Dredging in North Brazil - August 2005 Jose Coltro Jr. and Dr. Paulo Marcio Costa

Preparing the dredge

I always wanted to go on a good dredging trip in a remote place. I tried in 1993 when I rented the oceanographic ship from the Rio Grande Museum. That was a disaster. For many years, the only good results were from our humble dredging on the São Paulo coast, but never deeper than 50 meters.

Last year, Dr. Paulo Marcio Santos Costa, from our National Museum (Museu Nacional do Rio de Janeiro) told me of the possibility of using a fishing boat from a big company in Fortaleza, Ceará State, to dredge the offshore banks of the north Brazilian coast. It would be a dream come true!

We arrived in Fortaleza on August 21st. On the following days, we went to visit the fishing boat - a trawler 28 m long. The boat was very rusty, and my first thought was about anti-tetanus vaccine! As in most fishing boats, comfort was minimum, but acceptable for 5 days. We met the crew, 5 well-experienced members. I got the first cabin, Dr.Costa the next one, and four the crew members the next one. One of the crew had to sleep on the wheelhouse . The boat had been well cleaned and they had used insecticide to kill all the cockroaches. Guess what I saw crawling on the wall of my cabin on the very first day?

My next bad surprise was the outside bathroom. It was next to the kitchen door. And the inside was a little bit disgusting. When the manager of the company saw my face, he sent some people to change the pieces, paint and clean it again!

We started to work hard to prepare the big dredges we ordered (1 x 1.2 x 0.3 meters), very strong and heavy. They also had to get stronger and longer cables to use with the dredges. And had to build 4 boxes with different mesh sizes for screening. This all took three days to get ready.

During the days we were in Fortaleza, the wind was very low and the sea looked very calm. Of course, on August 25th this situation changed! We left the dock about noon. I had taken one Dramamine in the morning, another just before boarding the boat, and a third one hour after we left. I offered one pill to Dr. Costa, but he refused telling me he was used to boats in any condition. He was wrong!
For the next two and a half days he almost couldn't leave the bed! It took about 14 hours to reach the offshore banks and the sea was very rough. The wind was very strong, the waves very high.

The first day of dredging, we started by putting some traps at depths of 280-300 meters. After that we went to the top of the banks and started dredging in depths of 60 to 70 meters. The bottom was only calcareous algae (Lithothamnium sp.), and mostly dead material. We found very few species, like a new Conus related to the C. mindanus group, Cymatium vespaceum, some turrids and a few other shells. We did most of the dredging in this area and it was very unproductive. Thanks to the Dramamine, I felt quite well. The crew had fixed a large cable on the deck that I could hold on to for walking. They had prepared a special seat where I could check some trays with the substrate. By the end of the day, we decided to try to dredge at 260 meters - the next level on the bank. On our first try we hit some very hard bottom. We raised the dredge quickly and saw that it was a little bit damaged, but it had some substrate inside. When we put that on the deck a big surprise: a very large unknown Fusinus appeared! I took all the substrate and I started checking for other shells. I had one surprise after another! I asked to dredge again in the same spot, and again the dredge hit hard bottom. This time, the dredge was smashed a lot, but it came up with some good substrate inside, too! I found in a kind of rubble, millions of sea-urchins spines, crazy starfish, sponges, etc. many shells, mostly unknown to science, and some unknown to Brazilian fauna. Besides that large beautiful Fusinus sp., I found a very large and beautiful kind of Lucapina (I think even the genus is new), a Pterynotus close to the P. ariomus, a small and gorgeous Babelomurex juliae. Lots of pteropods and small species.

We left this bank to go to the next one, the type-locality of Conus scopulorum. We arrived early in the morning and we started dredging on this small bank at depths of 50 up to 70 meters. It was a peak in shallow water surrounded by 800 meters deep. We dredged a lot, again in calcareous algae bottom and we found only broken pieces of C. scopulorum. It seemed we were in the wrong time of the year. For two days, we combed nearly the whole bank and it was very disappointing. We found very few species of shells, but lots of sponges, crabs, etc. The next day, we went back to the first spot. We retrieved the traps and found no shell, not even a crab. Just two stupid fish.

Although we lost one dredge we still had another two other ones and we used them in depths of 240-270 meters, but the good shells came only from 260 meters. We dredged another 12 stations, but suddenly the dredge became stuck on the bottom and the waves and the wind pushed the boat so much that we destroyed the arm holding the cable. The boat almost rolled over on its side. With additional care, we managed to free the dredge, almost completely smashed, but again with substrate and a big rock inside. After three hours trying to find a way to keep doing our job, the captain fixed the dredge and the arm. But the wind was so strong and the waves were so high (sometimes over 6 meters!) that we decided to come back to Fortaleza. We left the bank at night and we had the worst trip ever. Even the crew were complaining about how the boat shook. Nobody could sleep. I was thrown out of bed three times!

About 50 km off the coast, we dredged again. The boat was rolling a lot but we tried anyway. The bottom was sand and everybody was disappointed, but when we started to clean the sand we found many interesting species, such as Conus selenae, turrids, olives, etc. Just a few kilometers from Fortaleza, I was talking with the captain at the wheel when he warned me about a huge wave; as I turned to look at it, I was flying in the air and almost smashed the poor little captain! Thank God, he survived!

We brought back more than 200 kilos of sand and rubble to check and we are still working on that. We found more than 40 new species of shells, crabs, sponges, etc. Most the material went to our National Museum and to the Zoological Museum of the University of São Paulo. It was a great trip! In addition to the great material, I lost 5 kilos! I hope to be invited again soon!

English checking by John Wolff

Shells found on the trip:
FISSURELLIDAE - Diodora arcuata (Sowerby, 1862); Diodora minuta variegata Sowerby, 1862; Diodora mirifica Metivier, 1972; Emarginula sp.; Lucapina sp.; Puncturella antillana Farfante, 1947
TROCHIDAE - Calliostoma bullisi Clench & Turner,1960; Calliostoma sp.; Calliotropis actinophora (Dall, 1890); Margarella (?) sp.
TURBINIDAE - Astraea sp.; Homalopoma philippiana (Dall, 1889); Homalopoma sp.; Turbo aff. heisei Prado, 1999
SEGUENZIIDAE - Hadroconus altus (Watson, 1879)
ARCHITECTONICIDAE - Architectonica sunderlandi Petuch, 1987; Philippia sp.
MATHILDIDAE - Mathilda barbadensis Dall, 1889
TRIPHORIDAE - Triphora aff. colon (Dall, 1881); Triphora sp.
EPITONIIDAE - Epitonium aff. striatissimum (Monerosato, 1878); Epitonium krebsii (Morch, 1874); Opalia atlantis (Clench & Turner, 1952)
HIPPONICIDAE - Malluvium benthophilum (Dall, 1889)
CYPRAEIDAE - Cypraea acicularis Gmelin, 1791; Cypraea cinerea brasiliensis Lorenz & Hubert, 1993
TRIVIIDAE - Trivia sp.
PEDICULARIIDAE - Pedicularia sp.
NATICIDAE - Natica sp.
CASSIDAE - Casmaria ponderosa atlantica Clench, 1944; Cassis tuberosa (L., 1758)
RANELLIDAE - Cymatium vespaceum (Lamarck, 1822)
BURSIDAE - Bursa pacamoni Matthews & Coelho, 1971
MURICIDAE - Aspella sp.; Attilliosa sp.; Pazinotus sp.; Poirieria sp.; Pterynotus aff. ariomus Clench & Farfante, 1945
CORALLIOPHILIDAE - Babelomurex juliae Clench & Aguayo, 1939; Coralliophila sp.
COLUMBELLIDAE - Mitrella sp.; Zafrona cf. idalina (Duclos, 1840)
NASSARIIDAE - Nassarius sp.
FASCIOLARIIDAE - Fusinus sp.; Pleuroploca aurantiaca (Lamarck, 1816)
VOLUTIDAE - Enaeta sp.
OLIVIDAE - Ancilla sp.; Oliva sp.
HARPIDAE - Morum oniscus (L.,1767)
MARGINELLIDAE - Dentimargo sp.; Volvarina sp.
COSTELLARIIDAE - Vexillum sp.
CONIDAE - Conus cf. scopulorum Van Mol, Tursch & Kempf, 1971; Conus sp.
TURRIDAE - Crassispira affinis (Reeve, 1846); Fenimorea halidorema Schwengel, 1940; Fenimorea sp.; Fenimorea sunderlandi (Petuch, 1987); Glyphostoma sp.; Inodrillia aff. acova Bartsch, 1943; Mitrolumna aff. biplicata (Dall, 1889)
CAVOLINIIDAE - Cavolina inflexa imitans (Pfeffer, 1880); Cavolinia gibbosa (Orbigny, 1836); Cuvierina spoeli Rampal, 2002; Diacria trispinosa (Blainville, 1821)
MYTILIDAE - Botula sp.
ARCIDAE - Arca cf. imbricata Bruguiere, 1789
GLYCYMERIDIDAE - Glycymeris decussata (L., 1758); Glycymeris pectinata (Gmelin, 1791); Glycymeris sp.
LIMIDAE - Lima sp.
PECTINIDAE - Argopecten noronhensis (E.A.Smith, 1885); Euvola sp.
THYASIRIDAE - Thyasira aff. croulinensis Jeffreys, 1874
CARDIIDAE - Americardia media (L., 1758); Papyridea semisulcata (Gray, 1825); Trachycardium magnum (L., 1758)
TELLINIDAE - Tellina listeri Röding, 1798
VENERIDAE - Chione cancellata (L., 1767)