Justin Waraniak
LightNews LightNews
banner
marathon-rana.bsky.social
Justin Waraniak
@marathon-rana.bsky.social
380 followers 520 following 57 posts
Molecular ecologist, focusing on landscape genetics and conservation of freshwater ecosystems.
Postdoctoral Researcher, PA Fish & Wildlife Co-op at Penn State
he/him/they/them
Digital illustrator: www.marathonrana.com (Commissions Open)
Posts Replies Media Videos
marathon-rana.bsky.social
Happy Pride! The diversity of life, in all its forms, is pretty rad!

(Side note: there's not a whole lot of purple fish, so the pink/silver goldeye is the best I got)

#SundayFishSketch #Pride
Six fish arrayed diagonally over the top of a rainbow pride flag. At the top left on the red stripe is a northern redbelly dace (Chrosomus eos), on orange is a male rainbow darter (Etheostoma caeruleum), a shorthead redhorse (Moxostoma macrolepidotum) on the yellow stripe, a northern pike (Esox lucius) for the green stripe, an orangespotted sunfish (Lepomis humilus) on the blue strip and a goldeye (Hiodon alosoides) on the purple stripe.
June 8, 2025 at 4:23 PM
marathon-rana.bsky.social
2) Lipids acted as a mediating factor so that fish could maintain reproductive allocation in the presence of parasites, but this came at a cost of lower lipid stores in heavily parasitized fish.

🧵(3/3)
Relationships between lipids as a proportion of dry weight and some of the most important variables that explained variation in lipid content of Cyprinodon tularosa, including the presence of yolked eggs (panel A), gonadosomatic index (GSI, panel B), and parasite density (panel C). Fish with yolked eggs had lower proportions of lipids. Lipid proportions were also negatively correlated with GSI and parasite density
June 4, 2025 at 7:17 PM
marathon-rana.bsky.social
1) Life history traits did not differ much among populations, despite the fact that they occupy very different habitats and have developed very different body shapes.

🧵(2/3)
Redundancy analysis biplot showing associations between variation in life history traits (black labels) and parasite counts (red labels with arrows) for the two most important redundancy analysis axes, accounting for 6.41% and 0.71% of the total variation in life history traits respectively. Individuals are depicted as colored points and 80% confidence interval ellipses are drawn for each population to show the similarity of typical RDA scores among the four populations. All four ellipses have roughly the same center near the origin of the plot and are mostly overlapping. The position of the labels for the life history dependent variables (in black) and the constrained parasite count variables (in red with arrows) indicates the strength and direction of association each variable has with the respective RDA axis. Gonadosomatic index, condition factor, age, wet weight, and length are all along one side of the x-axis, in that order increasing in intensity, and lipid content and dry weight are in the opposite direction. All four of the types of parasites (Gill, Liver, Eye, and Mesentery) are pointed in the same direction as the GSI, Age, Length, etc., indicating that the parasite loads may be positively correlated with those factors and negatively correlated with lipids and dry weight.
June 4, 2025 at 7:17 PM
marathon-rana.bsky.social
To celebrate the start of Pride Month, here are some Pride rainbow trout! Happy Pride everyone! #SundayFishSketch
Digital illustration of a rainbow trout, recolored with the colors of the bi pride flag, with dark blue on top, pink along the side, and deep magenta along the belly. Digital illustration of a rainbow trout recolored with the colors of the trans pride flag with light blue along the top and belly, pink along the sides, and a white stripe along the lateral line. Digital illustration of a rainbow trout recolored with the colors of the lesbian pride flag with oranges along the top, purples along the belly, and a white stripe along the lateral line.
June 1, 2025 at 3:37 PM
marathon-rana.bsky.social
A little late, but finished a least darter for #SundayFishSketch! The mating displays of this species may not be as intense as some other darters, but males of this species still develop bright red blotches on their fins!
Digital illustration of a breeding male least darter (Etheostoma microperca). This fish has a long oval-shaped body with a nearly rectangular tail that accounts for about a third of the length. It has a small mouth and dark stripes crossing the eye, one going from the top of the gill cover horizontally across the eye to the snout, the other starting just above the eye and continuing down across the cheek. It has two dorsal fins, the first spiny with sharp bony spines, the second soft supported by fan-like bony filaments. The tail fin is fan-shaped with no fork or distinct lobes. The anal fin has two sharp spines in the front before more soft rays arcing behind to make the rest of the fin. The pectoral and pelvic fins are large and very close together near the gill cover. The body is a mottled green-yellow color with dark brown splotches along the midline. There are bright red splotches on fin membrane between the rays of the first dorsal fin, pelvic fins, and anal fin.
May 26, 2025 at 3:17 PM
marathon-rana.bsky.social
Some old art of the Quitobaquito pupfish, an endangered species endemic to Organ Pipe Cactus National Monument and the Sonoyata River along the Arizona-Mexico border! #SundayFishSketch #CincoDeMayo
A digital illustration of a Quitobaquito pupfish (Cyprinodon eremus). This fish has a large head with a small mouth and a short, stout body. It has one trapezoidal dorsal fin along its back. The tail is very stout and the tail fin is shaped like a pentagon. There are small pectoral, pelvic, and anal fins along the fish's underside. This fish is bright blue in color with four darker teal bars along its back and a yellowish splotch on the upper side of the tail. The Mexican flag is in the background.
May 4, 2025 at 1:53 PM
marathon-rana.bsky.social
A johnny (the Baptist?) darter for this week's Easter-themed #SundayFishSketch! I was out doing some stream sampling this week and the darters were all colored up in their breeding colors, one of the surest signs of spring!
Digital illustrations of johnny darters, with the male breeding pattern shown in the upper left and the normal coloration in the bottom right. These fish have long cylindrical bodies and somewhat froglike faces with relatively small mouths and a gill cover that comes to a sharp point. They have two large dorsal fins along the back, the first with bony spines and the second with soft rays. The tail is fan-shaped and has no fork. The pectoral and pelvic fins are large and shaped like leaves. The breeding male has a dark grey head and belly, has dark stripes along the side of the body, and has dark grey fins with light colored rays and lots of dark spots. The normal coloration is more uniformly light brown with some small dark saddles on the back, markings in the shape of w's and x's along the side, and light colored fins with sparser spots. Both color morphs have a dark teardrop marking under the eye.
April 21, 2025 at 2:28 AM
marathon-rana.bsky.social
I feel like winter ice fishing is the prime season for catching burbot, and I live in the wrong part of the country to catch them now, but I always thought the eelpout festival in Minnesota looked kind of fun! #SundayFishSketch
Digital illustration of a burbot (Lota lota). This is a long eely fish closely related to cod. It has one long barbel on its chin. It has a small eye and a short, stout head. There are two dorsal fins on its back, the first short and roughly square shaped, and the second equal in height, but about four times as long. The anal fin is almost a direct mirror of the second long dorsal fin, just on the bottom side of the fish. The tail fin is comparatively small and round in shape. The pelvic fins and pectoral fins are similarly shaped, very close together, and positioned just behind the gill cover. The body of the fish is covered in tiny scales that are barely visible. The belly of the fish is a light cream in color, while the top side and the fins are covered in yellowish-orange splotches on a mottled dark brown background.
April 13, 2025 at 8:48 PM
marathon-rana.bsky.social
It was the trout season opener this weekend in Pennsylvania, so to celebrate here's a brown trout! #SundayFishSketch
Digital illustration of a brown trout (Salmo trutta). This fish has a torpedo-shaped body with a large mouth. The lower jaw is longer than the upper jaw. It has one rectangular dorsal fin and a small round adipose fin on its back. The tail is wide and very slightly forked. The body is brown with some orange and yellow highlights and is covered in dark red and brown spots of varying sizes, some with light colored outlines. The whole body is covered in very small scales.
April 7, 2025 at 3:41 AM
marathon-rana.bsky.social
Inking some spots for the next fish I'm working on. Any guesses on who they belong to?

#SundayFishSketch #WIP
Closeup of a work in progress digital illustration of a fish. The close-up only shows the side of the fish, with no fins or parts of the head visible. The field of the fish's body is an orange-brown, darker on top with a brighter yellow cream color on the bottom. There are also tons of spots, some larger brownish-red ones with light colored outlines, smaller densely packed dark grey spots, and even smaller sparse bright red spots.
March 30, 2025 at 3:54 PM
marathon-rana.bsky.social
We found specific genes that vary with temperature. As we learn how these genes vary across populations and environmental conditions, we can use them to find fish that are particularly stressed by heat or may be most able to adapt to future climate conditions! (5/5)
A collection of graphs showing how expression of four genes, a cold-shock protein (AN32B, top), a heat-shock protein (HSP47, 2nd row), a splicing factor (TRA2B, 3rd row) and a ubiquitinase (USP9X, bottom) co-varied with temperature. The leftmost graphs show scatterplots of expression versus temperature with lines of best fit, all color coded by stream. The graphs for the cold shock protein shows expression decreased log-linearly with temperature, increased linearly for the heat shock protein, and expression of the splicing factor formed a curve that dipped around 18ºC, but had similar levels of expression at higher and lower temperatures. These three genes showed similar expression in all four streams, but the scatterplot for the ubiquitinase shows a situation where the expression did increase along with temperature in each stream, but all the streams have different levels of expression even when they are at the same temperature. The right side of the figure four graphs through time for each gene, comparing the temperature (dotted line) and gene expression (big circles with arrows) in each stream during the study period.
March 18, 2025 at 6:17 PM
marathon-rana.bsky.social
...which lets us compare the paths that gene expression takes through time in each stream. All the streams followed similar paths, especially during the second heatwave when changes in gene expression were the most pronounced. (4/5)
March 18, 2025 at 6:17 PM
marathon-rana.bsky.social
We used TagSeq to quantify the relative amounts of different mRNAs. Because we sampled the same streams multiple times, we could track how the composition of genes being expressed changed with temperature. We tracked these changes using a trajectory analysis... (3/5)
Graph of a trajectory analysis. The x and y axis are labeled as principal component 1 and 2 respectively. These are composite variables constructed by linear combinations of gene expression data that vary most across the time points and streams. The axis labels also say what biological processes and molecular functions are most related to each part of the axes. The left side of the x-axis is most heavily influenced by genes that make up ribosomal components, there were no clear functions associated with the right side of the x-axis. The low values of the y-axis are driven by expression of genes involved in oxygen carrier activity and the upper values are driven by immune response genes. The graph itself is a scatterplot, with points representing the gene expression of each individual fish sampled, color coded by stream. There are also four sets of numbers (1-8) plotted along with the points showing the average expression across individuals from the same stream for each sample date. The numbers are connected in sequence by arrows, drawing the "paths" gene expression makes in each stream through the two heatwaves. The paths the four streams make are pretty similar, mostly moving along a diagonal with a negative slope. The path segments for most streams tend to be quite short for time points 1-4, but get longer during the second heatwave time points 5-8. The exception to this is East Branch, where the path segments are comparatively long during both the first and second heatwaves.
March 18, 2025 at 6:17 PM
marathon-rana.bsky.social
Climate change makes heatwaves more frequent, hotter, and longer, which is bad news for brook trout which need cool streams in which to spawn, grow, and live.

We collected gill samples from brook trout in streams around Penn State across two heatwaves during the summer of 2023 (2/5)
A figure showing a map of the area to the southeast of State College, Pennsylvania, USA. Four streams are highlighted in bold colors, Big Poe, Shaver's Creek, Standing Stone, and East Branch. Below the map are four charts, each showing average daily water temperature at a site in each stream from July 15th to August 20th. Big Poe and Shaver's Creek are the warmest, each having two periods where the temperature exceeds 20ºC for several days. Standing Stone follows a similar pattern, but is slightly cooler, staying below 20ºC. East Branch is the coolest stream, staying between 14ºC and 18ºC for the entire study period.
March 18, 2025 at 6:17 PM
marathon-rana.bsky.social
I'm really excited to share our most recent paper on gene expression in wild populations of brook trout in response to heatwaves! We identified candidate biomarkers of heat stress and tracked changes across the whole transcriptome in multiple populations. (1/5)

www.sciencedirect.com/science/arti...
Graphical abstract for a study about the transcriptomic response of brook trout to heat stress. The abstract starts with an illustration of a brook trout in the upper left, with a cutout zooming into an illustration of the fish's red stringy gill filaments. An arrow points from the gill filaments to an illustration of mRNA molecules. Next to the fish illustration is a chart tracking temperature during the study with date on the x-axis (from July 15 to August 15) and daily high temperatures showing two roughly week long periods of elevated temperatures (>20ºC), each followed by periods of cooler temperatures (~18ºC). A text box below the graph reads: "Brook trout (N=116) gill samples were collected 8 times across 4 streams over the course of successive heatwaves. Gill mRNA was sequenced using TagSeq." The abstract continues with a summary of the results. "Potential biomarkers tracked temperature" appears over a series of graphs that overlay the expression levels of a heat shock protein on top of the temperature trends in each stream through time. The lines tracking temperature and the amount of heat shock protein mRNA look very similar. "Trajectory analysis tracked changes in the whole transcriptome through time" appears above a graph describing how expression changed during each of the sampled time points along two principal component axes. A text box to the right reads: "Results: 43 temporally differentially expressed genes detected. Most patterns in the transcriptomic response were conserved among streams. Significant differences in expression patterns between streams for many differentially expressed genes and multivariate metrics of whole transcriptome changes." "Gene functions found in multiple analyses" appears above three illustrations, a thermometer representing heat shock proteins, red blood cells representing oxygen binding, and a T-cell representing the immune response.
March 18, 2025 at 6:17 PM
marathon-rana.bsky.social
I re-drew a common shiner for this week's #SundayFishSketch! This was one of the first fish I drew while figuring out my digital art workflow, and it's fun to see how my style has developed over the years! #redraw
Two digital illustrations of common shiners, the more recent one in the upper left and the older one in the lower right. Both have deep fusiform bodies, large eyes, red bellies, and red tips on all the fins. Both are also covered in tall shiny diamond-shaped scales. The main differences are that the older lower illustration has a high-contrast dark colored back and very simply drawn light-colored eye, while the newer drawing has a more naturalistic lower contrast dark silver back, a more detailed dark colored eye, and a series of small breeding tubercles on the top of its head.
March 16, 2025 at 8:55 PM
marathon-rana.bsky.social
Finished a flathead chub for this week's #SundayFishSketch!
Side profile digital illustration of a flathead chub (Platygobio gracilis). This fish has a fairly long pointed snout with a short lower jaw. There is a small barbel hanging off the upper lip near the corner of the mouth. This fish has one concave dorsal fin midway down its body. The tail fin is deeply forked and there is a dark black edge along the bottom of the lower lobe. The body is a dusky greyish pink and covered in fairly large shiny scales.
March 9, 2025 at 5:03 PM
marathon-rana.bsky.social
Did you know: NOAA manages US marine fisheries, including the fisheries in the Great Lakes! So if you like having sustainable local fisheries, thank NOAA scientists (and maybe advocate against the indiscriminate firing policies pushed by power-crazed billionaires).

#SundayFishSketch #LakeWhitefish
Digital illustration of a lake whitefish. This fish is closely related to salmon and has a similar body shape. The mouth is small and opens beneath the snout. The fish has one short square-ish dorsal fin halfway down its back and a small circular adipose fin closer to the tail. The tail is robust and the tail fin is very deeply forked. The body is a dusky greenish gray, darker on top and lighter on the belly. It is covered in hundreds of small shiny scales.
March 2, 2025 at 5:07 PM
marathon-rana.bsky.social
Since it's the Super Bowl, here's a repost of a carmine shiner, native to the KC area (and that I drew for the Chiefs last year 😞) and a brook trout, the state fish of Pennsylvania! Go Birds I guess? #SundayFishSketch
Digital illustration of a carmine shiner. This minnow has a slender, torpedo-shaped body. It has a large eye and a fairly large mouth that extends underneath the front of the eye. It has a single small dorsal fin, a moderately forked tail, and a trapezoidal anal fin. The body is mostly olive brown, but there are hints of red on the head, the belly, along the lateral line, and at the origins of the fins. A digital illustration of a brook trout. This fish has a triangular head with a very large mouth that extends well past the eye. The body is torpedo-shaped with a rectangular dorsal fin and small round adipose fin on the top. The tail is fan-shaped with a small notch at the fork. The pectoral, pelvic, and anal fins are bright red-orange, except the leading edges which are white with a black border. The body is mostly green with bright yellow spots and small blue and red bullseye patterns across the sides. The coloration along the back has squiggly yellow shapes instead of spots.
February 10, 2025 at 1:48 AM
marathon-rana.bsky.social
One-line rock bass for this week's #SundayFishSketch challenge!
Digital drawing of a rock bass (Amblopites rupestris) where the outline consists of a single continuous black line. This fish has a deep body and large spiny anal and dorsal fin sections. The spines are drawn as loops that come to sharp points at the tips and the soft fin rays are drawn as squiggles that tend to be narrow at the base and have soft round tips near the outer edges of the fins.
February 3, 2025 at 2:48 AM
marathon-rana.bsky.social
Diversity is pretty neat actually.

#SundayFishSketch
A collage of a bunch of digital drawings of North American fishes, showcasing different body shapes, body sizes, and colors, including silver redhorse, longnose gar, black bullhead, rainbow darter, orangespotted sunfish, lake chub, bowfin, emerald shiner, pallid sturgeon, white crappie, central stoneroller, red shiner, largemouth bass, greater redhorse, quillback, blacknose dace, and paddlefish.
January 27, 2025 at 1:18 AM
marathon-rana.bsky.social
The lake chub is a widespread minnow found throughout most of Canada, a few watersheds in the northern lower 48, and is the only minnow native to Alaska!

#SundayFishSketch
Digital illustration of a lake chub (Couesius plumbeus). This minnow has a torpedo-shaped body. The mouth is fairly short, opening just underneath the tip of the snout and does not extend under the eye. There is one trapezoidal dorsal fin about halfway down the body. The lake chub has fan-shaped pectoral fins low on the body just behind the gill cover, and smaller pelvic fins further down the body, on the underside opposite the dorsal fin. The chub also has a short anal fin at the base of its tail. The caudal fin is deeply forked. The body is a dark dusky green on top and beige on the bottom with a dark black stripe bordered with some gold color along the midline, extending onto the gill cover and ending just behind the eye. Except for the head and gill cover, the whole body is covered in small scales.
January 12, 2025 at 3:56 PM
marathon-rana.bsky.social
Rainbows 🌈 are a classic sign of good luck, so here is a rainbow darter to start the year! I always love spotting these little fish bringing a dash of brilliant color to midwestern streams! #SundayFishSketch
Digital illustration of a male rainbow darter in full breeding coloration. This fish has a cylindrical body with a short, wide head, large round cheeks, and a short flat snout. There is a small hump on the back just behind the head. There are two long dorsal fins along the back. The first one has sharp spines and is blue on top and orange below. The second dorsal fin has soft rays and is mostly orange with a blue border. The dorsal fin is fan shaped and is less colorful, but has some small orange and blue spots in between the fin rays. There is a blue anal fin below the second dorsal fin, and it has three sharp spines in the front followed by a series of soft rays with orange spots in between the rays. The darter has wide paddle-shaped pectoral fins and pelvic fins positioned just behind the head, with the pelvic fins positioned just underneath the pectoral fins. The body of the darter is very colorful, with alternating orange and blue bars where the orange becomes a darker red closer to the tail.
January 5, 2025 at 4:42 PM
marathon-rana.bsky.social
A #GarWeek #25DaysofFishmas #SundayFishSketch crossover with one of the coolest fish in the Great Lakes region, the longnose gar? It's a Christmas miracle!
Digital illustration of a longnose gar (Lepisosteus osseus). This is a very narrow fish with a long, cylindrical body and a very long crocodile-like snout with many small pointy teeth. The dorsal and anal fins are set far back on the body, just in front of the tail. The tail itself is asymmetrical, with a fleshy portion extending along the top, while the tail fin is fairly large and diamond shaped. The gar also has smaller pectoral fins right behind the gill cover and pelvic fins about halfway down the length of the body. The gar is a mottled grey-green in color, darker on the top and lighter on the bottom, with a few dark spots. The fins are orange with large grey spots. The whole body of the fish is covered in large, thick diamond-shaped scales.
December 23, 2024 at 3:14 AM
marathon-rana.bsky.social
A bit of a peek behind the curtain (and and actual sketch) with this WIP red shiner for this week's #25DaysofFishmas #SundayFishSketch!
An unfinished digital drawing of a red shiner. This fish is a type of minnow with a deep body. It has a fairly large terminal mouth and some small tubercles on the top of the head. There is one fan-shaped dorsal fin, short fan-shape pelvic fins, longer pectoral fins and an anal fin about the same size and shape as the dorsal fin. Tail end of the body is quite wide and straight and the caudal fin has two round lobes with a fairly deep fork. The drawing has the flat colors on the body filled in. The colors are mostly blue, darker and more purple on top with very light whitish hues on the belly. There is also a bright blue stripe flanked by pink and orange stripes above the pectoral fins behind the gill cover. The fins are not colored yet, but there are roughly sketched lines where the fin rays will go. An unfinished digital drawing of a red shiner. This fish is a type of minnow with a deep body. It has a fairly large terminal mouth and some small tubercles on the top of the head. There is one fan-shaped dorsal fin, short fan-shape pelvic fins, longer pectoral fins and an anal fin about the same size and shape as the dorsal fin. Tail end of the body is quite wide and straight and the caudal fin has two round lobes with a fairly deep fork. The drawing has no color yet, but the body and fins are outlined in tapered clean black lines. The body is also filled with a light gray masking layer. An unfinished digital drawing of a red shiner. This fish is a type of minnow with a deep body. It has a fairly large terminal mouth and some small tubercles on the top of the head. There is one fan-shaped dorsal fin, short fan-shape pelvic fins, longer pectoral fins and an anal fin about the same size and shape as the dorsal fin. Tail end of the body is quite wide and straight and the caudal fin has two round lobes with a fairly deep fork. The drawing is sketched out in rough red lines.
December 15, 2024 at 9:49 PM