Multispecies hierarchies and capitalist value: Insights from salmon aquaculture

Research in animal geographies is increasingly paying attention to hierarchies and inequalities within and between nonhuman animals. The way that animals are valued differently and hierarchically within this growing body of scholarship has tended to focus on a range of biopolitical differences between and within species. Collard and Dempsey’s recent contribution, in contrast, points to the importance of hierarchy and difference in the valuation of nonhuman animals under capitalism. Their framework identifies five orientations of human and nonhuman bodies in relation to capitalist value, which in turn provides a heuristic to explore how capitalist accumulation produces and depends on differentially oriented natures. Our contribution to these debates – and to the Collard and Dempsey framework – draws on our ongoing research in Eastern Canada where salmon aquaculture is a growing yet highly contested industry. We focus on two instances of multispecies hierarchy and difference in and around the salmon cage that are central to this form of ocean-based production. In focusing on multispecies relations, we build on Collard and Dempsey's framework in two main ways. First, we show how valuation and devaluation reflect competing but relational capitalist interests, which rely on and produce different natures refracted through the logic of the nature/culture divide: Atlantic salmon are valued as game fish, and as the key species for Canada's aquaculture sector. Second, we show how capital's valuation of one species, in our case farmed salmon, implicates the valuation of others, namely sea lice and lumpfish. Our case studies extend Collard and Dempsey's framework by demonstrating how capitalist differentiation produces violence through and outside of commodification in terms of multispecies difference and hierarchy; the lives and futures of wild and farmed salmon, lumpfish and sea lice are entangled, and reflect relational and changing orientations to capitalist value over time.

Comparative Analysis of Pejerrey Fish (Odontesthes bonariensis) Gonadal Development During Two Consecutive Spawning Seasons in Relation to Sex Steroids and Temperature Variation in Cochicó Lake (Pampas Region, Argentina)

Cochicó belongs to “Encadenadas del Oeste” system of lakes being a typical water body of the Pampas region. The most abundant fish species in this lake is the pejerrey (Odontesthes bonariensis) valued due to the quality of its flesh and as a game fish. The aim of this study was to compare the gonadal stages of pejerrey during two consecutive spawning seasons (August to December) in relation to sexual steroids and temperature in this lake. In general, pejerrey gonadal development, the Gonadosomatic index and the plasma levels of estradiol and testosterone fluctuated in relation with temperature. In 2014 samplings, females started to ovulating in early August, with a peak during September-October and ending in December with many of them with atretic oocytes. However, in 2015, a marked delay in maturation was observed with ovulated fish only in October and December. This fact may be because the minors mean temperatures recorded in this year. For males, it was possible to find spermiating animals during the whole spawning season and only arrested animals in December. Unexpectedly, histological gonadal analysis revealed for the first time pejerrey with testis-ova, probably due to the intensive use of agrochemicals in this region.

A paradoxical knowledge gap in science for critically endangered fishes and game fishes during the sixth mass extinction

Despite unprecedented scientific productivity, Earth is undergoing a sixth mass extinction. The disconnect between scientific output and species conservation may be related to scientists studying the wrong species. Given fishes have a high extinction rate, we assessed the paradox between scientific productivity and science needed for conservation by comparing scientific output created for critically endangered fishes and game fishes. We searched 197,866 articles (1964–2018) in 112 journals for articles on 460 critically endangered fishes, 297 game fishes, and 35 fishes classified as critically endangered and game fish—our analysis included freshwater and marine species. Only 3% of the articles in the final database were on critically endangered fishes; 82% of critically endangered fishes had zero articles. The difference between the number of articles on game fishes and critically endangered fishes increased temporally with more articles on game fishes during the extinction crisis. Countries with 10 or more critically endangered fishes averaged only 17 articles from 1964 to 2018. Countries with the most critically endangered fishes are most in need of science. More scientific knowledge is needed on critically endangered fishes to meet the challenges of conserving fishes during the sixth mass extinction.

Toxicity assessment of gold ions and gold nanoparticles to golden perch larvae (Macquaria ambigua)

Golden perch (Macquaria ambigua) is a freshwater game-fish native to central and southeast Australia. Larvae of this fish species were used in two different types of experiments to evaluate the effects of short-term exposures (up to 6 days) to aqueous gold, 5 nm gold nanoparticles (AuNPs), or 50 nm AuNPs. Relative to the control, increased gold concentrations corresponded with yolk-sac edema (swelling). Larvae exposed to 50 μM of 5 nm AuNPs had yolk-sacs that were ~1.5 times larger resulting in the appearance of bent notochords. After two days of exposure, 100% mortality was observed. Total mortalities were <25% in the other larvae–gold systems, suggesting that these larvae can quickly adapt to the presence of gold. In terms of an oxidative stress response, the larvae from all systems did not express high enzymatic activity. The state of the gold determined how much could be taken up (or immobilised) by a larva. Aqueous gold and 5 nm AuNPs easily pass through cells; therefore, larvae exposed to these forms of gold contained the highest concentrations. Scanning electron microscopy confirmed that cells comprising the epithelium and fins contained AuNPs. Aqueous gold was reduced to nanometre-scale particles within cells. Comparatively, 5 nm AuNPs appeared to be aggregated within cells forming clusters hundreds of nanometres in size. On the contrary, 50 nm AuNPs were not observed within cells but were detected within larvae by (single particle) inductively coupled plasma mass spectroscopy, suggesting that these AuNPs were probably taken up through the mouth or gills. The results of the present study demonstrate that exposure to AuNPs had adverse effects on developing golden perch larvae. Additionally, these effects were dependent on the size of the AuNPs.

‘The Bold are the Sociable’: Personality, sociability and lateralized utilization of brain hemisphere in the juveniles of a megafish Deccan Mahseer (Tor khudree)

The present study explored relationships between personality traits; boldness, activity and sociability, and lateralized utilization of brain hemispheres in the hatchery reared juveniles of Deccan Mahseer (Tor khudree), a game fish inhabiting the rivers of central and southern India. Our results revealed a significant positive correlation between boldness and activity in this species when tested in isolation. However, boldness was positively correlated with the time spent near the individual conspecific but not with the individual alien invasive heterospecific tilapia (Oreochromis mossambicus). Although juvenile Deccan mahseer exhibited significant variation in the preference towards conspecific over heterospecific, no divergence in the utilization of right or left eye was seen while observing these individuals suggesting the lack of lateralized utilization of the brain hemispheres. Furthermore, laterality in visual preference failed to show any significant correlation with any of the personality traits tested in this species. Results are discussed in the light of the existing literature on the impact of life in homogenous hatchery conditions on the behaviour, personality traits and cognitive abilities of fishes.Significance statementThe present study is one of the first that focuses on personality and lateralization in Deccan Mahseers, an endangered freshwater megafish. We report a positive linkage between boldness and sociability but do not find any correlation of personality with lateralized utilization of brain hemispheres in diverse social contexts. These findings have implications in the conservation and cultivation of this ecologically, culturally and economically important indigenous fish.

Evaluation of an Educational Campaign to Improve the Conscious Consumption of Recreationally Caught Fish

Consumption guidelines are a common way of improving conscious consumption behaviors in areas where game fish are known to contain contaminants. However, guideline information can be difficult to distribute, and effectiveness difficult to measure. To increase the distribution and effectiveness of guideline information for the Detroit River, an educational campaign was launched in 2010, which included distribution of pamphlets with consumption information, posting of permanent signs at popular fishing locations, and hiring River Walkers to personally communicate with anglers. In 2013 and 2015, we conducted in-person surveys of active shoreline anglers to determine the effectiveness of education and outreach efforts. Results from the survey indicated that 55% of anglers were aware of the guidelines in 2013, and by 2015 36% had communicated the information to family or friends. However, anglers were often unwilling to reduce consumption of popular game species, despite high contaminant levels. Encouragingly, black anglers were most likely to supplement their diet with species lower in contaminants. Our results suggest that utilizing multiple educational strategies including reaching out directly to individual anglers may improve conscious consumption behavior among the targeted population, providing a template for educational campaigns to successfully target vulnerable populations.

Evaluation of the status of threatened catfish Bagarius bagarius (Hamilton, 1822) from the Padma and Meghna river stretches of Bangladesh

Bagarius bagarius (Hamilton, 1822), a freshwater catfish species, is important as food and game fish in Bangladesh, Bhutan, India and Nepal. In Bangladesh, it is known as Baghair and has been enlisted as critically endangered (CR) species in the IUCN Red List of Bangladesh 2000 and 2015, under the criteria A2cd version 3.1 mentioning declining trend in its population around 80% during the last 25 years (3 generation time). We studied the abundance of B. bagarius at 8 sites in three riverine habitats. We identified 8 individuals of B. bagarius from the Meghna river only (Shibpur site, Bhola Sadar). However, focus group discussion with fishers revealed that the species was frequently present in the catch from the river, although the abundance reduced considerably over the decade. We also found several other studies which reported the abundance of B. bagarius in different natural habitats. The findings from this study in combination with other published literature in the last 5 years indicated that the current status of B. bagarius in natural waters in Bangladesh do not fall below the threshold limits of CR species. Therefore, B. bagarius should be reclassified into a lower threatened status (but not Least Concern) than the current CR. Dhaka Univ. J. Biol. Sci. 28(1): 111-119, 2019 (January)

Improving the Conscious Consumption of Fish Through an Educational Campaign on the Detroit River (Michigan, USA)

Consumption guidelines are a common way to improve conscious consumption behaviors in areas where game fish are known to contain contaminants. However, guideline information can be difficult to distribute, and effectiveness difficult to measure. To increase the distribution and effectiveness of guideline information for the Detroit River, an educational campaign was launched in 2010, which included distribution of pamphlets with consumption information, posting of permanent signs at popular fishing locations, and hiring River Walkers to personally communicate with anglers. In 2013 and 2015, we conducted in-person surveys of active shoreline anglers to determine the effectiveness of education and outreach efforts. Results from the survey indicated that 55% of anglers were aware of the guidelines in 2013, and by 2015 36% had communicated the information to family or friends. However, anglers were often unwilling to reduce consumption of popular game species, despite high contaminant levels. Encouragingly, black anglers were most likely to supplement their diet with species lower in contaminants. Our results suggest that utilizing multiple educational strategies including reaching out directly to individual anglers may improve conscious consumption behavior among the targeted population, providing a template for educational campaigns to successfully target vulnerable populations.