The Offseason

I am in the process of bolstering my knowledge of statistics in order to write a better thesis.  I won't be engaging in actual research until April, when the sparrows return.  In the meantime I am also about to obtain audio software from Cornell with which to analyze lark sparrow songs.  I'm hoping that my recordings from last summer are clear enough to provide me with solid analysis.

That's it for now, and probably for a while.

List of Species in Cape LaCroix Creek

Here is a list of the species found in Cape LaCroix Creek this fall.  I will have an official report finished by Friday.

Topminnows (Fundulus) were the most abundant species.  Although I captured and released individuals without prominent black spots, all of my specimens were F. olivaceus.  Therefore I can only with certainty that the blackspotted topminnow is found in the creek.  Further downstream I have seen gar (Lepisosteus) and silver carp (Hypophthalmichthys molitrix) neither of which were present in my study area.  A different assemblage of fish is likely found in the deeper, lower gradient portions of the creek.  However, depth and an uneven bottom rendered sieving impractical here.  Other methods of sampling would be necessary to determine the fish fauna of the entire creek.

Cyprinidae
Semotilus atromaculatus  creek chub
Notropis boops  bigeye shiner
Lythrurus umbratilus  redfin shiner
Luxilus chrysocephalus  striped shiner
Pimephales notatus  bluntnose minnow
Campostoma oligolepis  common stoneroller

Centrarchidae
Micropterus salmoides  largemouth bass
Micropterus punctulatus  spotted bass
Lepomis macrochirus  bluegill
Lepomis megalotis   longear sunfish (pictured)

Fundulidae
Fundulus olivaceous  blackspotted topminnow

Atherinidae
Labidesthes sicculus  brook silverside

Poecilidae
Gambusia affinis  mosquitofish 

Percidae
Etheostoma spectabile  orangethroat darter

New updates coming soon

It's been quite a while since I've updated this blog.  Finals week has arrived and as soon as I finish both of my exams on Tuesday, I will identifying the fish I captured in Cape LaCroix Creek.  Details will be soon to follow.

Second Day of Seining

Almost exactly one month after my first day of seining I went out a second time to collect and identify the fish species in Cape LaCroix Creek.  The water was cooler but this time I had chest waders so it wasn't a problem.  Between my own research and ichthyology field trips, I can resoundingly pronounce them a worthwhile investment.

Andrew and I seined from seven in the morning until around ten o'clock.  Initially my plan was to count the number of seines and divide by the total number of individuals of each species.  This would give me the number of individuals per seine and would help to determine the overall abundance of each fish species.  However, there was at least one major flaw in this methodology.  When we seined and saw a large fish (or fishes) swim into the net, we immediately pulled it up.  This would count as one seine but we didn't cover the same length of stream as the standard seines.  Thus, the results would be skewed because each trial would not be the same.

With this in mind I have decided to focus my research on the composition of species in Cape LaCroix Creek, with abundance tentatively determined.  Although I counted the number of individuals for each species this time, I did not do so on last month's trip, so the exact abundance of each species will be largely speculative.  There is also an obvious bias in using mesh seines, as very small fish can slip through the netting and faster fish can out-swim (or outsmart) the net as well.  Considering these two things I will avoid any statistical attempt to determine the abundance of fish in the creek.  However, I see nothing wrong with unofficially estimating abundance based on observation (and in today's case, total number of individuals).

I may or may not seine one more time, but the most difficult aspect of this research remains to be done.  Identification of the cyprinids is incredibly meticulous and keying them out is going to take some time.  This would present another difficulty in determining abundance.  Since my permit only allows me to capture fifty specimens, I had to release most of the fishes that I captured.  Minnow identification in the field is very difficult (especially for someone with very little experience), so I may well have released some specimens that would have been different species.

Since I am in ichthyology and identification of Missouri fishes is a class requirement, I am waiting to key my research specimens until I gain some experience in class.  Therefore I will probably begin identification come November.  The specimens will have to wait in formalin until then.  There are a few species I can already identify with confidence, though.  Longear sunfish (Lepomis megalotis) is very common in the stream, much more so than the bluegill (L. macrochirus).  Among the Macrochirus basses, the spotted bass (M. punctulatus) looked to be much more common than the largemouth (M. salmoides).  Identification was based on jaw size and tail color (in juveniles), although positive ID will be made in the lab.  Topminnows (Fundulus; pictured) were abundant, for certain blackspotted (F. olivaceus) and likely blackstripe (F. notatus).  Mosquitofish (Gambusia affinis) were especially common under beds of Ludwigia and other emergent vegetation.  Brook silversides (Labidesthes sicculus) were present but not abundant.  There was also a species of shiner, two Etheostoma darters, a likely bluntnose minnow (Pimephales notatus), stonerollers (Campostoma spp.), and several unknown cyprinids.  Positive identification will take place in the lab.

Seining Again

This Sunday will be exactly one month since my first time seining at Cape LaCroix Creek.  That excursion focused on capturing a wide variety of species in order to determine what was in the stream.  This time I will focus on abundance and note how many individuals I capture for each species.  The fish will then be released unless I am unsure of identification because my license only allows me to collect 50 specimens (and I am near that amount already).

A Day in the Field

This past Friday I began my research of the fish fauna of Cape LaCroix Creek.  My friend Andrew and I gathered the seine, formalin, and other materials and ventured out to the creek in the middle of the morning.

The weather was overcast and quite humid.  The forecast called for rain but we didn't receive any until the early afternoon.  Our first stop was a deep, rocky part of the creek near Shawnee Park, relatively close to where the stream empties into the Mississippi River.  Seining here proved to be nearly impossible as we both found ourselves treading for water at times.  We did observe several silver carp (Hypophthalmichthys molitrix) that leaped from the water when they discovered our presence.  According to Pflieger's Fishes of Missouri this highly invasive species has not been seen at many localities in the state, but the book is now fifteen years old and recent propagation has likely led to greater abundance than it indicates.

We had much greater luck when we moved to shallower waters, in particular those with heavy weed growth.  Water primrose (Ludwigia spp.) was abundant in the creek, as were several other small aquatic plants whose identity currently eludes me.  I intend to try to identify the aquatic flora of Cape LaCroix as well, but that will have to wait for another day.  There was abundance of terrestrial plants along the shoreline as well, including mist flower (Conoclinium coelestinum), monkey flower (Mimulus ringens), cup plant (Silphium perfoliatum; pictured).  In fact, the plant life is diverse enough that I intend to speak with the city of Cape Girardeau to see if I need a permit to collect along the creek.  I think a floral survey of the area would be a great asset as well.

Topminnows (Fundulus spp.) were the most abundant species in the creek, with several specimens captured in every seine attempt.  Although I need to further examine the specimens, I believe we caught both blackstripe (F. notatus) and blackspotted topminnow (F. olivaceus) Other common species included mosquitofish (Gambusia affinis), an unknown cyprinid with a definitive golden hue above the lateral line, several catostomids (suckers), two darters, longear sunfish (Lepomis megalotis), bluegill (L. macrochirus), largemouth bass (Micropterus salmoides), brook silverside (Labidesthes sicculus), and two unmarked, unknown cyprinids just over a decimeter in length.  Exact identification is pending and will involve meticulous keying in the lab.

Even though it was only one day, I believe that our sample is a good overall indication of the fish fauna of Cape LaCroix Creek.  I have at least two more trips planned, one near the source of the creek and one just before the concrete channel in the center of Cape Girardeau.  During most of the summer this channel remains too dry for most fish to cross, isolating individuals away from the Mississippi River.  I am curious as to whether different fish are present east of the concrete.  I would hypothesize that larger species (such as the silver carp we observed) enter the creek via the river but do not swim through the shallow impounded channel, and are therefore limited to the deeper, easternmost portion of the stream.

Licensed to Begin

Yesterday I received my official permit to begin collecting fishes in Cape LaCroix Creek.  My first collection day will be this Friday.  I can take no more than 50 specimens so I will be releasing all individuals that I can identify in the field.

Updates will soon follow.