Morphometry, Growth, and Condition of Hatchery-Reared Cisco ( Coregonus
artedi ) and Bloater ( Coregonus hoyi)
Abstract
The re-introduction of native species that have been extirpated or in
low abundance in the Great Lakes has been a binational initiative
between the United States and Canadian governments. Recently, new
management programs have been unway that use current hatchery facilities
for the restoration of native forage fishes in Lake Ontario. These
species include Bloater ( Coregonus hoyi), which has been extirpated
from Lake Ontario for approximately four decades, and Cisco ( C.
artedi), which exists at a fraction of its former abundance. We assessed
morphometrics, length-weight relationships, and condition factors during
early life development for eight cohorts of Cisco and Bloater reared
during 2012-2019. Weekly samples for Cisco and Bloater were measured
from hatch until release (29-45 weeks, 133-1,002 samples annually). Head
width, gape, mandible length, and mouth height metrics were all larger
for Cisco than Bloater at any given size but increased at similar rates
for both species. Average condition factors for Cisco and Bloater were
0.54317 and 0.55892, respectively. his information may also improve
field identification of these species, helping managers evaluate the
relative success of different release strategies for rehabilitation of
populations of these native species.