Effects of commercial fishing on local abundance of Pacific cod (Gadus macrocephalus) in the Bering Sea

Groundfish fisheries in the southeast Bering Sea in Alaska have been constrained in recent years by management measures to protect the endangered Steller sea lion (Eumetopias jubatus). There is concern that the present commercial harvest may produce a localized depletion of groundfish that would affect the foraging success of Steller sea lions or other predators. A three-year field experiment was conducted to determine whether an intensive trawl fishery in the southeast Bering Sea created a localized depletion in the abundance of Pacific cod (Gadus macrocephalus). This experiment produced strongly negative results; no difference was found in the rate of seasonal change in Pacific cod abundance between stations within a regulatory no-trawl zone and stations in an immediately adjacent trawled area. Corollary studies showed that Pacific cod in the study area were highly mobile and indicated that the geographic scale of Pacific cod movement was larger than the spatial scale used as the basis for current no-trawl zones. The idea of localized depletion is strongly dependent on assumed spatial and temporal scales and contains an implicit assumption that there is a closed local population. The scale of movement of target organisms is critical in determining regional effects of fishery removals.

Semiempirical down-scaling of GCM output to the local scale for temperature, precipitation, and runoff

EXTRACT (SEE PDF FOR FULL ABSTRACT): An empirically derived multiple linear regression model is used to relate a local-scale dependent variable (either temperature, precipitation, or surface runoff) measured at individual gauging stations to six large-scale independent variables (temperature, precipitation, surface runoff, height to the 500-mbar pressure surface, and the zonal and meridional gradient across this surface). ...The area investigated is the western United States. ... The calibration data set is from 1948 through 1988 and includes data from 268 joint temperature and precipitation stations, 152 streamflow stations (which are converted to runoff data), and 24 gridded 500-mbar pressure height nodes.

Some effects of tropical storm Agnes on water quality in the Patuxent River estuary

A post Agnes study emphasizing environmental factors...weekly sampling at eight stations from 28 June to August 30, 1972. Spatial and temporal changes in the distribution of many factors, e.g., salinity, dissolved oxygen (DO), seston, particulate carbon and nitrogen, inorganic and organic fractions of dissolved nitrogen and phosphorus, and chlorophyll a were studied and compared to earlier extensive records. Patterns shown by the present data were compared especially with a local heavy storm that occurred in the Patuxent drainage basin during July 1963. Some interesting correlations were observed in the data. (PDF has 39 pages.)

Some effects of Hurricane Agnes on water quality in the Patuxent River Estuary

A post-Agnes study that emphasized environmental factors was carried out on the Patuxent River estuary with weekly sampling at eight stations from 28 June t o 30 August 1972. Spatial and temporal changes in the distribution of many factors , e.g., salinity , dissolved oxygen, seston, particulate carbon and nitrogen, inorganic and organic fractions of dissolved nitrogen and phosphorus, and chlorophyll a were studied and compared t o extensive earlier records. Patterns shown by the present data were compared especially with a local heavy storm that occurred in the Patuxent drainage basin during July 1969. Estimates were made of the amounts of material contributed via upland drainage. A first approximation indicated that 14.8 x l0 (3) metric tons of seston were contributed t o the head of the estuary between 21 and 24 June. (PDF contains 46 pages)

A comparison of seafloor habitats and associated benthic fauna in areas open and closed to bottom trawling along the central California Continental Shelf

Executive Summary: A number of studies have shown that mobile, bottom-contact fishing gear (such as otter trawls) can alter seafloor habitats and associated biota. Considerably less is known about the recovery of these resources following such disturbances, though this information is critical for successful management. In part, this paucity of information can be attributed to the lack of access to adequate control sites – areas of the seafloor that are closed to fishing activity. Recent closures along the coast of central California provide an excellent opportunity to track the recovery of historically trawled areas and to compare recovery rates to adjacent areas that continue to be trawled. In June 2006 we initiated a multi-year study of the recovery of seafloor microhabitats and associated benthic fauna inside and outside two new Essential Fish Habitat (EFH) closures within the Cordell Bank and Gulf of the Farallones National Marine Sanctuaries. Study sites inside the EFH closure at Cordell Bank were located in historically active areas of fishing effort, which had not been trawled since 2003. Sites outside the EFH closure in the Gulf of Farallones were located in an area that continues to be actively trawled. All sites were located in unconsolidated sands at equivalent water depths. Video and still photographic data collected via a remotely operated vehicle (ROV) were used to quantify the abundance, richness, and diversity of microhabitats and epifaunal macro-invertebrates at recovering and actively trawled sites, while bottom grabs and conductivity/temperature/depth (CTD) casts were used to quantify infaunal diversity and to characterize local environmental conditions. Analysis of still photos found differences in common seafloor microhabitats between the recovering and actively trawled areas, while analysis of videographic data indicated that biogenic mound and biogenic depression microhabitats were significantly less abundant at trawled sites. Each of these features provides structure with which demersal fishes, across a wide range of size classes, have been observed to associate. Epifaunal macro-invertebrates were sparsely distributed and occurred in low numbers in both treatments. However, their total abundance was significantly different between treatments, which was attributable to lower densities at trawled sites. In addition, the dominant taxa were different between the two sites. Patchily-distributed buried brittle stars dominated the recovering site, and sea whips (Halipteris cf. willemoesi) were most numerous at the trawled site though they occurred in only five of ten transects. Numerical classification (cluster analysis) of the infaunal samples also revealed a clear difference between benthic assemblages in the recovering vs. trawled areas due to differences in the relative abundances of component species. There were no major differences in infaunal species richness, H′ diversity, or J′ evenness between recovering vs. trawled site groups. However, total infaunal abundance showed a significant difference attributable to much lower densities at trawled sites. This pattern was driven largely by the small oweniid polychaete Myriochele gracilis, which was the most abundant species in the overall study region though significantly less abundant at trawled sites. Other taxa that were significantly less abundant at trawled sites included the polychaete M. olgae and the polychaete family Terebellidae. In contrast, the thyasirid bivalve Axinopsida serricata and the polychaetes Spiophanes spp. (mostly S. duplex), Prionospio spp., and Scoloplos armiger all had significantly to near significantly higher abundances at trawled sites. As a result of such contrasting species patterns, there also was a significant difference in the overall dominance structure of infaunal assemblages between the two treatments. It is suggested that the observed biological patterns were the result of trawling impacts and varying levels of recovery due to the difference in trawling status between the two areas. The EFH closure was established in June 2006, within a month of when sampling was conducted for the present study, however, the stations within this closure area are at sites that actually have experienced little trawling since 2003, based on National Marine Fishery Service trawl records. Thus, the three-year period would be sufficient time for some post-trawling changes to have occurred. Other results from this study (e.g., similarly moderate numbers of infaunal species in both areas that are lower than values recorded elsewhere in comparable habitats along the California continental shelf) also indicate that recovery within the closure area is not yet complete. Additional sampling is needed to evaluate subsequent recovery trends and persistence of effects. Furthermore, to date, the study has been limited to unconsolidated substrates. Ultimately, the goal of this project is to characterize the recovery trajectories of a wide spectrum of seafloor habitats and communities and to link that recovery to the dynamics of exploited marine fishes. (PDF has 48 pages.)

A quantitative analysis of the phytoplankton of the Gulf of Panama: I. Results of the regional phytoplankton surveys during July and November 1957 and March 1958

ENGLISH: 1. Quantitative phytoplankton samples were collected by the Inter-American Tropical Tuna Commission at the surface and ten meters in the Gulf of Panama, as follows: a) 18-21 March, 1958 (31 stations)-during the height of the upwelling season, b) 10-12 July, 1957 (10 stations)-during the transition to the rainy season at a time when mild upwelling winds reappear, c) 7-8 November, 1957 (15 stations)-during the height of the rainy season. 2. Maximum phytoplankton populations occurred during the upwelling season, followed by a considerable decline during July, and a further Subsidence during November. 3. A remarkable regional uniformity in species composition was observed during the surveys despite regional differences in growth conditions. Diatoms overwhelmingly dominated the communities. 4. During all surveys, the innermost regions, generally north of 8°30'N, were the most productive. The least productive areas were in the offing of San Miguel Bay and Parita Bay, suggesting that nutrient accretion via runoff is inadequate to sustain sizeable autotrophic plant populations in those regions. 5. During all surveys, phytoplankton growth appeared to be limited by nutrient availability. 6. During all surveys, phytoplankton growth appeared to be related to depth of the water column. 7. Although below average rainfall contributed to unusually favorable growth conditions (reduced stability, increased transparency and, presumably, nutrient reserves) during the November survey relative to November 1955 and 1956 at 8°45'N, 79°23'W, the anticipated heightened phytoplankton response was not observed. 8. During the November survey, the local diatom responses and their regional fluctuations could be satisfactorily related to the accompanying surface salinity conditions. However, this correspondence is undoubtedly attributable to factors associated with the observed salinity levels, probably nutrients, rather than salinity directly. 9. Unusually warm conditions occurred during the March survey, attributable to considerably weaker upwelling winds than normally occurring then, which contributed to a considerably lower standing crop and a retardation in succession of three to five weeks relative to that observed during 1955-1957 at 8°45'N, 79°23'W in the Gulf of Panama. 10. During the March survey, a well defined inverse relationship existed between mean temperature and mean diatom abundance in the upper ten meters, and between transparency and mean diatom abundance. A direct relationship occurred between surface salinity and mean diatom abundance in the upper ten meters. These relationships are interpreted to indicate that diatom abundance primarily reflected the nutrient concentrations associated with a given upwelling intensity, rather than describing casual relationships. 11. The survey results indicate that the phytoplankton dynamics observed at 8°45'N, 79°23'W from November, 1954 through May, 1957 are generally representative of the Gulf of Panama. 12. The following new forms, to be described in a later publication, were observed during the surveys: Actinoptychus undulatus f. catenata n.f., Asterionella japonica f. tropicum n.f., Leptocylindrus maximus n. sp., Skeletonema costatum f. tropicum n.f. SPANISH: 1. La Comisión Interamericana del Atun Tropical recolectó en el Golfo de Panama muestras cuantitativas de fitoplancton en la superficie y a los diez metros, como sigue: a) Del 18 al 21 de marzo de 1958 (31 estaciones)-durante el maximum de la estación de afloramiento. b) Del 10 al 12 de julio de 1957 (10 estaciones)-durante la epóca de transición a la estación lluviosa cuando reaparecen los vientos ligeros que causan el afloramiento. c) Del 7 al 8 de noviembre de 1957 (15 estaciones)-durante el maximum de la estación lluviosa. 2. Las poblaciones maximas de fitoplancton aparecieron durante la estación de afloramiento, seguido por una considerable disminución durante el mes de julio y una calma durante noviembre. 3. Durante la investigación se observó una remarcable uniformidad regional en la composición de las especies a pesar de las diferencias regionales en las condiciones de crecimiento. Las diatomeas predominaban en gran numero en las comunidades. 4. Durante todas las investigaciones, las regiones mas cerca de la costa, generalmente al norte de los 8°30'N, eran las mas productivas. Las areas menos productivas fueron las mar afuera de las Bahias de San Miguel y Parita, lo que sugiere que el aumento en las sales nutritivas causado por las escorrentias es inadecuado para sostener poblaciones grandes de plantas autotróficas en estas regiones. 5. Durante todas las investigaciones, el crecimiento del fitoplancton parecio estar limitado por la disponibilidad de las. sales nutritivas. 6. Durante todas las investigaciones el crecimiento del fitoplancton parecio estar relacionado con la profundidad de la columna de agua. 7. Aunque las precipitacion por debajo del promedio normal contribuyo a condiciones desusadamente favorables de crecimiento (estabilidad reducida, aumento de la transparencia y, presumiblemente, de la reserva de sales nutritivas) durante la investigación de noviembre en relación a noviembre de 1955 y de 1956 en los 8°45'N, 79°23'W, no se observo-la alta reacción de fitoplancton que se esperaba. 8. Durante la investigación de noviembre, las reacciones locales de las diatomeas y sus fluctuaciones regionales pudieron relacionarse en forma satisfactoria con condiciones asociadas con la salinidad de la superficie. Sin embargo, esta correspondencia puede atribuirse sin duda a factores asociados con los niveles observados de salinidad, probablemente con las sales nutritivas, en lugar de directamente con la salinidad. 9. Condiciones calurosas no comunes ocurrieron durante la investigación de marzo, las que pueden atribuirse a que los vientos que ocasionan el afloramiento fueran mas debiles que los normales, lo que contribuyó a que la cosecha estable fuera considerablemente mas baja y a la demora de tres a cinco semanas en la sucecion relativa a la que se observó durante 1955-1957 en los 8°45'N, 8°23'W, en el Golfo de Panama. 10. Durante la investigación de marzo, existió una relación inversa bien definida entre la temperatura y la abundancia media de las diatomeas en los diez metros superiores, y entre la transparencia y la abundancia media de las diatomeas. Una relación directa ocurrio entre la salinidad de superficie y la abundancia media de las diatomeas en los diez metros superiores. Estas relaciones se interpretan como indicadoras de que la abundancia de diatomeas refleja primeramente las concentraciones de las sales nutritivas asociadas con una intensidad de afloramiento dada, en lugar de describir relaciones causales. 11. Los resultados de la investigacion indican que la dinamica del fitoplancton observada en los 8°45'N, 79°23'W, desde noviembre de 1954 a mayo de 1957, es generalmente representativa del Golfo de Panama. 12. Durante las investigaciones se observaron las siguientes formas nuevas, las que seran descritas en una publicación posterior: Actinoptychus undulatus f. catenata n.f., Asterionella japonica f. tropicum n.f., Leptocylindrus maximus n. sp., Skeletonema costatum f. tropicum n.f.

"Future fit your catalog" Panel [Presentation]:World Cat Local Implementation as part of a Consortia of Libraries within the University System of Maryland and Affiliated Institutitons

Power Point from Panel presentation giving implementation and search result displays and linking (17 slides)

Engaging local communities in aquatic resources research and activities: a technical manual

This document is part of a series of 5 technical manuals produced by the Challenge Program Project CP34 “Improved fisheries productivity and management in tropical reservoirs”. The objective of this technical manual is to relay the field experience of a group of scientists who have worked extensively in small fisheries in sub-Sahara Africa and Asia and lay out a series of simple and pragmatic pointers on how to establish and run initiatives for community catch assessment. The manual relies in particular on practical experience gained implementing Project 34 of the Challenge Programme on Water and Food: Improved Fisheries Productivity and Management in Tropical Reservoirs. (PDF contains 26 pages)

An investigation of the organization of canoe fisheries in Nigeria: A case study of Ilaje/Esedo local government area of Ondo State

The effects of some socio-economic variables on the performance of artisanal fishermen were investigated. The variables include the age-structure of the fishermen, level of investment, educational background, membership of co-operative societies and marketing arrangements. All these variables were found to be crucial to productivity in the artisanal fishing sector

Local solutions to local problems: A stormwater education collaborative

Currently completing its fifth year, the Coastal Waccamaw Stormwater Education Consortium (CWSEC) helps northeastern South Carolina communities meet National Pollutant Discharge Elimination System (NPDES) Phase II permit requirements for Minimum Control Measure 1 - Public Education and Outreach - and Minimum Control Measure 2 - Public Involvement. Coordinated by Coastal Carolina University, six regional organizations serve as core education providers to eight coastal localities including six towns and cities and two large counties. CWSEC recently finished a needs assessment to begin the process of strategizing for the second NPDES Phase II 5-year permit cycle in order to continue to develop and implement effective, results-oriented stormwater education and outreach programs to meet federal requirements and satisfy local environmental and economic needs. From its conception in May 2004, CWSEC set out to fulfill new federal Clean Water Act requirements associated with the NPDES Phase II Stormwater Program. Six small municipal separate storm sewer systems (MS4s) located within the Myrtle Beach Urbanized Area endorsed a coordinated approach to regional stormwater education, and participated in a needs assessment resulting in a Regional Stormwater Education Strategy and a Phased Education Work Plan. In 2005, CWSEC was formally established and the CWSEC’s Coordinator was hired. The Coordinator, who is also the Environmental Educator at Coastal Carolina University’s Waccamaw Watershed Academy, organizes six regional agencies who serve as core education providers for eight coastal communities. The six regional agencies working as core education providers to the member MS4s include Clemson Public Service and Carolina Clear Program, Coastal Carolina University’s Waccamaw Watershed Academy, Murrells Inlet 2020, North Inlet-Winyah Bay National Estuarine Research Reserve’s Coastal Training and Public Education Programs, South Carolina Sea Grant Consortium, and Winyah Rivers Foundation’s Waccamaw Riverkeeper®. CWSEC’s organizational structure results in a synergy among the education providers, achieving greater productivity than if each provider worked separately. The member small MS4s include City of Conway, City of North Myrtle Beach, City of Myrtle Beach, Georgetown County, Horry County, Town of Atlantic Beach, Town of Briarcliffe Acres, and Town of Surfside Beach. Each MS4 contributes a modest annual fee toward the salary of the Coordinator and operational costs. (PDF contains 3 pages)

Stormsmart coasts in action: Two case studies of local level climate change adaptation

Coastal communities throughout the United States have dealt with the devastating effects of storms for centuries, however today’s threats are greater due to three factors. First, the population along the coastline has grown, and is projected to increase.i Additionally, past land use management decisions in the coastal zone have rarely led to the greatest protection from threats. Finally, climate change is predicted to affect coastal areas by accelerating current sea level rise rates and possibly increasing storm intensity.ii These factors compounded together mean that coastal communities are facing a very dangerous situation that threatens economies and human life. (PDF contains 4 pages)

Studies of the effects from extracts from two local plants (Tephrosia vogelii and Parkia clappertoniana) on Clarias gariepinus (Tengels)

Studies were carried out using 96hr static toxicity bioassay to determine the effect of lethal concentrations of extracts from two local plants Tephrosia vogelii and Parkia clappertoniana which are known fish poison, on a species of mud fish. Clarias gariepinus Phytochemical analysis of the plant extracts was done and the extract from T. vogelii was found to contain alkaloids, tannins and flavonoids, while the extract from P. clappertoniana was formed to contain alkaloids tannins and saponins. Experimental fish were exposed to test water separately polluted by varying concentrations of extraction of both plant species ranging from 0.50mgl super(-1), 1.50mgl super(-1), 2.50mgl super(-1), 3.0mgl super(-1), 5.00mgl super(-1), 10.00mgl super(-1) in the case of T. vogelii and 5.00mgl super(-1), 7.50mgl super(-1), 10.00mgl super(-1), 15.00mgl super(-1), 20.00mgl super(-1) and 30.00mgl super(-1) in the case of P. clappertaniana. Behavioural hispathological and heamatological examinations were made. Both plant extracts were found to have lethal effects at the higher concentrations, affecting the gills and the central nervous system as well as having a depressive effect on the total count and increasing platelet and white blood cell count. Symptoms of toxicosis observed include, initial inactivation agitated swimming, tumbling movement air gulping, increased opercular beat and period of quiescence/knockdown before death. Marked differences were also observed in the hematological and histopathological analysis of poisoned fish. Lower concentrations of the extracts had sub lethal effects on the fish, which manifested as zigzag movement air gulping increased opercular movement etc. None of these effects were observed in the control experiment

Poverty alleviation among fishermen within the floodplains of Kaduna River: implication for introducing commercial fish farming at village level in Doko local government area of Niger State, Nigeria

A diagnostic survey was conducted among the fishermen in six selected villages in Doko Local Government Area of Niger State. One hundred and fifty fishermen were randomly selected and interviewed to find out whether or not they had interest in commercial fish farming aimed at improving their livelihood. The dwindling fish catches in the natural flood plain ponds and Ex-bow Lakes continue to have a serious negative effect on the socio-economic well being of the village communities in question. A break on natural regular annual flooding of the plains had resulted into very low natural fish recruitment. Data analysis using simple descriptive statistics revealed that land tenure system, educational status, inadequate infrastructural facilities, religious taboos, existing fish species among others were found to be favourable indices for commercial fish farming. However, serious conflicts among the fishermen concerning the ownership status of these natural fish ponds are found to be major obstacles to commercial fish farming despite that the traditional ownership of the ponds were vested in the lands of individuals and village communities. Extensive fish farming and small-scale fish farming in the ponds and Ex-bow Lake with improved management practices are considered to be profitable venture. Despite the fact that fish seeds supply and extension effort are still inadequate, the fish farmers have indicated willingness to adopt commercial fish farming in the Ex-bow Lakes and flood plains in order to restore abundant fish production thereby providing for their food security and also increasing the daily income

Impact assessment of Niger State fisheries legislation on fisheries conservation in Edozhigi local government area (L.G.A.) of Niger State

A preliminary survey was conducted among the fishermen in five selected villages in Edozhigi L.G.A. of Niger State. One hundred and fifty fishermen were randomly selected and interviewed to find out the impact of Niger State fisheries legislation on fisheries conservation resources in the area. The analysis of data collected using descriptive statistics indicated that undersized mesh of gill nets, beach seines and traps are being used unabated. Also, fenced barriers across the entrance of flood plain ponds and Ex-bow lakes from the main stream are in the area. The fisheries rules and regulations implementers are rarely seen or not seen at all in the area. The decreasing nature of fish catches was detected. It is observed that government policy on fish conversation is neglected due to inadequate or lack of funding for meaningful extension and implementation of the fisheries rules and regulations