Catch of the Day: The Fish Families of Ohio

This week’s lab involved taking a tour through the fish families of Ohio, guided by Dr. Sheil.  We began by covering the basics of fish morphology. The first thing emphasized was the arrangement of fins and their proper titles, which included: the dorsal fin, caudal fin, anal fin, pelvic fin and pectoral fin. The bony supports within fins are fin rays, which are softer and more flexible, and spines, which are stiffer processes. The bony plate that covers the gills is called the operculum. The line running the length of the fish’s body is known as the lateral line, and it is a sensory organ used to detect pressure changes in water.

Our lecture also covered the three basic scale types: ganoid, cycloid and ctenoid scales. Ganoid scales are the basal, or ancestral, scale type that has an upper surface covered in ganoine, which is a mineralized tissue comparable to enamel. Cycloid scales are a rounded type of scale, whereas ctenoid scales have more of an irregular shape.

Another of the basic morphological characteristics discussed were the two types of tails. The ancestral condition is a heterocercal tail, which is asymmetrical, with the vertebral column extending into the larger lobe. Alternately, the symmetrical homocercal tail type is derived and seen much more commonly in the fish of Ohio.

After learning the basics we were ready to take a plunge through the different families of fish found in Ohio. We traveled to each of the different tables throughout the lab and sketched the preserved representatives of the families, taking note of particular morphological features that will aid in identification.

Petromyzontidae: Lampreys

Lampreys are parasites of other fish. They use their buccal funnel (mouth), which is lined with cornfield “teeth,” and rasping tongue to feed of host fish. Although lampreys have a mouth, they are jawless, so they lack an operculum. The lamprey’s over all morphology resembles an eel in the sense it lacks pelvic and pectoral fins. The dorsal fin is posteriorly displaced and is fused with the caudal and anal fin. The dorsal fin can be undivided, have a wide notch between the dorsal and caudal fins, or have a deep notch between the two fins. The condition of the dorsal fin and the anatomy of the mouth are often used to characterize species belonging to this family.

Acipenseridae: Sturgeons

The sturgeon is a large, prehistoric-looking fish that has an ancestral heterocercal tail. This fish has bony plates, or scutes, that are arranged in rows running the length of the body. Under the snout, one can see 4 distinct barbels and a tubular mouth used for sucking food items off the substrate. There are two species in Ohio, Acipenser fluuescens and Scaphirhynchus platorychus. Scaphirhynchus platorychus can be differentiated due to its long, slender tail and large, bony plates on the caudal peduncle.

Lepisosteidae: Gars

Gars have a long snout that is filled with long, fang-like teeth, making them look fierce in appearance. Typically found in slow-moving and turbid tributaries, these fish turn right or left to grab prey as they swim through the water column. This fish has an elongated body that is covered with rhomboid, ganoid scales, which function as “armor-plated” protection. The dorsal fin is posteriorly displaced, which is often associated with “sprinter” fish or fish that swim near the surface. The operculum of members of this family has many bones on the “cheek” rather than just one singular opercular shield. It should also be noted the gars have an abbreviated heterocercal tail. The genus we have in Ohio is Lepisosteus.

Clupeidae: Herrings and Herring allies

Alewife specimens. Note the vertical eyelid and the ventral row of keeled scales that help distinguish this fish. (Photo credit)

This “cute” family of fish has a few unique morphological characteristics that can help in identification. First, the dorsal fin is situated almost directly over the pelvic fin. Secondly, this family of fish has no lateral line system. Also, on the underside of the fish there is a row of keeled scales that resemble saw teeth. Furthermore, the anal fin is so broad and long it almost appears to interact with the caudal fin. A particularly interesting member of this group is the alewife (Alosa pseudohasengus), which has a “bizarre” eyelid that opens and closes vertically opposed to horizontally, and is a dead giveaway for identification.

Salmonidae: Salmons, Trouts, and Whitefish

These fish have small cycloid scales which give them a smooth appearance. Both male and female fish of this family possess a bilateral axillary process located above the pelvic fin. Cameron shared that he recently completed work for a research project that utilized this fleshy process for genetic testing. Researchers remove the process without significant negative impact on the fish by clipping it with a pet nail trimmer and have enough material for genetic analysis. Another feature in this group is presence of an adipose fin which is a small fleshy fin, comprised of fat, located between the dorsal and caudal fin. The Brook Trout (Salvelinus frontinalis) and the Lake trout (S. namaycush) are two examples from this family found in Ohio.

Esocidae: Pikes

These fish look distinct because their snouts resemble duck bills and are filled with large canine teeth. Similar to gars, the pike’s dorsal fin is displaced posteriorly because this fish swims near the surface and is a “sprinter.” These voracious predators rest in the grass, wait for prey, and then shoot out to grab them with their sharp teeth. Esox is the genus primarily found in Ohio. Muskellunge and Pike are typically found in large lakes and pickerels live in small streams.

Catastomidae: Suckers, Redhorses and Buffalo fish 

The common carp (left), which is member of the Cyprinidae family, can be confused with Carpoides (right), which is a member of the Catastomidae family. The center photo shows the ventral view of both fishes. Note the striate, sucker-like lips of Carpoides and lack of barbels.

The most obvious feature of fish in this family is the subterminal mouth. The large and striated, sucker-like lips are used to adhere to substrate and suck up food, such as periphyton from rocks and logs. In Ohio, we can find the red horse (Moxostoma), the buffalo fish (Carpoides), and the common white sucker (Catastoma commersoni). We were cautioned not to confuse Carpoides with the common carp, which belongs to Cyprinidae. Carpoides superficially resembles a carp, but is distinguished by a nipple-like process on the bottom lip and a lack of barbels.

Ictaluridae: Catfishes, Madtoms

Madtom (left) and catfish (right) specimens. Note the small size of the madtom, as well as the unforked, rounded caudal fin. Alternately, the larger catfish displays the characteristic forked caudal fin. (Photo credit)

Members of this family usually have more than eight barbels around their mouth. An interesting feature lies within the fins, with both the dorsal and pectoral fins having a large spine. These fish lack scales, but an adipose fin is present. Catfish (Ictalurus) and madtoms (Noturus) can be easily confused if one does not know what specific morphological features to compare. However, adult madtoms do not get much larger in length than the distance between your extended thumb and pinky finger, while catfish can grow to be quit large. Looking at the tail can also help one decipher between the two. Madtoms have an unforked, rounded caudal fin, whereas the caudal fin of the catfish is forked.

Cyprinidae: Carp, Minnows, Daces, Shiners and Goldfish

Cyprinids have a more terminal mouth and in some species, the upper jaw has fleshy barbels that hang from it. Sometimes these barbels can be cryptic. One example of a very common Ohio cyprinid is the common carp (Cyprinus carpio). The goldfish (Carassius auratus) is distinguished from the common carp due to a lack of barbels on its upper jaw. Another group of Cyprinidae is the minnows (Campostoma), which are said to resemble “green beans” in a seine net, and can be characterized by a large “c-shaped” upper lip that causes a heavy overbite. Fathead minnows (Pimephales) have only a slight overbite, but very crowded scales on the dorsum.

Anguillidae: Freshwater Eels

American eel specimens. Note the continuous dorsal, caudal and anal fin. (Photo credit)

The freshwater eel has almost a serpent-like appearance, with pelvic fins absent and a fused dorsal, caudal and anal fin. This fish has scales so small it appears to be scaleless. On each side of the fish we find a single opercular opening. A freshwater eel species found in Ohio is the American eel (Anquilla rostrata).

Atherinidae: Sliversides

Sliversides resemble a miniature freshwater barracuda. These fish have a very flat head and back along with a “bird–beak” shaped mouth. Sliversides also have very large eyes. Running down the length of the body is row of serrated scales that stand out against the conspicuous cycloid scales of the rest of the body. Sliversides also have two dorsal fins, the first of which is shorter and has six spines. In Ohio, we find the Brook silverside (Labidesthes sicculus). When captured in a seine net, these fish are easily recognized by the silver flash on their side that reflects the light.

Moronidae: White Basses

The fish in this group have two dorsal fins, the first of which has spines that are sharp and the second just has flexible rays. The key feature for this family is a spine that is located on the opercular flap. Members of this family commonly seen in Ohio are the White Bass (Morone chrysops), the Striped Bass (M. saxatilis) and White Perch (M. americana). Moronids can be distinguished from members of Centrarchidae by the condition of the dorsal fins, which as previously mentioned, are fused in centrarchids.

Centrarchidae: Blackbass, Crappies and Sunfishes

When it comes to members of this family, attention to detail is critical for identification. Counting the number of dorsal and anal fin spines as well as examining the size of the scales is very important. In Ohio, members of this family include blackbass (Micropterus), which have fused dorsal fins and small scales. The sunfishes also have fused dorsal fins, but larger scales than the blackbass. Finally there are crappies (Pomoxis), which have 5-8 dorsal spines and 5-7 anal spines.

Percidae: Walleyes, Perch and Darters

Fish in this family generally have large, blocky heads and the body depth tends to be less than the head length. The overall shape of the body resembles a torpedo. These fish also have conspicuously paired dorsal fins and a spine associated with the anterior end of the anal fin. In Ohio, we find walleye (Stizostedion), which have a very flat belly and two dorsal fins. We also have darters (Etheostoma), which have very blunt faces and huge pectoral fins. Finally, we have the roughbelly darters and logperches (Percina) that have a more tapered face compared to darters in the genus Etheostoma, as well as significantly smaller pectoral fins.

Gobiidae: Gobies

This invasive group of fish is distinguished by its cup-shaped pelvic fin, which acts as a suction cup to allow them to withstand the current and sit in place on the benthos. As we learned in a previous lab, these voracious gobies will eat the eggs of other fish species in the time that it takes a fisherman to pose with the caught fish for a photo. There are strict restrictions on fishing activity due to the threat of goby predation on the eggs of native fish species.

Cameron labels new preservation jars as we update the JCU fish collection as Alison enjoys the aroma of preservatives. Meanwhile, Chelsea digs deep for more unknown fishes and Kim supervises the search.

We concluded the lab by helping improve the JCU Biology Department’s fish collection by identifying and sorting unknown fish specimens. Using a dichotomous key specific to families of Ohio fishes, we were able to organize mixed collections of unknown fish into fresh and properly labeled preservation jars. 

Professors and students work together to identify this mystery fish.

In addition to basic morphological features such as fin condition, presence or absence of barbels, tail type and snout shape, it was necessary to count scales to determine finer classifications of unknown specimens.

Adventures at Old Woman Creek, Sheldon Marsh, and Magee Marsh

An aerial view of Old Woman Creek (Photo credit)

Old Woman Creek

Old Woman Creek (OWC) is a naturally functioning estuary, which is an environment where sources of water with different chemical properties combine. Backflow from Lake Erie into OWC creates a unique habitat for a diverse floral and faunal community. Located in Huron, OWC is a state nature preserve and the only national estuarine sanctuary in Ohio. 

Ben gathers a plankton tow sample from Lake Erie

On the first night of our trip, we went to the beach to get algae samples with plankton tows from Lake Erie and OWC. Plankton towing is an algal sampling method in which a funnel shaped mesh fabric attached to a collection jar is tossed into the water and then dragged across the surface to collect specimens. 

The tow obtained from the estuary had a large quantity of zooplankton (Daphnia). According to Dr. Johansen, depending on the density, the zooplankton can sometimes consume most of the algae from a tow before you take it back to the lab and get a chance to look at it under a microscope! In the samples we found cyanobacteria (Merismopedia and Afanizomenon), a cryptomonad (Cryptomonas), diatoms (Fragilaria crotonensis and Aulocosira gramulata), green algae (Pediastrum), and dinoflagellates (Peridinium and Ceratium). 

 

Alex and Ben are stoked to begin the canoe trip! (Photo credit: Kim Daut)

The next morning, we set off in canoes to explore the diversity of OWC. As we traveled along the creek, we collected algal samples by scraping partially submerged logs and by attaching a plankton tow net to the canoe. Our guide informed us that the plankton tow sample we collected for the OWC research center was only qualitative. For a quantitative measure of phytoplankton, a GPS device is necessary to standardize tow length.

Curran's Lotus Lillies, 1988 (left, Photo credit) The floating-leaf macrophyte, Nelumbo (right, Photo credit: Kim Daut)

One of the first organisms identified by our tour guide was a genus of water lotus called Nelumbo. These plants occupied the open water area of the estuary and were the featured in well-known paintings of the OWC estuary, created by Charles Courtney Curran in the late 1800's. The white water lily (Nymphaea odorata) was another floating macrophyte that we encountered. On the bottom of these leaves, Dr. Johansen pointed out lophotrochozoan worms.

We were able to see the nest of a bald eagle (left) in an open spot near the top of the treeline (Photo credit). The high-pitched rattle of the belted kingfisher (center) was unmistakeable (Photo credit). The great egret (left) uses it's sharp bill to catch unsuspecting prey, such as fish and amphibians, with quick jabs (Photo credit: Kim Daut).

There was a great diversity of avian species present at OWC, which serves as an important nesting ground. Our guide informed us of the incredibly successful bald eagle conservation effort at OWC. Spanning 30 years, the reestablishment project, which involved field work such as climbing trees to get blood samples from eaglets, increased the eagle population from 4 to 250 nests per year. Since the bald eagle population is now thriving, the nest monitoring has ceased and avian research is currently focused on the migration of the sandhill crane. Other exciting bird species that were seen while canoeing through the estuary include, ospreys (Pandion haliaetus), great blue herons (Ardea herodias), belted kingfishers (Megaceryle alcyon), and great egrets (Ardea alba). The distinctive "meow-like" call of the gray catbird (Dumetella carolinensis) was also heard at various locations in the creek. 

In the photo on the left, Phragmites dominates the edge of the estuary. In the photo on the right, our guide explains how coconut logs containing plant "plugs" of native species are being used to combat Phragmites invasion. (Photo credit: Kim Daut)

As we progressed through the estuary, our knowledgeable guide frequently identified Phragmites, a European invasive reed species that was introduced by ballast water from ships. Phragmites has recently been the focus of a great deal of management and restoration research at OWC. Phragmites will disrupt the community by displacing native plants and drying out the wetlands. This alteration results in negative environmental impacts including the acceleration of eutrophication, reduction of open water, and loss of habitat and food sources for many species. This resilient reed is not consumed by other species and does not die off on its own. The success of Phragmites is aided by a high reproduction rate and rhizomes that can reestablish organisms despite damage to other parts of the plant body. Management strategies include burning, mowing with a Marsh Master (a machine similar to a bulldozer), spraying herbicides from a helicopter, and flooding. Of those methods, only flooding with four feet of water was greatly effective, but unfortunately flooding to that degree is not feasible in most situations. After removing Phragmites from an area, restoration is achieved by using coconut logs to replant native macrophyte “plugs” before invasive species have a chance to reestablish their populations. The coconut logs slowly decay and the native species repopulate and restore the community.

Cameron startles nekton into our nets by splashing around with his hands and feet. (Photo credit: Kim Daut)

Following the canoe trip, we strapped on our waders and headed back into the estuary to sample the fish population. The method we used to capture fish specimens involved the use of a large seine net held against the sediment. Two people held poles at the ends of the seine net and walked in unison with the net in a "U-shape" behind them toward another group of people. The other group walked toward the net, disturbing the area and causing fish to swim into the net. Once the pair and group met, the poles attached to the net were brought together and the bottom of the net was gathered so none of the trapped fish could escape. The net was carried back to shore so that the specimens could be identified and placed in a bucket of water for later use. 

As we searched through the seine net (left, Photo credit: Kim Daut), we found emerald shiners (center, Photo credit) and placed them in a bucket (right, Photo credit: Kim Daut), so that the living specimens could be used by the OWC-ERR staff.

The only species of fish we caught in our net was the emerald shiner (Notropis atherinoides). The emerald shiner belongs to the family Cyprinidae, which is composed of carp and minnow species. The emerald green coloration on its lateral sides distinguishes this species of fish. 

These collected macroinvertebrates and pouch snail are in a petri dish with 70% ethanol and ready to be examined under a dissecting microscope.

Macroinvertebrate sampling was accomplished with the use of dipnets. Triangle dipnets were bumped along the bottom of the estuary, stirring up the sediment, and then quickly lifted to the surface to trap organisms. Edges of the estuary with macrophytes in shallow water were excellent areas for macroinvertebrate collection. 

 

Examples of organisms belonging to Bacillaria (Photo credit), Euglena (Photo credit), and Synura (Photo credit).

After fish and macroinvertebrate sampling, we visited the laboratory at the Ohio Division of Wildlife’s National Estuarine Research Reserve (OWC-ERR) to examine our specimens. Using dichotomous keys provided by the research center, algae identification books, our familiar macroinvertebrate guide, and the assistance of resident algal expert Dr. Johansen, we were able to achieve finer taxonomic identification for our samples. One of the highlights of our algal identifications included Bacillaria, the "accordion-like" diatom (Bacillariophyta). A colony of these pennate diatoms will slide back and forth with an appearance similar to an accordion. Among our samples were the familiar genera of Euglena (Euglenophyta), which possess a red "eyespot" and Synura (Syurophyta), which have distinctive siliceous scales. 

 

Examples of species from Gerridae (left, Photo credit), Corixidae (center, Photo credit), and Coenagrionidae (right, Photo credit)

A hemipteran (true bugs) commonly called a toe-biter was found in a dipnet catch. Toe-biters, or the giant water bugs, are members of family Belostomatidae and in addition to feeding, can use their piercing mouthpart to inflict a painful bite to humans. Some of the other macroinvertebrate families collected included members of Gerridae (water striders), Corixidae (water boatmen), and Coenagrionidae (narrow-winged damselflies).

 

Water quality testing equipment

During our time at the research center, we were able to take a behind the scenes tour of the facility and find out a little more about the research currently taking place at OWC. During our canoe trip we were cautioned not to bump into the expensive water monitoring equiment throughout the estuary. Our guide explained that those instruments measure water conditions and transmit information to the National Oceanic and Atmospheric Administration (NOAA). We were also shown laboratories where chemical properties of water, such as dissolved oxygen (DO) and pH are measured. Our guide stressed the importance of biomonitoring and how phytoplankton is an indicator of community health, as primary producers impact on all levels of the food web above them. The water samples collected from that morning produced a DO value of 8.1 for the lake and 6.3 for the estuary. The amount of DO can vary with sunlight due to photosynthetic activity, so the cloudy conditions of the morning most likely affected the DO value of our sample.

Sheldon Marsh

 

Sheldon Marsh

Sheldon Marsh State Nature Reserve is located in Erie County. As we learned in lecture, marshes are a type of wetland that represents a transitional zone between aquatic and terrestrial habitats. Marshes are characterized by the presence of herbaceous plants. 

 An interesting feature of the marsh was the barrier beach. A piece of land perpendicular to the shoreline protects the lagoon from the harsh wave action of the lake that can be produced during storms. Plants, such as purple sand grass (Triplasis purpurea), which is unique to the barrier beach, are able to survive in this environment because of the protection provided by the barrier. 

Zebra mussel shells were easy to identify due to their characteristic striped pattern.

Invasive zebra mussel shells were also found on the shore of the beach. As we learned in lecture, zebra mussels are contributing to the toxic blooms of Microcystis by selectively consuming diatoms, which compete with Microcystis, from the phytoplankton, while rejecting the cyanobacteria. With reduced competition from diatoms and available phosphorus, Microcystis can form blooms.  

 

A common carp (Photo credit)

While exploring the marsh, we came across a wildlife viewing enclosure that shielded organisms from seeing us so that we could observe their behavior. Turbulence in the water drew our attention, and someone proposed that the disturbance could be due to sparring snapping turtles. Unfortunately, after closer examination, we discovered that the activity at the surface was just an invasive carp splashing around. Like the emerald shiner that we caught in our seine net at OWC, the common carp belongs to the Cyprinidae family.

 

Sheldon Marsh

Immediately adjacent to Sheldon Marsh is the Sawmill Creek Resort Golf Course. We discussed the detrimental environmental effects of the chemicals that are used to maintain golf courses and how the run-off from fertilizers can enter the wetlands. As we learned in lecture, wetlands are fortunately able to function as buffers from this type of nutrient input and prevent its spread through the watershed.

Magee Marsh

 

Magee Marsh

Magee Marsh is located in Oak Harbor, OH. The marsh is a popular spot for birders because of the large amount of migratory birds that use the area as a pit stop. Although the boardwalk was closed for controlled waterfowl hunting, we did get to check out the nature center and take a lap around one of the loop trails. The nature center was very informative and had detailed descriptions of many of the bird species that can be found at Magee Marsh throughout the year. There was also an impressive taxidermy collection of most of the species that can be encountered at the marsh, as well as a few live specimens, such as the blanding's turtle (Emydoidea blandingii) and the common snapping turtle (Chelydra serpentia). 

The brown snake specimen was determined to be male because female snakes typically have a greater taper after their cloaca.

  As we walked around the trail, we noticed native (Typha latifolia) and non-native (Typha angustifolia) cattail species. Native cattails have wider leaves, measuring 1/2-1 in., and adjacent female and male parts. Invasive cattails have more narrow leaves, measuring 1/4-3/4 in., and female and male parts separated by a 1-4 in. gap.  Since it was rainy and a little chilly, we were surprised when we found two brown snakes (Storeria dekayi) on our hike. We ended our trip with an encounter with a non-native praying mantis that we found on a path. The praying mantis was most likely a female due to its large size.

Our trip to Old Woman Creek rocked!

Hester-Dendy Sampler Collection at the Chagrin River and Dipnetting for Macroinvertebrates at a Lentic Pond in the West Woods (3 October 2013)

Our Chagrin River field site

Today we returned to the Chagrin River, which runs through the South Chagrin Reservation of the Cleveland Metroparks, to check on our Hester-Dendy (H-D) samplers from 19 September 2013. It was noted that in the two weeks since we had been to the site to place our H-D samplers, the leaves from riparian vegetation had begun to fall into the river, producing a significant coarse particulate matter (CPOM) input. It was a cloudy, but pleasant day for rounding up macroinvertebrates, with a temperature of 25°C.

Using the flags on the trees as a guide, we search the stream for the flagged bricks anchoring our Hester-Dendy samplers. Good eye, Cameron!

Hester-Dendy samplers consist of wooden block substrates separated by spacers along an eyebolt, which are held in place by a nut. Although researchers utilizing H-D samplers leave them in the environment for longer periods of time (about eight weeks) to allow for a more complete representation of species present in the system, after a brief inspection of our samplers, it was determined that for our class’s purpose, two weeks was adequate for a “decent” colonization of species. Typically, grazers and shredders are the first to colonize the wooden board pieces, with predators moving in afterward. We predicted that a few species of trichopterans would likely be found on the samplers.

Ziploc bags are used to enclose the H-D samplers immediately after they are removed from the water to ensure that specimens do not get the opportunity to escape.

We were able to recover the H-D samplers by finding the orange flags attached to trees along the side of the river and searching the water perpendicular to their location. The samplers were attached to bricks so that they would not be carried away by the current. We were relieved to find that our Boy Scout-approved knots held up and that all of our H-D samplers were recovered. When a flagged brick with samplers attached was found, the brick was removed from the water first and carried toward the location of the samplers. It was important to have a Ziploc bag ready before taking the samplers out of the water because organisms tend to drop-off once the samplers are removed. Each sampler was placed in its own Ziploc bag and then all the samplers and the attached brick were placed in a garbage bag.

These biologists are not afraid to get their hands dirty rustling rocks to release macroinvertebrates into the seine net.

After we recovered all the samplers, we used a method called kicknetting to sample the riffle zones for more macroinvertebrate species. This method of sampling involves placing a one meter square seine net along the bottom of the river in a riffle zone and disturbing the area immediately upstream by flipping over and rubbing rocks to release attached macroinvertebrates. These macroinvertebrates then flow with the current and get trapped in the seine net. Making sure that the bottom of the net is flush with the sediment and that the net is quickly scooped to the surface after collection is complete are important measures to prevent the loss of specimens. We searched the seine net, gently removed macroinvertebrates with forceps and then placed them in vials containing 70% ethanol.

Our West Woods field site

 The next site that we visited was a lentic pond in the West Woods, which is part of the Geauga Park District in Novelty, OH. We expected to find predacious hemipterans and odonates in this non-moving body of water.

A triangle dipnet can be used to collect macroinvertebrates from the substrate and littoral macrophytes

The method we used to collect specimens is called dipnetting, which is ideal for pond sampling, but may also be used in streams. The optimal type of net to use for dipnetting is called a D net, which is shaped like a capital letter D. The flat side of the “D” is used to bump along bottom of the pond to disturb the sediment and vegetation at the benthos to collect macroinvertebrates. Since JCU does not own D nets, we used triangle nets for our collection.

In the photo on the left, biologist Ben is having the time of his life dipnetting for macroinvertebrates! In the photo on the right, Cameron carefully sifts through sediment and vegetation looking for macroinvertebrates in his dipnet haul.

After bumping the net along the bottom to stir up the sediment, it is quickly scooped to the surface so that specimens do not have a chance to escape. In addition to the expected odonates and hemipterans, we caught tadpoles in our nets.



Back in the laboratory, the proper method of organism collection from the H-D samplers was demonstrated. First, for convenience, the rope connecting the samplers to the brick was cut. The nut holding the wood blocks to the eyebolt was then removed. Next, the wood block substrates were each systematically searched on both sides for macroinvertebrates, which were removed gently with forceps and placed in a 70% ethanol solution. Alcohol was used to rinse sediment from the substrates to ensure that no specimens were overlooked.

Note the caddisfly cases attached to the wooden block. These cases are made from detritus and allow the caddisflies to withstand the fast-moving current of the riffle zone.

It was observed that several wooden blocks had the cases, or retreats, of caddisfly larvae attached to them. The leaves that were found attached to the H-D samplers were also searched for organisms.

Using a dichotomous key to identify a specimen of family Simuliidae

The specimens were then examined under the dissecting microscopes. Finer taxonomic distinctions of organisms from familiar invertebrate orders were accomplished by the use of dichotomous keys from the Guide to Aquatic Invertebrates of the Upper Midwest. Dichotomous keys use specific morphological characteristics presented in a certain sequential order to distinguish taxonomic rankings.

The flathead mayfly of family Heptageniidae

Ephemeropterans (mayflies), trichopterans (caddisflies) and pelcopterans (stoneflies), which are classified as "pollution sensitive" taxa are used as bioindicators of water quality in a measure called an EPT Index. The EPT Index quantifies the health of a stream by the number of species of these orders present, with healthier streams containing a larger abundance of these orders. The ephemeropteran families collected included Baetidae, the small minnow mayflies, and Heptageniidae, the flathead mayflies. Baetidae are strong swimmers and can have antennae longer than twice the width of their head. Members of Heptageniidae, like their common name implies, have flattened heads, bodies, and legs.

Note the hardened exoskeleton on the head (characteristic of trichopterans) of this member of Philopotamida

A few trichopteran families were also collected, including Hydropsychidae and Philopotamida. Species belonging to Hydropsychidae, the common net-spinner caddisflies, can be distinguished by a conspicuous brush of hairs on the posterior of the abdomen. A defining characteristic of philopotamidans, the finger-net caddisflies, is a T-shaped labrum, which is a structure located between the mouthparts. Philopotamidans are filter feeders that spin nets to trap edible particles from the water and then use the labrum to scrape the food from the net. No plecopteran species were found on the H-D samplers.

A larval riffle beetle of family Elmidae
(Photo credit: http://www.csuchico.edu/~mmarchetti/FRI/elmidae/elmidae.html)

Representing Diptera (true flies) was a specimen from family Simuliidae, the black flies. Black flies have a ring of hooks on the posterior of the abdomen that allows them to attach to substrate and withstand the water current. A larval coleopteran (beetles) from family Elmidae, the riffle beetles, was also collected. As their common name suggests, riffle beetles are found in fast-moving and highly oxygenated areas of streams.

Check out this radical anisopteran that we collected from the West Woods!

Finally, a nymph odonate belonging to suborder Anisoptera was collected from the West Woods. As we learned from lecture, anisopertans (dragonflies) are distinguished from damselflies (zygoptera) because in the larval stage their head is the same width or narrower than their thorax and abdomen, they do not have three elongate gills extending from the posterior of their abdomen and in adults, their wings are spread out when resting.

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Organisms Collected

C: Insecta

o   O: Coleoptera (beetles)

·         F: Elmidae (riffle beetles)

o   O: Diptera (true flies)

·         F: Simuliidae (black flies)

o   O: Ephemeroptera (mayflies)

·         F: Baetidae (small minnow mayflies)

·         F: Heptageniidae (flathead mayflies)

o   O: Odonata (dragonflies and damselflies)

·         F: Anisoptera (dragonflies)

o   O: Trichoptera (caddisflies)

·         F: Hydropsychidae (common net-spinner caddisflies)

·         F: Philopotamida (finger-net caddisflies)