John R. Waldman

An holistic approach to fish stock identification

Abstract The concept of the ‘stock’ is fundamental for both fisheries and endangered species management. We review different approaches used in identifying and classifying stocks and advocate that an holistic approach (e.g., involving a broad spectrum of complementary techniques) be used in future stock identification studies. Stock definitions should evolve as management requirements do and be re-evaluated when the need arises or when break-through technologies become available.

Dramatic Declines in North Atlantic Diadromous Fishes

We examined the status of diadromous (migratory between saltwater and freshwater) fishes within the North Atlantic basin, a region of pronounced declines in fisheries for many obligate marine species. Data on these 24 diadromous (22 anadromous, 2 catadromous) species are sparse, except for a few high-value forms. For 35 time series, relative abundances had dropped to less than 98% of historic levels in 13, and to less than 90% in an additional 11. Most reached their lowest levels near the end of the observation period. Many populations persist at sharply reduced levels, but all species had suffered population extirpations, and many species are now classified as threatened or endangered. Habitat loss (especially damming), overfishing, pollution, and, increasingly, climate change, nonnative species, and aquaculture contributed to declines in this group. For those diadromous fishes for which data exist, we show that populations have declined dramatically from original baselines. We also discuss the consequences of these changes in terms of lost ecosystem services.

The threatened status of acipenseriform species: A summary

...increased demand has recently driven the price of black market smoked sturgeon as high as

The importance of comparative studies in stock analysis

26 a kilogram. With poachers standing to gain roughly a third of this price [besides the much higher price of caviar], a large fish could be worth thousands of dollars. Gary Hamilton in Canadian Geographic, July/August 1996, p. 62

When the American sea sturgeon swam east

Abstract The identification and discrimination of stocks of fishes lies at the interesting juncture of fishery biology and fish microevolution. Fish have been “taken apart” in the search for features that discriminate between stocks. Early stock studies focused on morphological characters (meristic counts and morphometric measurements) that are expressed phenotypically, and hence, benefit from incorporation of both genetic and environmental information, but suffer from the absence of information on their respective contributions. However, the ability to discriminate stocks has risen with the emergence of more sophisticated laboratory and statistical tools. Some of these techniques are mostly sensitive to environmental information, i.e., microchemical analysis of otoliths. Others are purely genetic (i.e., various forms of DNA sequence analysis), and reflect time, selection pressure, and the degree of isolation among populations. But despite this diversity of approaches, all are based on a common principle: the signal from the among-stock variation must exceed the noise of within-stock variation. Much of the uncertainty concerning the application of stock concept approaches stems from the lack of synchronicity in the development of the many potentially differentiating features between fish stocks. If so, then this field would benefit from a greater understanding of the trajectories of differentiation of analyzable features-gained from comparison between approaches from a microevolutionary point of view. Because only heterogeneity, and not homogeneity of fish stocks can be demonstrated, and because sophisticated stock identification is costly, it is imperative to select an appropriate approach from the outset. Unfortunately, comparative studies among stock identification approaches have only rarely been conducted. Although this “black art” could continue to muddle along, there is no doubt that useful information on the relative sensitivities of stock analysis techniques would be gained via well-planned intercalibration studies.

Fish populations: When the American sea sturgeon swam east

The two species of Atlantic sea sturgeon on either shore of the North Atlantic, Acipenser sturio in Europe and A. oxyrinchus in North America, probably diverged with the closure of the Tethys Sea and the onset of the North Atlantic Gyre 15–20 million years ago, and contact between them was then presumably precluded by geographic distance. Here we present genetic, morphological and archaeological evidence indicating that the North American sturgeon colonized the Baltic during the Middle Ages and replaced the native sturgeon there, before recently becoming extinct itself in Europe as a result of human activities. In addition to representing a unique transatlantic colonization event by a fish that swims upriver to spawn, our findings have important implications for projects aimed at restocking Baltic waters with the European sturgeon.

Sturgeon biodiversity and conservation

The two species of Atlantic sea sturgeon on either shore of the North Atlantic, Acipenser sturio in Europe and A. oxyrinchus in North America, probably diverged with the closure of the Tethys Sea and the onset of the North Atlantic Gyre 15–20 million years ago, and contact between them was then presumably precluded by geographic distance. Here we present genetic, morphological and archaeological evidence indicating that the North American sturgeon colonized the Baltic during the Middle Ages and replaced the native sturgeon there, before recently becoming extinct itself in Europe as a result of human activities. In addition to representing a unique transatlantic colonization event by a fish that swims upriver to spawn, our findings have important implications for projects aimed at restocking Baltic waters with the European sturgeon.

Altered gene expression and genetic damage in North American fish populations

Prelude to Sturgeon Biodiversity and Conservation E.K. Balon. Sturgeon Biodiversity and Conservation: An Introduction W.E. Bemis, et al. Part 1: Diversity and Evolution of Sturgeons and Paddlefishes. An Overview of Acipenseriformes W.E. Bemis, et al. Osteology and Phylogenetic Interrelationships of Sturgeons (Acipenseridae) E.K. Findeis. Phylogeny of the Acipenseriformes: Cytogenetic and Molecular Approaches V.J. Birstein, et al. How Many Species are there within the Genus Acipenser? V.J. Birstein, W.E. Bemis. Part 2: Biology and Status Reports on Sturgeons and Paddlefishes. Sturgeon Rivers: An Introduction to Acipenseriform Biogeography and Life History W.E. Bemis, B. Kynard. Past and Current Status of Sturgeons in the Upper and Middle Danube River K. Hensel, J. Holcik. Endangered Migratory Sturgeons of the Lower Danube River and its Delta N. Bacalbasa-Dobrovici. Present Status of Commercial Stocks of Sturgeons in the Caspian Sea Basin R.P. Khodorevskaya, et al. Species Structure, Contemporary Distribution and Status of the Siberian Sturgeon, Acipenser baerii G.I. Ruban. Endemic Sturgeons of the Amur River: Kaluga, Huso dauricus, and Amur Sturgeon, Acipenser schrenckii M.L. Krykhtin, V.G. Svirskii. Biology, Fisheries, and Conservation of Sturgeons and Paddlefish in China Q. Wei, et al. Biology and Life History of Dabrys Sturgeon, Acipenser dabryanus, in the Yangtze River P. Zhuang, et al. Observations on the Reproductive Cycle of Cultured White Sturgeon, Acipenser transmontanus S.I. Doroshov, et al. Contemporary Status of the North American Paddlefish, Polyodon Spathula K. Graham. Life History and Status of the Shovelnose Sturgeon, Scaphirhynchusplatorynchus K.D. Keenlyne. The Status and Distribution of Lake Sturgeon, Acipenser fulvescens, in the Canadian Provinces of Manitoba, Ontario and Quebec: a Genetic Perspective M.M. Ferguson, G.A. Duckworth. Lake Sturgeon Management in the Menominee River, a Wisconsin-Michigan Boundary Water T.F. Thuemler. Life History, Latitudinal Patterns, and Status of the Shortnose Sturgeon, Acipenser brevirostrum B. Kynard. Status and Management of Atlantic Sturgeon, Acipenser oxyrinchus, in North America T.I.J. Smith, J.P. Clugston. Atlantic and Shortnose Sturgeons of the Hudson River: Common and Divergent Life History Attributes M.B. Bain. Biological Characteristics of the European Atlantic Sturgeon, Acipenser sturio, as the Basis for a Restoration Program in France P. Williot, et al. Part 3: Controversies, Conservation and Summary. Sturgeons in the Aral Sea Ecological Catastrophe I. Zholdasova. Threatened Fishes of the World: Pseudoscaphirhynchus spp. (Acipenseridae) V.J. Birstein. Molecular Analysis in the Conservation of Sturgeons and Paddlefish I.I. Wirgin, et al. Sensitivity of North American Sturgeons and Paddlefish to Fishing Mortality J. Boreman. Alternatives for the Protection and Restoration of Sturgeons and their Habitat R.C.P. Beamesderfer, R.A. Farr. Threatened Fishes of the World: Scaphirhynchus suttkusi Williams & Clemmer, 1991 R.L. Mayden, B.R. Kuhajda. Threatened Fishes of the World: Scaphirhynchus albus (Forbes & Richardson, 1905) R.L. Mayden, B.R. Kuhajda. Sturgeon Poaching and Black Market Caviar: A Case Study A. Cohen. The Threatened Status of Acipenseriform Fishes: A Summary B.J. Birstein, et al. Species and Subject Index.

The Hudson River Estuary

Populations of marine, estuarine, and freshwater fish from highly urban and industrialized sites in North America often exhibit elevated prevalences of neoplastic, preneoplastic, and nonneoplastic hepatic lesions, and sometimes epidermal neoplasms compared to conspecifics from more pristine reference locales. Positive statistical associations with environmental concentrations of PAHs and other xenobiotics and experimental laboratory studies suggest a chemical etiology to these epizootics. Studies have investigated the expression of carcinogenically relevant genes, the extent of overall DNA damage, somatic cell mutations, germ line polymorphisms, and overall levels of genetic diversity in fish from these populations and other polluted sites. In general, elevated levels of cytochrome P4501A expression have been found in fish from contaminated locales; however, inhibition of gene induction has been seen in hepatic lesions and in normal tissue in fish from the most contaminated sites, perhaps due to genetic adaptation or physiological acclimation. Levels of bulky hepatic DNA adducts, as detected by 32P-postlabeling, are almost always elevated in fish from populations that are exposed to highly contaminated environments. However, levels of DNA adducts were not always predictive of the vulnerability to neoplasia of populations and species from polluted sites. Elevated levels of oxygen radical-induced DNA damage have been observed in hepatic tumors, preneoplastic lesions, and normal livers in a single species of flatfish from contaminated sites; however, the prevalences of these alterations in other species and at other polluted sites has yet to be evaluated. Frequent alterations in the K-ras oncogene have been reported in hepatic neoplasms in several species from highly contaminated sites and also in embryos that were experimentally exposed to oil-contaminated sediments. Studies also suggest that heritable germ line polymorphisms, altered allelic frequencies, and reductions in overall genetic diversity may have occurred in some highly impacted populations; however, the origin and functional significance of altered allelic frequencies have largely yet to be evaluated. In summary, feral fish appear particularly sensitive to DNA alterations from xenobiotics, perhaps due to their unusually high levels of exposure, relatively inefficient DNA repair, and the high frequency of polyploidy in some taxa and provide excellent models to explore the relationships between xenobiotic exposure and altered gene structure and expression.

Stock Composition of the New York Bight Atlantic Sturgeon Fishery Based on Analysis of Mitochondrial DNA

The Hudson River Estuary is a comprehensive look at the physical, chemical, biological, and environmental management issues that are important to our understanding of the Hudson River. Chapters cover the entire range of fields necessary to understanding the workings of the Hudson River estuary; the physics, bedrock geological setting and sedimentological processes of the estuary; ecosystem-level processes and biological interactions; and environmental issues such as fisheries, toxic substances, and the effect of nutrient input from densely populated areas. This book places special emphasis on important issues specific to the Hudson, such as the effect of power plants and high concentrations of PCBs. The chapters are written by specialists at a level that is accessible to students, teachers, and the interested layperson. The Hudson River Estuary is a unique scientific biography of amajor estuary, with relevance to the study of any similar natural system in the world.