No abstract

Ontogenetic changes in the relative growth of males and females of the spider crab Maja squinado were analyzed and related to their reproductive (maturity) status in order to define criteria to assign individuals to each growth phase. The sampling was carried out in two different areas of southern Galician waters, northwestern Spain, in shallow water (�10 m) with mixed rocky-sandy bottoms (juvenile and postpubertal adult areas) and deep water (�20 m) with soft bottoms (adult habitat). A Principal Component Analysis (PCA) of morphometric variables and a nonhierarchic K-means cluster of PCA scores differentiated two morphometric groups defined as juvenile and adult phases. A significant change in allometry of cheliped size was detected in juvenile males with a break point at a 109-mm carapace length (CL). This point may indicate a change in the relative growth of juveniles, separating the immature and adolescent phases. Histological analysis of a subsample of males showed that sperm were present in most adolescent crabs, but not in immature crabs. Bivariate morphometric linear discriminant functions allow for the identification of juvenile and adult males (classified previously by K-means cluster) with over 99% correct classification using CL and the length or height of the right cheliped. Carapace length at the onset of sexual maturity was estimated to be 132.7 mm (50% of adult males), although in a broad range, 112-165 mm, the size of juveniles and adults overlap. The life history of male spider crabs shows 3 phases differentiated by the relative growth rate of chelipeds separated by two 2 critical molts: prepubertal molt (immature-adolescent) determines a slight increase in allometry, and pubertal or terminal molt (adolescent-adult) determines an increase in the relative size and allometry of chelipeds and the onset of functional maturity. Females showed only 2 phases separated by the terminal molt. Growth of chelipeds in females showed no changes in allometry and was similar to juvenile males. Juvenile females presented a smaller relative width and a higher allometry of the abdomen with regard to adult females. Unlike juvenile females with a flat abdomen, adult females with a domed abdomen have well-developed pleopods, gonads, and seminal receptacles. Carapace length at the onset of sexual maturity was estimated to be 130.4 mm (50% of adult females). The range of overlap of the size of juveniles and adults (114-143 mm) was smaller than in males.

Coastal ecosystems and artisanal "sheries show a great complexity due to the high number of human factors that in#uence their functioning and to the number of components involved in the "shing activity. Moreover, a great number of stocks exploited by coastal artisanal "sheries are invertebrates with a strong and persistent spatial structure and a population dynamics that do not "t the "n"sh models. The present state of the artisanal coastal "sheries in Galicia (NW Spain) is analyzed, presenting di!erent symptoms of a general state of overexploitation derived from the mismatch between management (derived from models designed for industrial "n"sheries) and the biological and socioeconomic context. We propose to modify the strategies of research to use inexpensive and rapid methodologies and introduce the "shers' ecological knowledge. A new management policy is outlined based in the establishment of territorial users' rights, the involvement of "shers in the assessment and management process, and the use of protected areas and minimum sizes as key regulation tools.

Tunas and their relatives dominate the world's largest ecosystems and sustain some of the most valuable fisheries. The impacts of fishing on these species have been debated intensively over the past decade, giving rise to divergent views on the scale and extent of the impacts of fisheries on pelagic ecosystems. We use all available age-structured stock assessments to evaluate the adult biomass trajectories and exploitation status of 26 populations of tunas and their relatives (17 tunas, 5 mackerels, and 4 Spanish mackerels) from 1954 to 2006. Overall, populations have declined, on average, by 60% over the past half century, but the decline in the total adult biomass is lower (52%), driven by a few abundant populations. The trajectories of individual populations depend on the interaction between life histories, ecology, and fishing pressure. The steepest declines are exhibited by two distinct groups: the largest, longest lived, highest value temperate tunas and the smaller, short-lived mackerels, both with most of their populations being overexploited. The remaining populations, mostly tropical tunas, have been fished down to approximately maximum sustainable yield levels, preventing further expansion of catches in these fisheries. Fishing mortality has increased steadily to the point where around 12.5% of the tunas and their relatives are caught each year globally. Overcapacity of these fisheries is jeopardizing their longterm sustainability. To guarantee higher catches, stabilize profits, and reduce collateral impacts on marine ecosystems requires the rebuilding of overexploited populations and stricter management measures to reduce overcapacity and regulate threatening trade.

The goose barnacle, Pollicipes pollicipes, is an intertidal cirripede that lives attached to rocks on very exposed shores, forming dense aggregations. It occurs in the northeast Atlantic (from 48 to 14 • N). Commercial fisheries have been developed in several countries, but except for a short-lived local consumption, most of the production is traded in the Spanish market, where the price can reach ?80/kg in first-sale auctions. This species shows a strong spatial structure, constituting metapopulations with local adult populations sharing a common larval pool. Advection of larvae depends largely of oceanographic conditions that govern larval transport and survival. In Galicia (NW Spain), the regional government regulations promote a co-management system between fishers' organisations ("cofradías") and the fisheries authority through territorial user rights for fishing (TURFs). Since 1992, the exploitation is granted to "cofradías" after presentation of an annual plan of exploitation and management, where fishing (daily allocation of effort, maximum individual quotas and area of exploitation), surveillance and the commercialisation processes are established. The recent implementation of a geographic information system (GIS) designed for the management of Pollicipes in Galicia will allow for new ways to improve the elaboration and control of management plans by fishers' organisations using a combination of the available statistical data and computer-based methods. The system, including databases and software for the visualisation of geographic information, was designed for independent use in each "cofradía" or in a network, and its results are accessible in a web site (http://sigremar.cesga.es).