Chemicals cause inter-species mating
A new study has revealed hormone-mimicking chemicals released into rivers can impact the mating choices of fish. The chemical Bisphenol A (BPA) emits oestrogen-like properties, and it has been found to alter an individual’s appearance and behaviour, leading to inter-species breeding.
The research reveals the threat to biodiversity when the boundaries between species are blurred. Dr Jessica Ward from the University of Minnesota, led the study and focused on the impact of BPA on Blacktail and Red Shiner fish, which are found in rivers across the USA.
The team collected individuals of both species from two streams in the state of Georgia. The species were kept separated in tanks for 14 days, some of which contained BPA. On the 15th day, behavioural trials were undertaken as individuals from different tanks were introduced to each other. The scientists monitored any physiological or signalling differences the individuals displayed, such as colour, as well as any behavioural differences during courtship, such as mate choice.
Dr Ward concluded: “Our research shows how the presence of these manmade chemicals leads to a greater likelihood of hybridisation between species. This can have severe ecological and evolutionary consequences, including the potential for the decline of our native species.”
The BSAVA has opened submissions for the BSAVA Clinical Research Abstracts 2026.
