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When considering the biggest threats to marine ecosystems or biodiversity, we usually think about all the plastic waste we can see floating in our seas every summer, or about the world trade which, through its commercial ships, prevents cetaceans from keeping their route and often from breeding. The problems just mentioned are undoubtedly important, but we rarely stop to reflect on how fishing is the actual big threat, that risks turning our seas and oceans into empty pools. Yes, fishing, that primary activity that has provided sustenance to the human population for millennia. The first evidence of fishing activities has been discovered thanks to archaeological findings dating back to the Neolithic. We know that in ancient Egypt nets like ours were used to catch fish and that the Romans had begun to regulate this activity and to develop those fishing techniques that are still used today. So how is it possible that in 2021, despite all the progress made by mankind from Roman times to today, it is fishing that threatens the survival of marine biodiversity?

The world population has grown exponentially. Consequently, the demand has increased, as well as the consumption and, thanks to technological progress, the effective capacity of fishing vessels has also increased: if once a large part of fishing was carried out by traditional boats, today almost ¾ of the boats are motorized, larger and larger in number, to the point of talking about fishing fleets. A sad estimate shows that the demand for seafood will only decrease when there will be no more resources to satisfy it.

Furthermore, there is climate change, the effects of which are already being recorded in our seas and oceans. Waters are warming faster and faster, so that some streams are changing or even stopping, as in the case of the Gulf Stream. The acidification of the oceans, moreover, is an obstacle for the calcification process of marine organisms such as shrimps and oysters, which thus are becoming useless resources. Finally, this already critical situation is aggravated by non-regulated fishing, an activity that is eroding fish populations in an unsustainable way.

Reasoning in purely economic terms, fish biological populations have to be considered as renewable natural resources. This means that, even in the absence of human exploitation, the stock of these resources changes over time, until it reaches a balance within the ecosystem under consideration. When humans enter the ecosystem and exploit this resource, they alter its biological dynamics. Consequently, in order for the exploitation to be sustainable, it is necessary that the amount of resource extracted from the ecosystem is the same as the capacity of the same very resource to regenerate. If this does not happen, the stock declines until extinction.

This is exactly what is happening to fish resources. Nowadays there are no areas that are not subject to fishing activities, while on the contrary there are areas where fishermen’s nets are lowered several times during the same year: therefore, there is not enough space and time for fish resources to regenerate and compensate the exploitation. Unfortunately, in this case, we are not speaking in purely theoretical terms; all this happens in reality and is known as Fish dependence day. Fish dependence day is a date that symbolically identifies the end of the internal supply capacity of a country, including aquaculture, and the beginning of dependence on foreign imports. In 2020 this date for Italy was in the first days of April, and with every passing year, it moves back a few days.

Now, let’s think about the fact that our country (Italy) is located in the middle of the Mediterranean Sea: we should have plenty of fish all year round!

Considering that in 1990 domestic production was enough to sustain consumption until June/July, it is clear that this is a sign of suffering of the ecological status and sustainability: we are leading to the extinction of fishes and we are not doing anything to prevent this from happening.

The impacts of this unregulated fishing on fish stocks are divided into two categories: direct impacts include reduction in marine population size, changes in the structure of these organisms, mortality of non-target species (an estimated 30,000 sharks are killed every day due to nets) and modifications of the natural habitat of these species. Indirect impacts include changes in prey/predator relationships, modifications of energy flows and reductions in ecosystem resilience.

Moreover, we must not forget that when we import fish from developing countries, we are taking away from those populations their main source of protein, thus contributing to the increase of other phenomena such as malnutrition and an unbalanced diet.

So, what can we do to avoid the worst-case scenario? First of all, we need to adopt an ecosystem approach, i.e., we need to identify the species being fished as species that are part of a network of trophic interactions that are to be considered at the same time. There are then two levers on which to act: a top-down approach and a bottom-up approach.

The first approach involves rules and restrictions put in place by a country or a group of countries. At the international level, for example, the achievement of a totally sustainable and regulated fishery is a target of the SDG (sustainable development goal) 14, one of the goals of the Agenda 2030, the United Nations program of action signed in 2015 with which precise goals to be achieved by 2030 were set.

The second approach, however, involves us as consumers. Each of us must develop the awareness that with our choices we can affect not only the market but also the production systems. When we buy fish products, simply by reading the label, we can decide to buy the sustainable option. In this way we send a strong economic signal and as a result fishing activity will have to move towards more sustainable conditions.

The conservation of biodiversity and marine life is in our hands.

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