scholarly journals Asian copepods on the move: recent invasions in the Columbia–Snake River system, USA

2008 ◽  
Vol 65 (5) ◽  
pp. 753-758 ◽  
Author(s):  
Jeffery R. Cordell ◽  
Stephen M. Bollens ◽  
Robyn Draheim ◽  
Mark Sytsma

Abstract Cordell, J. R., Bollens, S. M., Draheim, R., and Sytsma, M. 2008. Asian copepods on the move: recent invasions in the Columbia–Snake River system, USA. – ICES Journal of Marine Science, 65: 753–758. Nine Asian copepod species have been introduced into the Northeast Pacific, seven of which are largely confined to the San Francisco estuary. However, several of these copepods recently invaded the Columbia–Snake River system in Washington state, USA. In addition to the calanoid copepod Pseudodiaptomus inopinus, which appeared in the 1980s, the Columbia River now has populations of the calanoids Pseudodiaptomus forbesi and Sinocalanus doerrii, and the cyclopoid copepod Limnoithona tetraspina. Sampling in the Columbia–Snake River system in 2005 and 2006 indicated that (i) newer invaders may have displaced the previously introduced P. inopinus; (ii) P. forbesi had moved upstream into the first five reservoirs in the system; (iii) the other species occurred only in the tidal regions of the lower river; (iv) P. forbesi dominates the late summer holoplankton in the lower river and estuary; and (v) P. forbesi is relatively rare, and the holoplankton is dominated by native species in upstream free-flowing segments of the Columbia River and in reservoirs of the Snake River. Zooplankton samples from ships in Puget Sound suggest that ballast water from California is a major source of the introduced copepods and that the Columbia River itself may be a new source of ballast-introduced copepods.

1998 ◽  
Vol 55 (3) ◽  
pp. 658-667 ◽  
Author(s):  
Richard W Zabel ◽  
James J Anderson ◽  
Pamela A Shaw

A multiple-reach model was developed to describe the downstream migration of juvenile salmonids in the Columbia River system. Migration rate for cohorts of fish was allowed to vary by reach and time step. A nested sequence of linear and nonlinear models related the variation in migration rates to river flow, date in season, and experience in the river. By comparing predicted with observed travel times at multiple observation sites along the migration route, the relative performance of the migration rate models was assessed. The analysis was applied to cohorts of yearling chinook salmon (Oncorhynchus tshawytscha) captured at the Snake River Trap near Lewiston, Idaho, and fitted with passive integrated transponder (PIT) tags over the 8-year period 1989-1996. The fish were observed at Lower Granite and Little Goose dams on the Snake River and McNary Dam on the Columbia River covering a migration distance of 277 km. The data supported a model containing two behavioral components: a flow term related to season where fish spend more time in regions of higher river velocity later in the season and a flow-independent experience effect where the fish migrate faster the longer they have been in the river.


1978 ◽  
Vol 56 (12) ◽  
pp. 2603-2607 ◽  
Author(s):  
J. J. Boers ◽  
J. C. H. Carter

A study of the life history of the cyclopoid copepod Cyclops scutifer Sars in a small lake of the Matamek River System, Quebec, indicates a 1-year life cycle with four cohorts produced annually. The primary cohort overwinters as early nauplii and reaches maturity during midsummer when it spawns the primary cohort of the succeeding year. The other cohorts may merge with either each other or the primary cohort and contribute somewhat less to the overall cycle. Slower development of copepodites of the second cohort in 1976 may have been the result of an inadequate number of naupliar prey from the calanoid copepod Diaptomus minutus.


Crustaceana ◽  
2014 ◽  
Vol 87 (3) ◽  
pp. 376-382
Author(s):  
Hanaa H. Mohammed ◽  
Frank D. Ferrari ◽  
M. F. Abbas

The cyclopoid copepod Limnoithona tetraspina was collected for the first time in the Shatt Al-Arab, a river in Iraq, in the summer of 2009; its abundance ranged from 2-16 specimens/m3. Its distribution was restricted to the areas around Al-Sindibad Island and Al-Kornish in waters with temperatures between 27-28°C and salinities less than 4.1‰. A larger number of specimens was collected in August 2012 around Al-Sindibad Island, 134 specimens/m3, and in July 2013 around Al-Kornish, 378 specimens/m3 in waters of comparable temperatures and salinities. The copepod initially was described from the mouth of the Yangtze River, China, in 1976. It was introduced from the Yangtze River into the San Francisco Bay estuary, U.S.A., in 1993, with ship ballast water, and into the Columbia River, U.S.A., in 2003, presumably from the San Francisco Estuary. The origin of the Shatt Al-Arab population is unknown, but it is likely to have been introduced.


2020 ◽  
Vol 4 (1) ◽  
pp. 1-12
Author(s):  
Elizabeth C. Lopardo ◽  
Clare M. Ryan

Four dams on the lower Snake River in Washington State generate hydropower and allow for regional agriculture and barge shipping to Portland OR. However, the dams impede the migration of local salmon populations (Oncorhynchus spp.), which are in steep decline, and drastically impact the populations of salmon and orca whales, for whom salmon are a primary food source. For years, environmental groups have argued for breaching the dams; other interests counter that the dams are too critical to the economy of the region to lose; and federal agencies assert that the dams can remain and salmon populations will recover with mitigation techniques. Scientific and economic analyses, litigation, and elected officials’ efforts have not been able to move the issue towards a solution. Readers will examine the interests of primary actors in the issue, how they influence the policy process, the role of scientific and economic analyses, and possible approaches for resolving the issue.


2019 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Robert M. Anderson ◽  
Amy M. Lambert

The island marble butterfly (Euchloe ausonides insulanus), thought to be extinct throughout the 20th century until re-discovered on a single remote island in Puget Sound in 1998, has become the focus of a concerted protection effort to prevent its extinction. However, efforts to “restore” island marble habitat conflict with efforts to “restore” the prairie ecosystem where it lives, because of the butterfly’s use of a non-native “weedy” host plant. Through a case study of the island marble project, we examine the practice of ecological restoration as the enactment of particular norms that define which species are understood to belong in the place being restored. We contextualize this case study within ongoing debates over the value of “native” species, indicative of deep-seated uncertainties and anxieties about the role of human intervention to alter or manage landscapes and ecosystems, in the time commonly described as the “Anthropocene.” We interpret the question of “what plants and animals belong in a particular place?” as not a question of scientific truth, but a value-laden construct of environmental management in practice, and we argue for deeper reflexivity on the part of environmental scientists and managers about the social values that inform ecological restoration.


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