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J.E. McKenna

Publications and source records attributed to J.E. McKenna.

14 recordsLinked to original sources
USGS2011

A heuristic simulation model of Lake Ontario circulation and mass balance transport

The redistribution of suspended organisms and materials by large-scale currents is part of natural ecological processes in large aquatic systems but can contribute to ecosystem disruption when exotic elements are introduced into the system. Toxic compounds and planktonic organisms spend various lengths of time in suspension before settling to the bottom or otherwise being removed. We constructed a simple physical simulation model, including the influence of major tributaries, to qualitatively examine circulation patterns in Lake Ontario. We used a simple mass balance approach to estimate the relative water input to and export from each of 10 depth regime-specific compartments (nearshore vs. offshore) comprising Lake Ontario. Despite its simplicity, our model produced circulation patterns similar to those reported by more complex studies in the literature. A three-gyre pattern, with the classic large counterclockwise central lake circulation, and a simpler two-gyre system were both observed. These qualitative simulations indicate little offshore transport along the south shore, except near the mouths of the Niagara River and Oswego River. Complex flow structure was evident, particularly near the Niagara River mouth and in offshore waters of the eastern basin. Average Lake Ontario residence time is 8 years, but the fastest model pathway indicated potential transport of plankton through the lake in as little as 60 days. This simulation illustrates potential invasion pathways and provides rough estimates of planktonic larval dispersal or chemical transport among nearshore and offshore areas of Lake Ontario. ?? 2011 Taylor & Francis.

Journal of Freshwater Ecology↗
USGS2010

Occurrence of the Great Lake's most recent invader, Hemimysis anomala , in the diet of fishes in southeastern Lake Ontario

The Ponto-Caspian mysid, Hemimysis anomala , was first observed in southeastern Lake Ontario in May 2006. During July and August 2007, gill nets were fished in 6 to 8 m of water at two locations of known Hemimysis colonization in southeastern Lake Ontario to determine if fish that consume macroinvertebrates were beginning to include this new invasive mysid in their diets. Of nine fish species captured in August, September, and October 2007, three species had consumed Hemimysis : alewife ( Alosa pseudoharengus ), rock bass ( Ambloplites rupestris ), and yellow perch ( Perca flavescens ); and six species had not: round goby Apollonia melanostoma , smallmouth bass Micropterus dolomieu , spottail shiner Notropis hudsonius , gizzard shad Dorosoma cepedianum , white perch Morone americana and log perch Percina caprodes . Diets of alewives from all samples were composed predominantly of Hemimysis (69.6% -100% frequency of occurrence, 46.0%–74.5% dry weight diet composition). Two of 6 rock bass stomachs sampled in August contained ≥ 98.9% Hemimysis (10 and 40 individuals each) and one of 61 yellow perch stomachs sampled in September contained 10.0% Hemimysis (6 individuals) and 90.0% fish. While Hemimysis were observed only sparsely in the diet of most nearshore fish, their predominance in alewife diets and their omnivorous feeding behavior indicated that they have the potential to alter energy flow in Great Lakes' foodwebs.

Journal of Great Lakes Research↗
USGS2010

Hierarchical multi-scale classification of nearshore aquatic habitats of the Great Lakes: Western Lake Erie

Classification is a valuable conservation tool for examining natural resource status and problems and is being developed for coastal aquatic habitats. We present an objective, multi-scale hydrospatial framework for nearshore areas of the Great Lakes. The hydrospatial framework consists of spatial units at eight hierarchical scales from the North American Continent to the individual 270-m spatial cell. Characterization of spatial units based on fish abundance and diversity provides a fish-guided classification of aquatic areas at each spatial scale and demonstrates how classifications may be generated from that framework. Those classification units then provide information about habitat, as well as biotic conditions, which can be compared, contrasted, and hierarchically related spatially. Examples within several representative coastal or open water zones of the Western Lake Erie pilot area highlight potential application of this classification system to management problems. This classification system can assist natural resource managers with planning and establishing priorities for aquatic habitat protection, developing rehabilitation strategies, or identifying special management actions.

Journal of Great Lakes Research↗
USGS2009

Spatial and temporal variation in distribution of larval lake whitefish in eastern Lake Ontario: signs of recovery?

The lake whitefish ( Coregonus clupeaformis ) is one of the native Lake Ontario fishes that declined severely over the past century. Recent evidence of larval lake whitefish production in a historic spawning area (Chaumont Bay) might signal a recovery of this species in New York waters. We surveyed coastal and open water areas to evaluate densities and estimate total abundance of larval lake whitefish in Chaumont Bay. Other historic spawning areas and embayments with appropriate spawning and nursery habitat were also surveyed, but only a few larvae were found outside of Chaumont Bay. Lake whitefish larvae were found in every embayment sampled within Chaumont Bay, with larval densities of nearly 600/1000 m 2 in some samples. Greatest abundances occurred in the northern sectors and near the mouth of the bay. Open water densities were generally less than half that of nearshore sites. The total bay-wide estimate for 2005 was approximately 644,000 lake whitefish larvae, but dropped to 230,000–400,000 in 2006 and 2007, respectively. Mean larval growth rates (0.36 mm/day) did not differ by year, but were consistently higher in early May than in late April. Lake whitefish production in Chaumont Bay is encouraging for this species, but the cause and persistence of the decline after 2005 can be determined only by continued monitoring. Other possible bottlenecks of survival may exist at juvenile and adult stages and could significantly affect recruitment dynamics. This species is sensitive to normal climatic fluctuations and increased variability associated with global climatic change could make winter nursery conditions unfavorable for this species.

Journal of Great Lakes Research↗
USGS2008

Ichthyoplankton assemblages of coastal west-central Lake Erie and associated habitat characteristics

Early life stage survival often determines fish cohort strength and that survival is affected by habitat conditions. The structure and dynamics of ichthyoplankton assemblages can tell us much about biodiversity and fish population dynamics, but are poorly understood in nearshore areas of the Great Lakes, where most spawning and nursery habitats exist. Ichthyoplankton samples were collected with a neuston net in waters 2-13 m deep weekly or biweekly from mid-April through August, during 3 years (2000-2002) as part of a study of fish assemblages in west-central Lake Erie. A suite of abiotic variables was simultaneously measured to characterize habitat. Cluster and ordination analyses revealed several distinct ichthyoplankton assemblages that changed seasonally. A lake whitefish (Coregonus clupeaformis) dominated assemblage appeared first in April. In May, assemblages were dominated by several percid species. Summer assemblages were overwhelmingly dominated by emerald shiner (Notropis atherinoides), with large gizzard shad (Dorosoma cepedianum) and alewife (Alosa pseudoharengus) components. This seasonal trend in species assemblages was also associated with increasing temperature and water clarity. Water depth and drift processes may also play a role in structuring these assemblages. The most common and widely distributed assemblages were not associated with substratum type, which we characterized as either hard or soft. The timing of hatch and larval growth separated the major groups in time and may have adaptive significance for the members of each major assemblage. The quality and locations (with reference to lake circulation) of spawning and nursery grounds may determine larval success and affect year class strength.

Journal of Great Lakes Research↗
USGS2008

Diel diet composition and feeding activity of round goby in the nearshore region of Lake Ontario

Expansion of the invasive round goby Apollonia melanostoma (=Neogobius melanostomus) throughout the Great Lakes drainage has created considerable concern among fisheries management agencies. These concerns have led to several studies on the biology and impact of the goby in the basin. However, little information exists on diel patterns in food consumption of the round goby. We examined the diets of 300 round gobies collected during crepuscular, diurnal, and nocturnal periods in Lake Ontario. There was little variation in the diel diet composition of the goby, as chironomid larvae were the major prey consumed during each period. Feeding intensity of the round goby was significantly (P<0.05) greater at night than during crepuscular or diurnal periods.

Journal of Freshwater Ecology↗
USGS2008

Influence of summer water-level variability on St. Lawrence River-wetland fish assemblages

Water-level and associated variability are substantial influences on wetland and shallow aquatic communities. The Akwesasne Wetland Complex is an extensive St. Lawrence River system affected by water regulation. The responses of fish assemblages to short-term summer water-level variation were examined throughout this section of the St. Lawrence River and its tributaries. An influence of water-level variability was detected on abundance of three common species [bluntnose minnow (Pimephales notatus), rock bass (Amboplites rupestris), and white sucker (Catastomus commersonii)] and explained 30-44% of variation. This influence has implications for water regulation and natural resource management, and a larger scope evaluation may reveal more extensive effects.

Journal of Freshwater Ecology↗
USGS2008

Diel variation in near-shore great lakes fish assemblages and implications for assessment sampling and coastal management

I compared fish assemblages captured in three different microhabitats (shoreline, pelagic near-shore, and benthic near-shore) during day and night fishing in different protection (inside bay or tributary vs. outside in Lake Ontario proper) and turbidity regimes of four near-shore areas of Lake Ontario. The effects of diel movement and availability to gear were clearly evident. Fish assemblages were consistently and significantly more diverse at night than during the day, with nighttime assemblages often being supersets of daytime assemblages. Evidence for a turbidity effect was much weaker than the effects of nocturnal movements and changes in availability to the gear associated with darkness. Nighttime sampling is more likely to capture the full array of species in near-shore areas of the Great Lakes than daytime sampling.

Journal of Freshwater Ecology↗
USGS2007

Diel periodicity of drift of larval fishes in tributaries of Lake Ontario

Diel patterns of downstream drift were examined during mid-June in three tributaries of Lake Ontario. Larval fishes were collected in drift nets that were set in each stream for 72 consecutive hours and emptied at 4-h intervals. Fantail darter (Ethostoma flabellare) and blacknose dace (Rhinichthys atractulus) were the two most abundant native stream fishes and were two of the three species collected in the ichthyoplankton drift. Fantail darter larvae comprised 100%, 98.9%, and 70.2% of the ichthyoplankton in the three streams. Most larval fishes (96%) drifted at night with peak catches occurring at 2400h in Orwell Brook and Trout Brook and 0400h in Little Sandy Creek. Based on stream temperatures, peak spawning and larval drift of blacknose dace probably occurred later in the season.

Journal of Freshwater Ecology↗
USGS2003

An enhanced cluster analysis program with bootstrap significance testing for ecological community analysis

The biosphere is filled with complex living patterns and important questions about biodiversity and community and ecosystem ecology are concerned with structure and function of multispecies systems that are responsible for those patterns. Cluster analysis identifies discrete groups within multivariate data and is an effective method of coping with these complexities, but often suffers from subjective identification of groups. The bootstrap testing method greatly improves objective significance determination for cluster analysis. The BOOTCLUS program makes cluster analysis that reliably identifies real patterns within a data set more accessible and easier to use than previously available programs. A variety of analysis options and rapid re-analysis provide a means to quickly evaluate several aspects of a data set. Interpretation is influenced by sampling design and a priori designation of samples into replicate groups, and ultimately relies on the researcher's knowledge of the organisms and their environment. However, the BOOTCLUS program provides reliable, objectively determined groupings of multivariate data.

Environmental Modelling and Software↗
USGS2003

Community metabolism during early development of a restored wetland

Productivity is an important ecological function of any natural system and may be quite high in wetlands. Restoration of productive wetlands may play a key role in re-establishing ecological function to portions of the vast areas of wetlands (roughly 86%) drained and otherwise altered in the United States over the past two centuries. A restored wetland at the Montezuma National Wildlife Refuge (upstate New York, USA) was examined to determine if ecological function (i.e., productivity), as well as biotic structure, was restored. Physicochemical conditions and both aquatic and terrestrial productivity were measured at the restoration site and compared with rates and conditions in a reference wetland. Gross aquatic community production rates (based on diurnal oxygen curves) were similar at each site (1,679 and 2,311 g O 2 &middot; m &minus;2 &middot; yr &minus;1 ) and within the range expected for the habitat. Terrestrial Net Aboveground Primary Production rates (measured by monthly biomass changes) (2,400 and 2,500 g dry wt. &middot; m &minus;2 &middot; yr &minus;1 ) were also similar between sites when tree and herb production were combined. Aquatic respiration rates (3,704 and 4,552 g O 2 &middot; m &minus;2 &middot; yr &minus;1 ) were also similar but high, typically more than twice as large as gross aquatic production. As a result, net aquatic production rates at both sites were usually negative, indicating that these small wetlands are organic matter sinks that satisfy aquatic respiration by consumption of both autochthonous aquatic production and imported terrestrial production. They enhance diversity of the local landscape by producing populations of aquatic consumers that cannot be supported by aquatic production alone. Typical wetland conditions and processes developed quickly after restoration, but differences in biotic community structure indicate that observed rates of production and respiration at both sites were maintained by flow through different foodweb pathways. Despite the relatively high process rates, and successional progress of the restoration site is expected to be slow.

Wetlands↗