The Ones That Didn't Get Away

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The How and Why of the Museum Fish Collection
by Randy Mooi

Frequent visitors to the Milwaukee Public Museum are familiar with the large and varied exhibit halls, and they recognize that the specimens and artifacts on display come directly from the collections or are modeled from them. Many visitors, however, are unaware of the extent of the collections stored under curatorial care or that these collections are used for purposes other than exhibition. In actuality, less than 1% of the collections are on public display at any one time. The Museum houses more than four million specimens, of which about 700,000 are fishes!

If you were to tour the fish collection on the sixth floor, you would enter a quiet, dimly lit room with a low ceiling and rows of closely-packed shelving. The air has a faint odor, perhaps reminiscent of a doctor's office, and the ambiance is that of a mausoleum. A closer inspection of the shelves would reveal jar upon jar filled with what to most would seem a grisly and gruesome cocktail of fishes preserved in alcohol.

What is such an artificial and sterile environment doing in a Museum otherwise dedicated to the celebration of life and the natural world? And why so many? What purpose could so many dead fish possibly serve? And how did they get there? These questions can be answered by a behind-the-scenes introduction to a side of the museum that is seldom encountered by those outside the museum profession. We'll begin by looking more closely at the fish collection here in Milwaukee, then travel afield to see what was involved in collecting fishes during a recent expedition to Thailand. Finally, we will return to the Museum to see how the fishes are used for scientific research and how this relates to the exhibits that fill the Museum galleries.

For a curator, the dim hallways of the collection are not as sterile and lifeless as they at first appear. Although the specimens themselves are no longer alive, a good collection is a dynamic and exciting place. Ichthyologists (those scientists who study fishes), such as myself and others from around the world, examine Milwaukee's fish specimens to identify new species, determine where they live and how common they are, to explore fish life styles, and to uncover the earth's rich biological history ! all important steps to understanding and conserving nature's diversity.

Each Museum specimen has two stories to tell; one is on the biological level involving what species lives where, when and with whom. The other is on a human level, a true fish tale of trials and tribulations of field work often under difficult circumstances in interesting and, occasionally, exotic places. Whenever I pick up a jar of fishes for study, I cannot help but conjure up a picture of a research team slogging through a marsh or river, hauling a trawl in heavy seas, or perhaps diving on a coral reef to make that collection. And all of these situations have been experienced at one time or another by the various researchers who provided the fishes found in our collection.

The majority of our fishes have been collected in Wisconsin and have provided invaluable information on species distribution in the state. For conservation or habitat management, the fundamental requirement is knowledge of what species occur and where they live. Museum collections provide this critical knowledge. A species' status as rare or endangered can be determined with the help of museum collections. By retaining the captured specimen (called a voucher) rather than a mere paper or electronic record, previous identifications can be verified and further information can be gathered. Food preferences through gut content analysis and breeding condition are examples. Historical distributions are documented via the fishes collected and stored in earlier decades and provide information that can be used to determine long-term human impacts on the environment and to identify likely sites for reintroduction programs.

By keeping specimens of the same species obtained from numerous localities, variation among populations can be identified. This variation might reflect environmental differences among sites or suggest genetic influences and the recognition of a new species. If specimens from numerous localities collected over a number of years are to be maintained as vouchers in order to explore biological variation and provide conservation information, museum collections will grow to very large sizes, just as ours has done. And with this growth there is a concomitant growth in information content and inherent value to scientists and environmental managers.

Field collecting is, of course, where the Museum collections come from. Sampling new areas is the only way to fill gaps in our knowledge of the distribution of particular species of fishes, as exemplified by the Wisconsin portion of our collection, or to make faunal surveys of relatively poorly known areas of the world. There are many such areas in the Indian Ocean and West Pacific, even among some of the more populated regions. And in much of the developing world, knowledge of marine fish resources is important for socio-economic well as ecological reasons. In southeast Asia, a large proportion of the population is dependent upon the sea for food and occupation, but the basic research required for effective resource management, such as species surveys, has yet to be undertaken in most countries. Much of the initiative for exhaustive species surveys of these tropical environments comes from the well-established museums of North America and Europe, such as the Milwaukee Public Museum. They provide the equipment and expertise to train the local researchers in the latest techniques. Despite the obvious need, making collections in this part of the world is often a difficult task. Obtaining the necessary permits and the customs authorization to bring in scientific gear is a painfully slow process, and merely getting to the country is very expensive.

To give you a taste of some of the field work on coral reef fishes, I'll bring you along on the Thailand Coral Reef Survey that took place in November 1993. Such a survey requires a great deal of collaborative effort on a number of fronts. For the Thailand expedition, resources were pooled by four research institutions: Milwaukee Public Museum, Royal Ontario Museum (Toronto, Canada), Albany Museum (Grahamstown, South Africa), Phuket Marine Biological Center (Phuket, Thailand). Additional financial support was provided through the generosity of private donors within the cities of Milwaukee and Toronto. Three years of planning and a scramble of last minute negotiations with Thai officials resulted in an extremely productive trip.

The Thailand expedition was a four week collecting trip on the coral reefs along its southwestern coast with the aim of providing the most complete single survey of the Phuket area while training local personnel in collecting and identification techniques. By nature, coral reef areas are in warm and beautiful locales, but the work itself is tough.

A typical day began at daybreak (we were awakened by the crowing of roosters that run free-range around the Biological Center) and involved 10-12 hours of work, including about four hours of diving time. The dives were exhausting, but very rewarding both on a scientific and spiritual level. To swim among schools of thousands of fish as they turn and twist together almost as a single organism, to see the flashing iridescence of a rare species vanishing among the tangled branches of a coral, or to watch a lionfish, as beautiful as it is poisonous, slowly stalk its prey ! these are all cherished experiences one does not soon forget. But back on the surface, the bustle of human existence and recognition of our need to accomplish our survey in four short weeks rudely interrupted any undersea revery. The remainder of the day would be spent coaxing boat engines and other equipment to keep running, bailing boats, getting to and from collection sites, buying supplies, and processing the days catch in the laboratory.

We would head out to a chosen reef first thing in the morning and sample a relatively deep site, between 80 and 100 feet. After lunch we would make a shallower dive in 10-50 feet of water. This routine avoided the physiological stresses that can otherwise build up from a repetitive diving schedule. The fishes at the site would be immobilized with a chemical mixture that includes rotenone (often used by organic gardeners), and the fishes would be collected in hand nets. The affected area remains small, about 10-15 square meters, because the chemical is quickly diluted to an ineffective concentration in the seawater, and it biodegrades naturally in a couple of days. This method of collecting is a sad part of our work; no field scientist enjoys killing the organisms he works on. But many coral reef fishes are camouflaged, live in cracks and crevices in the coral, and/or are nocturnal (active only at night) so they are otherwise very rarely seen. Collecting with a chemical is the only way to discover what really lives in these areas.

Once we bring the fishes to the surface, they are stored on ice to protect them from the decay that otherwise occurs rapidly in the hot climate and to maintain their beautiful life colors. Back at the lab, they are roughly sorted by species, and those of special interest are pinned out to display their fins and are photographed. The photography is important because when the fishes are wrapped in fixative-soaked gauze and put in plastic bags to ship home, their colors will have disappeared by the time they arrive in the Museum lab. The photographs provide a record to help with final identification once we return and to help determine the differences among male, female, and juvenile coloration which occur in some species. In the four weeks of collecting we obtained photographs of over 400 species of fishes! Some of these were new to science and others had been rarely collected in the past, or were known only from other localities. This one brief collecting trip gives an idea of the incredible diversity of fish in coral reefs. In all of Wisconsin we have only about 150 species of fishes. It also gives an idea of the difficulty of understanding the complexity of coral reefs and other tropical habitats in terms both of numbers of species and of the interactions among those species. Our expedition was a first step in helping Thailand towards the goal of enlightened stewardship of their rich marine environment.

All trips must come to an end and, despite working in a wonderful country like Thailand and having the opportunity to explore and experience a wonderful habitat, it was still nice to come home ! even to Milwaukee in December! Once the fishes are in the lab, the specimens are carefully identified. This can be tricky work, and it is rare to return from a collecting trip on an Indo-Pacific coral reef without species new to science. Often experts from other museums are asked to examine some of the specimens that fall into groups with which they have special familiarity. Identification work on the Thailand fishes has not been completed but by examining anatomical details and comparing color photographs of specimens in the collections at Milwaukee and at other museums all over the world, I have already described a number of new species of coral reef fishes.

Proper identification and species descriptions are important steps to understanding nature's diversity, but are only the beginning of the research process. Once we know what species we have, the real work begins. My own research focuses on determining the relationships among the species and reconstructing their family trees. These genealogies are used to explore the history of their distribution on the Earth's surface (how they came to live where we find them today), as well as to examine how their unique behaviors might have arisen. To build the family trees, specimens are prepared for examination of internal organs and muscles through dissection and for examination of bones through enzyme and stain solutions. By finding a number of special or derived features of muscle arrangements and bone shapes that are shared by successively less and less inclusive groups, the fish family history or tree can be sketched out. Overlaying the geographical distributions or behaviors of the fishes on the tree can provide clues to their origin or suggest other avenues of investigation. For example, the males of all members of the prettyfin family care for their eggs until they hatch. The males either guard them in a small cave or carry the eggs in their mouth. By looking at the relationships among the prettyfin species, we can see that guarding the eggs arose first and is primitive, whereas carrying the eggs in the mouth is a new or derived behavior. Knowing this, we can examine more closely the anatomy and life style associated with carrying eggs that makes such a behavior possible and how it might have come about.

Of course, not all aspects of fish natural history can be studied at any one museum; the collections are made available to researchers all over the globe to help discover the secrets of a fish's watery world. The fish research program here at the Museum, and the many other biological, geological and historical research efforts, are made possible by our strong and active collections. The studies based on the collections not only help scientists understand our place in the natural world, but are an important component of exhibits seen by Museum visitors. New findings inspire original exhibit subjects, and new understanding is reflected by updated and scientifically accurate displays.

This behind-the-scenes tour of the collections, and introduction to their role in the Museum, has now come full circle. It began at the familiar exhibit galleries that hold but a small fraction of the Museum collections, and came through the extensive collections themselves and their value to conservation efforts and wise resource use. It visited a field site and showed how collections are made. It then followed the new specimens to the Museum laboratory where the collection, as a cornerstone of a research program, was seen to contribute to our understanding of nature and our place in it. Finally, it returned to the exhibits and education programs that interpret the research for public consumption. The collections, though containing dead organisms, are truly active and vibrant knowledge sources.

Only through continued collaboration with other institutions and, most importantly, with the help of the community and its donors can such Museum work continue. Only in this way can we maintain our place on the international scientific stage and our high standard of accurate and informative exhibits and educational programs. And it is the only way we can ensure that the collection of preserved fishes (the ones that didn't get away), and the many other Museum collections, will not become lifeless and sterile from disuse and neglect.