Food web alterations that promote native species: the recovery of cisco (Coregonus artedi) populations through management of native piscivores

2005 ◽  
Vol 62 (10) ◽  
pp. 2177-2188 ◽  
Author(s):  
Damon M Krueger ◽  
Thomas R Hrabik

We evaluated the effects of fisheries management on food webs in three northern Wisconsin lakes with exotic rainbow smelt (Osmerus mordax). In two of the lakes, restrictions on fishing reduced mortality rates on adult walleye (Sander vitreus) during the study period. In these lakes, walleye populations increased concurrently with a decline in rainbow smelt populations. As rainbow smelt populations declined in both lakes, native cisco (Coregonus artedi) populations increased. Our analysis of walleye diets illustrated that walleye fed selectively on rainbow smelt but did not feed on cisco during the summer months. When entered into bioenergetics simulations, this information demonstrates that walleye predation alone was enough to cause the observed rainbow smelt declines in our study lakes. Our results indicate that increased walleye density allows for a parallel increase in cisco density. Based on our results, fishery regulations to restore walleye to high densities in lakes invaded by rainbow smelt may restore native planktivores that have co-evolved traits.

2003 ◽  
Vol 60 (12) ◽  
pp. 1552-1574 ◽  
Author(s):  
Charles R Bronte ◽  
Mark P Ebener ◽  
Donald R Schreiner ◽  
David S DeVault ◽  
Michael M Petzold ◽  
...  

Changes in Lake Superior's fish community are reviewed from 1970 to 2000. Lake trout (Salvelinus namaycush) and lake whitefish (Coregonus clupeaformis) stocks have increased substantially and may be approaching ancestral states. Lake herring (Coregonus artedi) have also recovered, but under sporadic recruitment. Contaminant levels have declined and are in equilibrium with inputs, but toxaphene levels are higher than in all other Great Lakes. Sea lamprey (Petromyzon marinus) control, harvest limits, and stocking fostered recoveries of lake trout and allowed establishment of small nonnative salmonine populations. Natural reproduction supports most salmonine populations, therefore further stocking is not required. Nonnative salmonines will likely remain minor components of the fish community. Forage biomass has shifted from exotic rainbow smelt (Osmerus mordax) to native species, and high predation may prevent their recovery. Introductions of exotics have increased and threaten the recovering fish community. Agencies have little influence on the abundance of forage fish or the major predator, siscowet lake trout, and must now focus on habitat protection and enhancement in nearshore areas and prevent additional species introductions to further restoration. Persistence of Lake Superior's native deepwater species is in contrast to other Great Lakes where restoration will be difficult in the absence of these ecologically important fishes.


NeoBiota ◽  
2021 ◽  
Vol 66 ◽  
pp. 75-94
Author(s):  
Sergey Golubkov ◽  
Alexei Tiunov ◽  
Mikhail Golubkov

The paucity of data on non-indigenous marine species is a particular challenge for understanding the ecology of invasions and prioritising conservation and research efforts in marine ecosystems. Marenzelleria spp. are amongst the most successful non-native benthic species in the Baltic Sea during recent decades. We used stable isotope analysis (SIA) to test the hypothesis that the dominance of polychaete worm Marenzelleria arctia in the zoobenthos of the Neva Estuary after its invasion in the late 2000s is related to the position of this species in the benthic food webs. The trend towards a gradual decrease in the biomass of Marenzelleria worms was observed during 2014–2020, probably due to significant negative relationships between the biomass of oligochaetes and polychaetes, both of which, according to SIA, primarily use allochthonous organic carbon for their production. The biomass of benthic crustaceans practically did not change and remained very low. The SIA showed that, in contrast to the native crustacean Monoporeia affinis, polychates are practically not consumed either by the main invertebrate predator Saduria entomon, which preys on M. affinis, oligochaetes and larvae of chironomids or by benthivorous fish that prefer native benthic crustaceans. A hypothetical model for the position and functional role of M. arctia in the bottom food web is presented and discussed. According the model, the invasion of M. arctia has created an offshoot food chain in the Estuary food webs. The former dominant food webs, associated with native crustaceans, are now poorly developed. The lack of top-down control obviously contributes to the significant development of the Marenzelleria food chain, which, unlike native food chains, does not provide energy transfer from autochthonous and allochthonous organic matter to the upper trophic levels. The study showed that an alien species, without displacing native species, can significantly change the structure of food webs, creating blind offshoots of the food chain.


<em>Abstract.</em>—The main channel of the Hudson River is a tidal estuary from its mouth in New York Harbor to Troy, New York, 247 km upstream. It drains about 35,000 km<sup>2</sup> and is an important navigational, commercial, and recreational system. Since the arrival of European settlers over 400 years ago, it has undergone numerous environmental changes. These changes have included channel maintenance by dredging, wholesale dumping of industrial and domestic wastes, scattered in-basin urbanization and shoreline development, deforestation of the watershed and an increase in agriculture, and water removal for commercial, industrial, and agricultural needs. In addition, the biota of the river has supported commercial and recreational harvesting, exotic species have become established, and habitats have become fragmented, replaced, changed in extent, or isolated. The tidal portion of the Hudson River is among the most-studied water bodies on Earth. We use data from surveys conducted in 1936, the 1970s, the 1980s, and the 1990s to examine changes in fish assemblages and from other sources dating back to 1842. The surveys are synoptic but use a variety of gears and techniques and were conducted by different researchers with different study goals. The scale of our assessment is necessarily coarse. Over 200 species of fish are reported from the drainage, including freshwater and diadromous species, estuarine forms, certain life history stages of primarily marine species, and marine strays. The tidal Hudson River fish assemblages have responded to the environmental changes of the last century in several ways. Several important native species appear to be in decline (e.g., rainbow smelt <em>Osmerus mordax </em>and Atlantic tomcod <em>Microgadus tomcod</em>), others, once in decline, have rebounded (e.g., striped bass <em>Morone saxatilis</em>), and populations of some species seem stable (e.g., spottail shiner <em>Notropis hudsonius</em>). No native species is extirpated from the system, and only one, shortnose sturgeon <em>Acipenser brevirostrum</em>, is listed as endangered. The recent establishment of the exotic zebra mussel <em>Dreissena polymorpha </em>may be shifting the fish assemblage away from openwater fishes (e.g., <em>Alosa</em>) and toward species associated with vegetation (e.g., centrarchids). In general, the Hudson River has seen an increase in the number and importance of alien species and a change in dominant species.


2014 ◽  
Vol 71 (7) ◽  
pp. 1039-1049 ◽  
Author(s):  
Kevin N. McDonnell ◽  
Brian M. Roth

We developed a bioenergetic-based foraging model to evaluate how the composition of the pelagic zooplankton community influences the growth of zooplanktivorous larval walleye (Sander vitreus). Our model incorporates field observations of pelagic zooplankton composition and density as well as size-specific prey preferences of larval walleye to simulate both foraging and consumption rates. The model was evaluated in four lakes in northern Wisconsin: two with invasive populations of rainbow smelt (Osmerus mordax) and two without populations of rainbow smelt. Invasive rainbow smelt are known to alter the composition of pelagic zooplankton communities as well as cause declines in walleye recruitment, thus providing a unique opportunity to evaluate our model. The results suggest that larval walleye growth is slowed in systems that lack high densities of large-bodied Daphnia. Such conditions may create an energetic bottleneck for larval walleye. This approach could easily be applied to other species that are also affected by rainbow smelt or more generally where success of larval foraging is suspected to have a large influence on year-class strength.


2018 ◽  
Vol 96 (7) ◽  
pp. 739-747 ◽  
Author(s):  
K.T. Sheppard ◽  
B.J. Hann ◽  
G.K. Davoren

The second largest inland walleye (Sander vitreus (Mitchill, 1818)) and sauger (Sander canadensis (Griffith and Smith, 1834)) fishery in Canada is found in Lake Winnipeg, Manitoba. To manage the fishery for a sustainable future, the growth and condition of these fish must be understood. Objectives were to (1) examine baseline growth and condition of walleye and sauger in Lake Winnipeg, (2) evaluate variation between the North and South basins, and (3) contribute observational findings on the distribution of dwarf walleye. Gill nets were set to catch walleye, sauger, and dwarf walleye throughout both basins at various locations and in all seasons during 2010 and 2011. North Basin walleye and sauger had higher growth rates and condition relative to the South Basin. This may be due to differential exploitation rates or diets such as the consumption of invasive rainbow smelt (Osmerus mordax (Mitchell, 1814)) in the North Basin and not in the South Basin. Dwarf walleye were observed more frequently in the South Basin than in the North Basin. Overall, this study provides important baseline data on the growth and condition of walleye and sauger populations prior to invasion of the spiny waterflea (Bythotrephes longimanus Leydig, 1860) and zebra mussels (Dreissena polymorpha (Pallas, 1771)).


2010 ◽  
Vol 77 (6) ◽  
pp. 1379-1405 ◽  
Author(s):  
B. M. Roth ◽  
T. R. Hrabik ◽  
C. T. Solomon ◽  
N. Mercado-Silva ◽  
J. F. Kitchell

2009 ◽  
Vol 66 (8) ◽  
pp. 1199-1215 ◽  
Author(s):  
David M. Warner ◽  
Jeffrey S. Schaeffer ◽  
Timothy P. O’Brien

Spatial patterns in the biomass of pelagic fish in Lake Huron have persisted over 10 years even though biomass decreased 86% and the fish community shifted from dominance by non-native species (rainbow smelt, Osmerus mordax ) to dominance by native species (bloater, Coregonus hoyi ). Based on multivariate analyses of acoustic biomass data and abiotic variables from the years 1997, 2004, 2005, and 2007, the strength of relationships between abiotic variables (primarily bottom depth) and fish community composition gradients decreased with fish biomass, suggesting that at high biomass, the influence of the measured abiotic variables is minimal. We observed consistently higher biomass in the North Channel and Georgian Bay than in the Main Basin, and as a result, we conclude that these smaller basins are likely important contributors to lakewide fish biomass, production, and dynamics. These results suggest that at current biomass levels, efforts to understand ecology, population dynamics, and lakewide abundance need to incorporate the effects of depth and geographic variation on fish distributions and ecology.


2004 ◽  
Vol 30 ◽  
pp. 407-413 ◽  
Author(s):  
Timothy B. Johnson ◽  
William P. Brown ◽  
Timothy D. Corry ◽  
Michael H. Hoff ◽  
Jill V. Scharold ◽  
...  

2010 ◽  
Vol 8 (1) ◽  
pp. 171-178 ◽  
Author(s):  
Manuel Mendoza-Carranza ◽  
David J Hoeinghaus ◽  
Alexandre M Garcia ◽  
Ángel Romero-Rodriguez

Mangrove and seagrass habitats are important components of tropical coastal zones worldwide, and are conspicuous habitats of Centla Wetland Biosphere Reserve (CWBR) in Tabasco, Mexico. In this study, we examine food webs in mangrove- and seagrass-dominated habitats of CWBR using stable isotope ratios of carbon and nitrogen. Our objective was to identify the importance of carbon derived from mangroves and seagrasses to secondary production of aquatic consumers in this poorly studied conservation area. Carbon and nitrogen isotope ratios of basal sources and aquatic consumers indicated that the species-rich food webs of both habitats are dependent on riparian production sources. The abundant Red mangrove Rhizophora mangle appears to be a primary source of carbon for the mangrove creek food web. Even though dense seagrass beds were ubiquitous, most consumers in the lagoon food web appeared to rely on carbon derived from riparian vegetation (e.g. Phragmites australis). The introduced Amazon sailfin catfish Pterygoplichthys pardalis had isotope signatures overlapping with native species (including high-value fisheries species), suggesting potential competition for resources. Future research should examine the role played by terrestrial insects in linking riparian and aquatic food webs, and impacts of the expanding P. pardalis population on ecosystem function and fisheries in CWBR. Our findings can be used as a baseline to reinforce the conservation and management of this important reserve in the face of diverse external and internal human impacts.


1998 ◽  
Vol 55 (2) ◽  
pp. 318-327 ◽  
Author(s):  
Peter S Rand ◽  
Donald J Stewart

Estimates of production and predation rates from bioenergetic models of chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and lake trout (Salvelinus namaycush) suggest a long-term decline in their gross conversion efficiency (gross production/prey consumption) and the gross production to biomass ratio in Lake Ontario during 1978-1994. The former pattern was caused primarily by a declining trend in adult alewife (Alosa pseudoharengus) energy density during 1978-1985; the latter pattern resulted from reductions in growth rates (coho salmon) and a buildup of the older age-classes in the population (lake trout) over time. Model results suggest that over 100 and 25% of the annual production of adult alewife and rainbow smelt (Osmerus mordax), respectively, was consumed by salmonines during 1990 in Lake Ontario; hence, we claim that recent observations of reduced salmonine growth in Lake Ontario may be a result of prey limitation. Energy transfer from primary production to salmonines appeared to be more efficient in Lake Ontario than in Lake Michigan, probably due to higher stocking levels per unit area and higher densities of preferred prey fish in Lake Ontario. Through separate analyses, we arrived at conflicting conclusions concerning the sustainability of the food web configuration in Lake Ontario during 1990.


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