Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
Rhode Island ◽  
Field Experiments ◽  
Fish Habitat ◽  
Quantitative Model ◽  
Narragansett Bay ◽  
Fishing Gear ◽  
Essential Fish Habitat ◽  
Side Scan Sonar ◽  
Biological Communities ◽  
The Impact

<em>Abstract.</em> —Seabed disturbance by mobile bottom-fishing gear has emerged as a major concern related to the conservation of essential fish habitat. Unquestionably, dredges and trawls disturb the seabed. However, the seabed is also disturbed by natural physical and biological processes. The biological communities that utilize a particular habitat have adapted to that environment through natural selection, and, therefore, the impact of mobile fishing gear on the habitat structure and biological community must be scaled against the magnitude and frequency of seabed disturbance due to natural causes. Fishers operating in the mouth of Narragansett Bay, Rhode Island use trawls to harvest lobsters, squid, and finfish and dredges to harvest mussels. These mobile fishing gears impact rock, sand, and mud substrates. Side-scan sonar data from 1995 with 200% coverage were available from the National Oceanic and Atmospheric Administration for the mouth of Narragansett Bay. Analysis of these data indicates that evidence of bottom scarring by the fishing gear is restricted to deeper waters with a seabed composition of soft cohesive sediments, despite the observation that fishing activity is ubiquitous throughout the bay mouth. A quantitative model has been developed to compare the magnitude and frequency of natural seabed disturbance to mobile fishing gear disturbance. Wave and tidal currents at the seabed are coupled with sediment characteristics to estimate the degree of seabed disturbance. Field experiments designed to compare the longevity of bottom scars indicate that scars in shoal waters and sand sediments are short-lived, as compared to scars in deep water and mud sediments, which are long-lasting. Finally, the model results are compared to the recovery time of sediments disturbed by the interaction of the fishing gear with the seabed. The impact of mobile fishing gear on the seabed must be evaluated in light of the degree of seabed disturbance due to natural phenomena. The application of this model on a larger scale to continental shelf waters and seabed sediment environments will allow for the identification of problematic areas relative to the degradation of essential fish habitat by mobile fishing gear.

Managing the Impacts of Human Activities on Fish Habitat: The Governance, Practices, and Science

2015 ◽  
Keyword(s):  
Benthic Invertebrates ◽  
Marine Mammals ◽  
Fish Habitat ◽  
Fishing Gear ◽  
Governance Practices ◽  
Coexisting Species ◽  
The Government ◽  
The Impact ◽  
Poor Infrastructure ◽  
Technical Measures

<em>Abstract.</em>—Mexico is an important producer of fish resources, contributing 1.5% to the total world production. However, most of the fisheries are overexploited or fished to the maximum sustainable level as a result of problems such as overexploitation, poor infrastructure, poaching, limited knowledge of fishing laws, high discard rates, weak fisheries institutions, and little ability to research and manage these difficulties. To solve these problems, the National Program of Fisheries and Aquaculture was established in order to achieve sustainability in Mexican fisheries with the participation of the government, the fishing industry and research institutions. The program has been implemented for the 22 main fisheries of the country, notably the tuna, shrimp and shark fisheries, for which technical measures have been implemented for controlling the catch, the effort and the impact on coexisting species. Specifically, these measures have been aimed at reducing the bycatch of marine mammals and turtles, demersal and benthopelagic fishes and benthic invertebrates. Also, measures have been implemented to mitigate impacts of fishing gear on the benthos and coral reefs. However, many issues still need to be resolved both for these and other lower revenue fisheries, which are important in terms of their effect on ecosystems.

scholarly journals Evaluating benthic impact of the Gulf of Maine lobster fishery using the swept area seabed impact (SASI) model

2021 ◽  
Author(s):  
Andrew G Goode ◽  
Jonathan H Grabowski ◽  
Damian C. Brady
Keyword(s):  
Gulf Of Maine ◽  
Fish Habitat ◽  
Fishing Effort ◽  
American Lobster ◽  
Fishing Gear ◽  
Marine Habitats ◽  
Small Footprint ◽  
Lobster Fishery ◽  
The Impact ◽  
Swept Area

The Magnuson-Stevens Fishery Conservation and Management Act mandates U.S. fisheries minimize adverse effects of fishing on essential fish habitat (EFH). The Gulf of Maine (GoM) American lobster fishery is the most valuable U.S. fishery, and can deploy more than three million traps annually. To date, the impact of this fishery on benthic EFH has not been addressed quantitatively. To evaluate the impact of the GoM lobster fishery on EFH, lobster fishing effort was incorporated into a model linking habitat susceptibility and recovery to area impacted by fishing gear; the Swept Area Seabed Impact model. Impact to EFH was localized along the coast and highest along mid-coast Maine. Upwards of 13% of the benthos is in the process of recovery, but between 99.92 – 99.96% of initially affected habitat fully recovers. These estimates suggest that lobster fishing negligibly contributes to accumulation of EFH damage in the GoM due to the expansive area fished and the small footprint of each trap. Identifying areas of persistent impact is crucial in developing effective fisheries management for critical marine habitats.

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
Rhode Island ◽  
Statistical Tests ◽  
Fish Habitat ◽  
Sampling Technique ◽  
Homarus Americanus ◽  
Sidescan Sonar ◽  
Density Estimates ◽  
Side Scan Sonar ◽  
Contour Interval ◽  
Definition Of

<em>Abstract.</em> —The American lobster <em>Homarus americanus </em> is usually associated with rocky substrate that provides or can be modified into shelter and that may be an essential habitat to early benthic-phase juveniles. The dependence on shelter-providing habitat not only makes possible the definition of essential habitat for lobsters but also permits the assessment of abundance based on the areal extent of habitat. Here, we describe such a habitat-based assessment, performed in response to an oil spill on the coast of Rhode Island, USA. Results from a side-scan sonar survey performed after the spill indicated that the amount of lobster habitat affected by the oil was approximately 9.8 km2 along nearly 15 km of coastline. Postspill lobster density ranged from 0.24 lobsters m22 in the impact region to 1.63 lobsters m22 in the control region. Qualitative (map contours of lobster density) and quantitative (statistical tests) approaches suggested a significant effect of the spill had been detected by our sampling. An estimate of the total number of lobsters killed was required to scale restoration efforts. We calculated the total number of lobsters in the area by overlaying contours of lobster density on a habitat map generated by side-scan sonar, then multiplying the density of lobsters in each contour interval by the area of appropriate lobster habitat (cobble and boulder) in the contour interval. To calculate loss, we subtracted postspill abundance from prespill abundance. Prespill density was estimated to be 1.76 m22, which is an adjusted average of airlift samples taken at six Rhode Island sites four months prior to the spill. Calculations of loss based on habitat-specific density estimates were adjusted to reflect undersampling. The loss was estimated to be to be 9.0 × 106 lobsters. Variability associated with this loss estimate is large; 95% confidence intervals estimated that between 6.7 × 106 and 15.6 × 106 lobsters were lost. The calculated loss was very sensitive to changes in prespill density estimates; a change of 0.1 lobsters m22 resulted in a change of 0.75–0.9 × 106 lobsters lost. Habitatbased assessment of lobster population size is possible but requires detailed habitat maps and accurate density estimates. Natural variability and sampling limitations give such assessment a wide range of possible values. Nevertheless, the airlift sampling technique, together with sidescan sonar maps of habitat, could provide a powerful tool for estimating the abundance of inshore lobsters.

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
New England ◽  
Fisheries Management ◽  
Habitat Management ◽  
Fish Habitat ◽  
Regulatory System ◽  
Initial Study ◽  
Accurate Information ◽  
Fishing Gear ◽  
Essential Fish Habitat ◽  
Management Plans

<em>Abstract.</em> —This study sought input from fishermen on their knowledge of fish habitat and the effects of fishing gear to fill some gaps in the science. We looked for any documentation of habitats and effects to habitats from fishing gear or other causes that fishermen could or were willing to provide. This report summarizes documentation provided by fishermen of fish habitat, changes to habitat observed over time, and fishing gear effects. In addition, the report evaluates the effectiveness of different approaches to identify fishermen’s knowledge and document their observations. To better represent fishermen and provide accurate information, we were interested in fishermen’s responses to two questions: (1) How can we better solicit fishermen’s knowledge of habitat, and (2) what would make it possible for fishermen to share that information? The results of this study were influenced by several factors, including the fact that methodologies for integrating fishermen’s knowledge into fisheries scientific literature and fisheries management are at an embryonic stage. In addition, for this initial study, resources were limited, which gave the survey a strong New England bias. We also found that fishermen are reluctant to get involved in essential fish habitat identification for several reasons, including the perceived proprietary nature of their habitat information. This review represents an important first step toward making the crucial linkage between fisheries management and fishermen’s local knowledge. This study and future similar studies will provide opportunities to bring fishermen’s knowledge to the forefront as essential fish habitat management plans are being developed. The contribution of fishermen’s knowledge should help managers design a balanced regulatory system that will lead to sustainable fisheries and fisheries communities.

scholarly journals Inexpensive Video Drop-camera for Surveying Sensitive Benthic Habitats: Applications from Glass Sponge (Hexactinellida) Reefs in Howe Sound, British Columbia

2017 ◽  
Vol 131 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Lena Clayton ◽  
Glen Dennison
Keyword(s):  
British Columbia ◽  
Software Package ◽  
Fishing Gear ◽  
Benthic Habitats ◽  
Glass Sponge ◽  
Side Scan Sonar ◽  
Cost Efficient ◽  
Ground Truthing ◽  
The Impact ◽  
Sponge Bioherms

Where marine waters are shallow and bathymetric features are steep, the typically employed multi-beam side scan sonar is not always reliable for identifying complex biological structures. Here, we present a cost-efficient method used in Howe Sound, British Columbia, for bathymetric mapping, exploration, and ground-truthing of glass sponge bioherms. A simple depth sounder and software package was used to produce bathymetric maps. From these maps, prospective sites were selected and surveyed to investigate bioherm presence with a simple drop-camera towed off the bow of a small drifting vessel during calm seas. This method was used during a 4-year citizen science initiative that led to the discovery of 12 glass sponge bioherms in Howe Sound, the first step in protecting these globally unique reefs from the impact of bottom-contact fishing, anchoring, and potential industrial contamination. Before our work using this method, only two glass sponge bioherms had been identified in Howe Sound. The method also proved effective as a means to quantify damage to bioherms from fishing gear.

Impact of elevated temperature on the growth, survival, and trophic dynamics of winter flounder larvae: a mesocosm study

2000 ◽  
Vol 57 (12) ◽  
pp. 2382-2392 ◽  
Author(s):  
Aimee A Keller ◽  
Grace Klein-MacPhee
Keyword(s):  
Rhode Island ◽  
Narragansett Bay ◽  
Winter Flounder ◽  
Trophic Dynamics ◽  
Zooplankton Abundance ◽  
Pseudopleuronectes Americanus ◽  
Egg Survival ◽  
Cumulative Impact ◽  
Commercial Fish ◽  
The Impact

Winter flounder (Pseudopleuronectes americanus) is a dominant commercial fish in Narragansett Bay, Rhode Island, and yet factors controlling its recruitment remain unclear. An experiment was conducted with six 13-m3 land-based mesocosms (5 m deep) from February to April 1997 to address the impact of increased temperature (+3°C) on growth, survival, and trophic dynamics of winter flounder larvae. Objectives were to determine if warmer winter temperatures result in lower survival of winter flounder as a result of increased predator activity or if temperature-induced alterations in the food web result in greater food availability, perhaps leading to increased survival. Analyses of variance revealed significant (P < 0.05) or near-significant (P < 0.10) differences in phytoplankton and zooplankton abundance and biomass between warm and cool mesocosms. Winter flounder egg survival, percent hatch, time to hatch, and initial size were significantly greater in cool systems (P < 0.05). Mortality rates were lower in cool systems and significantly related to the abundance of active predators (P < 0.05). The cumulative impact of decreased survival of eggs and larvae in warm systems may partially explain the decline of winter flounder in Narragansett Bay, which has experienced elevated winter water temperatures in recent years.

INFLUENCE OF THE DIFFERENT SOIL PREPARATION METHODS ON THE PEA YIELD

2018 ◽  
pp. 16-20
Author(s):  
А. М. Grebennikov ◽  
А. S. Frid ◽  
V. P. Belobrov ◽  
V. А. Isaev ◽  
V. М. Garmashоv ◽  
...  
Keyword(s):  
Field Experiments ◽  
Morphological Properties ◽  
Mineral Fertilizers ◽  
First Year ◽  
Zero Tillage ◽  
Preparation Methods ◽  
Soil Preparation ◽  
Multifactor Analysis ◽  
The Impact ◽  
Central Chernozem

The article assesses the relationships between the morphological properties of agrochernozems and yield of peas on the plots, experience with different methods of basic treatment (moldboard plowing at the depth of 20 - 22, 25 - 27 and 14 - 16 cm, moldboard plowing to a depth of 14 - 16 cm, combined midwater moldboard, mid-water subsurface, surface to a depth of 6 - 8 cm and zero tillage) is inherent in V.V. Dokuchaev Research Institute of Agriculture of the Central Black Earth strip, in the fall of 2014. The research was conducted in 2015 - 2016, with the application of mineral fertilizers (N60Р60К60) and unfertilized background. The highest pea yields in the fertilized as the background, and without the use of fertilizers was observed in dumping plowing and especially in the variant with deep moldboard plowing, which creates in comparison with other ways of handling the best conditions for the growth and development of peas. The lowest yield of pea was obtained with zero processing. Apparently legalistic migrational-mizelial agrochernozems the Central Chernozem zone of minimum tillage in the cultivation of peas are not effective, what is evident already in the first year after the laying of experience with different basic treatments. As shown by the results of applying multifactor analysis of variance studied the mapping properties of the soil can have the same significant impact on the yield of agricultural crops, as options for the field experiments aimed at assessing the impact of various treatments on yield.

AMOUNT AND STRUCTURE OF THE BIOLOGICAL FERTILITY OF SOYA, DEPENDING ON THE SYSTEM OF MAIN TILLAGE OF SOIL AND MEASURES TO OPTIMIZE NUTRITION MODE

2020 ◽  
Author(s):  
M. Novokhatskyi ◽  
◽  
V. Targonya ◽  
T. Babinets ◽  
O. Gorodetskyi ◽  
...  
Keyword(s):  
Field Experiments ◽  
Optimal Number ◽  
Soil Tillage ◽  
Forest Steppe ◽  
Biological Productivity ◽  
Tillage Systems ◽  
Application Rates ◽  
Tillage System ◽  
Biological Yield ◽  
The Impact

Aim. Assessment of the impact of the most common systems of basic tillage and biological methods of optimization of nutrition regimes on the realization of the potential of grain productivity of soybean in the Forest-Steppe of Ukraine. Methods. The research used general scientific (hypothesis, experiment, observation) and special (field experiment, morphological analysis) methods Results. The analysis of the results of field experiments shows that the conservation system of soil cultivation, which provided the formation of 27.6 c/ha of grain, is preferable by the level of biological yield of soybean. The use of other systems caused a decrease in the biological yield level: up to 26.4 c/ha for the use of the traditional system, up to 25.3 c/ha for the use of mulching and up to 23.0 c/ha for the use of the mini-till. With the use of Groundfix, the average biological yield of soybean grain increases to 25.6 c / ha for application rates of 5 l/ha, and to 28.2 c/ha for application rates of 10 l/ha when control variants (without the use of the specified preparation) an average of 22.6 c/ha of grain was formed with fluctuations in soil tillage systems from 21.0 (mini-bodies) to 25.8 c/ha (traditional).The application of Groundfix (10 l/ha) reduced the seed abortion rate from 11.0% (average without biofertilizer variants) to 8.0%, forming the optimal number of stem nodes with beans, increasing the attachment height of the lower beans and improving other indicators of biological productivity soybeans. Conclusions. It has been found that the use of the canning tillage system generates an average of 27.6 cent soybean grains, which is the highest indicator among the main tillage systems within the scheme of our research. The use of Groundfix caused a change in this indicator: if the variants with a conservative system of basic tillage without the use of biological preparation (control) were formed on average 24.1 c/ha, the use of Ground Licks caused the increase of biological productivity up to 29.4 c/ha, and at a dose of 10 l/ha biological yield was 32.2 c/ha. It was found that both the use of Groundfix and the basic tillage system influenced the elements of the yield structure: the density of the plants at the time of harvest depended more on the tillage system than on the use of Groundfix; the use of Groundfix and increasing its dose within the scheme of our studies positively reflected on the density of standing plants; the height of attachment of the lower beans and reduced the abortion of the seeds.

Influence of temperature and humidity on the angle of repose of wood bulk materials

2016 ◽  
Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов
Keyword(s):  
Field Experiments ◽  
Bulk Material ◽  
Average Particle Size ◽  
Operating Conditions ◽  
Angle Of Repose ◽  
Wood Dust ◽  
Average Particle ◽  
Bulk Materials ◽  
Technical Literature ◽  
The Impact

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.

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