Distribution patterns of the gooseneck barnacle (Pollicipes Pollicipes [GMELINn, 1789]) in the Cantabria region (N Spain): exploring different population assessment methods

The gooseneck barnacle Pollicipes pollicipes is a very valuable marine resource on the coasts of Spain and Portugal. To maintain the sustainable exploitation of this species, periodical large-scale population assessments are essential. Because of the heterogeneous distribution of these populations in aggregates, together with the difficulties associated with sampling (i.e., access to rocky reefs, wave exposure, high tides, etc.), there is a lack of studies in this regard. In light of these constraints, the coverage, biomass, and available stock of gooseneck barnacle were first estimated using a novel semiquantitative method along a 215-km long coast at 10 fishing zones and three tidal levels. This study contributed to the first assessment of the distribution variability of gooseneck barnacle in the Cantabria region (N Spain), as the first step toward a long-term monitoring goal. The proposed method is based on a general coverage (GC) estimation, by means of (1) quantitative coverage measurements on quadrats (50 cm350 cm) located along vertical transects covering the intertidal bandwidth and corrected by tidal level bandwidths, (2) semiquantitative coverage estimates in larger areas, including 5 m on either side of the quadrats along the transect. Biomass samples were collected at each sampling point by scraping the 50 cm350 cm quadrat and fresh weight of the samples was measured. This method arrives at the biomass estimates by means of a power regression model for the coverage?biomass relationship. The population distribution pattern along the coast was also explored separately, by commonly used (1) quantitative coverage estimates in quadrats with no bandwidth correction (sample coverage, SC) and (2) semiquantitative estimates, as in the proposed method (transect coverage, TC), both of which included biomass sampling. Biomass and standing stocks values obtained using GC were lower and consumed less sampling time than those obtained by TC, and particularly SC. The results suggest that the proposed method might be suitable for the assessment of P. pollicipes populations in large coastal areas, as it potentially avoids stock overestimation by detecting the spatial distribution heterogeneity and reduces the sampling time.The main Directorate of Fisheries of Cantabria (DFC) funded this work. We wish to thank DFC technicians, fishery guards and shell-fishermen for the specific support during the fieldwork, and the colleagues from DFC, who helped us in the laboratory works

Desarrollo de procedimientos aplicables a la evaluación del estado ecológico de las masas de agua costeras, sensu Directiva Marco del Agua

RESUMEN: En la presente tesis doctoral se desarrollan una serie de procedimientos para evaluar el estado de los diversos componentes bióticos (fitoplancton, macroalgas, invertebrados bentónicos) y abióticos (calidad fisicoquímica de las aguas) del medio marino en relación a la incidencia humana sobre el mismo. El objetivo de dichos procedimientos es dar respuesta a las exigencias establecidas en la Directiva Marco del Agua (Directiva 2000/60/CE) en lo que respecta a la evaluación del estado ecológico de las masas de agua costeras. En este sentido, además de ampliar el conocimiento existente sobre las características fisicoquímicas y biológicas de las masas de agua costeras de Cantabria, constituye una importante aportación tanto desde el punto de vista científico como desde el punto de vista de la gestión. Entre las contribuciones más destacadas de esta tesis cabría mencionar el desarrollo del Índice de Calidad de Fondos Rocosos (CFR) para la valoración de las comunidades de macroalgas costeras.ABSTRACT: In this PhD. Thesis, several procedures are developed to assess human influence on the status of the marine environment biotic (phytoplankton, macroalgae, benthic invertebrates) and abiotic (physicochemical quality of water) components. The purpose of these approaches is to meet the requirements of the Water Framework Directive (2000/60/EC) regarding the ecological status assessment of coastal water bodies. In this sense, besides increasing the existing knowledge on the physicochemical and biological characteristics of the Cantabrian coastal water bodies, it provides an important contribution both from a scientific and a management point of view. One of the most outstanding contributions of this thesis is the development of the Quality of Rocky Bottoms Index (CFR) for the assessment of coastal macroalgae communities

Application of Landscape Mosaics for the Biological Quality Assesment of Subtidal Macroalgae Communities Using the CFR Index

The assessment of anthropogenic impacts on coastal waters is an important task to accomplish under the European Water Directive Framework (WFD2000/60/EEC). Macroalgae are one of the biological quality elements that must be considered, but their assessment has been generally limited to intertidal areas. In this work the suitability of using landscape mosaicing techniques for the application of the CFR index in subtidal areas is analyzed. The study was carried out at two impacted areas (urban and industrial discharges) and at a control site located on the coast of Cantabria (N Spain). Underwater video transects of 5–20 m length were recorded by scuba divers at three depth ranges and treated with specific application software in order to build landscape mosaics of the assessment sites. Each mosaic was then introduced into a Geographical Information System, where all distinguishable macroalgae species were identified and their coverages measured. Subsamples of different areas (0.25 m 2 , 0.5 m 2 , 1 m 2 and 2.5 m 2 ) were extracted from each mosaic for the estimation of the indicators which compose the CFR index (characteristic macroalgae coverage, fraction of opportunistics and characteristic macroalgae richness). The stations located near the industrial discharge obtained bad qualities at all depths, while the stations located near the urban discharge and the control site obtained moderate to high qualities depending on depth ranges and sample sizes. Deeper samples produced lower CFR values, mainly associated to lower characteristic macroalgae coverages. On the other hand, bigger samples produced higher CFR values, mainly associated to higher richness values, and more accurate results, due to smaller variability in the replicates. The use of landscape mosaicing techniques have provided a new tool for the study of subtidal environments by allowing the visualization of extensive subtidal areas, which has been very useful for the application of the CFR index