| Impact ID |
Scientific Name
|
Impact Type
|
Study Type
|
Study Location
|
Impact Description
|
Geographic Location
|
Reference
|
|
8367
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
Unlike Bythotrephes longimanus, Cercopagis pengoi (fishhook waterflea) is too small to impact populations of the native predatory cladoceran, Leptodora kindtii, via predation.
|
Lake Champlain, New York, USA
|
42488
|
|
8368
|
Cercopagis pengoi
|
Predation/Herbivory
|
Anecdotal
|
N/A
|
Fishhook flea (Cercopagis pengoi) has a long spine that makes it less palatable to small planktivorous fish. For these reasons, C. pengoi could have a serious effect on the food supply of planktivores.
|
|
39292
|
|
8369
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
The fishhook waterflea (Cercopagis pengoi) is known to make up a portion of the adult alewife diet in Lakes Ontario, Erie, and Michigan, but this contribution does not appear significant relative to Bythotrephes longimanus, another nonindigenous spined cladoceran, when these species co-occur.
|
Great Lakes, USA
|
24426
|
|
8370
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
The fishhook waterflea's (Cercopagis pengoi) establishment in Lake Ontario in 1998 corresponded with the lowest alewife populations in twenty years.
|
Hamlin Beach State Park, Lake Ontario, New York, USA
|
13069
|
|
8371
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
Surveys in the following year indicated that the fishhook waterflea (Cercopagis pengoi) was found to account for as much as 73% of crustacean zooplanktonic biomass in the lake.
|
Lake Ontario, USA
|
24542
|
|
8372
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
Many studies have been conducted on the food web effects of Cercopagis pengoi (fishhook flea) in Lake Ontario. A 2002 study showed that the depth at which C. pengoi exists is depleted of small organisms (<0.15 mg) in Lake Ontario. It was unclear as to whether this is due to predator evasion or C. pengoi consumption, but in either case, the smaller organisms are forced into deeper, cooler strata, causing growth rate changes.
|
Lake Ontario, USA
|
13829
|
|
8373
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
Further study in Lake Ontario indicated that in the years following Cercopagis pengoi (fishhook flea) invasion, the density of small zooplankton began to drop in the late summer and fall seasons (when C. pengoi is most abundant).
|
Lake Ontario, USA
|
24549
|
|
8374
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
Importantly, increasing Cercopagis pengoi (fishhook flea) abundance was correlated with declines in populations of native zooplankton Daphnia retrocurva, Bosmina longirostris, and Diacyclops thomasi in Lake Ontario between 1999 and 2001. D. retrocurva and B. longirostris are important prey items of C. pengoi, and appeared to be limited by predation rather than food availability or any decrease in fecundity.
|
Hamlin Beach State Park, Lake Ontario, New York, USA
|
24540
|
|
8375
|
Cercopagis pengoi
|
Predation/Herbivory
|
Anecdotal
|
N/A
|
Evidence thus suggests that Cercopagis pengoi (fishhook flea) may have played a role in the decline of zooplankton abundance in Lake Ontario. It does not appear, however, that zooplankton species richness has been altered as a result of C. pengoi invasion.
|
Lake Ontario, USA
|
19593
|
|
8376
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
Based on findings in the Baltic Sea and Gulf of Finland, it has been predicted that increased predation pressure on zooplankton caused by increases in Cercopagis pengoi (fishhook flea) abundance could lead to an increase in phytoplankton abundance and an eventual shift in the energy fluxes and eutrophication rates in an ecosystem.
|
Gulf of Finland, Baltic Sea
|
24541
|
|
8377
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
In Lake Ontario, we documented an additional correlation between an increase in chlorophyll a concentration and the increase of Cercopagis pengoi (fishhook flea) and decrease of herbivorous zooplankton. This suggests that C. pengoi likely had a significant top-down (albeit variable) effect on zooplankton communities in Lake Ontario, although these predatory effects appear to have declined steadily since the species’ establishment.
|
Hamlin Beach State Park, Lake Ontario, New York, USA
|
24540
|
|
8378
|
Cercopagis pengoi
|
Predation/Herbivory
|
Anecdotal
|
N/A
|
Initial research in southwestern Lake Michigan suggested that Cercopagis pengoi (fishhook flea) could have an effect on the food web due to predation of rotifers, whose abundance dropped significantly following C. pengoi establishment. However, this implication is taken with caution, as overall zooplankton abundance had been in steady decline previous to this study.
|
Lake Michigan, USA
|
16633
|
|
9556
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
Cercopagis pengoi predate on native zooplankton communities and have influenced zooplankton decline in North America.
|
North America
|
43134
|
|
9557
|
Cercopagis pengoi
|
Predation/Herbivory
|
Observational
|
Field
|
In the Great Lakes, adult Alosa pseudoharengus predate upon Cercopagis pengoi, but they do not predate as juveniles.
|
Great Lakes
|
43134
|