Troy M. Farmer

Short winters threaten temperate fish populations

Although climate warming is expected to benefit temperate ectotherms by lengthening the summer growing season, declines in reproductive success following short, warm winters may counter such positive effects. Here we present long-term (1973–2010) field patterns for Lake Erie yellow perch, Perca flavescens, which show that failed annual recruitment events followed short, warm winters. Subsequent laboratory experimentation and field investigations revealed how reduced reproductive success following short, warm winters underlie these observed field patterns. Following short winters, females spawn at warmer temperatures and produce smaller eggs that both hatch at lower rates and produce smaller larvae than females exposed to long winters. Our research suggests that continued climate warming can lead to unanticipated, negative effects on temperate fish populations.

Mercury Concentration in Two Estuarine Fish Populations across a Seasonal Salinity Gradient

Abstract Mercury (Hg) cycling in estuaries is complex, and little is known about the extent of Hg bioaccumulation in the ecologically diverse fishes that inhabit coastal areas. Using tissue analysis combined with otolith microchemistry, analysis of Hg concentration in common prey species, diet analysis, and age-and-growth analysis, we investigated seasonal and spatial trends of Hg accumulation in largemouth bass Micropterus salmoides and southern flounder Paralichthys lethostigma inhabiting the Mobile—Tensaw River Delta, Alabama. The Hg concentrations in largemouth bass (which are known to have high site fidelity) were lowest at downstream, low-salinity estuarine areas and highest at upstream freshwater areas. Conversely, southern flounder, which have a highly variable migratory life history across salinity gradients, had Hg concentrations that were similar across the study area and lower than those for largemouth bass. Both largemouth bass and southern flounder had negative relationships between individu...

Using Seasonal Variation in Otolith Microchemical Composition to Indicate Largemouth Bass and Southern Flounder Residency Patterns across an Estuarine Salinity Gradient

Abstract Estuaries are transitional zones where salinity largely controls the distribution of both freshwater and marine species. However, the degree to which freshwater and marine species use these variable habitats as year-round residents or transient migrants is largely unknown. We used otolith strontium: calcium ratios (Sr: Ca) as a marker for salinity exposure to reconstruct lifetime salinity exposure plots for individual Largemouth Bass Micropterus salmoides and Southern Flounder Paralichthys lethostigma collected across a seasonally variable estuarine salinity gradient. Initially, we determined that a definable relationship existed between salinity, water chemistry, and otolith Sr: Ca for both species. We then used otolith Sr: Ca profiles to indicate lifetime salinity exposure and subsequently classified each fish as either a freshwater resident, transient (combination of freshwater and estuarine signals in otolith), or estuarine resident. For Southern Flounder we also used Sr: Ca profiles from the...

Maximize Your Meeting: A Student's Guide to AFS Meetings

Maximize Your Meeting: A Students Guide to AFS Meetings David A. Dippold, Grant D. Adams, Troy M. Farmer & Benjamin A. Staton To cite this article: David A. Dippold, Grant D. Adams, Troy M. Farmer & Benjamin A. Staton (2017) Maximize Your Meeting: A Students Guide to AFS Meetings, Fisheries, 42:4, 187-189, DOI: 10.1080/03632415.2017.1288472 To link to this article: http://dx.doi.org/10.1080/03632415.2017.1288472