Eshenroder R.L.,Great Lakes Fishery Commission
Transactions of the American Fisheries Society | Year: 2014
The origin of populations of the landlocked Sea Lamprey Petromyzon marinus in Lakes Champlain and Ontario, whether by artificial canals or by natural colonization following the last ice age, is controversial, in part because the related history and ecology had been poorly documented. This situation favored a native classification for the populations in both lakes based mainly on genetics. A native classification for the Lake Champlain population was predicated on either of two erroneous dates of first record, 1841 and 1894, whereas the correct date, 1929, was much more recent and strongly supports a nonnative classification. The detection of the Sea Lamprey in Lake Champlain occurred shortly after the opening in 1916 of the Champlain Barge Canal, which opened the upper Hudson River to fish passage. The case for a native Lake Ontario population did not account for a watershed breach in 1863 between the Susquehanna River, where the Sea Lamprey had been common, and the Lake Ontario drainage. Shortly after this canal-related connection was made, Sea Lamprey populations became abundant, nearly simultaneously, in four locations in the Lake Ontario drainage, suggesting this breach was the entry point for the founding population. The genetic distances between the landlocked populations and the Atlantic Ocean population appear to have been caused by recent bottlenecks rather than long-term residence; a recent genetic bottleneck was detected in the Lake Ontario population. Native classifications rested, in part, on extraordinary ecological scenarios, whereas nonnative classifications are consistent with experience in the upper Great Lakes and with well-known vectors of range expansion (canals, dam openings, watershed breaches). These findings in aggregate favor a nonnative classification of the Sea Lamprey in both lakes. © American Fisheries Society 2014.
Lawrence T.J.,Great Lakes Fishery Commission |
Lawrence T.J.,University of Michigan |
Watkins C.,Culture and Conservation
International Journal of Sustainable Development and World Ecology | Year: 2012
Decentralisation policies in least developed countries have emerged in response to failed centralised natural resource governance programmes because high-value natural resources are distributed unequally, with central governments often reaping more than local-level users. Current natural resource governance institutions have been created to remedy the problems that central governments formerly posed. Here, we argue that Uganda's forestry and fishery resources are biologically diverse and thus amenable to current decentralised management programmes, provided that there is compromise between market values and local cultural and subsistence values and uses. We observe, however, Uganda's current institutional arrangement favours the former over the latter and determine that successful natural resource decentralisation requires strengthening local-level natural resource institutions with increased fiscal flow, enforcement, monitoring and judicial powers. A strong and reliable partnership between local-level resource users and the central government is necessary for this to occur. © 2012 Copyright Taylor and Francis Group, LLC.
Muir A.M.,Michigan State University |
Blackie C.T.,Dalhousie University |
Marsden J.E.,University of Vermont |
Krueger C.C.,Great Lakes Fishery Commission
Reviews in Fish Biology and Fisheries | Year: 2012
In this paper, we (1) describe field observations of lake charr (trout) reproductive behaviour, focusing on two morphs from Great Bear Lake, N. T; (2) review and synthesize observations from the literature; and (3) summarize uncertainties and pose hypotheses regarding lake trout spawning behaviour. Our description is set within the context of an existing conceptual model that included three sequential stages to spawning behaviour-traveling, sinking, and gamete release. Spawning morphs did not overlap in time and space. Strong onshore winds seemed to trigger lake trout movement toward shoals in mid- to late-August where males outnumbered and seemed to precede female arrival at the shoals. A new behaviour termed finning was observed and interpreted as display courtship. Finning was observed at all spawning sites in Great Bear Lake and involved two or more fish that were either stationary or moving slowly just beneath the water surface with a partially erect dorsal fin, adipose fin, and only occasionally the dorsal lobe of the caudal fin breaking the water surface. On the basis of our observations and review of the literature, we propose to modify the Esteve et al. model to add (1) pre-courtship and spawning behaviour and (2) display courtship behaviour as occurring prior to traveling, sinking, and gamete release. Potential future research questions are described to address uncertainties regarding how spawning lake trout relate to their physical habitat, environmental cues to spawning, factors driving assortative mating among morphs, and the role of olfactory cues in spawning. © 2012 Springer Science+Business Media B.V.
Bergstedt R.A.,U.S. Geological Survey |
Argyle R.L.,U.S. Geological Survey |
Krueger C.C.,Great Lakes Fishery Commission |
Taylor W.W.,Michigan State University
Transactions of the American Fisheries Society | Year: 2012
A study conducted in LakeHuron duringOctober 1998-June 2001 found that strains ofGreat Lakes-origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes-origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002-2005. Based on those data,we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002-2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998-2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002-2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998-2001. Aside fromthe sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002-2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both. © American Fisheries Society 2012.
Czesny S.J.,University of Michigan |
Rinchard J.,New York University |
Hanson S.D.,U.S. Fish and Wildlife Service |
Dettmers J.M.,Great Lakes Fishery Commission |
Dabrowski K.,Ohio State University
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2011
Lipid concentration and fatty acid composition of common prey species or taxonomic groups from four distinct regions of Lake Michigan were quantified (n = 894). We used a combination of parametric and nonparametric statistics to assess the differences in fatty acid signatures (FAS) among species and to evaluate intraspecies variation relative to interspecies variation in FAS. Discriminant function analysis performed on 13 species or taxa groups using the 18 most abundant fatty acids revealed clear separation among taxa, with overall classification success reaching 89%. Species were readily distinguished based on their overall fatty acid profile in spite of intraspecies variation (temporal, regional, and size-related). Among species sampled, pelagic and benthic clusters were formed based on the degree of fatty acid profile similarity. In alewife (Alosa pseudoharengus) and round goby (Neogobius melanostomus), fatty acid compositions differed with fish size, sampling location, and temporal variation; however, the magnitude of these differences was small relative to differences between species. Our results demonstrate the utility of fatty acid signatures in studies of food webs in large freshwater ecosystems. This study is also a necessary first step toward development of mechanistic research that investigates the effects of variation in fatty acids within the prey base on top predators.