Cryptic invertebrates on subtidal rocky reefs vary with microhabitat structure and protection from fishing

The deployment of flat concrete blocks on subtidal rocky reefs can replicate natural reef microhabitats and provides a means for standardized sampling of cryptic invertebrates. The shape of the cavity beneath the block is related to reef topography and may influence the invertebrate community by affecting the amount of space for cryptic fauna to colonise and influencing the effectiveness of their predator-defence mechanisms. To determine the effect of sub-block reef structure and different levels of external predators on cryptic molluscs and echinoderms, I deployed concrete blocks at locations inside and outside the Maria Island marine reserve in eastern Tasmania, Australia. Relationships between sub-block reef structure and the cryptic invertebrate assemblage were evident between locations, whereas only a small but significant proportion of variation of assemblages between blocks within location was explained by reef surface area. No clear association with external predation pressure was evident in multivariate analyses of variation in assemblage structure. Juvenile abalone Haliotis rubra were not influenced by micro-habitat structure but were significantly less abundant at protected locations, the only species to exhibit such a response. This result follows a decline of emergent adult abalone in the marine reserve and raises the possibility of recruitment failure of abalone at some fully protected locations in the longer term.

Simulation of the Impact of Dams and Fishing Weirs on Reproductive Potential of Silver-Phase American Eels in the Kennebec River Basin, Maine

I modeled the cumulative impact of hydroelectric projects with and without commercial fishing weirs and water-control dams on the production, survival to the sea, and potential fecundity of migrating female silver-phase American eels, Anguilla rostrata in the Kennebec River basin, Maine, This river basin has 22 hydroelectric projects, 73 water-control dams, and 15 commercial fishing weir sites. The modeled area included an 8,324 km(2) segment of the drainage area between Merrymeeting Bay and the upper limit of American eel distribution in the basin. One set of input,, (assumed or real values) concerned population structure (Le., population density and sex ratio changes throughout the basin, female length-class distribution, and drainage area between dams), Another set concerned factors influencing survival and potential fecundity of migrating American eels (i.e., pathway sequences through projects, survival rate per project by length-class. and length-fecundity relationship). Under baseline conditions about 402,400 simulated silver female American eels would be produced annually reductions in their numbers due to dams and weirs would reduce the realized fecundity (i.e., the number of eggs produced by all females that survived the migration). Without weirs or water-control dams, about 63% of the simulated silverphase American eels survived their freshwater spawning migration run to the sea when the survival rate at each hydroelectric dam was 9017, 40% survived at 80% survival per dam, and 18% survived at 60% survival per dam. Removing the lowermost hydroelectric dam on the Kennebec River increased survival by 6.0-7.6% for the basin. The efficient commercial weirs reduced survival to the sea to 69-76%( of what it would have been without weirs', regardless of survival rates at hydroelectric dams. Water-control dams had little impact on production in this basin because most were located in the upper reaches of tributaries. Sensitivity analysis led to the conclusion that small changes in population density and female length distribution had greater effects on survival and realized fecundity than similar changes in turbine survival rate. The latter became more important as turbine survival rate decreased. Therefore, it might be more fruitful to determine population distribution in basins of interest than to determine mortality rate at each hydroelectric project.

Elaboración artesanal de mermeladas de tres ecotipos de tuna (Opuntia ficus indica f. inerme) roja, anaranjada y verde

La tuna es una fruta presente principalmente en zonas áridas y semiáridas. Su aporte nutricional podría aprovecharse consumiéndola en forma directa, como así también a través de productos elaborados en forma artesanal. Dichos productos podrían incorporarse a la economía del mercado de consumo interno y eventualmente externo. Por tal motivo, se evalúa la posibilidad de desarrollar mermeladas con tres ecotipos de tuna de la misma variedad, considerando la aceptación del producto. Se trabajó con tunas (Opuntia ficus indica f. inerme), cultivadas en el Centro Regional de Investigaciones Científicas y Tecnológicas (CRICYT) ubicado en el Parque General San Martín, Capital, Mendoza. El objetivo general del trabajo estuvo dirigido a la elaboración de mermeladas de tres ecotipos de tuna: tuna roja o morada, tuna anaranjada o amarilla y tuna verde o blanca acorde a la legislación vigente. Los ítems específicos estuvieron conducidos hacia el desarrollo de una mermelada utilizando una fruta no convencional, para determinar el valor nutricional del mismo, y sus características fisicoquímicas, ampliar la producción de subproductos de tuna en la región árida y semiárida, para así finalmente evaluar el grado de aceptabilidad sensorial y comercial del producto. Se caracterizaron los tres ecotipos de tuna y sus respectivas mermeladas mediante determinaciones fisicoquímicas, se verificó el contenido nutricional y se realizaron los análisis microbiológicos de cada una de ellas. Dentro de las determinaciones fisicoquímicas de las mermeladas se incluyó K, P, Ca y vitamina C, teniendo en cuenta que se parte de una materia prima con buenas cantidades de estos minerales y vitamina C con respecto a otras frutas. Se llevaron a cabo pruebas de evaluación sensorial del producto terminado y se consultó el precio que estarían dispuestos a pagar los potenciales consumidores. Los jueces entrenados contribuyeron al diseño de un perfil sensorial para cada una de las mermeladas y evaluaron en forma global al producto obtenido. Los resultados obtenidos en cuanto a la caracterización de la materia prima arrojan un buen contenido en sólidos solubles, vitamina C y en minerales como el fósforo, calcio, potasio y un contenido bajo en sodio con respecto a otras frutas que se consumen habitualmente. Los análisis microbiológicos realizados para evaluar la conservación permiten expresar que se trata de un producto de bajo riesgo microbiológico, bajo las condiciones de conservación que se obtuvieron. En base a lo expuesto, se puede concluir que es técnicamente posible elaborar artesanalmente mermeladas de tres ecotipos de tuna, las cuales poseen un buen aporte nutricional, son aptas para el consumo humano desde el punto de vista bromatológico y aceptadas sensorialmente por los consumidores.

Compilation of Thunnus thynnus (bluefin tuna) catches in the Northeast Atlantic Ocean 1950-2010

The data have been extracted and compiled from various sources but mainly from the ICES data base. The ICES data are from catch databases downloaded from the ICES website on 2014-01-14. These data are resolved by ICES area, country and year. During inspection of these data, it was noted that Norwegian data for years before 1950 had not been entered into the catch database on the ICES website. ICES has been notified of this omission by B. R. MacKenzie. The Norwegian data from ICES Bulletins. Statistiques has been added. Additional historical bluefin tuna catch data from other fishery reports and sources have been included in the data file for years preceding those when countries started reported their landings officially to ICES. These additional data have been reported in the literature previously (MacKenzie and Myers 2007, Fisheries Research).

Spatially explicit estimates of North Atlantic albacore tuna (Thunnus alalunga) biomass in the North Atlantic for the period 1956-2010 - Gridded data product (NetCDF)

The development of the ecosystem approach and models for the management of ocean marine resources requires easy access to standard validated datasets of historical catch data for the main exploited species, together with the model estimates achieved from these data, allowing models inter-comparison and evaluation of model skills. North Atlantic albacore tuna is exploited all year round by longline and in summer and autumn by surface fisheries and fishery statistics compiled by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Catch and effort with geographical coordinates at monthly spatial resolution of 1° or 5° squares were extracted for this species with a careful definition of fisheries and data screening. Length frequencies of catch were also extracted according to the definition of fisheries for the period 1956-2010. Using these data, an application of the spatial ecosystem and population dynamics model (SEAPODYM) was developed for the North Atlantic albacore population and fisheries and provided the first spatially explicit estimate of albacore density in the North Atlantic by life stage. These densities by life stage (larval recruits, young immature fish adult mature fish and total biomass) are provided in gridded file (Netcdf) at resolution of 2° x 2° x month.

Compilation of Thunnus thynnus (bluefin tuna) catche in the Northeast Atlantic Ocean 1906-1949

The data have been extracted and compiled from various sources but mainly from the ICES data base. The ICES data are from catch databases downloaded from the ICES website on 2014-01-14. These data are resolved by ICES area, country and year. During inspection of these data, it was noted that Norwegian data for years before 1950 had not been entered into the catch database on the ICES website. ICES has been notified of this omission by B. R. MacKenzie. The Norwegian data from ICES Bulletins. Statistiques has been added. Additional historical bluefin tuna catch data from other fishery reports and sources have been included in the data file for years preceding those when countries started reported their landings officially to ICES. These additional data have been reported in the literature previously (MacKenzie and Myers 2007, Fisheries Research).

Literature review of elasmobranch bycatch and retention rate

To address growing concern over the effects of fisheries non-target catch on elasmobranchs worldwide, the accurate reporting of elasmobranch catch is essential. This requires data on a combination of measures, including reported landings, retained and discarded non-target catch, and post-discard survival. Identification of the factors influencing discard vs. retention is needed to improve catch estimates and to determine wasteful fishing practices. To do this we compared retention rates of elasmobranch non-target catch in a broad subset of fisheries throughout the world by taxon, fishing country, and gear. A regression tree and random forest analysis indicated that taxon was the most important determinant of retention in this dataset, but all three factors together explained 59% of the variance. Estimates of total elasmobranch removals were calculated by dividing the FAO global elasmobranch landings by average retention rates and suggest that total elasmobranch removals may exceed FAO reported landings by as much as 400%. This analysis is the first effort to directly characterize global drivers of discards for elasmobranch non-target catch. Our results highlight the importance of accurate quantification of retention and discard rates to improve assessments of the potential impacts of fisheries on these species.