Michael F. Tlusty

The benefits and risks of aquacultural production for the aquarium trade

Production of animals for the aquarium hobbyist trade is a rapidly growing sector of the aquacultural industry, and it will continue to become more important as restrictions are placed on collecting animals for the wild. Currently, approximately 90% of freshwater fish traded in the hobbyist industry are captively cultured. However, for marine ornamentals, the reverse is true as only a handful of species is produced via aquaculture technology. Given the future importance of aquaculture production of ornamental species, it is important to elucidate the benefits and risks for this sector. Thus, here the production of ornamental species is compared to the production of food species. The most notable difference is that the marine coastal environment is not currently utilized in the production of ornamental species. Thus, public opposition will not be as great since there is no direct impact on the marine environment. In assessing the benefits and risks of ornamental aquaculture production, the cases where further development should and should not be pursued are developed. In general, aquaculture production of ornamental species should be pursued when species are difficult to obtain from the wild, breeding supports a conservation program, there is some environmental benefit or elimination of environmental damage via the breeding program, or to enhance the further production of domesticated species. Aquaculture production of ornamental species should be avoided when it would replace a harvest of wild animals that maintains habitat, a cultural benefit, or an economic benefit.

Revealing the Appetite of the Marine Aquarium Fish Trade: The Volume and Biodiversity of Fish Imported into the United States

The aquarium trade and other wildlife consumers are at a crossroads forced by threats from global climate change and other anthropogenic stressors that have weakened coastal ecosystems. While the wildlife trade may put additional stress on coral reefs, it brings income into impoverished parts of the world and may stimulate interest in marine conservation. To better understand the influence of the trade, we must first be able to quantify coral reef fauna moving through it. Herein, we discuss the lack of a data system for monitoring the wildlife aquarium trade and analyze problems that arise when trying to monitor the trade using a system not specifically designed for this purpose. To do this, we examined an entire year of import records of marine tropical fish entering the United States in detail, and discuss the relationship between trade volume, biodiversity and introduction of non-native marine fishes. Our analyses showed that biodiversity levels are higher than previous estimates. Additionally, more than half of government importation forms have numerical or other reporting discrepancies resulting in the overestimation of trade volumes by 27%. While some commonly imported species have been introduced into the coastal waters of the USA (as expected), we also found that some uncommon species in the trade have also been introduced. This is the first study of aquarium trade imports to compare commercial invoices to government forms and provides a means to, routinely and in real time, examine the biodiversity of the trade in coral reef wildlife species.

Crawling to Collapse: Ecologically Unsound Ornamental Invertebrate Fisheries

Background Fishery management has historically been an inexact and reactionary discipline, often taking action only after a critical stock suffers overfishing or collapse. The invertebrate ornamental fishery in the State of Florida, with increasing catches over a more diverse array of species, is poised for collapse. Current management is static and the lack of an adaptive strategy will not allow for adequate responses associated with managing this multi-species fishery. The last decade has seen aquarium hobbyists shift their display preference from fish-only tanks to miniature reef ecosystems that include many invertebrate species, creating increased demand without proper oversight. The once small ornamental fishery has become an invertebrate-dominated major industry supplying five continents. Methodology/Principal Findings Here, we analyzed the Florida Marine Life Fishery (FLML) landing data from 1994 to 2007 for all invertebrate species. The data were organized to reflect both ecosystem purpose (in the wild) and ecosystem services (commodities) for each reported species to address the following question: Are ornamental invertebrates being exploited for their fundamental ecosystem services and economic value at the expense of reef resilience? We found that 9 million individuals were collected in 2007, 6 million of which were grazers. Conclusions/Significance The number of grazers now exceeds, by two-fold, the number of specimens collected for curio and ornamental purposes altogether, representing a major categorical shift. In general, landings have increased 10-fold since 1994, though the number of licenses has been dramatically reduced. Thus, despite current management strategies, the FLML Fishery appears to be crawling to collapse.

Health Evaluation of Leatherback Turtles (Dermochelys coriacea) in the Northwestern Atlantic During Direct Capture and Fisheries Gear Disentanglement

Abstract Health evaluations were conducted in the northwestern Atlantic for 19 leatherback turtles, which included 12 turtles directly captured as part of a satellite telemetry study and 7 turtles entangled in fishing gear. Assessment included physical examination; determination of heart rate and respiratory rate; and hematologic, plasma biochemical, nutritional, toxicologic, parasitologic, and microbiological investigations. Significant differences were found between directly captured and entangled turtles for curved carapace length, curved carapace width, blood urea nitrogen, chloride, sodium, triglycerides, relative heterophil count, relative monocyte count, relative and absolute eosinophil count, pH, bicarbonate, lead, and beta-hydroxybutyrate. Directly captured turtles showed evidence of mild respiratory acidosis. Significant differences were found between sexes for curved carapace length, curved carapace width, total protein, globulin, sodium, relative monocyte count, gamma-globulin, and anion gap. Relatively high blood concentrations of selenium and cadmium were found in all turtles.

Hematologic and plasma biochemical findings in cold-stunned Kemp's ridley turtles: 176 cases (2001-2005).

OBJECTIVE To document hematologic and plasma biochemical values for a large number of cold-stunned Kemps ridley turtles at the beginning of rehabilitation, to investigate differences in hematologic and plasma biochemical values of turtles that ultimately survived versus those that died, and to compare values of survivors during convalescence with initial values obtained at the time of admission. DESIGN Retrospective case series. ANIMALS 176 stranded, cold-stunned Kemps ridley turtles hospitalized between 2001 and 2005. PROCEDURES Hematologic and plasma biochemical values obtained at the time of admission were compared retrospectively for turtles that died versus turtles that survived. Initial results for survivors were compared with convalescent results obtained later in rehabilitation. RESULTS Turtles that died had significantly greater plasma concentrations of sodium, chloride, potassium, calcium, phosphorus, and uric acid than did turtles that survived. For survivors, values obtained during convalescence for BUN concentration and plasma calcium concentration were significantly greater than initial values obtained at the time of admission, whereas values obtained during convalescence for glucose, sodium, and uric acid concentrations were significantly lower than initial values. CONCLUSIONS AND CLINICAL RELEVANCE Cold-stunned Kemps ridley turtles may be affected by electrolyte derangements, dehydration, and decreased renal function. Hematologic and plasma biochemical evaluation of such turtles provided useful clinical and prognostic information during the rehabilitation process.

Metabolic and respiratory status of cold-stunned Kemp’s ridley sea turtles (Lepidochelys kempii)

Abstract“Cold-stunning” of sea turtles has been reported as a naturally occurring stressor for many years; however, the physiologic status of cold-stunned turtles has only been partially described. This study investigated initial and convalescent venous blood gas, acid-base, and critical plasma biochemical data for 26 naturally cold-stunned Kemp’s ridley sea turtles (Lepidochelys kempii) from Cape Cod, MA, USA. Samples were analyzed for pH, pCO2, pO2, bicarbonate, plasma osmolality, sodium, potassium, chloride, ionized calcium, ionized magnesium, glucose, lactate, and blood urea nitrogen using a clinical point-of-care analyzer. Data were corrected for the patient’s body temperature using both species-specific and more general correction methods. In general, venous blood gas, acid-base, and plasma biochemical data obtained for surviving cold-stunned Kemp’s ridley sea turtles were consistent with previously documented data for sea turtles exposed to a wide range of temperatures and physiologic stressors. Data indicated that turtles were initially affected by metabolic and respiratory acidosis. Initial pH-corrected ionized calcium concentrations were lower than convalescent concentrations, and initial pH-corrected ionized magnesium concentrations were higher than convalescent concentrations.

Host Susceptibility Hypothesis for Shell Disease in American Lobsters

Epizootic shell disease (ESD) in American lobsters Homarus americanus is the bacterial degradation of the carapace resulting in extensive irregular, deep erosions. The disease is having a major impact on the health and mortality of some American lobster populations, and its effects are being transferred to the economics of the fishery. While the onset and progression of ESD in American lobsters is undoubtedly multifactorial, there is little understanding of the direct causality of this disease. The host susceptibility hypothesis developed here states that although numerous environmental and pathological factors may vary around a lobster, it is eventually the lobsters internal state that is permissive to or shields it from the final onset of the diseased state. To support the host susceptibility hypothesis, we conceptualized a model of shell disease onset and severity to allow further research on shell disease to progress from a structured model. The model states that shell disease onset will occur when the net cuticle degradation (bacterial degradation, decrease of host immune response to bacteria, natural wear, and resorption) is greater than the net deposition (growth, maintenance, and inflammatory response) of the shell. Furthermore, lesion severity depends on the extent to which cuticle degradation exceeds deposition. This model is consistent with natural observations of shell disease in American lobster.

Exposures of Homarus americanus Shell to Three Bacteria Isolated from Naturally Occurring Epizootic Shell Disease Lesions

ABSTRACT Epizootic shell disease (ESD) is an emerging form of shell disease of the American lobster (Homarus americanus) that has had detrimental effects on the fishery in southern New England. Three bacteria commonly isolated from lesions of wild lobsters with ESD—a novel Aquimarina sp. (A. ‘homaria’ I32.4), a novel Rhodobacteraceae species (‘Thalassobius’ sp. I31.1) and a Pseudoalteromonas sp. (Pseudoalteromonas ‘gracilis’ ISA7.3)—were applied directly to normal and abraded juvenile lobster carapaces, and then monitored for persistence over time and for the development of shell-disease lesions at 3 different temperatures (10°C, 15°C, and 20°C). Without abrasion of the carapace, no lesions developed in the exposures. After abrasion and exposure with a pure culture of A. ‘homaria’ I32.4, lesions developed at all 3 temperature and A. ‘homaria’ was detected in the lesions of all animals tested. Surprisingly, ‘Thalassobius’ sp. I31.1 also colonized these lesions. A coexposure with all 3 bacteria also demonstrated lesion development and the persistence of A. ‘homaria’ I32.4 and ‘Thalassobius’ sp. I31.1. The bacterium P. ‘gracilis’ ISA7.3 was not able to persist in any of the challenged lesions. Abraded areas of the cuticle with no bacteria added directly were also colonized by A. ‘homaria’ and ‘Thalassobius’ sp., and moderate lesions developed; however, the directly exposed lesions were significantly more severe (P < 0.05). The bacterium A. ‘homaria’, but not ‘Thalassobius’ sp., was detected in spontaneous lesions that developed independent of any abrasion and/or bacterial exposures. A novel bacterium, ‘Candidatus Kopriimonas aquarianus’ was also detected in spontaneous lesions. This study shows that 2 bacteria isolated from ESD lesions of wild lobsters are able to persist in and act together as important components of lesion development on abraded surfaces of American lobsters. This indicates that they are likely major contributors to lesion development in the ESD polymicrobial infection and may represent significant pathogens of the American lobster.

Opportunities for Public Aquariums to Increase the Sustainability of the Aquatic Animal Trade

The global aquatic pet trade encompasses a wide diversity of freshwater and marine organisms. While relying on a continual supply of healthy, vibrant aquatic animals, few sustainability initiatives exist within this sector. Public aquariums overlap this industry by acquiring many of the same species through the same sources. End users are also similar, as many aquarium visitors are home aquarists. Here we posit that this overlap with the pet trade gives aquariums significant opportunity to increase the sustainability of the trade in aquarium fishes and invertebrates. Improving the sustainability ethos and practices of the aquatic pet trade can carry a conservation benefit in terms of less waste, and protection of intact functioning ecosystems, at the same time as maintaining its economic and educational benefits and impacts. The relationship would also move forward the goal of public aquariums to advance aquatic conservation in a broad sense. For example, many public aquariums in North America have been instrumental in working with the seafood industry to enact positive change toward increased sustainability. The actions include being good consumers themselves, providing technical knowledge, and providing educational and outreach opportunities. These same opportunities exist for public aquariums to partner with the ornamental fish trade, which will serve to improve business, create new, more ethical and more dependable sources of aquatic animals for public aquariums, and perhaps most important, possibly transform the home aquarium industry from a threat, into a positive force for aquatic conservation.

Trace Metal and Organochlorine Pesticide Concentrations in Cold-Stunned Juvenile Kemp's Ridley Turtles (Lepidochelys kempii) from Cape Cod, Massachusetts

Abstract Whole blood and keratin mercury concentrations, complete blood cell counts, and plasma biochemical health profiles were evaluated in 31 juvenile cold-stunned Kemps ridley turtles (Lepidochelys kempii) from Cape Cod, Massachusetts. In addition, plasma copper, zinc, selenium, and cadmium concentrations were measured for 16 of these turtles. Liver mercury concentrations were measured for 6 turtles that were dead upon acquisition or died during rehabilitation. Concentrations of 18 organochlorine pesticides were measured in plasma of 18 live turtles, and liver, kidney, fat, and brain of 3 deceased turtles. Metal levels were generally similar to those previously published for sea turtles, with mean values (wet weight) of 24 ng/g for blood mercury, 67 ng/g for liver mercury, 389 ng/g for keratin mercury, 690 ng/g for plasma copper, 2290 ng/g for plasma zinc, and 490 ng/g for plasma selenium. Cadmium was not detected in any sample. Organochlorine levels were generally low in comparison to values published for cold-stunned juvenile Kemps ridley turtles in the 1980s. Several significant correlations between metal levels, hematology, and plasma biochemical health parameters were detected; however, the cause of these correlations could not be determined. This study demonstrates that Kemps ridley turtles may be exposed to contaminants at a young age. Further investigation of the sources and effects of contaminants in juvenile sea turtles is warranted.