Ichthyological Adventures in Central America Part 1: Collecting Fishes in Costa Rica

May 2011

From February 15 to the 24th the freshwater people in my lab (Caleb McMahan, Dr.Wilfredo Matamoros) and I went on a trip to collect fishes in Costa Rica. Marine postdoctoral fellow, Dr.Matt Davis, was left back in Baton Rouge to hold down the fort. (Don’t worry he will go to Panama with the rest of the lab in March and April, while I stay behind with my very pregnant wife.) Caleb, Will and I were after cichlids, poeciliids (livebearers) and other freshwater species that are related to my NSF funded project in Central America.

         This was my first freshwater collecting trip to Central America in six years and I learned quickly that my team was much better at this than I was and even better than I thought I was. Caleb has been collecting heavily from freshwaters in Mexico, the U.S. and Jamaica for his masters and undergraduate projects and Wilfredo (without exaggeration) is one of the most well respected collectors of Central American fishes alive today. Wilfredo has many years of experience collecting in remote parts of Central America, which is why I brought him aboard as a postdoctoral fellow this past fall. Also with us were two superior Costa Rican collectors, Arturo Anguilo Sibaja and Carlos Garita Alvarado. These two master’s students from the Universidad de Costa Rica were tremendous collectors and they knew many remote sites where we could collect. They were also very intelligent young gentleman who we made fun of constantly (they did the same to us with less success). In the eight days that we were sampling fishes we put nearly 1000 miles on our rented vehicle in a country that has a coastline of 1100 miles. We collected in every major drainage, in 26 localities, and in six out of the seven provinces as we circumnavigated the entire country.

         We collected about 90% of our targeted species. Our final tally was nearly 4000 specimens from over 150 species. It was one of the most successful collecting trips I’ve ever been on, which was a surprise given how we started. After a couple of days of getting settled in San Jose getting our rental car and gear together, we started our drive to the southern Pacific slope in the province of Puntarenas. We arrived just as the sun was setting and found ourselves a nice little beach hotel (one of many Hotel Iguanas that we encountered) with Golfo Dulce and the Pacific just to our west and with Panama to the east. We decided we would sample that night right in the back of the hotel, which was conveniently located on the beach. Although we were primarily after freshwater fishes, marine fish were also on our mind particularly mullets (Mugilidae) a taxon Caleb has an unusual, and perverse, fondness for. After about an hour at the beach we had collected a marine catfish, a spadefish (Ephippidae) a rare threadfin (Polynemidae) and several other species. It was already 9pm and I was toast, but the site of fish made the blood lust come out of Caleb and Will and they decided that we needed to hit a freshwater site, the Rio Coto, that night. The entire time the strange hotel manager was following us around and he even helped (sort of) pull seines on the beach. As we headed off to the Rio Coto he grabbed a couple of beers and hopped into the back of our SUV.

         As I started recording GPS coordinates and writing field notes the UCR students started pulling a seine in the shallows near shore, almost immediately Arturo cried out in pain. He climbed out of the water with a nasty gash across his foot, he said he was pinched by a crab but it looked much worse than anything a crab could impart. He went to lie down and to elevate his foot while we stoically carried on with the fishing, we ended up getting an additional 10 species at that site after about half-an-hour. We called it quits around 10pm with the intention of returning the next morning. Back at the hotel the arduous work of sorting, photographing, IDing, tissue-ing, and labeling began. One of the unfortunate things about collecting is the necessity of processing these materials while fresh. The hotel manager, now completely drunk, did not make things go faster with his bad jokes and shenanigans but any hotel owner who didn’t mind us laying out 100 or so muddy fish across his bathroom floor surrounded by razor blades and alcohol vials is an okay guy in my book. Not to mention the olfactory nightmare that the mix of formalin, ETOH, fish, sweat, beer, and Arturo’s bleeding foot produced. I’m not sure when we got done that night, but as it was with the rest of the trip, we were off early the next morning before we could get too relaxed.

         We didn’t actually catch a cichlid until our eighth field site on the third day of collecting, a fact that had me very worried since we were there primarily to collect members of this family. Cichlids are very species rich in Central America, with over 100 species, and this family has been there for a long time (more than 50 million years in some parts if you believe my publications). Because they are obligate freshwater fish, cichlids can tell us about the history of the geological blocks that make up Central America. Central America is a landbridge that connects North and South America that has only been in its present arrangement of four interconnected geological blocks for the past three million years. The geological blocks are older but their arrangement and the movement of those blocks over the course of the last 60 million years is hotly debated among geologists. The history and phylogenetic relationships of cichlids and other freshwater fishes on these landmasses can tell us a great deal about which geological hypotheses make the most sense. The biological data provide an independent line of evidence for supporting or rejecting the geological theories. Our plan was to collect as many cichlids and other freshwater species as possible. Although we didn’t collect any cichlids at first they started coming in bunches after day three. We ended up with 20 of the 22 species of cichlids we were targeting. It was amazing to see how each river drainage had its own assemblage of endemics. Cichlids are gorgeous fish, almost all have brightly colored bodies and fins and many have blue or lightly colored eyes. (This coloration is why they are among the most popular aquarium fish.) Even though we were not traveling tremendous distances between sites we could see huge differences between upland and lowland sites and between Pacific and Caribbean coasts. Costa Rica is one of the most developed countries in Central America so it was great to see that the diversity of forms were still there. In fact, we know of at least two new species that we are planning on describing. In July Arturo and Carlos will be coming to LSU to help us describe those species and to determine if we have even more new taxa.

Besides the upcoming Panama trip my lab will also be traveling to Nicaragua, Guatemala, El Salvador, Mexico and Honduras over the next few months. Stay tuned....