This past week the manuscript that was the product of an REU (Research Experiences for Undergraduates) student I had the opportunity to mentor at Ohio State’s Stone Laboratory was published online in Behavioural Processes. Alex’s project focused on how dominance relationships form between round goby of varying sizes. It’s pretty well established in many species (including round goby) that larger individuals are socially dominant to smaller individuals. This means larger individuals generally have greater resource holding potential – whether that resource is food, shelter, or mates.
Alex predicted that this trend would hold true (its already been established in a number of studies on round goby), but was interested in how these relationships are established in more complex social settings. Do dominance relationships form between larger individuals before smaller individuals? Does the actual size difference between individuals influence how quickly the relationship is resolved? Do males and females differ in how they resolve conflict over dominance?
After 5 weeks of intense work while at Stone Lab, Alex set up many groups of three individuals of the same sex that varied in relative size. He then collected an impressive amount of data on these fish and groups, scored behavioral videos, and analyzed the results. He presented his preliminary findings at the end of the 5 week session, and after subsequent analysis of the data the manuscript is finally out!
Alex found that larger individuals establish dominance over smaller individuals quickly, and that smaller individuals in groups did not differ in their dominance score. Interestingly, there was no difference between males in females in their behavioral interactions.
Alex did a phenomenal job carrying out this experiment and completing this paper, great work!
I’ve always loved salmon. Not just eating them (I enjoy that too); I’ve found them fascinating for as long as I can remember. One of my fondest childhood memories was a family vacation to Lake Huron where I caught a pink salmon, Onchorynchus gorbuscha. At Wittenberg University, two classmates and I focused our senior Capstone paper and presentation on salmon and salmon fisheries. In my Introductory Biology course at Ohio State University, I developed a classroom activity focused on the impacts of salmon (and their migrations) in both aquatic and terrestrial ecosystems. While I’ve never done research on salmon myself, I’ve always jumped at opportunities to tag along with colleagues at UC Davis whose work does focus on them. With that in mind, it should come as no surprise that I was VERY excited to visit Goldstream Provincial Park on Vancouver Island during this year’s salmon run.
Goldstream Provincial Park boasts a large Chum salmon (Onchorhynchus keta) run. There are also Coho (Onchorhynchus kisutch) and Chinook (Onchorhynchus tskawytscha) salmon, but the vast majority of the spawning fish here are chum. Male chum develop vertical stripes, hooked jaws, and long teeth (which may explain their common nickname – dog salmon). Females develop a long dark stripe along their side during spawning.
Spawning is an aggressive event for chum salmon. Males fight aggressively with one another for access to mates; they also bite females in their attempts to mate. Eventually, females will dig into the streambed and lay eggs which will then be fertilized by the males. Shortly thereafter, the adults will die and become food for the many animals that depend on salmon runs for a late season nutrient boost. In fact, many terrestrial ecosystems depend on salmon as a source of nutrients that sustain these ecosystems, and salmon have been described as “keystone species” in these ecosystems (Willson & Halupka 1995, Cederholm et al. 1999) meaning they play a unique, critical role that other species would not be able to fulfill.
The rest of the year there may be less activity in Goldstream Provincial Park, but there are still young salmon growing up before heading out to sea, as well as the year round resident cutthroat trout (Oncorhynchus clarkii) and plenty of other wildlife! Below is a video I filmed at the same spot in Goldstream Provincial Park in June, 2018.