Temagami Stewardship Council

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To preserve, protect, restore and improve, the natural resources and environment of Lake Temagami & Cross Lake !
Fisheries News
January 20, 2006

MEMORANDUM TO: District Managers
Great Lake Unit Managers
Dave Maraldo, Manager, Fisheries Section, Fish and Wildlife Branch

SUBJECT: CFWIP Hatchery Gamete Collections and Fish Health Risks

As you are aware, the fish disease Viral Hemorrhagic Septicemia (VHS) was diagnosed in association with a mass mortality of freshwater drum (Aplodinotus grunniens) in the Bay of Quinte, Lake Ontario, during the spring of 2005. VHS has not been confirmed as the cause of death, however this is significant because it is the first occurrence of the virus in freshwater in North America.

Walleye gametes were collected by the White Lake Fish Culture Station (WKFCS) from the Bay of Quinte, at approximately the same time as the drum deaths were occurring throughout the Bay. Fish Culture Section took a cautious approach and delayed the stocking of all walleye from the WKFCS until the Bay of Quinte walleye fingerling could be re-tested for VHS. We received the test results in early December indicating that the Bay of Quinte walleye at WKFCS do not have VHS and that the stocking of the walleye does not present a health risk to wild fish populations.

As a result of the discovery of VHS in the Bay of Quinte, and in the absence of information regarding the pathogenicity and species susceptibility of this new strain of VHS (see attached Technical Bulletin), Fish Culture Section has decided to seek an alternate source of gametes for its walleye stocking program.

Fish Culture Section proposes that fish health testing of adult brood fish should continue to occur to monitor the health status of the Bay of Quinte walleye during the spring CFWIP gamete collection.

Most CFWIP fish stocking programs do not currently carry out routine fish health testing of their wild brood stock or production fish, and this poses a risk to wild and naturalized fish populations. Many pathogens can be detected prior to stocking hatchery-reared fish through routine fish health monitoring, such as is done in the provincial fish culture system. Steps can then be taken to reduce or eliminate the health risks to our aquatic ecosystems. I understand that limited resources may make routine fish health monitoring a significant challenge for CFWIP clubs, but there are steps that can be taken to reduce the risks.

In order to reduce the risks posed by not monitoring (through routine testing) fish health at CFWIP hatcheries, Fish Culture Section recommends that Districts work with the clubs to find local sources of fish gametes and to ensure that fish are stocked only within the same drainage basin from which the gametes were collected. This is a prudent step in our efforts to manage fish health in Ontario, and helps to avoid transferring fish pathogens from one drainage basin to another.

In particular, I recommend that clubs collecting walleye eggs from the Bay of Quinte only stock the progeny in the Lake Ontario drainage basin. Any district that currently has CFWIP groups transferring gametes or fish from the Lake Ontario drainage basin to inland or other Great Lake drainage basins should work with the clubs to find an alternate local source of gametes for the spring of 2006. The Bay of Quinte is currently the only location in Ontario in which VHS and the fish parasite Heterosporis have been diagnosed and these measures will reduce the risk of expanding their geographic range.

If you have any questions regarding these recommendations, please contact Lisa Miller-Dodd, A/Coord. – Fish Health and Aquaculture, at 705-755-1928 or by email at lisa.miller-dodd@mnr.gov.on.ca .

Sincerely,

Quentin Day
Manager, Fish Culture Section

c. Alec Denys, Great Lakes Branch
Cameron C. Mack, Director, Fish and Wildlife Branch
Regional Directorsmailto:lisa.miller-dodd@mnr.gov.on.cashapeimage_6_link_0