Researchers from the University of Oviedo describe the drift of barnacle larvae in the Cantabrian Sea
November 13, 2013
The conclusions of the research, conducted in collaboration with the Center for Fishing Experimentation of the Principality of Asturias, have a direct effect on the management and conservation of the species
Researchers from the University of Oviedo and the Center for Fishing Experimentation of the Principality of Asturias have managed to describe, in an article published in the latest issue of the prestigious PLOS ONE journal, the effect of marine currents on barnacle larvae in the Cantabrian coast. It is the first study that explains how coastal outcrop, a system of marine currents, affects the development and survival of the larvae of the valuable crustacean. The conclusions have a strong bearing on the management and conservation of the species.
The research has been conducted as part of the PhD Thesis of Antonella Rivera, which has been directed by Professor José Luis Acuña of the Department of Biology of Organisms and Systems of the University of Oviedo. The research has been funded by the projects COSTAS (Ministry of Education and Science), DOSMARES (Ministry of Science and Innovation) and FRENTES, through the FICYT.
The research, published in the latest issue of the prestigious PLOS ONE journal, reveals the effect of marine currents on the offsprings of the valuable crustacean
For two years, the researchers have taken samples and data thanks to a landslide installed in the proximities of the port of Cudillero. The reference of genetic tests made by other teams in barnacles found at different points of the coast and the study of the series of winds registered by the National Meteorological Agency (AEMET) has allowed the researchers to prove movements of dozens of kilometers by the barnacle larvae from the place in which they are born to the point where they are recovered by the fishermen. The study published in PLOS ONE has proved that coastal outcrop, a system of currents that enrichens the coast with cold waters full of nutrients, plays a key role in this process.
The mysterious voyage of the barnacles
Barnacles have an average period of development that spans around four years. They spend the initial phase of the their life cycle as larvae that, in opposition to the adults, freely float on the waters. During this critical phase, the currents take the larvae to different places from where they were born. But the details of this voyage remain shrouded in msytery. How much distance do the larvae cover in this process of dissemination? Does this dissemination take place in all directions, or is there a preferred one? How many larvae are lost to the ocean without being able to go back to the rocks on the coast?
The study published in the PLOS ONE journal shows that coastal outcrop plays a key role in the dissemination and survival of barnacle larvae. The outcrop is a system of currents that takes to the coast and the surface the deepest and coldest layers of water, very rich in nutrients. In the Cantabrian Sea, this phenomenon takes places when the wind blows from the north-east during the summer, precisely during the period when barnacles mate and produce larvae.
The data recovered in the proximities of the port of Cudillero has allowed the researchers to demonstrate that the larvae are moved dozens of kilometers to the west during a normal year of outcrop, but only a few kilometers to the east during a year without outcrop.
The researchers checked the analysis of genetic similarities conducted in barnacles found in different points of the coast, which confirms the movement of the larvae and the dependency of these populations on the contribution of genes from eastern zones. Moreover, the calculations of the currents indicate that, when there is no outcrop, the majority of barnacle larvae are lost in the open sea. Nevertheless, the data confirms that if during a summer the wind blows consistently and the outcrop is active, more barnacles than usual will be fished four years later.
Implications for the management of the species.
The results of the research have a direct bearing on the management and conservation of the species. On the one hand, they allow for an explanation and prediction of the fluctuations on the production of barnacles. On the other hand, they indicate that the way in which barnacles are managed in a specific zone may affect other areas to the west, due to the dissemination of larvae caused by the outcrop.
The campaign of extraction of barnacles in Asturias establishes that the fishermen of each are have exclusive rights over the exploitation of their zone, in exchange for a compromise in the co-management of the resource. Apart from respecting bans and quotas, this compromise demands from the fishermen an exhaustive detail of the captures, which has a great scientific value. For around its 20 years of life, this management system has allowed for the sustainable exploitation of this species in the Principality.
Authors of the article
Antonio F. Pardiñas
Lucía García Flórez
José Luis Acuña
Asturian fishermen collecting barnacles in the Cantabrian Sea. PHOTO: ANTONELLA RIVERA.