Expediton to Galapagos

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Scientific Significance of the 
Galapagos Research

INTRODUCTION

The Galápagos Islands have long been a popular location for scientific exploration. Their geographic isolation, distinctive habitats, recent volcanic origin, and unique species help scientists study how plants and animals change over time.

A voyage that included a brief stop in the Galápagos in the 1830s inspired English naturalist Charles Darwin’s groundbreaking theories about natural selection and the origin of species. Since then, scientists have been using his work to better understand the origin and diversity of life on Earth.

An expedition to the Galápagos Islands in the summer of 1998 to make the Smithsonian/IMAX 3-D film Galapagos provided marine biologists with research opportunities that Darwin never had. While Darwin was able to glimpse the underwater world only through a glass-bottom bucket, Drs. Carole Baldwin, David Pawson, and John McCosker had scuba gear that allowed investigation of the shallow underwater realm and a modern research submersible that enabled them to explore to depths of 3000 ft. Over a two-month period, the scientists made 30 dives in the Johnson Sea Link II submersible. Their findings included the discovery of numerous new species of marine fishes and echinoderms and the collection of many species of marine life previously not known to occur in the Galápagos Islands.


NEW SPECIES, NEW RECORDS

"In the Galápagos, we scientists were doing underwater very much what Charles Darwin and others already have done on land. And I think that by going to this place that already has a long history of biological exploration on land, and then, using modern technology, discovering numerous new species of marine life, the film shows that the exploration of our natural world is a continuum. And that there’s a lot yet to be done." Carole Baldwin, National Museum of Natural History, Smithsonian Institution.

Anthias - new species

New wrasse species

New Bythaelurus shark

Coronaster - new species

Pencil urchin

Centrocidaris doederteini

Peribolaster cf. folliculatus

Volute - Adelomelon

(Click on any of these photographs to see a larger view and to read information for each new species or new record.)


COLONIZATION OF THE GALÁPAGOS ISLANDS

"Sea stars and sea urchins can be found in many places, including isolated islands like the Galápagos, because as babies they’re able to float great distances in ocean currents." David Pawson, National Museum of Natural History, Smithsonian Institution

Every major group of plants and animals that occurs in Galápagos includes at least some species that are endemic – that is, they occur nowhere else in the world. The percentages of endemic species, however, vary greatly among different organisms, based in part on how good the species is at dispersing over large spans of air or water.

For example, although about 15% of fish species that occur in Galápagos are endemic, endemism of Galápagos reptile species is approximately 86%! 

For plants and animals that do not have a dispersal stage easily capable of colonizing oceanic islands, few species will arrive at such places, and of those that do, few will leave the islands to colonize other distant areas.

Terrestrial wildlife may have reached Galápagos by rafting on floating mats of vegetation or by island hopping on pieces of land that are now submerged. Large marine organisms such as tuna, sharks, large jacks, etc., may have been able to colonize Galápagos by swimming the distance to the islands. But most marine life that inhabits the Galápagos could not have arrived that way. The dispersal stage for most marine organisms, even relatively sedentary creatures such as starfish and flounder, is the young, or larval, stage, which is carried along in the surface currents of the ocean.

The surface currents of the world’s oceans, however, are a dangerous place for a tiny organism to live, and most don’t survive the pelagic larval period. This environment also is very different from an adult habitat, whether that happens to be a shallow coral reef or a sand bottom at 3000 ft. Presumably because of this, the young stages of marine organisms often look very different from adults. For example, compare adult and larval stages of the deep-sea black dragon fish:

 

Adult Dragonfish
Where are the eyes in the adult?

Larval Dragonfish
Where are the eyes in the larva
?

Adult Dragonfish

Larval Dragonfish

(Click to view images and information)

 

Below is another example of extreme morphological differences between adult and larval stages of fishes, the Cave Bass:

 

Adult Cave Bass

Larval Cave Bass

Adult Cave Bass

Larval Cave Bass

(Click to view images and information)

Elongate, modified fin rays and modified eyes are just two of many different categories of specializations of larval fishes. Because they are present in larvae but lacking in adults, they are almost certainly adaptations to the pelagic period. For the systematic biologist (one who studies diversity and relationships among organisms), examining features of larvae and adults provides more information on which to base their classifications than examining adults alone. Carole Baldwin and colleagues at the Smithsonian’s Natural History Museum, Dr. G. David Johnson and Dr. David G. Smith, frequently include larval characters in their studies of fish systematics.

However, identifying fish larvae can be difficult because larvae may lack the distinctive features that characterize adults, and much more basic descriptive work is needed. Throughout the two film expeditions to the Galápagos Islands, Carole made collections of fish larvae. Collections were made with a fine-mesh plankton net, similar to the one shown below, that was deployed from the ship at night. Organisms that were collected were then observed with the aid of a dissecting microscope.

 

Plankton Net at Carrie Bow Cay

Carole looking at larval fish under a microscope

Plankton Net

Carole at microscope

(Click to view images and information)

At least initially, the work Carole is doing with the larval-fish collections from Galápagos is trying to identify the material, and then illustrating and describing it in the scientific literature. Because sampling was conducted in the summer of 1998, during a time when El Niño resulted in a mass of warm water moving in to the Galápagos from the west, Carole will try to determine if the samples contain tropical western Pacific species not currently known to occur in Galápagos. The frequency and severity of El Niño effects in Galápagos may have contributed and continue to contribute to the diversity of marine life in the islands.


EXTINCTION IN GALÁPAGOS

"The severe 1997/1998 El Niño event that coincided with our expedition allowed us to observe dramatic changes in the Galapagos ecosystem, including what we thought might be the first documented extinction of a marine fish species by natural causes." John McCosker, California Academy of Sciences.

There have been several known extinctions of species or subspecies of terrestrial vertebrates in the Galápagos Islands that are believed to be the direct result of man’s presence there. For example, several subspecies of the Galápagos giant tortoise are now extinct, presumably because early sailing vessels that visited Galápagos greatly impacted the tortoise populations when they carried them away on their ships for food (the tortoises survived well with no care for many months on the ships). Also, the introduction of goats to the islands by humans resulted in competition between the tortoises and goats for vegetarian food.

Extinctions in the marine environment are much more difficult to identify, because if a species capable of dispersing long distances dies out in one place, it is always possible that it had previously dispersed elsewhere. Investigations into a possible extinction event of a marine fish species in Galápagos have been undertaken because of observations made during the IMAX film expeditions there in 1998 and 1999. A small marine fish known as the Galápagos barnacle blenny, Acanthemblemaria castroi, is typically abundant throughout the archipelago but was not observed on either trip. We are concerned that the devastating effects of the 1997-98 El Niño event on the marine environment in Galápagos may be to blame. During El Niño, the upwelling of cold, nutrient-rich water is suppressed, and the entire food chain is affected. 

Fortunately, McCosker received confirmation in September 2000 that a graduate student conducting research on fishes in Galapagos has recently seen the barnacle blenny in two localities in the islands. This suggests that the species did survive the most recent El Nino phenomenon. Since the barnacle blenny is only known from Galapagos, its disappearance there would have meant extinction of the species. Investigations into other 'missing' Galapagos species is still underway.

Barnacle Blenny
Copyrighted by Paul Humann, 2000

Barnacle Blenny

(Click to view images and information)



Scientific Publications Resulting from 
Galápagos Film Expedition

Anderson, W. D., Jr. and C. C. Baldwin. 2000. A new species of Anthias (Teleostei: Serranidae: Anthiinae) from the Galápagos Islands, eastern Pacific Ocean, with comments on hermaphroditism in the Anthiinae. Proc. Biol. Soc. Wash. 13:369-385.
Baldwin, C. C. and J. E. McCosker. In Press. Wrasses of the Galápagos Islands, with the description of a new deepwater species of Halichoeres (Perciformes: Labridae). Pp. 00-00 In: Hastings, P. A. and D. R. Robertson (eds.), Systematics of eastern Pacific Fishes. Revista de Biologia Tropical.
McCosker, J. E., L. Compagno, C. C. Baldwin. In Prep. A new catshark from deep waters of the Galápagos Islands, Ecuador.
Proc. Calif. Acad. Sci.
Pawson, D. L. and C. A. Ahearn. In Press. Bathyal echinoderms of the Galápagos Islands. Barker, M. F. (Ed.), Proceedings of the 10th International Echinoderm Conference. A. A. Balkema, Rotterdam.
Poss, S. G., J. E. McCosker and C. C. Baldwin. In Prep. A new genus and several new species of deep-water Scorpaenidae from Galápagos Islands, Ecuador. Revista de Biologia Tropical.

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