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En Chile la pesquería de crustáceos demersales se sustenta en la explotación de camarón nailon (Heterocarpus reedi), langostino amarillo (Cervimunida johni) y langostino colorado (Pleuroncodes monodon). Estos recursos poseen una relevancia económica y social para el país, ya que dan origen a una importante actividad industrial y artesanal que genera numerosos empleos directos y aporta divisas por concepto de exportación de productos, principalmente en el rubro de congelados. Este boletín presenta los resultados resumidos del monitoreo de la pesquería de crustáceos demersales explotados entre las regiones de Antofagasta y Biobío. Programa de seguimiento de las principales pesquerías nacionales Published Non Refereed

En Chile la pesquería de crustáceos demersales se sustenta en la explotación de camarón nailon (Heterocarpus reedi), langostino amarillo (Cervimunida johni) y langostino colorado (Pleuroncodes monodon). Estos recursos poseen una relevancia económica y social para el país, ya que dan origen a una importante actividad industrial y artesanal que genera numerosos empleos directos y aporta divisas por concepto de exportación de productos, principalmente en el rubro de congelados. El recurso el camarón nailon (H. reedi), es una especie de la familia Pandalidae, que se caracteriza por sus hábitos bentónicos es depredadora y detritívora. Se distribuye entre los 100 y 500 metros de profundidad; y latitudinalmente se encuentra entre los 25°y 38° S. Se encuentra en régimen de plena explotación y cuenta con una unidad de pesquería entre las regiones de Antofagasta y Biobío. La cuota de captura establecida para el año 2021 fue de 5.992 t. En cuando al langostino amarillo (C. johni) de la familia Munididae se caracteriza por ser una especie endémica que se distribuye entre los 29° y 38° S, a profundidades entre 150 y 500 m. Su pesquería se divide en dos unidades con sistemas de manejo independientes. La unidad de pesquería norte (UPN) entre las regiones de Atacama y Coquimbo, declarada bajo un régimen de plena explotación desde el año 1995, con una cuota de captura para el año 2021 de 1.457 t. La unidad de pesquería sur (UPS) comprendida entre las regiones de Valparaíso y del Biobío está declarada desde 1996 como pesquería en recuperación. Para el año 2021 la cuota de captura asignada fue de 2.260 t. Por último, el langostino colorado (P. monodon) se distribuye desde los 15°N hasta los 41°S y en profundidades entre los 50 y 350 m. Cuenta con dos unidades de pesquería una entre la Región de Arica y Parinacota y la Región de Coquimbo, área que se encuentra en régimen de plena explotación. Para el año 2021, se estableció una de 1.078 t. La otra unidad de pesquería comprende entre las regiones de Valparaíso y Biobío y está declarada como pesquería en recuperación, con una cuota de captura para el año 2021 de 6.160 t. Este boletín presenta los resultados resumidos del monitoreo de la pesquería de crustáceos demersales explotados entre las regiones de Antofagasta y Biobío. Instituto de Fomento Pesquero Programa de Seguimiento de las Principales Pesquerías Nacionales Published Non Refereed

Natural mortality (M) is a key parameter for understanding population dynamics, especially in relation to harvested populations. Direct observations of M in crustaceans are scarce, due to the moulting process. Indirect methods to estimate M with easier-to-obtain life history attributes are therefore used routinely. Given their theoretical background, we reviewed the applicability of these methods for crustaceans. We applied the selected methods to two crustacean species harvested in Chilean waters: the yellow squat lobster (Cervimunida johni) and red squat lobster (Pleuroncodes monodon). Uncertainty of each M estimate was incorporated in the life history parameters that input into the indirect method (trait-error) and parameters defining the indirect method (coefficient-trait-error). Methods based on the relationship between total mortality and maximum age, or with different ages and based on life history theory were the most appropriate for crustaceans since they apply across taxa. M estimates showed high variability between species, sexes and areas. Estimations of M for C. johni varied from 0.13 to 0.28 (year−1) for males and 0.17 to 0.51 (year−1) for females. For P. monodon values for the north varied from 0.26 to 0.37 (year−1) for males and 0.24 to 0.45 (year−1) for females. In the south, values of M were higher for both males (0.43–0.68 year−1) and females (0.41–1.06 year−1). High variability in the M estimates was associated with the method and number of parameters, their uncertainty, theoretical background and probability distribution. M estimates are not comparable, raising the need to propagate the uncertainty of M into the stock assessment of Chilean squat lobsters.

Estimating relative abundance indexes based on spatio-temporal variations in fishing effort has been one of the greatest challenges in fisheries sciences. Obtained from the catch per unit of effort (CPUE), such indexes are generally used within evaluation models as "relative" to the stock abundance. Herein, a Bayesian spatio-temporal model was used to obtain an index for yellow squat lobster (Cervimunida johni) between the III and IV regions of Chile based on CPUE data (Kg/h.a) from fishing logs. The spatial field was approximated by a GMRF using the SPDE method and posterior distributions of interest were approximated using the Integrated Nested Laplace Approximation (INLA). By taking into account the distributional assumption of the CPUE the proposed model showed a good fit to the observed data. The proposed method allowed obtaining a relative index of abundance which could be included within the classic stock assessment models.

Fitting length data in age-structured stock assessment is a common method for evaluating hard-to-age animals, such as crustaceans. Growth specification and the uncertainty in the stock recruitment relationship are key issues in length-based assessment models. We conducted sensitivity analyses to evaluate the impact of growth and recruitment parameters on the stock assessment and management variables of the yellow squat lobster (Cervimunida johni) caught off the Chilean coast. Nine different scenarios of the length at first capture ( L a = 1 ) and the coefficient of variation at age ( c v a ) were tested for six combinations of values for the steepness parameter (h) and the recruitment variance ( &sigma, R 2 ). We also investigated the reliability of these estimates using an operating model. Our findings indicate that the parameter related to growth, L a = 1 , has the greatest impact on the assessment and management variables of this fishery resource, with c v a having a lesser effect. Recruitment and fishing mortality estimates were the main variables affected. Parameters h and &sigma, R 2 did not profoundly impact the variables assessed. In addition, L a = 1 was the most biased estimated parameter. We discuss that the high influence of growth parameters is related to model structure, and thus implications for determination of the status of yellow squat lobster should be addressed in the future. We recommended developing simulation protocols for the selection of growth parameters when using an age-structured model with length observations, and we believe that our findings are relevant for all Chilean fisheries with a similar stock assessment framework.

Fecundity is directly related to the reproductive potential in all exploited marine species. The gravimetric method has been widely used for the estimation of fecundity in the commercially valuable squat lobsters Cervimunida johni and Pleuroncodes monodon due to its simplicity and precision. However, the procedure is time-consuming because it requires counting of all eggs from the subsample. The fecundity of some fish species has been successfully estimated using the autodiametric method, which consists of the conversion of oocyte size into oocyte density per weight of the ovary. The purpose of this study was to apply and assess an automated image analysis and the autodiametric method for the estimation of fecundity in C. johni and P. monodon . A total of 204 ovigerous females of C. johni and 176 of P. monodon were collected from a fishing survey in August 2015. The results showed that the “counting error” was lower than 12% in the particles analyzed in both squat lobster species. In addition, the “measurement error” generated an average particle exclusion of 16% and 42% for the measurement of egg size in C. johni and P. monodon females, respectively. During the processing time to analyze the mass of eggs from a female in laboratory, the autodiametric method proved to be faster and more efficient because it lasted on average 61% and 73% less than the gravimetric method in C. johni and P. monodon , respectively. The potential fit between the volume-based mean egg diameter ( D V ) and egg density (g −1 egg mass) was significant for both species. The relationship between female size and fecundity was significant for both squat lobster species. Furthermore, the analysis of covariance indicated that the coefficients were not significantly different between both methods. We discussed the autodiametric procedure and the precision of fecundity estimates for both squat lobster species.

Catch efficiency is an important index to relate observed density to the size of a population in the context of bottom trawl surveys. The estimation of catch efficiency is challenging because it involves independent measures of animals in the path of the bottom trawl. We estimated catch efficiency using an underwater camera system on three trawl fishing vessels used for estimating the density of the yellow squat lobster (Cervimunida johni) off central Chile. During 2015 and 2018, 54 hauls were analyzed, and a total of 20 h of filming were recorded. A total of 4,155 yellow squat lobster individuals were analyzed approaching the net in the path of the trawl, of which 2,330 (56%) were captured and 1,825 escaped underneath the groundrope. The median estimated ranges of catch efficiency varied between 0.81–0.90 for vessel 1, 0.15–0.72 for vessel 2 and 0–0.58 for vessel 3. According to a hierarchical generalized linear model (HGML), fishing vessels and mean depth of hauls showed significant differences in catch efficiency (p

Biodiversity and biomass patterns of megafaunal assemblages were assessed from the yellow (Cervimunida johni) and red (Pleuroncodes monodon) squat lobster fishing grounds in the Southeastern Pacific Ocean during four years. Bottom trawls were conducted applying the swept-area method in a stratified sampling design, obtaining global and specific catch per unit area (CPUA). We recorded two target and 47 by-catch species, with a total CPUA of 80.000 t/km2 (cumulative from 2005 to 2008) Fishes and crustaceans dominated over other taxonomic groups. Classes Actinopterygii and Malacostraca attained the highest specific richness; the presence of a few dominant and many rare species in terms of CPUA and frequency, was characteristic of the studied assemblages, hence, the general CPUA pattern parallels that of the most abundant species in the bathymetric and latitudinal gradients. The three most conspicuous non-target species, Heterocarpus reedi, Merluccius gayi gayi and Hippoglossina macrops accounted for 91% of the by-catch CPUA, whereas Class Malacostraca also represented 91% of the total CPUA. The highest average specific richness occurred at intermediate depths (300–400 m) and the lowest in shallow waters (50–100m); the highest overall CPUA occurred at 100–200m and the lowest at both 400–600m and 50–100m. Depth was the most significant factor in the variability of our assemblages. However, particular features of the Humboldt Current System might act as drivers of important effects across the latitudinal gradient on the high productivity and dynamism of the squat lobster fishery, despite the homogeneous composition of the community. This study shows the importance of considering the whole biodiversity within appropriate management actions, in order to achieve ecological benefits (e.g. resilience, functional diversity, water quality, primary productivity) in communities subjected to fishing pressure.

The current study describes the variation in cheliped form of two species of squat lobsters that inhabit the continental margin off Chile: Cervimunida johni and Pleuroncodes monodon. We compared their cheliped form in the context of the reproductive strategy. The general tendency of form variation of both species is similar: chelipeds change, on average, from longer and narrower pollex with short manus to a relatively shorter and wider pollex with longer manus from small to large individuals, respectively. The degree of cheliped arching was greater in males than in females of similar carapace length, and only C. johni males showed fully arched morphology. The allometric trajectories (cheliped shape vs. carapace length) were largely aligned with vectors of mean shape difference in both species. Cheliped form variation of C. johni (extended mate-guarding) resembles the cheliped morphology reported for the related species Munida rugosa more than P. monodon (short mate-guarding). Our results are consistent with previous finding and suggest that the cheliped form variation (from straight and slender to a fully arched morphology) is, or has been, subject to sexual selection through male-male competition for mates. ResumoO presente estudo contém uma descrição da variação da forma dos quelípodos de duas espécies de lagostas que habitam a margem continental do Chile: Cervimunida johni e Pleuroncodes monodon. Foi comparada a forma dos quelípodos das espécies em relação à estratégia reprodutiva das espécies. Das espécies estudadas, C. johni apresenta um quelípodo arqueado, uma relação mais estreita entre a forma da quelípodo e comprimento da carapaça e um maior dimorfismo sexual. Apesar de que a tendência geral da variação da forma dos quelípodos de ambas as espécies é quase semelhante, a variação morfológica dos quelípodos C. johni ("extended mate-guarding") assemelha-se à relatada para M. rugosa mais do que assemelha-se P. monodon ("short mate-guarding"). Nossos resultados são consistentes com os resultados anteriores e sugerem que a variação na forma do quelípodo (de uma forma reta e fina para um formato arqueado) é ou foi sujeita à seleção sexual através da competição entre machos.

Para caracterizar agregaciones de langostino colorado (Pleuroncodes monodon) y langostino amarillo (Cervimunida johni), se utilizó un sistema de filmación remolcado sobre fondos marinos situados en la región de Coquimbo, Chile. Las filmaciones fueron realizadas en 2009 y 2010, a profundidades variables entre 102 y 215 m, a partir de las cuales se estimaron densidades medias por filmación entre 3 y 63 ind m-2 para P. monodon y entre 0,2 y 2,8 ind m-2 para C. johni. Igualmente, se registró la presencia de parejas de C. johni en julio de 2009 (~200 m de profundidad), presumiblemente en proceso de apareamiento. Los resultados indicaron que el sistema de filmación remolcado es un medio efectivo de registro de ejemplares de ambas especies, permitiendo tanto la caracterización cuantitativa del stock sobre el fondo, como la observación de su comportamiento y hábitat. El sistema tiene perspectivas de uso en la evaluación directa de abundancia y en la caracterización del hábitat tanto en términos bióticos como abióticos.

The reproductive potential of a population depends on the number of broods that individuals produce during the annual reproductive season. Determining the annual brood number is especially relevant for species that are actively fished. Herein we combined different approaches to estimate the annual brood number of two commercially exploited species of squat lobsters from the Chilean continental shelf and upper slope, Cervimunida johni and Pleuroncodes monodon. Long-term maintenance in the laboratory revealed that most females (>70%) produced 3 or more broods during the annual reproductive season. Incubation of individual broods required about 40 days, which would allow for 3 subsequent broods during the main reproductive period (June–September). The dynamics of brood release of ovigerous females that were collected from the field at approximately monthly intervals supported the estimate of 3–4 annual broods for adult females. Furthermore, these latter data also indicated a high degree of breeding synchrony among reproductive females. It is suggested that the production of successive broods might be an adaption to the variable oceanographic conditions during the reproductive period, ensuring that at least one larval cohort finds favorable conditions for development and settlement. Based on these results it is recommended that fishing effort is reduced during the main reproductive period of the two squat lobsters.

Changes in the annual density of the yellow squat lobster (Cervimunida johni) were modeled using a generalized linear model (GLM), using information obtained during direct stock assessment cruises carried out in central Chile (32°-38°S) between 1997 and 2009. The purpose of this approach was to minimize the effect of different sampling criteria and designs that have been used over time and to determine the factors explain in variations in the density of this resource. The above approach allowed estimating the expected value of the annual density for the biomass calculation through the "swept area" method. By using the haul-to-haul records of catch per unit of the swept area (CPUA), it was possible to identify and measure the points of abundance and characterize the distribution and area occupied by the resource over time. The significant effects identified by the GLM were the year, zone, depth, and first-order annual interactions; which explained 43% of the residual deviance in the model. The main effects that explain the CPUA variations are the year and the year-zone interaction. The zone with the greatest average abundance was located between 32° and 34°S; the same was for the depth range

Summary The size selectivity of alternative codends for nylon shrimp and yellow squat lobster was studied off the Chilean coast using the covered codend technique. Various mesh sizes (47 and 63 mm mesh opening) and shapes (diamond and square) in the codends were used. For both species, substituting the DM47 codend with the DM63 codend significantly increased 50% retention length (l50). The change of diamond (DM47) to square mesh (SM47) had a positive effect in size selectivity for nylon shrimp. For yellow squat lobster, no significant effect was observed when changing the diamond (DM63) to square mesh (SM63). Selectivity data were modeled by considering explanatory variables such as ‘codend catch weight’ and ‘vessel’. Increases in the catch significantly reduced the l50 for both species whereas the vessel factor was not significant. Finally, using the length at first maturity as a reference value, the authors concluded that the DM47 codend failed to protect the immature portion of either stock, thus the DM63 codend is recommended.

The reproductive biology of many species of anomuran crabs is only poorly known. Herein we studied the reproductive biology of two species of squat lobsters, Cervimunida johni Porter, 1903 and Pleuroncodes monodon (H. Milne Edwards, 1837), which are target of a trawl fishery operating on the continental margin along the Chilean coast. During the reproductive period (May-November) we maintained squat lobsters in the laboratory to examine whether mating is related to the reproductive molt of the female and to determine the interbrood interval between successive broods. In both species females mated during the intermolt period. Females became receptive shortly after having released larvae from a previous brood, when they formed pairs with males. The interbrood interval (from larval release until having a subsequent brood) lasted

Como aporte a la dinámica poblacional de especies que constituyen recursos pesqueros, se analizaron 160 muestras de zooplancton obtenidas con redes Bongo en 40 estaciones oceanógraficas entre Caldera y Coquimbo, en octubre y diciembre de 2005. De ellas se separó la totalidad de las larvas de crustáceos decápodos y se identificaron las de Heterocarpus reedi, Cervimunida johni y Pleuroncodes monodon. Las mayores abundancias de zoeas tempranas de las tres especies se encontraron en octubre en la zona de Coquimbo, mientras que en diciembre predominaron los estados más avanzados de desarrollo. En la zona de Caldera, en ambos meses de muestreo, predominaron los estados avanzados de desarrollo de H. reedi y P. monodon y zoeas tempranas de C. johni. La frecuencia de ocurrencia de las larvas de H reedi en la zona de Coquimbo fue similar en ambos meses, mientras que en la zona de Caldera fue mayor en octubre. La frecuencia de ocurrencia de las larvas de P. monodon y C. johni fue mayor en octubre en ambas zonas. Todas las megalopas capturadas en las dos zonas y meses de muestreo corresponden sólo a un morfotipo, con características morfológicas similares a los juveniles más pequeños de P. monodon. Sobre la base de la distribución y abundancia de larvas de las tres especies, se postula que el desove ocurre antes en la zona de Caldera que en la de Coquimbo, principalmente en zonas próximas a la costa, dada las diferencias de abundancia de los estados de desarrollo. To better understand the population dynamics of fishery resource species, 160 zooplankton samples were obtained with a Bongo net at 40 oceanographic stations around Caldera and Coquimbo in October and December, 2005, and analyzed. All crustacean decapod larvae were sorted, and Heterocarpus reedi, Cervimunida johni, and Pleuroncodes monodon larvae were identified. For all three species, the highest abundances of early zoea were found in October in Coquimbo, whereas advanced larval stages were predominant in December. In Caldera, advanced larval stages of H. reedi and P. monodon, and early zoeas of C johni were dominant during both sampling months. The frequency of occurrence of H. reedi larvae was similar during both sampling months in Coquimbo and greater in October in Caldera. The frequency of occurrence of the larvae of P. monodon and C johni was greater in both areas in October. All the megalops captured in both zones and sampling months corresponded to a single morphotype, with morphological characteristics similar to the smallest P. monodon juvenile specimens. Based on the larval distribution and abundance of these three species, it is postulated that spawning occurs earlier in the Caldera área than around Coquimbo, mainly in areas near the coast, given the differences in abundance of the developmental stages.

The main objective of the current research was to study and model the air drying kinetics of yellow squat lobster (Cervimunida johni) fishery waste. This study was carried out at temperatures from 50 to 90 °C, using five empirical equations (Newton, Henderson–Pabis, Modified Page, Wang–Singh) and a new model proposed in this study. The kinetic parameters ki = 1, 2, …, 5, for each model were temperature-dependent as evaluated using an Arrhenius-type equation. The empirical parameters ni = 1, 2, …, 4, did not show temperature dependence. The fit quality of models on experimental data were evaluated using three statistical tests, sum square errors, root mean square errors, and Chi-square. When comparing the experimental values with the calculated values, it was shown that the Modified Page equation presented the best fit quality, and represented an excellent tool for estimating the drying time of this material, thus leading to the first stage in the development and use of yellow squat lobster waste as a by-product of fishery for animal feed.

Instrumental and sensory textural characteristics of frozen blue squat lobster (Cervimunida johni) tails stored at -22C for 0, 15 and 60 days were evaluated. The influence of fishing area (north or south) was also studied. Instrumental texture was evaluated by shear and compression testing using a Warner-Bratzler blade for firmness and a flat plunger with two-cycle compression for texture profile analysis (TPA) testing. A trained panel was utilized to evaluate textural attributes using the score method. Results showed that fishing area and frozen storage did not affect the textural quality of blue squat lobster tails. However, a strong correlation (r > 0.9) between sensory and instrumental texture parameters was observed. Instrumental chewiness (r = 0.91), cohesiveness (r = 0.96) and sensory hardness (r > 0.84) obtained the strongest correlations. In this way, the use of instrumental analysis may be useful as an alternative to sensory analyses to evaluate the textural characteristics of blue squat lobster tails.

The MULTIFAN method was used to analyse a series of monthly length-frequency distributions of the squat lobster Cervimunida johni Porter (1903) (Galatheidae), for the estimation of growth and age composition in the fishing area off Coquimbo (29°59’S-71°22’W), in the northern-central area off Chile. Length frequency data (LFD) were collected from commercial catches made between 28°S and 32°10’S from September 1996 to September 1997. MULTIFAN distinguished 11 age classes in the LFD of males and 9 age classes in the LFD of females. This is an important result because usually only three to four age classes have been reported by analysing annual length-frequency data. Males and females were recruited to the fishery at 19.7 and 18.8 mm carapace length (CL) respectively. The von Bertalanffy growth parameters were estimated as K = 0.151 yr -1 and CL ? = 52.8 mm for males, and K = 0.174 yr -1 and CL ? = = 45.60 mm for females. Males reached larger sizes than females, which is in agreement with the growth of other Galatheids.

The relationships between mean intensity and prevalence of infestation of Pseudione humboldtensis and the size and sex of the hosts, the squat lobsters Cervimunidia johni and Pleuroncodes monodon, from three fishing grounds in northern Chile are described. The prevalences were 13.6% and 6.8% for C. johni in Coquimbo and Huasco, respectively, while in P. monodon they were 18.2% and 0.6% in Coquimbo and Caldera, respectively. Between fishing grounds, no significant differences were found in the prevalence of infestation between male and female C. johni, but in Coquimbo, the prevalence of infestation in P. monodon was significantly higher in females. The sizes of infested squat lobsters were significantly lower than those of uninfested hosts. Males and females parasitized by P. monodon showed significantly lower body weights than uninfested hosts. Parasitized males of C. johni showed lower body weight than uninfested males. Only 0.6% of ovigerous females of C. johni and none of P. monodon were infested. The near absence of infested ovigerous females suggests castration process in females. A nonlinear relationship was detected between host size and parasite size for both females and males. Multiple infestations of P. humboldtensis were found in both host species, but they were more common in P. monodon. Given the high prevalence of multiple infestations (50%) and the significantly lower body weights of infested P. monodon, we suggest that this host is more vulnerable to P. humboldtensis than is C. johni.

The large industrial fishery development that turn Chile into the third fishing nation in the world is described, and recent regulatory innovations introduced by new Fishery and Aquaculture legislation are reviewed. In addition to classical Fishery management tools, different types of limited entry systems are now defined in the law and applicable to Chilean fisherie. These for the first time include allocation of resources in the form of Individual Fishing Quotas and Individual Transferable Quotas (IFQs and ITQs). Territorial User’s Rights in Fisheries (TURF’s) were incorporated in the law to enhance self-regulatory practices among artisanal fishermen. Among them, the Areas for Management and Exploitation for Benthic Resources (AME) represent an associative assignment of TURFs. Large-scale zoning is used to re-define Aquaculture Grants and to ritualise the conflicts between Artisanal and Industrial fishermen by establishing the Artisanal Reserve in which small-scale coastal fishermen have Priority Access. Performance of the new management instruments are documented with case studies, for the following fisheries: the loco ( Concholepas concholepas ) a carnivorous snail, keyhole limpets (Fissurella spp.), langostino or squat lobster ( Cervimunida johni ), Black hake ( Dissostichus eleginoides ) and the Yellow prawn ( Pleuroncodes monodon ).

El objetivo general del proyecto fue evaluar el stock de la merluza común y estimar las características biológicas, pesqueras y oceanográficas relevantes del recurso. Unpublished

El presente informe analiza e informa el desempeño de las variables e indicadores de los principales recursos nacionales y su actividad pesquera, incluyendo aspectos ecosistémicos asociados e información científica disponible, basado en un sistema de monitoreo científicamente validado y con estándares dfe aseguramiento de calidad certificados. Unpublished

Unpublished

El objetivo general del proyecto fue evaluar el stock de la merluza común y estimar las características biológicas, pesqueras y oceanográficas relevantes del recurso. The overall project objective was to assess the hake stock and assess the biological, fisheries and oceanographic relevant resource. Published

Unpublished

Summary Spermatozoal morphology of the anomuran crab Cervimunida johni was investigated using scanning and transmission electron microscopy. The spermatozoon has an elongate shape and exhibits a total length of 22.7 μm with a maximum width of 4.4 μm. Three parts can be distinguished: (1) the elongate-ovoid acrosome located anteriorly, measuring 7.7 μm in length and 2.7 μm in width; (2) the cytoplasmic region, 3.0 μm in length and 1.5 μm in width; and (3) the nuclear region measuring 11.9 μm in length and 4.4 μm in width. The acrosome is composed of a thick electron-dense wall and a less electron-dense subacrosomal space showing actin-like filaments. The cytoplasmic region connects the acrosome with the nucleus, and three arms filled with microtubules arise from this region. The cytoplasm contains irregular mitochondria. The elongate nucleus has uncondensed DNA, its outer surface is highly folded and shows three principal longitudinal grooves. The microtubular arms are located in these three nuclear groove...

La información obtenida en cruceros de evaluación directa de langostino amarillo (Cervimunida johní) realizados en la zona central del Chile (32°-38°S) entre 1997 y 2009, permitió modelar los cambios en la densidad anual de este recurso mediante Modelo Lineal Generalizado (MLG). El objetivo de este enfoque fue tanto minimizar el efecto de los distintos criterios y diseños de muestreo que han sido empleados en el tiempo, como también determinar los efectos que explican las variaciones en la densidad de este recurso. Lo anterior permitió estimar el valor esperado de la densidad anual para el cálculo de biomasa mediante el método de "área barrida". Los registros lance a lance de captura por unidad de área barrida (CPUA) permitieron la identificación y medición de los focos de abundancia, además de caracterizar la distribución y área que ha ocupado el recurso en el tiempo. El MLG identificó como efectos significativos el año, la zona, la profundidad, y las interacciones anuales de primer orden, explicando con ello el 43% de la devianza residual del modelo. Los principales efectos que explican las variaciones de la CPUA son el año y la interacción año-zona. Se determinó que la zona con mayor abundancia promedio corresponde a la delimitada entre 32° y 34°S, de igual manera que en el rango de profundidad menor a 250 m. Dentro del período analizado, se determinó que la población de este recurso incrementó en biomasa de manera sostenida hasta el 2006, principalmente en la zona norte del área de estudio, seguida de una fuerte reducción que al 2009 equivale al 75% respecto del máximo, reflejada en una biomasa de 11.000 ton. Changes in the annual density of the yellow squat lobster (Cervimunida johni) were modeled using a generalized linear model (GLM), using information obtained during direct stock assessment cruises carried out in central Chile (32°-38°S) between 1997 and 2009. The purpose of this approach was to minimize the effect of different sampling criteria and designs that have been used over time and to determine the factors explain in variations in the density of this resource. The above approach allowed estimating the expected value of the annual density for the biomass calculation through the "swept area" method. By using the haul-to-haul records of catch per unit of the swept area (CPUA), it was possible to identify and measure the points of abundance and characterize the distribution and area occupied by the resource over time. The significant effects identified by the GLM were the year, zone, depth, and first-order annual interactions; which explained 43% of the residual deviance in the model. The main effects that explain the CPUA variations are the year and the year-zone interaction. The zone with the greatest average abundance was located between 32° and 34°S; the same was for the depth range

Cada operación de pesca en pesquerías multiespecíficas puede ser descrita por medio del análisis de la proporción de especies en la captura, área y arte de pesca. A un conjunto de operaciones de pesca similares, se ha definido en la literatura como táctica de pesca. En este trabajo, se identificaron tácticas de pesca empleadas en la pesquería multiespecfica de crustáceos (PMC), entre 26°03'S y 38°28'S frente a Chile. Se utilizó la proporción de especie en la captura por lance, registrada en bitácoras de pesca por observadores científicos entre 2007 y 2009. Durante este periodo, se registraron 1599 lances con 57 especies recurrentes. Se realizó un análisis de componentes principales para reducir la dimensionalidad de especies y posteriormente, se aplicó un análisis jerárquico de agrupación sobre los componentes retenidos. Se obtuvieron y analizaron cuatro tácticas, la primera orientada a capturar Heterocarpus reedi (camarón nailon) con capturas en un amplio rango latitudinal. La segunda táctica enfocada a Cervimunida johni (langostino amarillo) con lances realizados en un estrecho rango de latitud y menor profundidad. La tercera táctica centró su esfuerzo en Haliporoides diomedeae (gamba de profundidad), siendo los lances realizados a mayor profundidad y la última táctica hacia Pleuroncodes monodon (langostino colorado), enfocados en aguas someras cerca de la costa. En el caso de la PMC, la identificación de tácticas de pesca es importante en la asignación de intencionalidad de captura y la construcción de índices de abundancia derivados de bitácoras de pesca. Los resultados son discutidos en términos de caracterizar las tácticas y como su asignación permitirá obtener índices de abundancia menos sesgados.

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This study was conducted to determine the reduction in bycatch and the loss of target catch in trawl hauls for three commercial crustacean species (yellow squat lobster, Cervimunida johni , nylon shrimp, Heterocarpus reedi , and red squat lobster, Pleuroncodes monodon ) in central Chile. Two experiments were carried out using the covered codend method; the first used different mesh sizes (56 and 70 mm, knot-centre to knot-centre) and shapes (diamond and square), and the second tested different reduction devices (escape panel and sorting grid). We analysed the escape proportions of the species caught and the size frequency distributions of the target species and Chilean hake ( Merluccius gayi ), the main commercial bycatch species. The results demonstrate that it is feasible to significantly reduce bycatch while keeping losses within acceptable ranges. In particular, the best option for yellow squat lobster was the combination of a 70-mm diamond mesh with an escape panel that reduced non-target and target catches by 48% and 7%, respectively. For nylon shrimp, the best option was the use of a 56-mm diamond mesh with a sorting grid that reduced non-target and target catches by 41% and 11%, respectively. Although the results for red squat lobster were not as promising, they will help to guide future research.

The species composition and bycatches of a new trawl for crustaceans (Heterocarpus reedi, Cervimunida johni and Pleuroncodes monodon) was studied in central Chile between 2007 and 2009. The spatial and temporal variations of the catch composition were analyzed using univariate and multivariate comparison techniques. In 289 trawl hauls, 72 taxa were recorded, with target species accounting for most of the catch, while the bycatch consisted mainly of Merluccius gayi, Hippoglossina macrops, Coelorinchus aconcagua, Epigonus crassicaudus and Platymera gaudichaudii. 14 species of elasmobranchs were identified, and at least one of these species was present in 50% of the hauls made. The classification and ordination methods showed the existence of three groups, each one associated with a target species, with no significant spatial and temporal effects. The information obtained in this study represents the basis for setting targets in order to reduce the bycatch captured by this trawl. The focused strategy on the most recurring and sensitive species for these fisheries is also discussed. (C) 2011 Elsevier B.V. All rights reserved.

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En este documento se entrega de manera resumida es estatus de los principales recursos pesqueros chilenos (pelágicos, demersales y crustáceos demersales) y la recomendación de cuotas de capturas para el año 2011. This document is delivered in a summary status of the main Chilean fisheries (pelagic, demersal and demersal crustaceans) and recommendation of catch quotas for 2011. Unpublished

El objetivo general del proyecto fue evaluar el stock de la merluza común y estimar las características biológicas, pesqueras y oceanográficas relevantes del recurso. Metodológicamente se realizó un crucero de prospección que correspondieron al área de la plataforma continental entre las latitudes 31°25’S y los 41°30’S y desde la costa hasta el veril de los 500 metros de profundidad. The overall project objective was to assess the hake stock and assess the biological, fisheries and oceanographic relevant resource. Methodologically, we conducted a survey cruise which corresponded to the area of the continental shelf between latitudes 31°25’S and 41°30’S and from the coast to the reef 500 meters deep. Unpublished

En el presente etudio se entregan los resultados obtenidos del análisis de la fauna acompañante de las pesquerías industriales pelágicas de la zona norte y centro sur, con motivo de la información requerida por la Secretaría Interina del acuerdo Subregional denominado ."South Pacific Regional Fisheries Management Organisation". In the present study gives results of the analysis of bycatch of pelagic industrial fisheries in the northern and south-central, because of the information required by the Interim Secretariat of the agreement referred Subregional "South Pacific Regional Fisheries Management Organisation" Unpublished

Se realizó la evaluación de stock del recurso langostino amarillo, a partir de dos modelos de evaluación de stock: un modelo estructurado en edades y un modelo de biomasa dinámica; ambos separados por áreas (Área Norte: 26°03’-30°30’ L.S. y Área Sur: 30°30’01’’-38°28’ L.S.). Assessment was performed squat lobster resource stock, from two evaluation models Stock: An age structured model and a model of biomass dynamics, both separated by areas (Area North: 26 ° 03’-30 ° 30 ’S and Southern Area: 30 ° 30’01’’-38 ° 28’ LS). Unpublished

Se realizó la evaluación de stock del recurso langostino amarillo, a partir de dos modelos de evaluación de stock: un modelo estructurado en edades y un modelo de biomasa dinámica; ambos separados por áreas (Área Norte: 26°03'-30°30'; L.S. y Área Sur: 30°30'01''-38°28' L.S.) Assessment of the resource stock yellow shrimp was conducted from two stock assessment models: a structured model ages and biomass dynamics model, both separated by areas (North Area: 26°03'-30°30'; L.S. and South Area: 30°30'01''-38°28'L.S.) Unpublished

El informe da cuenta del monitoreo de los principales indicadores biológicos y pesqueros asociados a los crustáceos demersales explotados en la zona marítima centro-norte y centro-sur de Chile. Se analizó información proveniente de bitácoras de pesca recopiladas por observadores científicos a bordo de embarcaciones comerciales, así como de bitácoras de pesca entregadas por los armadores al Servicio Nacional de Pesca, para el año 2009. El área de estudio comprendió desde los 21°26' L.S. hasta 38°28' L.S. Se registró que la flota dedicada a la extracción de los crustáceos demersales estuvo constituida por 21 naves industriales y 5 artesanales The report presentes the monitoring of key indicators related to biological and fishery exploited demersal crustaceans in the sea area north-central and south-central Chile. We analyzed information from logbooks proviniente collected by scientific observers aboard commercial vessels as well as fishing logs submitted by the owners to the National Marine Fisheries Service for the year 2009. The study area included from the 21°26' L.S 38°28' L.S. Joined the fleet for the extraction of demersal crustaceans consisted of 21 industrial units and 5 craft. Unpublished

Se analizo el efecto economico debido a la disminucion de la captura por unidad de esfuerzo (CPUE) en la pesqueria de camaron nailon y langostino amarillo en la zona norte y central de Chile durante el periodo 1997-2000. Se utilizo un modelo de simulacion biologico-tecnologico que da cuenta de variables de desempeno fisicas y biologicas. A este modelo se le incorporo un submodelo economico para realizar un analisis integrado de la pesqueria de crustaceos que incluye el subsector de captura y procesamiento. Los resultados economicos obtenidos, sumados a los resultados de captura y de tamano del stock permiten explicar la dinamica de esta pesqueria en la zona centro-norte de Chile durante el periodo 1997-2000, donde la captura aumento en 21%, la produccion final aumento en 24%, pero la cuasi renta de los costos variables aumento solo 11%. En este mismo periodo los costos por marea incrementaron 117% y el costo total de produccion aumento 93%. Los resultados mostraron que parte del beneficio economico se pierde debido a la disminucion de la biomasa de ambos recursos y a un aumento excesivo en los costos medios de produccion, que fueron explicados por el aumento en los costos de marea. Se recomienda incorporar puntos de referencia economicos en orden a tener una mejor representacion del desempeno de la pesqueria, como un complemento a los indicadores de desempeno biologicos (biomasa) y pesqueros (CPUE y captura) usados tradicionalmente

Se analiza la selectividad por tamaño de las presas en la merluza común (Merluccius gayi gayi) a partir de una base de datos de contenidos estomacales que cubre el periodo 1992-1997. El índice de selectividad de presas de Ursin y los coeficientes de selectividad por tamaño a la edad se calcularon para la propia merluza común (canibalismo), los galatheidos langostino colorado (Pleuroncodes monodon) y langostino amarillo (Cervimunida johni), y los clupei-formes sardina común (Strangomera bentincki) y anchoveta (Engraulis ringens), y otras presas en conjunto. Se confirma que a medida que la merluza crece tiende a consumir presas de mayor tamaño, y que la merluza de más de 2 años tiene preferencia por la fracción juvenil de 0 a 4 años (canibalismo), por anchovetas de 0 y 1 año de edad, y langostinos de grupo de 0 y 1 año de edad. La merluza de más de 4 años presenta igual preferencia por langostino colorado y amarillo de más de 2 años de edad. Otras presas tienen altos coeficientes de selección por los grupos de edad 0 a 4 del predador, las que están representadas principalmente por zooplancton (eufáusidos) y mictófidos. Los coeficientes de selección aquí calculados constituyen una base cuantitativa para avanzar en modelos de evaluación multiespecífico que permitan cuantificar el impacto trófico de merluza común sobre especies de importancia comercial del sistema bento-demersal y pelágico de la zona centro-sur de Chile

El proyecto realiza el monitoreo de los principales indicadores asociados a las pesquerías de crustáceos demersales en la costa d e Chile, caracterizando las especies biológicas y el impacto de éstas pesquerías sobre otras especies The project carries out monitoring of key indicators related to the demersal crustacean fisheries off the coast of Chile, characterizing biological species and the impact of the se fisheries on other species. Unpublished

Se analizan factores que afectan las tasas de captura de langostino amarillo (Cervimunida johni) en la zona norte de Chile (26°03'-32°10'S), utilizando las bitácoras de pesca comercial entre los años 1993 y 2003. Se utilizaron los factores año, mes, estratos de profundidad, regiones de pesca y características operacionales de la flota como predictores lineales de un modelo lineal generalizado (MLG) que da cuenta de la variabilidad en las tasas de captura. A diferencia de otras pesquerías, en este recurso las características técnicas de la flota y su especialización explican escasamente la varianza en las tasas de captura y por el contrario, los factores temporales y su interacción son altamente significativos. Los resultados de esta investigación, en conjunto con la historia de vida, permiten suponer que las tasas de captura estandarizadas son un adecuado índice de abundancia relativa para este recurso An analysis was made of the factors affecting the catch rates of the yellow squat lobster (Cervimunida johni) in Chile's northern region (26°03'-32°10'S) by reviewing commercial fishing logbooks from 1993 to 2003. Factors evaluated included years, months, depth stratum, fishing areas and fleet characteristics as linear predictors in a generalized linear model (GLM) in order to explain variability in the catch rate. In contrast with other fisheries, with this resource the technical characteristics of the fleet and its' specialization poorly explain variations in catch rate; temporal factors and their interaction were, however, highly significant. The results of this study, together with the life history of the resource, allow the supposition that standardized catch rates are appropriate as an index of relative abundance in this fishery