USGS research frontiers on fish at the American Fisheries Society Conference

The theme of this year's conference is “New Frontiers in Fisheries Management and Ecology: Leading the Way in a Changing World.” For more information, visit http://afs2011.org/ All talks will be at the Washington State Convention Center. Highlighted USGS presentations are below:

Eat but don't get eaten: after restoration, young salmon better off: Habitat restoration has had major benefits for juvenile salmon in the Columbia River Estuary, including new rearing habitat where food is plentiful and where the risk of being eaten is low, accordingly to a USGS study. Models showed that temperature was an important reason for the increased young salmon growth in areas of the river that the current didn't reach, but this growth spurt was somewhat counteracted by the fact that typical foods eaten in the main part of the river were higher in energy. USGS scientists successfully used bioenergetics, a field of biology that looks at the flow of energy in living systems, to study the effectiveness of the restoration project. The study also points to the importance of refuges to keep young salmon safer from predators, a distinct benefit afforded by restoration. This study, Eat, but don't get eaten — quantifying the energetic benefit of Columbia River Estuary restoration to juvenile salmon, will be presented Sept. 5 at 2 p.m. in room 609. To learn more, contact Craig Haskell at chaskell@usgs.gov or at 509-637-3619.

Targeting young silver carp for control may pay off: Efforts to reduce the harmful effects of invasive silver carp on native fish should focus on younger silver carp, according to a recent USGS, Kansas State University and University of Missouri study. The USGS and university scientists projected a growth rate of 58 percent a year of silver carp, with their models demonstrating that the growth and maturation of young fish are most critical to the continuation of the explosive growth of this exceedingly noxious species. Currently, however, most management efforts are focused on adult silver carp because they are easier to locate and remove. First introduced to the United States in the 1980s, silver carp have quickly expanded their range with a combination of rapid growth, quick maturation and the ability to reproduce multiple times per year. These fish are also capable of eating large quantities of plankton and detritus, and are affecting native fishes in areas where they become established. The model, which looked at silver carp populations in large Midwestern rivers, indicates that resource managers may want to target the removal of younger fishes to better control the expansion of this prolific invasive species. This study, Age-specific demography of silver carp: implications for management and control, will be presented Sept. 7 at 9 a.m. in room 612. To learn more, contact Joseph Gerken at gerkenje@ksu.edu or at 785-477-4150.

Climate change likely to be both a boom and a bust for smallmouth bass populations: The smallmouth bass is a popular sport fish that has spread far and wide beyond its native range, but climate change may play a significant role in where it goes next. USGS and University of Missouri scientists modeled the effects of conservative climate change estimates on smallmouth bass population growth, assuming a 2-degree Celsius increase in temperature over the next 30 years. While smallmouth bass populations in more northern habitats were expected to increase growth, southern climates could expect a decline in growth, since this fish doesn't do as well when temperatures frequently exceed 27 degrees Celsius (80 F). This research shows that climate has direct implications for smallmouth bass survival and reproduction, and understanding how smallmouth bass populations will react to warmer temperatures can help decision makers manage and conserve this sought-after game fish. This study, Potential effects of climate change on growth of smallmouth bass in streams of the central U.S., will be presented on Sept. 8 at 1:45 p.m. in room 4C-3. To learn more, contact Allison Pease at peasea@missouri.edu or at 979-220-3930.

The Exxon Valdez oil spill and long-term effects on nearshore animals: Research in the aftermath of the 1989 Exxon Valdez oil spill has demonstrated the potential for oil to persist in the environment and for deleterious effects on wildlife to occur over an extended time scale. Oil from the spill remains in intertidal areas of western Prince William Sound, Alaska, presenting a risk of chronic exposure for species that use nearshore areas. Sea otters, harlequin ducks and other species at risk are vulnerable to exposure and potential effects as long as oil remains in sediments, perhaps for several decades; it now appears that cumulative chronic effects may be as significant as acute effects on wildlife. Reduced survival has been identified as a concern for both sea otters and harlequin ducks in oiled areas; however, recent data suggest recovery is under way for both species. The extended timeline over which impacts from lingering oil are being documented is an unanticipated finding, made possible by the long-term support of studies implemented after the spill. This study, The Exxon Valdez Oil Spill: Long-term effects and pathways of exposure to nearshore vertebrates, will be presented on Sept. 8 at 8:45 a.m. in room 4C-4; it is part of the Gulf Oil Session. To learn more, contact Brenda Ballachey at bballachey@usgs.gov or at 403-397-3073.

Working together a win-win for red knots, horseshoes, and fishermen: Fishery managers, scientists and stakeholders worked together in a USGS-led effort to create a multi-species management strategy for the Atlantic horseshoe crab fishery. This innovative management strategy used information from another USGS study indicating that managing horseshoe crab resources in the Delaware Bay has the potential to improve red knot population status. Red knots are an at-risk shorebird that dines upon the horseshoe crab's eggs during migration. The new management strategy has suggested a harvest limit for horseshoe crabs that takes shorebird needs into account. Most horseshoe crab harvest today comes from the fishing industry, which uses the crab as bait, and the pharmaceutical industry, which collects their blood for its clotting properties. This collaboration is the first to quantitatively connect the two species, and also to provide recommendations for management based on their connection. This study, An adaptive multispecies approach to managing the horseshoe crab fishery in Delaware Bay, will be presented on Sept. 5 at 6:00 p.m. in room 4E. To learn more, contact Conor McGowan at cmcgowan@usgs.gov or at 334-844-9231.

Free reign of the stream suits fish of the West: Scientists know that fish need to move freely in search of better habitat for feeding, refuge and reproduction – and that what is considered “good” habitat changes throughout the life cycle of a fish. This movement represents the path a fish takes over its lifetime from one point to the next, and the ability to freely move among these points is critical for the survival of both individual fish and other organisms that benefit from their presence in the ecosystem. Physical, chemical and biological factors that restrict movement along this path can have negative consequences. By looking at several charismatic fish species in the western U.S., researchers can better characterize why “free reign” of the stream is so essential to the survival of native fish throughout the west. This study, Role of connectivity in survival and persistence of potamodromous and non-migratory salmonids, will be presented on Sept. 6 at 8:45 a.m. in room 606. To learn more, contact Bob Gresswell at bgresswell@usgs.gov or at 406-994-7085.

Climate change could put Western fish in hot water: Climate in the western United States is expected to become warmer and more variable during the next century, putting pressure on water resources and the fish that inhabit western waterways. Fisheries ecologists and manager are striving to understand how future changes in both climate and land use will affect native coldwater fish species, especially those that are already vulnerable because of fragmented habitat and warming water. By using a dynamic array of historical data and modern technology, scientists identified the most critical temperature-suitable habitat for coldwater-loving fish. This information was combined with regional climate change predictions to estimate how stream temperatures may change over time in the face of a warming climate – providing a model of how increases in stream temperature will impact native fish and helping identify areas critical to maintaining suitable coldwater habitat in the future. This study, Predicting effects of land use and climate change on availability of suitable thermal habitat for native and nonnative salmonids, will be presented on Sept. 8 at 10:45 a.m. in room 4C-3. To learn more, contact Bob Gresswell at bgresswell@usgs.gov or at 406-994-7085.

Partners work together on whole-river fish survey of the Elwha River before dam removal: Ten anadromous fish populations are expected to recolonize over 115 kilometers (72 miles) of historical habitats after two large hydroelectric dams are removed from the Elwha River on Washington State's Olympic Peninsula. To understand watershed recolonization and ecosystem restoration, the collection of geographically continuous information on fish and aquatic habitats is necessary. The USGS, National Park Service and its partners conducted snorkel and habitat surveys in the Elwha River from the headwaters to its mouth in 2007 and 2008. This “riverscape” approach enabled scientists to characterize extent, abundance, age, and community make-up (what species occurred) of Pacific salmonids along almost the entire river. Not surprisingly, the study revealed that species richness was highest below the dams, where anadromous salmonids still have access. It also demonstrated clear differences in habitat along the river because of natural and human-caused factors. This comprehensive approach helped highlight species-specific biological hotspots – for example, it showed that nearly two-thirds of federally threatened bull trout occurred near or below the dams. The riverscape approach also helped address linkages between fish and aquatic habitats before dam removal. Such geographically continuous surveys will be vital in evaluating the effectiveness of upcoming dam removal projects at restoring anadromous salmonids. This study, A riverscape approach to assess fish and habitat relationships prior to dam removal on the Elwha River, Washington, will be presented Sept. 7 at 8:15 a.m. in room 608. To learn more, contact Jeff Duda at jduda@usgs.gov or at 206-526-6282; or contact Sam Brenkman at sam_brenkman@nps.gov or at 360-565-3081.

Designing a cookbook for Asian Carp control: The food and feeding behavior of invasive Asian carp may hold the key ingredients to designing a chemical or biological control that could reduce the population of these invaders in the Mississippi River. Asian carp have become a major threat to ecosystems in the Mississippi, Missouri and Ohio Rivers since their introduction in the 1970s. Asian carp filter feed selectively on microscopic algae and plankton, and scientists are exploring the size of preferred food particles and how the digestive system works to develop an Asian carp-specific toxicant with selective uptake and delivery. Preliminary findings suggest that to build a selective toxicant — 50-100 micron size particles, the presence of select enzymes and a late winter or spring timeframe are basic ingredients to blend for success. Asian carp were found to feed on the blank designer food particles, and now studies will begin with the chemical ingredient. This study, Using New Technologies for the Control of Filter-Feeding Aquatic Invasive Species Like Asian Carps, will be presented on Sep. 6 th at 10:15 a.m. in room 612 (Washington State Convention Center). To learn more, contact Jon Amberg at jamberg@usgs.gov or at 608-781-6322.

USGS provides science for a changing world. For more information, visit www.usgs.gov.