The fish’s courtship is being hampered by the increasing presence of anglers in the water, according to scientists who study the behavior of squaretail grouper. This type of fish seems to run away when it sees the fishermen, losing its erotic mood.

A team led by scientists from the University of Lancaster in the United Kingdom found that fish become increasingly fearful of the presence of humans and as a result spend less time courting. Subsequently, the levels of their populations are affected and consequently the very continuity of their existence.

The speargun “kills” love

The study’s lead author Rucha Karkarey, a senior research fellow at Lancaster University, told CNN that researchers have been working in India’s Lakshadweep archipelago, north of the Maldives, for 10 years.

About five years ago, there was an intensive rise in fishing in the area. So researchers started noticing more phobic behavior in this particular fish a little later, about two years ago, Karkarey said.

This coincides with a major change in the way of fishing. Instead of fishing with hook and line from their boats, fishermen began to dive into the water and hunt the fish with spearguns, she added.

“Avoiding predators is an evolutionary mechanism that helps animals survive hunting,” Karkarey said.

This affects the reproduction of squaretail groupers. In particular, during breeding seasons, fish move from a certain area and gather to find a mate in another designated area a few times a year.

Humans perceiving this behavior aim to fish during those exact periods, i.e. reproduction, in order to catch more fish.

Hero fish sacrifice themselves for flirting

Interestingly, more “fit” male fish are more vulnerable to fishing, as they are more likely to express riskier courtship behavior to find a mate.

This involves defending a particular territory by refusing to cede it to a potential love rival or a fisherman, Karkarey explained.

Unfortunately, female fish choose their mates based on these qualities, which means that more fishing not only affects the population by removing the most suitable fish from the sea, but also reduces the reproductive ability of those that remain, as they are less suitable for companions and are more afraid of man.

Significant effects on fish populations

“In the long term, not only do fish decline because they ‘fall into fishing nets,’ but they reproduce less and less during these periods,” Karkarey said.

In many populations, these spawning times are the only time the fish mate, he pointed out.

While other research has suggested that fish can adapt to human intervention by choosing to congregate at different times or in different locations, Karkarey said this has not been seen in this area.

Finally, Karkarey wants to investigate whether these fearful fish find other ways to mate despite the behavioral changes the researchers observed.