Tall oaks from little acorns grow.
By David Everett (1791)
The microscopic babies of aquatic animals abound in lakes, rivers and oceans at certain times. Both vertebrates and invertebrates possess embryos that hatch from eggs and inhabit watery nursery grounds. These microscopic embryos are usually dispersed in natural bodies of water by feeble swimming efforts, tidal currents, and currents of water produced by winds. Newly hatched fish, fry, larval fish or baby fish are one of those microscopic water babies which are rarely seen or examined close at hand because they are so small, so transparent, and so difficult to capture and keep alive. The Federal Water Pollution Control Act amendments of 1972 in the United States caused a biological revolution in North America. Those amendments required heating plants, generating plants, and any other commercial endeavours using large volumes of water to monitor the young fish and other invertebrate organisms passing through machinery by entrainment (straining water) methods. As a result, biologists began to search for and record the details of the early life stages of fish.
The early life stages of fish are minute, possess transparent blood, have very little skin pigment, no bones, and are widely spread out in natural bodies of water. Although baby fish are normally termed larval fish or fish larvae, they do not transform dramatically from larvae to adults, such as butterflies. The baby fishes shown in this Web site were captured from natural open waters with conical, fine-mesh townets and/or light traps while those baby fish that normally live in shallow water and/or on or near the bottom are unavailable to townets. All the captured specimens were preserved with dilute formaldehyde; unfortunately, the actual specimens illustrated in this Web site were lost during moving operations within the National Museum of Natural Sciences. In the Illustration Gallery, complete data are presented about the specimens illustrated in the section entitled: "DATA ABOUT SPECIMEN ABOVE". The term “baby fish” has been maintained throughout this Web site because the majority of the general public is completely unfamiliar with what baby fish really look like and their importance. Recently, numerous live baby fish have been photographed under the microscope and a few can be said to be 'the most beautiful living creatures on Earth’. There are numerous people to thank for helping with this Web site, see: "Acknowledgments".
Drawing the Illustrations
The purpose of drawing these illustrations was to "properly illustrate these animals" in order to visualize and to be able to identify each species or group of species in preserved zooplankton collections or in a living condition. The specific sizes of the specimens that are illustrated in the "Illustration Gallery" were determined by the availability of specimens in good condition from preserved zooplankton collections. Most specimens examined in preserved collections are torn, broken and/or ripped apart. We had to balance the funds available with the many species and the many stages that one species goes through. The illustrator was asked to duplicate, as best as possible, the melanophore pigmentation seen under the microscope. The specimens were carefully drawn with a black pen on drawing paper and then a graphic designer digitized the drawings with a Macintosh (TM) computer using the program Photoshop (TM). The results of this work indicate that these kinds of illustrations can be more useful for certain biological research purposes than shriveled up specimens stored in alcohol. Chromatophores are certain cells in the dermis and cells associated with other anatomical parts of baby fish; they also occur in other animals and plants that possess pigments. One type of chromatophore is a melanophore which possesses blackish or brownish colors. The melanin in melanophores are the pigments described and illustrated in this baby fish Web site. Melanophores are easily visible, are mostly resistant to formalin preservation, and are grouped in distinctive patterns (maculae) on different species. Melanophores, which show up as blackish or brownish micro- melanophores and/or macro- melanophores on baby fish, occur in an extremely wide variety of shapes and sizes. This study has led to an in– depth study of the structures and functions of melanophores on baby fish (See: melanophores).
Early Movements of Baby Fish After Hatching
Based on data gleaned from a variety of field studies together with data in other publications, information in the “Illustration Gallery” describes the early movements of baby fish shortly after hatching of the species shown. After several decades of intensive research on early life stages, there is now a mature body of knowledge that is ready to be summarized and distilled for students and the non-specialist audience (Ref. 24). In the Illustration Gallery, the section entitled: "Movements of Babies after hatching:" describes the early movements of baby fish shortly after hatching from eggs. This information about the early life of fishes has normally been minimized in treatises of adult fish. The study of baby fish is extremely complex and encompasses numerous fields of biology, including ichthyology, anatomy, ecology, vertebrate zoology, invertebrate zoology, and several others.
The number of species of fish in any body of water is closely related to water quality, so surveys of larval fish can be a true gauge of pollution. Experiments have shown that both eggs and larvae are more sensitive to the general aquatic environment than adults; that is, they die quicker when pollution occurs. It has been demonstrated in laboratory studies that excess heavy metals and other toxic pollutants cause spinal abnormalities, curved tails, abnormal development, and generally increased death among early stages of fish. More study and conservation work needs to be applied to the bodies of water where the early life stages of both marine and freshwater fishes live.
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