyke in 2004. Egg viability was 46.1% and 6.25 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 39 shipments of American shad eggs (17.3 million eggs) was received at Van Dyke in 2004. Total egg viability was 54% and survival of viable eggs to stocking was 60%, resulting in production of 5.6 million larvae. Larvae were stocked in the Juniata River (2.6 million), Susquehanna River near Montgomery Ferry (280 thousand), Conodoguinet Cr. (200), Conestoga River (60 thousand), Swatara Creek (53 thousand), West Conewago Cr. (142 thousand), the North Branch Susquehanna River (NY-485 thousand), the Chemung River (NY- 343 thousand), the North Branch Susquehanna River (PA-480 thousand), the West Branch Susquehanna River (282 thousand), the Lehigh River (366 thousand), the Schuylkill River (422 thousand) and the Raritan River in New Jersey (119 thousand).

Overall survival of larvae was 60%. Problems with mortality associated with foam bottom screens did not re-occur in 2004. High, turbid water postponed stocking and contributed to additional mortality while larvae waited in the hatchery for river conditions to subside.

All American and hickory shad larvae cultured at Van Dyke were marked by 4-hour immersion in 256 ppm 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 on day three. Mark retention for hickory shad was 5%.

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 is previous years, production goals for American shad for 2004 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 13.6 million hickory shad eggs (33.4 L) were received in four shipments from tank-spawning operations at Conowingo Dam (Table 1). Some 6.2 million (46.1%) of the hickory shad eggs were viable.

American shad

A total of 17.3 million American shad eggs (462 L) were received in 43 shipments in 2004 (Table 1). This was the second lowest quantity of eggs received since 1982 (Table 2). Poor spawning runs on the Hudson and Delaware River, coupled with rapidly increasing water temperatures which truncated the spawning period were responsible for the reduction in egg collection success. Overall American shad egg viability (which we define as the percentage which ultimately hatches) was 54.0%.

Sixteen Hudson River egg shipments (9.4 million eggs) were received from May 3 to May 23, 2004. Overall viability was 74.9%. 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 only from the site at Coxsackie, where water depths permit gill netting at all stages of the tide.

Delaware River egg shipments were received from May 10 to May 28. A total of 13 shipments were received (2.4 million eggs) with a viability of 43.0%. By comparison, in 2003, the Delaware River produced 3.6 million eggs.

The U.S. Fish and Wildlife Service obtained eggs by strip-spawning ripe adult shad collected by gill net in the lower Susquehanna River near Lapidum MD. Three shipments were received (20.8L) between May 12 and May 14. A total of 752 thousand eggs were received with a viability of 41.7%.

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 4.7 million eggs, in 7 shipments, were delivered to the Van Dyke Hatchery, with a viability of 20.0%. By comparison, 11.7 million eggs, in 14 shipments, were received from this source in 2003. Rapidly increasing water temperatures negatively impacted tank-spawning efforts at Conowingo Dam.

SURVIVAL

Overall survival of American shad larvae was 60% compared to a range of 19% to 94% for the period 1984 through 2003. The 18% decline in survival from 2003 (78%) was due, in part, to rearing the larvae longer, while waiting for river flows and turbidity to decrease. Average age at stocking was 23.4 days in 2004, compared to 19.5 days in 2003. In addition, nearly complete mortality occurred in tanks E11 and H21 (Figure 1). The mortality episode in E11 occurred at 10-d of age when a piece of fiberglass insulation fell out of the loft and lodged in the influent valve, shutting off flow and resulted in nearly complete mortality of the 300,000 larvae in the tank. Tank H21 suffered nearly complete mortality immediately after hatch. The tank received an MSXXX jar with 350,000 eggs from shipment 36, a tank-spawn shipment. Only 13% (45,000) of the eggs were viable and, because the dead did not layer, they could not be siphoned off. The larvae hatched on schedule, after sunning, but could not exit the jar due to the large number of overlying dead eggs. Live larvae could be seen struggling to swim up against the weight of the large volume of dead eggs. So few live larvae remained after a few days of culture that they were ultimately discarded.

Survival of individual tanks followed patterns similar to those observed in the past. Fifteen tanks, reared from 26 to 42 days of age, exhibited 26-d survival of 63% (Figure 1). Seven tanks, reared from 17 to 21 days of age, exhibited 17-d survival of 75%. Two tanks, reared from 9 to 11 days of age, exhibited 9-d survival of 92%. As was typical of mortality patterns experienced in the past, mortality increased at about 11 days of age. Tanks E11 and H21 exhibited nearly complete mortality as explained above (Figure 1). Four tanks of larvae were partially stocked to relieve crowding in the tank. High densities (330 to 604 thousand larvae) were cultured in these tanks in anticipation of abundant egg deliveries, which never materialized. Survival of these four tanks of larvae is plotted separately (Figure 2).

LARVAL PRODUCTION

Hickory shad larvae (3.4 million) were stocked in the lower Susquehanna River at Muddy Creek Access in the Conowingo Reservoir. Some 2.7 million hickory shad were also stocked in the Delaware River (1.8 million) and its tributaries Pennypack Creek (667 thousand) and Ridley Creek (267 thousand).

Production and stocking of American shad larvae, summarized in Tables 2, 3 and 4, totaled 5.67 million. A total of 2.6 million was released in the Juniata River, 283 thousand in the Susquehanna River near Montgomery Ferry, 485 thousand in the North Branch Susquehanna River in New York, 343 thousand in the Chemung River in New York, 480 thousand in the North Branch Susquehanna River in Pennsylvania, and 282 thousand in the West Branch Susquehanna River. American shad larvae were also stocked in tributaries: 200 in Conodoguinet Creek, 60 thousand in the Conestoga River, 142 thousand in West Conewago Creek and 53 thousand in Swatara Creek. In addition, 366 thousand larvae were stocked in the Lehigh River, 422 thousand were stocked in the Schuylkill River, and 119 thousand were provided to New Jersey Division of Fish and Wildlife to support restoration efforts in the Raritan River.

TETRACYCLINE MARKING

All American and hickory shad larvae produced at Van Dyke received marks produced by immersion in tetracycline (Table 5). Immersion marks were administered by bath treatments in 256-ppm oxytetracycline hydrochloride for 4h duration. All hickory shad larvae were marked with a single mark on day 3, while all American shad larvae were marked according to stocking site and/or egg source. 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 out-of-basin egg sources and stocked in the Juniata River or Susquehanna River near Montgomery Ferry were marked at 3, 9 and 12 days of age. Larvae stocked in the Conodoguinet Creek were given a quadruple mark at 3, 6, 12 and 15 days of age. Larvae stocked in the Conestoga River were given a quadruple mark at 3, 9, 12, and 15 days of age. Larvae stocked in Swatara Creek were given a quintuple mark at 3, 6, 9, 15, and 18 days of age. Larvae stocked in West Conewago Cr. were given a quintuple mark at 3, 9, 12, 15 and 18 days of age. Larvae stocked in the North Branch Susquehanna River (NY) were given a quintuple mark at 3, 6, 9, 12, and 18 days of age. Larvae stocked in the Chemung River (NY) were given a triple mark at 3, 15 and 18 days of age. Larvae stocked in the North Branch Susquehanna River (PA) were given a quadruple mark at 3, 6, 9, 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 provided to New Jersey Division of Fish and Wildlife for the Raritan River were given a single mark at 3 days of age.

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). No fish from Tank E11 were analyzed for marks due to the high mortality in the tank (see discussion above). All surviving larvae in this tank (200) were stocked in Conodoguinet Cr.; none were transferred to raceways for mark retention studies.

Only 1 of 20 (5%) of the hickory shad otoliths examined exhibited marks. In 2003, 15% of the hickory shad were marked. The cause of this poor marking success is unknown. In 2005, we will attempt to mark hickory shad larvae at a higher OTC concentration (400ppm).

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 fisheries technician Joe Minnichbach and their 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. American shad eggs from the Susquehanna River below Conowingo Dam were collected by Richard St. Pierre, Mike Mangold, Tina McCrobie, Steve Minkkenen, 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.

LITERATURE CITED

Brooks, R. C., R. C. Heidinger, and C. C. Kohler. 1994. Mass-marking otoliths of larval and juvenile walleyes by immersion in oxytetracycline, calcein or calcein blue. North American Journal of Fisheries Management 14:143-150.

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.

Hendricks, M. L. and T. R. Bender, Jr. 1995. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1994. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. 1996. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1995. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. 1997. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1996. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. 1998. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1997. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. 1999. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 1998. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. 2001. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 2000. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. 2002. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 2001. Susquehanna River Anadromous Fish Restoration Committee.

Hendricks, M. L. 2003. Job III. American shad hatchery operations. In: Restoration of American shad to the Susquehanna River, Annual Progress Report, 2002. Susquehanna River Anadromous Fish Restoration Committee.

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.

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

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