5/19/2015  |   10:30 - 10:45   |  103DE

UNDERSTANDING THE ROLE OF DIRECT CELL-TO-CELL INTERACTION AND MIXOTROPHY IN THE HARMFUL ALGA PRYMNESIUM PARVUM Prymnesium parvum is a harmful alga that causes fish kills and inhibits the growth of competitors through the use of exotoxins. Although the nature of these toxins is not well characterized, these compounds are thought to give P. parvum a competitive advantage with regard to access of limiting nutrients. Recent studies have contradicted the role exotoxins in killing competitors and finfish. Cell-to-cell interaction may play a greater role in the mortality of competitors. Additionally, cell-to-cell interaction may play a role in turning competitors into prey. Using the non-toxic alga Rhodomonas salina as a competitor of P. parvum, I investigated the effects of exotoxicity versus cell-to-cell interaction. Culture plates were set up with permeable membranes, preventing direct cellular contact, but allowing diffusion of exotoxins produced by P. parvum. Results revealed that R. salina was killed when in contact with P. parvum, but persisted when separated from P. parvum by the permeable membrane. Preliminary results also demonstrate that P. parvum nutritionally benefits from the death of R. salina, indicating that mixotrophy may play a role in the proliferation of P. parvum.

Coridon Laws (Primary Presenter/Author), University of Texas Arlington, claws@uta.edu;

5/19/2015  |   10:45 - 11:00   |  103DE

SEASONAL POPULATION DYNAMICS AND PRODUCTION OF THE PREDACIOUS CHLOROPERLID, PLUMIPERLA DIVERSA, IN A MOUNTAIN STREAM. The seasonal growth and production of the 0+ and 1+ cohorts of P. diversa were compared to examine any influence of diet, as individuals in the 1+ cohorts were predacious, feeding on at least mayflies, chironomids, ceratopogonids and nematodes. Instantaneous growth rates for both cohorts were higher in the summer than in the autumn, but that of the 0+ cohort (4.4%/d) was almost twice that of the 1+ cohort (2.4%/d). Annual production of the 0+ cohort was similar to that of the 1+ cohort (50-60 mg/m2/year). However summer production of the 0+ cohort was 8x that of the autumn, while summer production of 1+ cohort was similar to that in the autumn. This difference may have resulted from abundance of algal resources in the summer versus the autumn for the 0+ cohort, whereas invertebrate prey resources for the 1+ cohort were similar between seasons.

Ronald Griffiths (POC,Primary Presenter), Oregon State University, Oregon Hatchery Research Center, Corvallis, OR 97331, ron.griffiths@oregonstate.edu;

5/19/2015  |   11:00 - 11:15   |  103DE

IMPLICATIONS OF GUPPY PHENOTYPE FOR BIO-CONTROL OF LARVAL MOSQUITOES Guppies (Poecilia reticulata) are frequently introduced to water bodies to control mosquito-borne illnesses. Laboratory studies have demonstrated that guppies can consume large numbers of larval mosquitoes. Our study investigates how intraspecific variability in guppy phenotype affects their importance as a mosquito bio-control. Guppies were collected from stream reaches where they faced either high or low predation pressure. These guppies are phenotypically distinct and have different diets in the wild. Using a blocked mesocosm design to mimic streamside pools, we allowed colonization by larval insects for one month prior to introducing guppies. This provided realistic diet choices and insect abundances. We also kept fish-free controls. After one month in the mesocosms, fish were sacrificed to examine gut contents; and insect larvae were collected, counted, and identified. Several mosquito genera have been identified, but full results are forthcoming. We additionally measured algal biomass and nutrient (NH4) concentrations in the mesocosms, however preliminary results show no difference between treatments and control. Since guppy phenotype responds to the local predator regime, it is an important consideration for bio-control policy.

Misha Warbanski (Primary Presenter/Author), University of Victoria, misha.warbanski@gmail.com;


Piata Marques (Co-Presenter/Co-Author), Universidade do Estado do Rio de Janeiro, piata_bio@yahoo.com.br;


Dawn Phillip (Co-Presenter/Co-Author), University of West Indies, Dawn.Phillip@sta.uwi.edu;


Rana El-Sabaawi (Co-Presenter/Co-Author), University of Victoria, rana@uvic.ca;


Therese C. Frauendorf (Co-Presenter/Co-Author), University of Victoria, tfrauend@uvic.ca;

5/19/2015  |   11:15 - 11:30   |  103DE

ASSESSING CONGRUENCY OF POPULATION STRUCTURE AND GENE FLOW BETWEEN FRESHWATER MUSSELS AND THEIR HOSTS: A GENOMIC APPROACH Freshwater mussels exhibit a distinctive lifestyle, using fish or amphibians as hosts for larvae and for dispersal. Although the causes for freshwater mussel declines are numerous, a host requirement for larval development and dispersal has direct conservation impacts, as host mobility can influence gene flow among mussel populations. We review and synthesize the current knowledge on the congruency of population structure and gene flow between mussels and hosts. We find that previous population genetic studies in freshwater mussels have been informative in demonstrating patterns of potential lineage boundaries and population structure across broad geographic scales; however, the standard molecular tools used in these studies (e.g., mitochondrial DNA, microsatellites, etc.) have been limited in their information content for diagnosing patterns at the fine-scale necessary for understanding the interplay mediated by host dispersal. We highlight the utility of next-generation sequencing methods to recover genome-wide patterns of genetic variation in mussels and their hosts. We provide preliminary data on our use of these methods to study genetic diversity in the imperiled salamander mussel (Simpsonaias ambigua) and its host, the mudpuppy (Necturus maculosus).

Mason Murphy (Primary Presenter/Author), University of Kentucky, masonomurphy@gmail.com;


Steven Price (Co-Presenter/Co-Author), University of Kentucky, steven.price@uky.edu;


Wendell Haag (Co-Presenter/Co-Author), US Forest Service, Center for Bottomland Hardwoods Research, whaag@fs.fed.us;


David Weisrock (Co-Presenter/Co-Author), University of Kentucky, dweis2@uky.edu;

5/19/2015  |   11:30 - 11:45   |  103DE

HISTORICAL CHANGE IN POPULATION CONNECTIVITY OF THE NINESPINE STICKLEBACK IN AN AGRICULTURAL LANDSCAPE Population connectivity of aquatic organisms has been historically altered by agricultural developments. Understanding the limits and the potential of the altered connectivity would be valuable for conservation planning. In modern wetland systems, artificial watercourse networks, such as agricultural ditches, maintain population connectivity as an alternative to river flooding. Here, we compared the historical and contemporary gene flow of wetland fish Pungitius pungitius using Bayesian approaches. The populations were divided into four genetically different clusters along the Tokachi river, Japan. We found that the contemporary gene flow was restricted to occurring only between neighbouring clusters, although widespread gene flow had been detected historically. Furthermore, we consistently found the same potential-source cluster from the past to the present, which is characterised by large amounts of remnant habitats connected by artificial watercourses. These findings highlight that (i) artificial connectivity can sustain short-distance migrations of wetland fish, which contribute to maintaining the potential source populations; however, (ii) migration over an entire landscape, which ensures longer species persistence, has been prevented by agricultural developments.

Nobuo Ishiyama (Primary Presenter/Author), Hokkaido University, night7mare@gmail.com;


Masanao Sueyoshi (Co-Presenter/Co-Author), Hokkaido University, sue07443@gmail.com;


Futoshi Nakamura (Co-Presenter/Co-Author), Hokkaido University, nakaf@for.agr.hokudai.ac.jp;

5/19/2015  |   11:45 - 12:00   |  103DE

RIVER OTTER OCCUPANCY IN ILLINOIS STREAM SYSTEMS AS A FUNCTION OF THE SEMI-AQUATIC MAMMAL COMMUNITY River otters play critical roles in freshwater aquatic systems as trophic-transfer agents and apex predators. We modeled multi-season occupancy dynamics of otter and co-occurrence of other semi-aquatic mammal species (beaver, mink, and muskrat) to better understand the riparian community in Illinois. We surveyed for semi-aquatic mammals at 120 bridge sites in Jan-Feb and Mar-Apr for 3 years in 11 major watersheds in southern Illinois (44,526 km²). Each survey unit was a 400-m stream segment visited twice by 2 observers. Sites located within otter reintroduction watersheds had a higher initial probability of occupancy (0.58) than did other watersheds (0.30). The probability of otters colonizing a site increased over the study period and increased from 0.22 to 0.35 when beavers were present. The ability of beavers to change the flow of a stream through the building of dams may create pools ideally suited for otter foraging. Probability of site extinction varied between seasons and decreased in the presence of mink, thus mink may indicate stable prey populations resulting in consistent otter occupancy.

Angela Holland (Primary Presenter/Author), Southern Illinois University Carbondale, amjackson@siu.edu;


Eric Hellgren (Co-Presenter/Co-Author), University of Florida, hellgren@ufl.edu;


Clayton Nielsen (Co-Presenter/Co-Author), Southern Illinois University Carbondale, kezo92@siu.edu;


Eric Schauber (Co-Presenter/Co-Author), Southern Illinois University Carbondale, schauber@siu.edu;