The past few decades have seen a pronounced increase in interest and attention to animal welfare and its management, as evidenced by growing public concern for animals’ quality of life; significantly more research with an explicit animal welfare focus (including a new discipline area of animal welfare science); and ongoing improvements in professional animal care standards and practices (e.g., [1
]). As interest in animal welfare has grown, so has the societal conviction that we should strive for the highest standards of animal care, and continually develop ways of improving the welfare of animals in all parts of our lives [3
]. High-quality zoos and aquariums typically seek accreditation by professional organizations, such as the Alliance of Marine Mammal Parks and Aquariums (AMMPA), the Association of Zoos and Aquariums (AZA), the European Association of Zoos and Aquaria (EAZA), and the European Association for Aquatic Mammals (EAAM). The animal welfare-related standards and guidelines of these organizations typically exceed governmental regulations [9
] (see, e.g., [10
]), but even with such shared high standards, there can be large variation in welfare outcomes [7
]. Moreover, not every facility chooses to participate in these organizations and, therefore, may not meet these same standards. Thus, legislation and regulations are important to ensure welfare protection for all animals in human care [9
The creation of such laws and regulations is a complex process during which policy-makers must navigate and balance a variety of competing interests, including personal values, political ideology, economic considerations, and practical feasibility [16
]. In addition, informed decision-making, by definition, requires an understanding of the facts relevant to the issue under consideration. In times of emergency, such as a disease outbreak or disaster at a nuclear power plant, governments may convene scientific advisory groups to quickly inform the government’s response [16
]. For other important but perhaps less urgent issues, there are numerous initiatives internationally to create accurate and unbiased syntheses of scientific information to inform policy-makers [16
]. Such credible scientific assessments of a topic, such as the Global Biodiversity Assessment [22
] and the Intergovernmental Panel on Climate Change [23
], can be powerful tools to inform policy and management discussions and initiatives [16
In recent years, the practice of housing and displaying killer whales (Orcinus orca
) in marine mammal facilities has received a lot of media attention and lobbying from anti-zoo organizations (e.g., [25
]), resulting in proposed legislative bans (e.g., [29
]). A recent paper in the Journal of Veterinary Behavior [31
] purported to review the state of knowledge regarding the welfare of killer whales in captivity, potentially providing a scientific assessment of the kind that could help legislators make informed decisions about this issue. Specifically, Marino et al. [31
] argued that, due to the complex needs conferred by their cognitive, emotional, and social characteristics, killer whales cannot thrive in traditional marine mammal facilities. Rather, they argued, captive killer whales exhibit abnormal behaviors and often die at an early age, likely due to chronic stress brought about by captive conditions.
In theory, comprehensive reviews of the research on the physiological, cognitive, behavioral, and social characteristics of a species, along with welfare indicators such as life expectancy, health, stress, behavioral issues, and so forth, should be extremely useful tools for informing discourse on animal welfare-related policy and management activities. Given that they are positioned to impact the legislative and regulatory decisions affecting these animals, it is critical that these assessments strive for an accurate representation of the state of the scientific knowledge about their topic. To do so, they must use sound and rigorous principles of scientific analysis and argumentation, and clearly communicate what is known (and not known) in order to give the public, policy-makers, and legislators the resources they need to participate in constructive dialogue and decision-making [16
]. Unfortunately, the Marino et al. [31
] paper falls short of these standards in a variety of ways, including problematic referencing, overinterpretation of the data, misleading word choice, and fallacious argumentation.
In the current paper, we highlight several of the major methodological flaws, biases, and misrepresentations of the scientific literature in Marino et al.’s [31
] review. Note that the specific examples discussed for each issue are not meant to be an exhaustive list of all instances in the paper, but rather are meant to be illustrative of repeated instances throughout their review. Note also that this critique is not intended as an explicit defense of, or argument for, keeping killer whales in captivity. In fact, we (the authors of this paper) hold disagreeing opinions on this topic and will not be taking a stance on this issue one way or the other. However, regardless of our disparate feelings about the underlying issue, we are strongly united in our belief that valid scientific evidence and argumentation is mandatory in order to have an accurate and productive discussion. We therefore offer this critique with the ultimate goal of increasing the level of evidence-based argumentation in the public, scientific, and legislative discourse surrounding this and similar issues.
In conclusion, the creation of good animal welfare-related practices and policies for any species are dependent on valid scientific information. Ideally, this information includes data on the behavioral, cognitive, physiological, and social characteristics of the species, along with known welfare outcomes for different environmental, veterinary, and behavioral practices relevant to their care. Because this information, by its very nature, will initially be spread among numerous scientific publications spanning a number of different disciplines, the creation of a credible, comprehensive review that gathers, explains, and contextualizes this body of knowledge can be an invaluable tool for informing discourse and decision-making relevant to these animals. Of course, to be credible and useful, such reviews must present the data in an objective and reliable manner, taking care to clearly communicate what is known, what is not known, what conclusions can be supported by the data, and what areas we are lacking the data needed to draw reliable conclusions.
The topics raised in Marino et al.’s [31
] review—e.g., life expectancy, stress, space, and whether the animals get enough physical, cognitive, and social simulation—are legitimate welfare issues for any animal under zoological care [45
]. Unfortunately, Marino et al.’s discussion of these topics falls far short of the kind of accurate and unbiased review of research needed to reliably inform public discourse and decision-making about best welfare practices for killer whales. Instead, the pervasive problems with flawed and misleading referencing, interpretation, and argumentation throughout Marino et al.’s [31
] paper make it impossible to determine the true state of knowledge of the issues raised, including whether there is reliable evidence regarding negative welfare indicators for killer whales, in which areas, and how best to address them.
Finally, the issues raised by our critique of Marino et al. [31
] go beyond the discussion of zoological practices regarding killer whales. The state of the scientific knowledge of a given topic is relevant to legislative, regulatory, and policy decisions in many areas [16
]. It is therefore incumbent upon scientists and science communicators to represent that scientific knowledge as completely, accurately, and objectively as possible [16
]. Misrepresentations of the information will lead to a biased and incorrect body of knowledge that, instead of informing advancements, will impede productive discourse and may ultimately result in misinformed, arbitrary, or even harmful decisions.