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Weight-length relations of fishes are useful for estimation of biomass from length observations, e.g., in fisheries or conservation research. Here we provide some guidance to authors of such papers, in order to facilitate the publication and review process

This handbook is the most comprehensive and interdisciplinary work on marine conservation and fisheries management ever compiled. Its many valuable contributions offer a way forward to both understanding and resolving the multifaceted problems facing the world's oceans.

The global marine fish catch is approaching its upper limit. The number of overfished populations, as well as the indirect effects of fisheries on marine ecosystems, indicate that management has failed to achieve a principal goal, sustainability. This failure is primarily due to continually increasing harvest rates in response to incessant sociopolitical pressure for greater harvests and the intrinsic uncertainty in predicting the harvest that will cause population collapse. A more holistic approach incorporating interspecific interactions and physical environmental influences would contribute to greater sustainability by reducing the uncertainty in predictions. However, transforming the management process to reduce the influence of pressure for greater harvest holds more immediate promise

Ucides occidentalis es un cangrejo de importancia pesquera en Ecuador. El objetivo del presente trabajo fue estimar su abundancia en un área de uso y custodia de manglar, en el Golfo de Guayaquil, Ecuador. La abundancia fue representada por la densidad y el tamaño poblacional, determinados conforme el muestreo por distancias utilizando transectos de puntos. Un total de 38 puntos fueron establecidos, basados en un muestreo no-probabilístico de oportunidad. Los individuos fueron recolectados por pescadores locales. Cada cangrejo fue sexado y su talla (i.e., ancho de cefalotórax-AC) registrada con un calibrador Vernier. Se determinó la proporción sexual, talla media, densidad y tamaño poblacional. La proporción sexual indica un número ligeramente superior de hembras (1:1,10). La talla media poblacional fue 7,47 cm AC; los machos presentaron una talla superior (7,69 cm AC) referente a las hembras (7,33 cm AC). La densidad poblacional fue 0,27 ind/m2 y el tamaño poblacional estimado fue de 743670 individuos. La mayor densidad la presentaron las hembras, seguidos de los machos comerciales (> 7,5 cm AC). Los machos no-comerciales (<0,75 cm AC) tuvieron una abundancia baja (0,03 ind./m2). La proporción sexual difiere entre los reportes previos, lo cual podría relacionarse con la prohibición de capturar hembras en Ecuador, que ocasiona una mayor presión pesquera sobre los individuos machos. La abundancia de U. occidentalis es inferior a lo reportados por otros autores (i.e., 0,61-1,2 ind./m2), lo cual debe ser tomado con cautela debido a las diferencias en las metodologías empleadas.

Removal of important predators by fishing can result in trophic cascades and indirect effects on marine benthic communities. Indirect effects are especially evident when prey populations released from predation by fishing have the ability to modify entire benthic communities, as do sea urchins. Sea urchins have been shown to dramatically alter the underwater landscape by grazing, by converting stands of large erect algae into coralline barrens. In the western Mediterranean, a recent extension of coralline barrens into areas formerly dominated by erect algal assemblages has been attributed to release of predation on sea urchins by overfishing. Most suggestions concerning the transition from erect algal assemblages to coralline barrens, however, have been speculative, and little descriptive and experimental work has been carried out to verify the hypothesis that fish predation on sea urchins (and its subsequent release by overfishing) drives this transition. Here we critically review the literature concerning the effect of fishing on sea urchin populations and its subsequent maintenance of different algal assemblages in the Mediterranean. The extant data cannot refute the \"fishes as important predators\" model, but we argue that other processes (recruitment, pollution, disease, large-scale oceanographic events, sea urchin harvesting, food subsidies, and availability of shelters) may also be important in regulating the structure of Mediterranean algal assemblages.

Models of population dynamics in which per capita reproductive success declines at low population levels (variously known as depensation, the Allee effect, and inverse density dependence) predict that populations can have multiple equilibria and may suddenly shift from one equilibrium to another. If such depensatory dynamics exist, reduced mortality may be insufficient to allow recovery of a population after abundance has been severely reduced by harvesting. Estimates of spawner abundance and number of surviving progeny for 128 fish stocks indicated only 3 stocks with significant depensation. Estimates of the statistical power of the tests strengthen the conclusion that depensatory dynamics are not apparent for fish populations at the levels studied

This book sheds light into the uneasy relationship between the 'IUU fishing' designation as a governance mechanism, and international law. Building on previous literature, this original study will be of interest to international fisheries governance academics and policymakers alike.

Variation at 14 microsatellite loci was surveyed in 26 chum salmon Oncorhynchus keta populations from Japan, one population from West Kamchatka and three populations from North America to determine population structure. Microsatellites were then applied to estimate stock composition of chum salmon in mixed-stock fisheries. The genetic differentiation index ( F st ) over all populations and loci was 0.031, with individual locus values ranging from 0.010 to 0.081. Seven regional populations were observed in Japanese chum salmon, with late-run populations from the Pacific Coast of Honshu the most distinct. Japanese populations displayed greater genetic diversity than did those in North America. Transplantation history in some Japanese river populations influenced their present genetic characteristics. Analysis of simulated mixtures from fishery sampling suggested that accurate and precise regional estimates of stock composition should be produced when the microsatellites were used to estimate stock compositions. Stock compositions for a 2005 sample of maturing, migrating chum salmon off the north-west coast of Hokkaido near the border of the Sea of Japan and the Sea of Okhotsk indicated that this region may be a migration corridor for Hokkaido populations from the Sea of Japan coast. Microsatellites have the ability to provide fine-scale resolution of stock composition in Japanese coastal fisheries.

Se presenta una reseña de los efectos del fenómeno \"El Niño 1997-98\" en los recursos pesqueros del ecosistema de afloramiento peruano, dando especial énfasis a los cambios en los patrones de distribución y abundancia de los recursos anchoveta, sardina y merluza; ya los cambios en la autoecología de los mismos recursos. Finalmente, se comenta sobre las similitudes y diferencias de los efectos de este fenómeno con otros eventos de la misma naturaleza.