Ecología y manejo de los lucios muskallonga y europeo: aspectos relevantes y necesidades de investigación Las nuevas técnicas de investigación y los cambios en las pesquerías de los lucios muskallonga, Esox masquinongy y europeo, E. lucius, han contribuido a modificar paradigmas sobre la ciencia y manejo de estas especies. Se llevó a cabo un simposio sobre biología, ecología y manejo de los lucios muskallonga y europeo en la reunión anual de la Sociedad Americana de Pesquerías, en Little Rock, Arkansas, y en un panel de discusión organizado después del simposio se identificaron diversas prioridades de investigación y manejo que incluyen identificación de hábitats de desove, restauración de hábitats y de poblaciones, genética, mortalidad selectiva y explotación. En el futuro, la investigación sobre los lucios muskallonga y europeo se debe enfocar en cuantificar la supervivencia a nivel de huevos y de edad 0; sobre la base de las características del hábitat, evaluar rigurosamente los esfuerzos de restauración de hábitat mediante diseño de sondeos estadísticos, descripción amplia de la estructuración genética de las poblaciones y desarrollar un mejor entendimiento acerca de cómo la mortalidad selectiva y la explotación pueden alterar la estructura de tallas, proporción de sexos y características de la historia de vida de estas especies. Los resultados y la información que se genere tanto de la investigación propuesta como de las prioridades de manejo, serán críticos para la conservación y restauración de las poblaciones auto sostenibles de los lucios muskallonga y europeo.

Accurate age estimates are critical for understanding life histories of fishes and developing management strategies for fish populations. However, validation of age estimates requires known-age fish, which are often lacking. We used known-age (ages 1–25) muskellunge (Esox masquinongy) to determine the precision and accuracy of age estimates from fin rays. We also determined whether fin location (anal or pelvic), fin ray number, and preparation methods affected accuracy and precision. Lastly, we determined whether von Bertalanffy growth parameters estimated from fin ray ages were similar to parameters estimated from known ages. Precision and accuracy of age estimates from anal and pelvic rays were similar and estimates were relatively precise (coefficient of variation = 8.5%) and accurate (mean absolute difference from known age = 0.85 years) for ages 4–15, but ages were overestimated for younger fish and underestimated for older fish. Growth models based on estimated age were similar to models based on known age. Anal and pelvic rays offer a nonlethal alternative for age estimation of muskellunge ages 4–15 and for producing reliable estimates of growth.

Feeding patterns and population structure of the non-native rudd Scardinius erythrophthalmus (Linnaeus) were examined to understand their ecology in Buffalo Harbor and the Niagara River. We hypothesized that (1) the diet of rudds would be omnivorous, but contain greater proportions of macrophytes in summer months, (2) feeding intensity would increase with water temperature, and (3) condition and growth would be similar to other populations. We collected rudds with a variety of gears in 2009 to test these hypotheses, and used data from 2007 to 2010 seining surveys to determine if the relative abundance of young-of-the-year rudd differed among sites with different flow conditions. Rudds were mostly herbivorous; they consumed aquatic macrophytes in summer and supplemented their diet with algae and fish in spring and fall. Feeding intensity was positively correlated with water temperature, but significantly reduced during spawning. Rudd condition and growth were greater than estimates from other populations, suggesting increases in abundance and range expansion are possible. Furthermore, reproduction was successful at lotic sites but very poor at sites without measureable flow, contrary to the paradigm of optimal rudd habitat. Research is needed to understand how herbivory by abundant rudd populations affects native aquatic communities.

We quantified genetic relationships among Muskellunge Esox masquinongy from 15 locations in the Great Lakes to determine the extent and distribution of measurable population structure and to identify appropriate spatial scales for fishery management and genetic conservation. We hypothesized that Muskellunge from each area represented genetically distinct populations, which would be evident from analyses of genotype data. A total of 691 Muskellunge were sampled (n = 10-127/site) and genetic data were collected at 13 microsatellite loci. Results from a suite of analyses (including pairwise genetic differentiation, Bayesian admixture prediction, analysis of molecular variance, and tests of isolation by distance) indicated the presence of nine distinct genetic groups, including two that were approximately 50 km apart. Geographic proximity and low habitat complexity seemed to facilitate genetic similarity among areas, whereas Muskellunge from areas of greater habitat heterogeneity exhibited high differentiation. Muskellunge from most areas contained private alleles, and mean within-area genetic variation was similar to that reported for other freshwater fishes. Management programs aimed at conserving the broader diversity and long-term sustainability of Muskellunge could benefit by considering the genetically distinct groups as independent fisheries, and individual spawning and nursery habitats could subsequently be protected to conserve the evolutionary potential of Muskellunge.