Parada, J. M., Outeiral, R., Iglesias, E., and Molares, J. 2012. Assessment of goose barnacle (Pollicipes pollicipes Gmelin, 1789) stocks in management plans: design of a sampling program based on the harvesters' experience. – ICES Journal of Marine Science, 69: 1840–1849. Management plans of coastal marine resources require a wealth of information on socioeconomic topics, harvesting activities, population dynamics, and stock status. Moreover, the information provided by technical experts must take into account the needs of the managers. It must also adapt to schedules to serve a useful purpose. In many cases, the methodologies used by research teams are not directly applicable as they may be too complicated, aimed at specific objectives related to basic scientific work, or too costly to apply to long-term monitoring of extensive shellfish beds. Also, rocky coastlines exposed to heavy wave action preclude the use of sampling techniques that involve time-consuming data collection. This paper proposes a quick and simple methodology for gathering data in the field, based on the knowledge of the harvesters, to obtain stock assessments in keeping with their information needs. This methodology uses coverage percentage as an abundance index and weighting factor for the biometric information gathered from 50 specimens in each sampling. The sampling design uses the knowledge of the harvesters to define homogeneous strata. The results are in agreement with both the scientific-technical knowledge and the harvesters' knowledge of the populations being analysed.

No abstract

Owing to the peculiar morphology of the goose barnacle Pollicipes pollicipes (Gmelin, 1789), many different biométrie variables have been used in its study. The lack of a standard morphological variable makes it difficult to compare results from different authors. This aspect takes on even greater importance, since the goose barnacle is a commercially exploited species and must be regulated with clear-cut technical measures related to its biology. The need to measure a large quantity of specimens in the management and control of the fishery calls for a biométrie variable that can be processed easily and requires little training. The base of the rostrum and the apex of the subcarina form two conspicuous clefts in the capitulum of the goose barnacle, allowing a calliper to be fitted quickly and easily. Tbe results of this study showed that tbe diameter of the base of the capitulum (DBC), defined as the distance between these two clefts, may be considered a consistent variable both when the same specimen is measured by two different technicians and when the measurements taken from a fresh specimen are compared with the measurements taken after the specimen has been frozen and then thawed. In order to make comparisons easier, two linear equations have been found to relate DBC and two of the more usual biométrie variables: rostral-earinal distance (RC) and capitulum height (CH). The mean length at sexual maturity was also calculated in terms of DBC (13.35 mm) for specimens collected on the Gaüeian coast (NW Spain). RESUMENDebido a la especial morfología del percebe Pollicipes pollicipes (Gmelin, 1789), en el estudio de esta especie se ha empelado una gran variedad de variables biométricas. La falta de un parámetro morfológico estandarizado dificulta el estudio de la especie y la comparación entre trabajos dê ) 1528 J. M. PARADA ET AL. distintos autores. Este aspecto adquiere más importancia al tratarse de una especie sometida a explotación comercial que se debe regular con medidas técnicas claras y relacionadas con su biología. La necesidad de medir una gran cantidad de ejemplares en la gestión y el control de la pesquería requiere de una variable biométrica fácil de medir y que precise poco entrenamiento para su procesado. La base del rostro y el ápice de la subcarena constituyen dos hendiduras conspicuas en el capítulo de los percebes que permiten fijar un calibre de forma rápida e inequívoca. Los resultados de este estudio mostraron que el diámetro de la base del capítulo (DBC), definido como la distancia entre estas dos hendiduras, puede considerarse una variable consistente tanto cuando un mismo ejemplar es medido por dos personas diferentes, como cuando se comparíin las medidas tomadas en fresco con las obtenidas tras la descongelación de los ejemplares. Para facihtar las comparaciones entre estudios, se han encontrado dos ecuaciones lineales que relacionan el DBC con otras dos variables biométricas usuales: distancia rostro-carena (RC) y altura del capítulo (CH). También fue calculada la talla de madurez sexual...

Environmental variables are known to regulate the reproductive output of marine intertidal organisms, but typically these variables are studied as averages and interpreted at a macroscale level. Along 200 km of coast in NW Iberia, great variability in the reproductive activity of the stalked barnacle Pollicipes pollicipes was found among 7 different locations. We found the highest number of broods reported to date in this species and suggest a more realistic method of predicting reproductive success that takes into account sea surface temperature (SST). At these same locations, we studied 13 yr of SST, thermal upwelling index (UI), ground skin temperature and chlorophyll a (chl a) satellite data, using spectral analyses to partition their temporal variability over ecologically relevant time scales. SST played the most relevant role as an environmental driver, explaining 48% of the variability in the proportion of breeding individuals (BI), but the SST-BI goodness-of-fit decreased sharply northwards. Variance-partitioning analyses indicated that cycles between 20 and 100 d in SST and UI were more important southwards, which is consistent with a latitudinal gradient in upwelling intensity and frequency along this coast. Thus, we found better biophysical coupling towards the south, where shorter fluctuation time scales in SST match the gonadal development period (around 1 mo). This pattern may explain the spatial variability in the strength of association between key environmental variables and the reproductive cycle of coastal species along their distribution range.