Stephen S. Crawford

Global introductions of salmon and trout in the genus Oncorhynchus: 1870-2007

The purpose of this review is to provide a global perspective on Oncorhynchus salmonine introductions and put-and-take fisheries based on modern stocking programs, with special emphasis on freshwater ecosystems. We survey the global introductions of nine selected salmonines of the genus Oncorhynchus: golden trout, cutthroat trout, pink salmon, chum salmon, coho salmon, masu/cherry salmon, rainbow trout/steelhead, sockeye salmon/kokanee, and chinook salmon. The information is organized on a geographical basis by continent, and then by species and chronology. Two different objectives and associated definitions of ‘success’ for introductions are distinguished: (a) seed introduction: release of individuals with the purpose of creating a wild-reproducing, self-sustaining population; and (b) put-and-take introduction: release of individuals with the purpose of maintaining some level of wild population abundance, regardless of wild reproduction. We identify four major phenomena regarding global salmonine introductions: (1) general inadequacy of documentation regarding introductions; (2) a fundamental disconnect between management actions and ecological consequences of introductions; (3) the importance of global climate change on success of previous and future introductions; and (4) the significance of aquaculture as a key uncertainty in accidental introductions. We conclude this review with a recognition of the need to terminate ongoing stocking programs for introduced salmonines worldwide.

Cause and Effect of Parental Care in Fishes: An Epigenetic Perspective

Publisher Summary This chapter presents an analysis of concepts associated with parental care in fishes, using selected examples. It gives an overview of historical trends in recent research, along with possible explanations of how these trends formed. The chapter focuses on the mechanisms that may be responsible for perceived patterns associated with parental care. The chapter aims to (1) examine the diversity of parental care in fishes, (2) describe an evolutionary model of the life history of fishes, with emphasis on reproduction, (3) present a simple concept of individual energy expenditures associated with reproduction, within the context of an integrated life-history model for fishes, (4) analyze the definitions and assumptions that have been associated with parental care, within the context of the energy expenditure model mentioned previously, (5) describe the focus of research on parental care in fishes over the past several years, and (6) develop hypotheses to describe causal mechanisms that could help to explain the evolution of reproductive styles, including parental care.

Alternative life histories of the genus Lucania: 3. An ecomorphological explanation of altricial (L. parva) and precocial (L. goodei) species

Important differences were observed in the early ontogenies of Lucania parva and Lucania goodei. These differences can be explained in terms of the altricial-precocial model of speciation. Lucania parva can be recognized as an altricial form that produces many eggs with relatively little yolk investment, compared to the more precocial L. goodei. Many of the differences observed in embryo, larva and juvenile specimens appear to be related to these differences in gamete investment. Accelerated developmental rates in the precocial form suggest that paedomorphosis is an important proximate mechanism in the bifurcation of alternative life-history styles in this genus. Some morphological characteristics, such as vitelline circulation and body shape, may be transformations associated with the particular environmental conditions in which the animals must develop and survive. Our observations suggest that these two species in the genus Lucania have followed different ontogenic trajectories in response to prevailing environmental conditions.

Alternative life histories of the genusLucania: 1. Early ontogeny ofL. parva, the rainwater killifish

SynopsisThis is the first of three papers devoted to the description and interpretation of early morphological development in altricial and precocial species within the genusLucania. This study focussed on the early life history of the rainwater killifish,Lucania parva. Reproductively mature specimens were collected in brackish impoundments of the St. Marks National Wildife Refuge in northwest Florida, and transported to the laboratory where they served as brood stock for specimens described in this study. Laboratory-reared offspring ofL. parva were described according to the saltatory theory of ontogeny, which gives a sampling design based on morphological, rather than chronological, progression. The morphological development of these offspring is described on the basis of detailed illustrations, photomicrographs, and measurements of mensural and meristic characters. This account of early ontogeny, in combination with a corresponding study on the early ontogeny of the bluefin killifish,L. goodei (Crawford & Balon 1994a), establishes the empirical basis for an altricial-precocial life history model (Crawford & Balon 1994b).

Alternative life histories of the genusLucania: 2. Early ontogeny ofL. goodei, the bluefin killifish

This is the second of three papers devoted to the interpretation of morphological development in altricial and precocial species within the genus Lucania. The focus of this paper was the early life history of the bluefin killifish, Lucania goodei. Reproductively mature specimens were collected in the run below Newport Spring, north of St. Marks National Wildlife Refuge in northwest Florida. These specimens were transported to the laboratory, where they served as brood stock for specimens described in this study. Offspring were reared under controlled conditions and were described according to the theory of saltatory ontogeny, which gives a sampling design based on morphological, rather than chronological, progression. The morphological development of these offspring is described on the basis of detailed illustrations, photomicrographs, and measurements of mensural and meristic characters. This account of early ontogeny, in combination with a corresponding study on the early ontogeny of the rainwater killifish, L. parva (Crawford & Balon 1994a), establishes the empirical basis for an altricial-precocial life history model (Crawford & Balon 1994b).

The Ecology of Body Size and Depth Use by Bloater (Coregonus hoyi Gill) in the Laurentian Great Lakes: Patterns and Hypotheses

Deepwater ciscoes (genus Coregonus, subgenus Leucichthys) radiated into six phenotypes that occupy different depths in the Great Lakes, based upon body size and lipid content. Large, lipid-dense ciscoes occupy greater depths than small, lean ciscoes. This relationship is observed between adults and juveniles of the most prevalent deepwater cisco, the bloater (C. hoyi Gill). Lipid-dense adult bloaters are restricted to the hypolimnion, whereas lean juveniles are found primarily in the epilimnion. This article critically reviews, synthesizes, and provides hypotheses from the literature on the ecology of body size and depth use of bloater. Factors influencing depth use in bloater are categorized by Frys (1971) environmental factors. The case is made for two parsimonious hypotheses to explain the depth distribution by body size of bloater: (1) the optimal foraging-antipredation (OFA) hypothesis, and (2) the mass-specific metabolism hypothesis. The OFA hypothesis relates abundance of piscivores with abundance and extent of diel vertical migration of bloater. The mass-specific metabolism hypothesis relates body size to density-dependent growth, metabolism, swimming activity and hence depth distribution of bloater. Follow-up hypotheses and predictions are presented and may broaden our understanding of trophic ecology and adaptive radiation of deepwater ciscoes in the Great Lakes.

Consistency of COSEWIC species at risk designations: freshwater fishes as a case study

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) is responsible for the assessment of Canadian wildlife at risk. The COSEWIC assessment process is primarily based on five quantitative criteria developed by the International Union for the Conservation of Nature, but allows for further modification of designations under certain conditions. This study investigated the consistency of designations predicted using the quantitative COSEWIC criteria compared with observed designations reported by COSEWIC. A total of 49 COSEWIC designations for freshwater fishes from 2000 to 2007 were compared for consistency in decision-making. Overall, there was a 57.1% agreement between predicted and observed designations. A substantial number (35.1%) of COSEWIC designations were downlisted from “Endangered” or “Threatened” without sufficient explanation to justify the modifications. For the cases of uplisting, these differences were associated with qualitative criteria not effectively represented in our a...

Indigenous Principles of Wild Harvest and Management: An Ojibway Community as a Case Study

In colonial nations such as Canada, there have been increasing requirements for governments to engage directly with Indigenous communities regarding their rights and interests in natural resource management generally, with specific focus on the role of Indigenous knowledge systems in harvest management decision-making (Tikina et al.2010). Canadian courts have repeatedly focused on two factors with extremely important consequences for the Nation-to-Nation relationships that exist between the Crown and the Indigenous communities: (1) Indigenous rights must be reconciled with other government responsibilities including justified infringements for the often ill-defined concept of ‘conservation’ (Crawford and Morito 1997; Ayers 2005; Nadasdy 2005), and (2) the ‘honour of the Crown’ must be maintained when consulting Indigenous communities, especially with regard to management decision-making about their natural resources (Morito 1999; Slattery 2005). Given the legal necessities for a Eurocentric government to engage in honorable and meaningful consultation with Indigenous communities about conservation ethics and natural resource management, it remains to be seen how these Indigenous-Western science cross-cultural consultations should be undertaken (Crawford et al.2010). The trend to date has largely been the domination of Western Science over Indigenous knowledge systems (in the sense described by Pentland 1995); circumstances in which Indigenous knowledge holders might be requested to provide information to scientists/managers who would evaluate it for reliability and utility before deciding whether to incorporate in a science-based management program (McGregor 2004; Clark and Slocombe 2009; Lyver et al.2009). Some scholars have suggested that conflict caused by this kind of cultural domination could be reduced if governments and Indigenous communities re-initiated their discussions with an examination of similarities and differences in principles regarding ‘conservation’ and ‘natural resource management’ (Ratner and Holen 2007; Ebbin 2011; Watson et al.2011). In this way, the communities could develop a structured and respectful dialogue about wild harvest management in the spirit of reconciliation and productive collaboration. There have been numerous attempts by Western scientists to reach internal consensus on general principles for natural resource management (Holt and Talbot 1978; Christensen et al.1996; Mangel et al.1996; Dale et al.2000), habitat management (Lindenmayer and Nix 1993; Botsford et al.2003; Naiman and Latterell 2005), harvest management (FSC 1996; Heissenbuttal 1996; Lauck et al.1998; Fowler 2003; FAO 2001; Gonzalez-Laxe 2005; Utne 2006; Shelton and Sinclair 2008; Francis et al.2007; MSC 2010) and biodiversity/endangered species management (Walters 1991; Tilman 1999; Ebbin 2011). Although the practice of ‘defining principles for resource management’ is not something that Indigenous societies typically engage in, there have been many attempts to survey and understand Indigenous values and social norms in this regard (Ratner and Holen 2007; Turner and Berkes 2006; Watson et al.2011). For example, Alcorn (1993) offered a general treatise on the relationship between Indigenous worldviews and the Western idea of ‘conservation.’ Berkes et al. (1998) explored fundamental properties of ecosystem-like concepts in Indigenous cultures. In the 2011 ‘Principles of Tsawalk,’ Umeek (E. Richard Atleo), a hereditary Nuu-Chah-Nulth chief, discussed his culture’s principles of Recognition, Consent, and Continuity and their important role in maintaining balance—in contrast to the global consequences of Western ‘sustainable’ development. Prober et al. (2011) characterized the principles of Australian Aboriginal ecological calendars and indicators and evaluated their possible interaction with Western social-ecological systems for natural resource management. Over the past decades, a growing body of community-based collaborative studies has provided more depth and insight into the structure and function of traditional Indigenous knowledge systems and their associated decision-making processes for harvest management (e.g., Feit 1986; Brightman 1993; Horstman and Wightman 2001; Ayers 2005; Castleden et al.2009; Lyver et al.2009; Moller et al.2009; Bilbao et al.2010). However, as Jones et al. (2010) caution, researchers must always be careful to consider Indigenous community-based value systems as spatially and temporally local expressions of their culture. Efforts to identify general Indigenous ‘principles’ of natural resource management must be tempered by conscious recognition that (1) ‘principles’ are social constructs which are deeply embedded in cultural and social norms that are typically complex and subtle to the outsider (Houde 2007; Peloquin and Berkes 2009), and (2) Indigenous cultures and worldviews are inherently more diverse than the relatively homogenous standards of Western science (although see a provoking challenge of this assumption about scientific homogeneity by Watson-Verran and Turnbull 1995). The goal of our investigation was to develop and demonstrate a process for engaging with Indigenous communities to inquire about the structure and function of social norms in their culture that could relate to Western ‘principles’ for natural, renewable resource management. In order to achieve this goal, we worked in partnership with a sponsoring Ojibway community on a case study to employ community-based, participatory research methods with traditional people who were most familiar with social norms for harvest management.

Effect of information availability on assessment and designation of species at risk.

Information required to evaluate the extent to which species are at risk of extinction is usually limited and characterized as highly uncertain. In this context, we define information availability as the presence or absence of information used to determine the value of an ecological variable. We examined which of three hypothetical approaches best matched how levels of risk are assigned to species: (1) precautionary approach in which analysts designate levels of risk regardless of the amount of information available, (2) worst-case approach in which analysts assign the maximum level of risk possible from the criteria, and (3) insurance approach in which analysts assign poorly known species to a high-risk category when little information is available. We used the quantitative assessment criteria of the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as a case study. We created a binary (0/1) matrix of all 2.4192 × 10(7) logical combinations of available information for the 14 ecological variables included in the quantitative criteria. We processed each combination of information availability represented in the matrix with a computer algorithm designed to emulate COSEWIC decision-making rules. Low information availability was associated with a relatively high frequency of not being able to assign a candidate taxon to a risk category, which does not follow the precautionary principle. Information availability and the level of risk assigned to species were directly related, which is associated with the worst-case approach, and counter to the insurance approach. Our results suggest that information availability can have a major effect on the level of risk assigned to a species. We recommend a conscious determination of whether such effects are desired, and we recommend the development of methods to explicitly characterize and incorporate information availability and other sources of uncertainty in decision-making processes.

A Mathematical Technique for Estimating Blastodisc:Yolk Volume Ratios instead of Egg Sizes

Egg size alone is a poor and misleading variable in life-history studies. A mathematical technique for estimating yolk and blastodisc volume ratios in fishes, a much more meaningful character, is generated from first principles. The technique is demonstrated with an example of early ontogeny in fishes of the genus Lucania (Pisces: Cyprinodontidae). Wild, adult rainwater killifish, Lucania parva, and bluefin killifish, L. goodei, were collected in Florida and transported to the laboratory, where offspring were reared under controlled conditions. Offspring were sampled at the onset of cleavage, for simple measurements of yolk and blastodisc morphology. Application of mathematical equations allowed estimates of yolk and blastodisc volumes in the two species. No significant differences were found in clutch size, blastodisc volume, or egg density; however, significant differences existed in the absolute yolk investments, and blastodisc:yolk volume ratios. These differences in reproductive investment within the genus Lucania are interpreted by the altricial-precocial life-history model as a possible causal mechanism in the evolution of species within this genus. The mathematical equations presented in this study enabled us to partition reproductive investment into components that are more biologically meaningful than simple ‘egg size’.