Guía práctica para el estudio del crecimiento de especies demersales en el Área ICES

Versión revisada 05-02-2015En el documento se presenta una síntesis de los métodos empleados para estudiar el crecimiento y la edad, mediante estructuras calcificadas (otolitos y vértebras), de las especies ícticas de interés comercial para la flota española en el área del ICES. El estudio de estas especies forma parte del requerimiento que la Comisión Europea ha establecido para el Programa Español de Recopilación, Gestión y Uso de Datos Pesqueros (PNDB) en base a los desembarcos nacionales, según establece la normativa vigente de la Unión Europea (UE). En este Programa está involucrado el Instituto Español de Oceanografía (IEO), y entre otros el proyecto BIODEMER, desarrollado en el Centro Oceanográfico de Vigo. Las especies objeto de estudio en este proyecto son: merluza ("Merluccius merluccius"), abadejo ("Pollachius pollachius"), congrio ("Conger conger"), faneca ("Trisopterus luscus"), gallineta ("Helicolenus dactylopterus"), locha ("Phycis blennoides"), maruca ("Molva molva"), maruca española ("Molva macrophthalma"), mendo ("Glyptocephalus cynoglossus"); incluyendo las especies de descarte: arete ("Chelidonichthys cuculus") y goyeta ("Microchirus variegatus"). Para complementar este documento se ha adjuntado el anexo: Fichas técnicas de Biología y crecimiento de 11 especies demersales en el área ICES, en el que se detallan para cada especie los protocolos aplicados en la interpretación de la edad. Para cada caso se incluye una revisión de la bibliografía existente, así como de los talleres e intercambios realizados sobre estudios de crecimiento y edad

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Genetic inference of demographic connectivity in the AtlanticEuropean hake metapopulation (Merluccius merluccius) over aspatio-temporal framework

Once the metapopulation structure of the European hake (Merluccius merluccius) has been outlined, temporal stability of its stock units and their connectivity pattern are key factors to understand its population dynamics and design appropriate management policies. Using five microsatellite markers from the European hake and an extensive sampling coverage within stocks, we have tested the connectivity pattern between the two managed fish stocks of this species, the Northern stock and the Southern stock, over the last decade. On the spatial domain, the non-significant genetic variance between stocks (FCT = 0.001, k = 1 gene pools) as opposed to the low but significant divergence within stocks (FSC = 0.008) suggests that demographic exchange occurs between stocks. On the temporal domain, the non-significant variation among years (FCT < 0.001) suggests that the genetic background within the Atlantic hake metapopulation did not change significantly over the last decade. The pattern of connectivity observed fits a classic Wright continuum model and the negative correlation between restriction to gene flow (FST) and migration rate (m) responds closely to theoretical expectations. No evidence of stable differences in gene diversity was observedbetweenstocks, whatis consistent withanintermittent andvariable intensity of bi-directionally exchange between them. The current pattern of connectivity indicates that uncoupling exists between actual management areas and the genetic commonality within this metapopulation. Nevertheless, the geographic segregation and the relative demographic independence of both stocks advocate for considering two sub-management units. A subsidiary stock assessment capable of modelling fishing effort upon stock interdependence would add up for their sustainability. Indeed, actual EU subsidiary management of both stocks matches social, economic and cultural needs as well as fishing capacity and fishing tradition of local fleets

Changes in size of European hake larvae and conversion factors for different preservation mediums

The objective of this study was to determine how preservation methods affect the standard length (SL, mm) of European hake larvae. We used five fixative methods: (i) freezing in seawater at −20°C; (ii) RNAlater at −80°C; (iii) 4% borax-buffered formalin; (iv) freezing with liquid nitrogen and (v) 95% ethanol. Standard length hake larvae were initially measured and individually fixed in each of the five fixatives. To evaluate the effect of the time preserved in each one, we obtained the SL of larvae for a second time after three different preservation periods: 15, 44 and 91 days. To assess the effect of initial size on final shrinkage, we analysed two groups of larvae born in captivity, 15 and 24 days post hatching respectively. Most shrinkage occurred within the first period of preservation in all fixatives, the preservation time having no effect on the percentage of shrinkage for any preservative. However, initial SL affects the percentage of shrinkage depending on the fixative used. We suggest five correlation equations to convert an initial SL into a final contracted size of hake larvae for each fixative.Postprin

Ejercicio de Lectura e Intercalibración de Otolitos y Vértebras 2015. Equipo BIODEMER

Se presentan los resultados del ejercicio de intercalibración 2015 de lectura de estructuras calcificadas (otolitos y vértebras) para las especies demersales requeridas en el marco del Programa nacional de recopilación, gestión y uso de datos del sector pesquero de España (PNDB)

age and growth of european conger eel (conger conger) in the north east atlantic using otoliths and vertebrae

A sample of 1107 fish served to age and to analyze growth of European conger eel (Conger conger) from NE Atlantic Ocean using otoliths and vertebrae