Thursday, January 28, 2016

Goosefish, the Best Animate Fish Trap in the Piscine World, by Don Orth

The Goosefish (Lophius americanus Valenciennes,1837) is a fun and fascinating fish.  It is one of 25 species in the Lophiidae.  The Goosefish occurs in the western Atlantic from Newfoundland south to Florida.  There is a fun assortment of local names, such as the American anglerfish, bellows-fish, devil fish, fishing frog, headfish, molligut, satchel-mouth, wide-game, or monkfish.  Monkfish is the name used in the seafood markets.  There are two closely related species, the European form and the American form. Linnaeus described the European species, Lophius piscatorius in 1758. French zoologist Achille Valenciennes examined North American specimens and found, in 1837, that they differed in teeth, lower lip and spots on its back.  These differences were enough for him to claim that the American form was a distinct species.  It took several decades and additional studies before other Ichthyologists agreed. Today there are seven species of Lophius worldwide and two in North America. The Blackfin Goosefish (Lophius gastrophysus Miranda-Ribeiro, 1915) is distributed in the western Atlantic from Cape Hatteras south to Argentina, including the Gulf of Mexico.

We can speculate about the habits of a fish by carefully examining its body form.   Louis Agassiz, Professor of zoology and geology at Harvard University and founder of the Harvard Museum of Comparative Zoology would often tell the naïve student to “Take this fish and look at it.”     Nathaniel Shaler, in his autobiography, also wrote of Agassiz’s minimalist teaching approach, which my students would find exasperating.  When Shaler asked for explicit instructions, Agassiz replied that he could not be more explicit than saying "find out what you can without damaging the specimen."  Well, the Goosefish is easier to read than most fish. Just look at this fish!
 Left: European Angler Lophius piscatorius illustration by Yarrell (1841)  Right: Photo of Monkfish at Museum of Nature, Ottawa, Canada, by Mike Beauregard
This is one fish that will not be confused with any other fish captured in the same region.  What do we see?   It has a very unique form and a scaleless body.  The head is very depressed and it has large eyes located on top of the flattened head.  Its huge mouth is terminal and the mouth is nearly as wide as the head.   The thick jaws possess long backward pointing teeth. The lower jaw projects well beyond upper.  The skin bears fleshy tendrils or cirri on lateral margins of head, lower jaw, and body.  Its body is flattened dorsoventrally to allow it to hide on the sea floor.  On the midline of the head stand modified anterior dorsal spines that are long and far forward for the normal location of dorsal spines. The first one originates on upper jaw and has a fleshly flattened tip.   The modified spine is called the illicium and the tip is the esca, which serve as fishing rod and lure, respectively.  

Even Aristotle was familiar with this fish and wrote “The accounts commonly given of the so-called  fishing frog are quite true … The fishing frog has a set of filaments that project in front of its eyes; they are long and thin like hairs and are round at the tips; they lie on either side, and are used as baits. Accordingly, when the animal stirs up a place full of sand and mud and conceals itself therein, it raises its filaments and, when the little fish strike against these, it draws them  underneath  into its mouth.... Furthermore, the fishing frog is unusually thin when he is caught after losing the tips of his filaments.”   Eugene Gudger, Ichthyologist with the  American Museum of Natural History described this fish as the “best animate fish trap in the piscine world"  (Gudger 1945).

Ever since the time of Aristotle, we have known (or at least believed) that the lure was used for catching fish prey!  It was not until the Anglerfish was observed carefully in aquaria in the 20th century that its actual “lie-in-wait” and use of lure behaviors were corroborated.   One such observation is based on an astute observer watching a live specimen:
 “An angler when hungry erects the lure immediately any suitable fishes come anywhere near and endeavor to attract one of them close enough to be caught.   The lure is quickly jerked to and fro and, as the rod is almost invisible, the bait  (in my specimens always forked and 'fly-like' not vermiform) simulates some tiny creature darting about.   An attracted fish rushes up in an endeavor to catch it; the bait is skillfully flicked out of its way just in time and, with a final cast, is dashed down in front of the mouth which may open very slightly.  The intended victim, still following the bait, turns slightly head downward; it is now more or less directly head-on to the angler's mouth.  The jaws snap faster than the eye can follow and the tail of the prey is next seen disappearing from sight through the firmly closed mouth.   As far as I have been able to observe, the bait is not actually touched by the victim before it is caught, as has sometimes been supposed.”  Wilson (1937)

Most of the time the Goosefish rests partially buried on soft bottom substrates.  The Goosefish is an opportunistic, non-selective, sit-and-wait predator, luring their prey by raising and moving the illicium.  Watch this video of the European Anglerfish feeding on a goby.  Fishes are the most common diet items.  But one infrequent diet item includes birds, such as the Dovekie (Alle alle), a seabird (see photo).   The Dovekies were preyed on by Goosefish at or near the surface, not the typical habitat or habit (Perry et al. 2013).  Hmm?!  How do you explain this phenomenon?  “Look at the fish” is not sufficient approach to answer the question.   The maximum diving depth of a Dovekie is 20-30 m, not deep enough to ever encounter this benthic predator.   However, those keen observers of the Goosefish know that they are known to rise off the bottom, possibly to ride currents during migration periods in spring and fall or to spawn at the surface (Hislop et al. 2000).  This infrequent behavior leads to infrequent encounters with birds.
Goosefish with Dovekie extracted from stomach.  Photo from Perry et al. (2013)
The whole structural anatomy of the Goosefish is designed to increase efficiency of the habits of the fish.   If you “Take the fish and look at it,” you must say “Wow! Look at those jawbones and pectoral fins and girdle.”   The axial skeleton is very short and the jaws and pectoral skeleton are enlarged. This is not the body of a great swimmer.  The muscles consist of white muscles adapted for non-aerobic swimming.  But the white flesh is moist, firm and very tasty, often marketed as the “poor man’s lobster.”  To prepare a Monkfish before cooking, watch this video.
Skeleton of the Goosefish source 
Lophius species are exploited worldwide; they were first taken as bycatch in trawls and later targeted fisheries with gillnets developed. Given the body form, the yield of tail meat to live weight is only 30%. Monkfish livers are also marketed, yielding another high value product.  The predominant fishing grounds in northeastern US are significantly impacted by human activities.  Offshore dumping of municipal, industrial, and explosive wastes were common from New York to Virginia before the passage of the Ocean Dumping Act in 1988. Consequently, high selenium and mercury levels in Monkfish muscle and livers are contemporary human health concerns (Johnson et al. 2011).    

The US commercial fishery for Monkfish increased in the 1980s.  This was soon after passage of the Magnuson Act (1976), which expanded U.S. management jurisdiction in waters out to 200 miles. The Act opened international markets of Europe and Asia and landings peaked by 1998. At this time Atlantic Cod stocks were in decline and harvesters switched to alternative less-valued species, including the Monkfish.    Recruitment of Monkfish has been below average since 2004 The New Englang Fishery Management Council, Mid-Atlantic Management Council along with the National Marine Fisheries Service published a Monkfish Fishery Management Plan in 1999 to rebuild the stocks.  
Landings reported for monkfish from 1964 to 2009 (Northeast Fisheries Science Center 2010)
The Goosefish provides students of the fishes a great opportunity to “take this fish and look at it!” and learn about connections between morphological traits and habits.  Recent trends in human uses are also instructive. This fish went from a trash fish to targeted high-value product in a decade.   Monkfish are considered a good seafood alternative by the Seafood Watch; however, there are concerns about bycatch associated with Monkfish harvest.  Most are harvested in multi-species trawling or gillnets or scallop dredges, which catch many undersized fish that must be discarded. Further, contaminant levels from legacy contaminants on many US fishing grounds should be further evaluated before you permanently switch from lobster to Monkfish.  The Fresh Lobster Company will ship fresh Monkfish fillets at $18.50/pound or one 3 pound lobster for $38.75 – your choice.  Neither one is a "poor man's" food.

Aristotle 1910. Historia  Animalium, D'Arcy W.  Thompson, trans., Oxford, 620
Fariña, A.C., and seven coauthors.  2008. Lophius in the world: a synthesis on the common features and life strategies.  ICES Journal of Marine Science 65:1272-1280.
Gudger, E.W. 1945.  The Angler-Fish, Lophius piscatorius et americanus, use the lure in fishing.  American Naturalist 79:542-548.
Hislop, J.R.G., J.C. Holst, and D. Skagen. 2000. Near-surface captures of post-juvenile anglerfish in the northeast Atlantic: An unsolved mystery. Journal of Fish Biology 57:1083–1087.
Johnson, A.K., B. Bediako, and E. Wirth. 2011. Metal concentrations in monkfish, Lophius americanus, from the northeastern USA. Environmental Monitoring and Assessment 177:385-397.
Perry, M.C., G.H. Olsen, R.A. Richards, and P.C. Osenton.  2013.   Predation on dovekies by Goosefish over deep water in the Northwest Atlantic Ocean.  Northeastern Naturalist 20(1):148-154.
Wilson, D. P. 1937. Journal of the Marine Biological Association U. K., Vol. 21 (in.s.) 477-496,
Yarrell, W.  1841. "History of British Fishes,' London, 2nd ed., Vol. 1, p. 310.

Thursday, January 14, 2016

How to learn Ichthyology and make it stick! By Don Orth

Help students learn, help students get good grades, or get good student evaluations?  I would think that the same learning activities would result in all three results.  But then, I would be wrong!  I start every semester with advice for students on how to learn; this semester it’s how to learn Ichthyology and make it stick.   If interested, watch the How to Become an Ichthyologist video.
Unfortunate dominant learning strategy.   Source
All college students are very capable at the "cram, pass, and forget" learning strategy. Unfortunately, for them, every semester is another in a long series of fill, dump, and reload activities.  One of the first principles I explain to students is the "forgetting curve," first described by Hermann Ebbinghaus in 1885.   If we do not have to retrieve what we just heard or read, most of what we heard or read will be quickly forgotten.   Therefore, I provide students of Ichthyology a number of reading prompts to accompany all assigned readings.  Read, recall, write it down, and summarize what it means in your own words.  It helps to relate a new reading with what you already know or explain it to somebody else in your own words.  Highlighting, cramming, and re-reading a passage do NOT work.  If you take the time to read and respond to reading prompts, you will retain information longer. 

Peter Brown and his colleagues explained a number of key principles of learning in the book, Make it Stick.  The book is a treasure for teachers and learners.  Authors emphasize the importance of activities that incorporate retrieval practice, generation, and elaboration.   One of the concepts I found most attractive was the notion of creating “desirable difficulties” in the classroom.   I will often provide the student a difficult quandary to read before reading a new chapter.  Students will not directly find the answer to the quandary in the reading alone.  Rather they will have to wrestle with thinking about the new problem and rely on other knowledge. Life is a comprehensive exam!

I am a big supporter of “Students quizzing students.”  Here the student is free to project their sketches, specimens, or dissected specimens under the document camera as they quiz their peers. Here students must use new terminology and concepts and generate non-trivial questions that quiz others.   In the Lab Notebooks, students struggle with deciding what information to include and what to write. This activity is the first stage of learning: acquisition of information and encoding it for later recall.  This is one of the desirable difficulties that encourage recall and connections with prior knowledge.   There is nothing simple about learning anatomy or how to efficiently identify closely related fishes.   Learning is plain and simply hard work, but the struggles increase intellectual abilities.

Students of Ichthyology, when they don’t challenge themselves with quizzes generated by other students, inevitably overestimate their preparedness for exams.  This is the Dunning-Kruger effect (Kruger and Dunning 1999). The Ichthyology student who diligently makes flashcards and uses them to practice recall will soon master the flashcards, but be unable to pass an authentic exam.  That is why I encourage students to quiz one another and be prepared for a true unknown in the practical exam of real life.    

Students of Ichthyology must realize the practical meaning of variance among individuals.  I use a class Flickr site to archive, tag, and annotate photographs.   Not every specimen will look just like the illustration in the field guide     Use of Flickr permits students to examine numerous specimens from the same species, genus or family.  I also encourage students to draw what they see in lab; it forces them to slow down and pay attention to what they are seeing.   I believe that drawing encodes visual features, which are easier to remember than words. “And learning to draw, without doubt, causes new connections in the brain that can be useful over a lifetime for general thinking. Learning to see in a different way requires that you use your brain different” (p. 3, Edwards 2012).

At the highest level of Bloom’s taxonomy is “creation.”  In Ichthyology class, my students create a digital story and an essay.  The digital story assignment encourages deeper reflection on their struggles to learn Ichthyology.  The essay is on a fascinating fish topic, such as “Punishment in cleaner fish,” Why are some fishes gonochoristic?” or “Is there a “love hormone” in fish?”  This learning activity develops their inquiry skills and challenges them to “make it interesting to others.”  Becoming an Ichthyologist may not be the career goal of each and every student, but learning to become a better student of the fishes develops numerous skills transferable in their future endeavors.


Edwards, B.  2012.   Drawings on the right side of the brain.  Tarcher/Penguin, NY. 283 pp.

Brown, P.C., H.L. Roediger, III, and M.A. McDaniel. 2014.  Make it stick: The science of successful learning. Belknap Press, Harvard University Press.  Cambridge, MA  313 pp.

Kruger, J. and D. Dunning. 1999.  Unskilled and unaware of it: How difficulties in recognizing one’s own incompetence lead to inflated self-assessments. Journal of Personality and Social Psychology 77:1121-1134.

Tuesday, January 5, 2016

Sound, Sediment, and Fishin’ with Minnows: Whitetail Shiner Cyprinella galactura. by Don Orth

No one is sure how or exactly when it happened; but the consequences were irreversible.  My guess is that some fishermen brought live bait caught near their homes (perhaps in Smyth county) to fish in the New River.  At the end of the fishing day, the bait bucket was emptied into the New River to feed the local minnow eaters.  This bait minnow dumping happened more than one time.  In the springtime the dumped minnows that survived the predator gauntlet would need to locate suitable mates in order to found a new population.  The surviving minnows realized the benefits of shoaling behavior and visual and auditory cues to identify the right individuals to mate with.  From these bait minnow introductions, a new population of minnows was founded in the New River.

The Whitetail Shiner Cyprinella galactura (Cope 1868) is now a common minnow in the New River drainage.  However, this species did not appear in any fish collections from the New River during the first half of the 20th century (Jenkins and Burkhead 1994).  The only other Cyprinella native to the New River is the Spotfin Shiner Cyprinella spiloptera.  The New River has relatively few native fish for a river of its size, but it does support several endemic fishes. During the last ice age, the New River was an upland refugia for fishes as the glaciers moved southward.  After the glaciers retreated, fishes colonized the New River drainage from uplands and lowlands, but dispersal from lowlands was inhibited by Kanawha Falls.   Consequently, many large river fishes such as the shads Dorosoma, carpsuckers Carpiodes, buffalofishes Ictiobus, and redhorses Moxostoma, never naturally colonized the New drainage.   However, many non-native fishes, including the Whitetail Shiner, are now established in the New River drainage (Buckwalter 2016). 
Whitetail Shiner  (top is live specimen from New River, bottom is same specimen after fixing in formalin) photo by DJ Orth
The Whitetail Shiner is one of 32 species of Cyprinella, the second largest North American genus of Cyprinidae after the Notropis, or true shiners.  The Whitetail Shiner is easily distinguishable by the pale white spots at the base of the caudal fin.  Otherwise it resembles the Satinfin C. analostana, Spotfin C. spiloptera, and Steelcolor C. whipplei shiners. Like these shiners, it has a terminal to slightly subterminal mouth and a terete body, only slightly compressed.  The membranes of the last 3-5 dorsal fin rays are pigmented. The name Cyprinella means little carp-like fish and galactura refers to the pale “white” spots on the caudal fin.  All species of Cyprinella are recognized by the large, vertically oriented, diamond-shaped scales, each outlined with black pigment. The head of breeding males is covered with many tubercles.  Breeding specimens are more colorful with red or orange coloration on snout and fins.   For other images of the Whitetail Shiner, click here for photo by Uland Thomas, here for photo by Lance Merry, or here for photo of breeding male by Isaac Szabo.  These photos provide examples of different specimens with different coloration of snout and fins.  

All species of Cyprinella are crevice spawners.  Males establish dominance hierarchies around crevice nesting territories.  Females deposit eggs inside small crevices of rocks and submerged logs or roots and males fertilize the eggs and defend the young until they embryos hatch. In this photoLance Merry captured several males in breeding coloration during agonistic encounters.

Whitetail Shiner occurs in highland streams both east (Ozark Plateau and Ouachita mountains) and west  (Tennessee and Cumberland drainages) of the former Mississippi Embayment, a relict feature from a warmer geologic period.  In these clear and cool streams the Whitetail Shiner occupies deep pools near riffles, often associated with large boulders and rocky banks.   Whitetail Shiners adapt well to life in aquaria and will readily feed on flake fish food; consequently, this species has been propagated by Conservation Fisheries, Inc., for use as a freshwater mussel host.  

The Whitetail Shiner appears to be able to persist in streams that are altered by excessive sedimentation (Sutherland 2007), whereas other crevice-spawning minnows appear more sensitive to stream sedimentation (Jelks and Burkhead 2001).   Sediment movement and deposition is a pervasive issue in flowing waters and fine sediment additions result in higher suspended loads after runoff and higher sediment deposition on streambeds.  Because of the dynamic nature, the influence on fine sediments on crevice-spawning minnows has seldom been investigated.   The experimental apparatus invented by Andrew Sutherland (2007) consisted of slow moving motor-driven paddles in experimental tanks to keep the fine (less than 45-μm) sediments suspended.   Experiments on the effects of suspended solids on Whitetail Shiners demonstrated a reduction in larvae produced as suspended solids increased (Sutherland 2007).  Additional experiments on Whitetail Shiners demonstrated an additional deleterious effect on suspended sediments on gill health and growth rates (Sutherland et al. 2007).  These findings suggest that gill damage and subsequent impairment of respiratory function may explain the reduced growth.  The mainstem New River, where the new population flourished, has a reduced sediment load due to Claytor Dam, which serves as an effective sediment trap. 
Claytor Lake and Dam  (dam located in upper right area of photo) Photo by Rui M.
How would those very first Whitetail Shiners manage to find appropriate mates in this large river?  The answer lies in the non-random and innate behaviors of these fishes.  They are not random wanderers in the river; rather, they have distinct habitat preferences, shoaling tendencies, specific spawning requirements, and acoustic signals.   Whitetail Shiners also communicate with each other with species-specific calls in addition to visual signals.  Catherine Phillips and Carole Johnston of the Fish Biodiversity Lab at Auburn University observed behaviors of Whitetail Shiners associated with different behaviors in lab experiments. They discovered that males make low frequency sounds as courtship signals as well as during agonistic encounters with other males; however, females did not produce sounds (Phillips and Johnston 2008b). This mixture of sound signaling with visual displays ensures that male Whitetail Shiners attract spawning ready mates. Sound may assist in species recognition or mate selection. Phillips and Johnston (2008b) further examined these acoustic signals in populations from Arkansas and Tennessee; they discovered that different populations shared the “same acoustic repertoire (producing knocks, short knocks, and pulse bursts), significant amounts of geographical variation were found.”  Although the disjunct populations were similar morphologically, the acoustic signals were divergent.  

Threats to populations of Whitetail Shiners are not fully studied; IUCN rates them as a “least concern” species.   However, where they do occur they are easy to observe with a mask and snorkel or capture with a minnow seine.   Just don’t dump these or other minnows into non-local streams!
Buckwalter, J.D. 2016. Invasion success and species traits of New River stream fishes. Master’s thesis. Virginia Polytechnic Institute and State University, Blacksburg, Virginia. 94 pp.
Burkhead, N. M., and H. Jelks. 2001. Effects of suspended sediment on the reproductive success of the tricolor shiner, a crevice-spawning minnow. Transactions of the American Fisheries Society 130:959–968.
Easton, R. S., and D. J. Orth. 1994. Fishes of the main channel New River, West Virginia. Virginia Journal of Science 45:265-277.
Jenkins, R.E. and Burkhead, N.M. 1994. Freshwater fishes of Virginia. American Fisheries Society, Bethesda, Maryland. 1079 pp.
Mayden, R.L. 1989. Phylogenetic studies of North American minnows, with emphasis on the genus CYPRINELLA (Teleostei: Cypriniformes). University of Kansas Museum Natural History Miscellaneous Publication 80:1-189.
NatureServe. 2013. Cyprinella galactura. The IUCN Red List of Threatened Species 2013: e.T202079A15364032. Downloaded on 04 January 2016.
Phillips, C.T., and C.E. Johnston. 2008a.  Sound production and associated behaviors in Cyprinella galactura.  Environmental Biology of Fishes 82:265-275 DOI 10.1007/s10641-007-9279-5
Phillips, C.T., and C.E. Johnston.  2008b. Geographical divergence of acoustic signals in Cyprinella galactura, the whitetail shiner (Cyprinidae).  Animal Behaviour 75:617-626. doi:10.1016/j.anbehav.2007.06.022
Sutherland, A.B. 2007. Effects of increased suspended sediment on the reproductive success of an upland crevice-spawning minnow. Transactions of the American Fisheries Society 136:416-422.  DOI: 10.1577/T06-046.1
Sutherland, A.B., and J.L. Meyer. 2007. Effects of increased suspended sediment on growth rate and gill condition of two southern Appalachian minnows.  Environmental Biology of Fishes 80:389–403 DOI 10.1007/s10641-006-9139-8