What do spiders, ants, and crabs all have in common?
Imagine that you’re a salmon. You were born in clean, healthy river waters. You grew, smolted, and migrated downstream, eventually reaching the ocean where you would attain your adult size. After a few years, you felt the urge to return to your home stream for your one chance at spawning. You traveled hundreds of miles through the Pacific Ocean and found the mouth of your home river. But when you tried to swim upstream, you found a barrier in the way – a giant wall that prevented you from getting back to your spawning stream.
For many fish in the Elwha River, this is exactly what happened.
Twitter followers will know that I was in a foreign land for most of this past week. (Are you following me on Twitter? Because you should be. I’m @iriskemp)
I’m speaking, of course, about Canada, land of lovely maple leaves and delicious maple syrup.
I spent this past Monday through Thursday on the University of Victoria campus attending Restoration 2012, the annual meeting for the Washington-British Columbia chapter of the American Fisheries Society.
Along with my fellow fisheries friends, Jessica Rohde (@RockyRohde) and Jessie Hale (@HaleJessie), I presented my thoughts about the importance of science communication in today’s world. While I recognize that the power of social media can be harnessed through many different venues (e.g., Twitter), I focused this presentation on science blogging and it’s assorted benefits. I also answered some of the most common questions that I hear from scientists when I mention blogging–questions about time commitment, blogging identity, and open science.
If I can be perfectly honest for a moment, I was feeling hesitant about my suitability to give this talk. I’m not the most prolific science blogger out there–my posting frequency tends to be negatively correlated with my thesis work–nor am I the most well-spoken. Even though I’ve been blogging for nearly 2 years (!!) now, I still sometimes feel uncomfortable putting myself out there for the world to see. I think some part of this is my natural tendency towards shy-ness, but also I’m quite prone to imposter syndrome.
But then I realized: I’m living proof that anyone can do this.
I’m not a natural writer. I’m shy and often insecure. I’m only at the beginning of my career, with so much more to learn. But I love science. And so I blog. And (I hope), I make a difference. I make a difference by posting about scientific studies that I find interesting. I make a difference by showing pictures of my research and my field work, experiences that a non-fisheries scientist may never get to have. I make a difference by sharing my graduate experiences. I make a difference simply by being me: a young female scientist who may still have a lot to learn, but who can’t wait to learn it. I blog because I want to get you as excited about science (and fish) as I am. I want to show you that I am science.
And I’m hesitant to share my muddled personal details with you. But I will. Because? If I can do this, you can too.
Imagine what a difference we would make as each of us shares our science stories.
Below is a modified version of my presentation slides. The modifications I made were in order to make the presentation compatible with slideshare; I tend to rely on pictures for the slides and verbalize my thoughts, so I’ve added some text slides for clarity. (I’m also kinda bummed that I couldn’t get animations to work with slideshare, because I had some fun with those in the actual talk–I like my points to come in one at a time. Ah well.)
Anyway, I hope you enjoy!
**Edit: I don’t know why the embed code is not working. Technologically-savvy people, help me out? The link below DOES work though, so please go there to view my slides.
(link to slideshare profile here)
It’s hard to relax when your work is always in the back of your mind. Your thesis invades all the tiny nooks and crannies of your brain and leaps out at unexpected moments, just to make sure you haven’t forgotten about it—as if you could! Add to that your classwork and your other commitments, and you find yourself on the express bus to Sleepless City. At a certain point, you realize you need a break. But when you turn off the computer, a familiar sinking feeling creeps in… Yep. Turns out grad school guilt applies to us science-y folk as well.
If you’re a regular reader, you know I talk a lot about salmon. And it’s pretty obvious that in anadromous species like salmon, juveniles occupy different habitats than adults (streams, rivers, estuaries vs. the open ocean). However, it’s not just salmon that show this pattern. Many coastal species of fishes live in different habitats at different life stages. High quality juvenile habitats are often called “nurseries”, and these nurseries are what I want to discuss today.
First: how do you define a nursery? Beck et al. (2001) give this definition: “A habitat is a nursery for juveniles of a particular species if its contribution per unit area to the production of individuals that recruit to adult populations is greater, on average, than production from other habitats in which juveniles occur.” Basically, if one habitat is contributing disproportionately more fish to the adult population, that habitat can be considered a nursery.
Second: so how do you determine if a habitat is a nursery for a particular species? Let’s look at one study that did just that: JA Brown (2006) investigated whether estuaries along the California coast could act as nursery habitats for English sole (Pleuronectes vetulus for those of you who, like me, love scientific nomenclature).
JA Brown looked at the chemical composition of English sole otoliths to determine a) whether otolith compositions were different in estuarine and coastal habitats and b) whether this could be used to determine the contribution of each habitat type to the adult population.
The otolith is a calcified structure in the head of a fish (basically, an ear bone). As the fish grows, the otolith grows as well, adding a new layer each day. This creates daily banding patterns and annual growth patterns (commonly, slow growth -> thin bands, while fast growth -> thick bands). These bands are used to age the fish similar to how you would age a tree by counting its rings. Otoliths are metabolically inert, so once a layer is added, its chemical composition does not change. Finally, the deposition of elements into an otolith layer can be influenced by the outside environment (e.g., temperature, salinity). Therefore, different habitats can produce otoliths with different chemical compositions.
From Brown (2006), an English sole otolith:
Brown’s first question was: is there a chemical tag that can distinguish English sole living in estuaries from English sole living in coastal habitats? She analyzed the chemical composition of otoliths from juvenile fish caught in each type of habitat and found that strontium (Sr) and lithium (Li) concentrations differed between estuaries and coastal habitats and that Sr:Ca and Li:Ca ratios could be used to separate fish from each type of habitat.
Brown’s second question: what is the contribution of each habitat type to the adult population of English sole?
She created two juvenile classification models under different assumptions. English sole are mostly non-migratory; however, some individuals might move along the coast. So Brown created a model for each movement type: one model assumed juvenile migration and the other assumed no juvenile migration. She then used a linear discriminant-function analysis to assign fish to estuarine or coastal habitats for each model. (For non-statistical-minded folks: basically, this analysis allows you to categorize your data into groups based on certain features–in this case, Sr and Li concentrations.)
For juvenile fish, she compared the model classification results to the known habitat of the fish (where they caught it). Under each model, classification accuracy was over 75%. She then analyzed the otolith cores from adult fish–only looking at the juvenile portion of the otolith–to see in what habitat these fish had been in as juveniles. Both models showed that about half the adult fish were from estuarine habitats. Brown went through several tests of other assumptions (for example, whether the otolith cutting technique and potential contamination might significantly affect the results). In all cases, about half the adult fish had spent their juvenile life stage in an estuarine habitat.
So okay, about half of the adult English sole were from estuaries. What does that tell us about the contribution of estuaries as opposed to coastal habitats? Not too much–until you consider the area of each habitat. For example, in Monterey Bay, estuarine habitat comprises about 6% of the available juvenile habitat. But that 6% contributes approximately half the adult English sole in the region! Definitely a disproportionate contribution.
Other research on English sole suggests that estuaries can support higher densities and faster growth rates than coastal habitats can. Those findings and the results of Brown’s work suggest that California estuaries can serve as nursery habitats for English sole. Unfortunately, estuaries are often vulnerable to habitat loss from things like erosion, pollution, and urbanization. Research like Brown’s, which shows the importance of certain estuaries to fish populations, help us realize that we should be concerned about targeting these areas for environmental monitoring and protection.
This is merely an overview of JA Brown’s work. She goes in-depth in her 2006 paper about her collection methods, otolith procedures, and statistical analyses–topics which I have skimmed over here. I definitely recommend you go and read the paper in its entirety. It’s cool stuff.
Also, the definition of nursery as stated above is from this paper:
Beck, MW, Heck, KL Jr, Able, KW, Childers, DL, Eggleston, DB, Gillanders, BM, Halpern, B, Hays, CG, Hoshino, K, Minello, TJ, Orth, RJ, Sheridan, PF, & Weinstein, MP. 2001. The identification, conservation, and management of estuarine and marine nurseries for fish and invertebrates. BioScience 51: 633-641.
If you’re interested in Infectious Salmon Anemia or salmon diseases in general, the USGS Western Fisheries Research Center has released a short YouTube video. Go watch it!
Also, the University of Washington’s American Fisheries Society student sub-unit (also known as the much less tongue-twisty AFSUW) has a new website! This is a shameless promo, since I am currently the VP for AFSUW and had a hand in the making of the website. But if I may say so myself, the new site is pretty darn cool. Go check it out–we love feedback!
Finals are over! Finally!
My brain is mushy. And I went to San Diego for the weekend. So now I will proceed to make your brains mushy too, by posting pictures of adorable animals that I took at the San Diego Zoo. Think of it as zombie protection. Zombies hate mushy brains. You’re welcome.
(lots o’ pictures below the fold)
The lab has been in a state of busy as of late. My office particularly so, as my office-mate and I prepare presentations for this year’s Graduate Student Symposium and organize said symposium (me: volunteer coordinator, him: A/V coordinator), along with all the normal classwork and thesis-work. We are crazy. But we think this year’s GSS will be awesome and so we invite anyone in the Seattle area to attend.
Alright, on to the third and final day of the Salish Sea Ecosystem Conference (plus the last session of Day 2 which was not included in last post)! If I haven’t mentioned it yet, the conference this year was in Vancouver, British Columbia. It was quite pretty, though a little chilly.