scholarly journals The impact of commercial fishing on the determination of habitat associations for sea scallops (Placopecten magellanicus, Gmelin)

2009 ◽  
Vol 66 (9) ◽  
pp. 2043-2051 ◽  
Author(s):  
Stephen J. Smith ◽  
Jerry Black ◽  
Brian J. Todd ◽  
Vladimir E. Kostylev ◽  
Mark J. Lundy
Keyword(s):  
Variance Reduction ◽  
Survey Design ◽  
Fishing Effort ◽  
Habitat Associations ◽  
Commercial Fishing ◽  
Placopecten Magellanicus ◽  
Bottom Type ◽  
Sea Scallops ◽  
The Impact

Abstract Smith, S. J., Black, J., Todd, B. J., Kostylev, V. E. and Lundy, M. J. 2009. The impact of commercial fishing on the determination of habitat associations for sea scallops (Placopecten magellanicus, Gmelin). – ICES Journal of Marine Science, 66: 2043–2051. The sea scallop (Placopecten magellanicus) population off southwestern Nova Scotia in Scallop Fishing Area 29 has been monitored by an annual drag survey since the fishery started there in 2001. A new stratification scheme based on surficial geology maps from a multibeam bottom mapping and geology ground-truth project completed in 2004 in the area have been used for survey design since 2005. Survey data from before 2005 have been post-stratified using the new strata. The efficiency of the design with respect to variance reduction appears to have diminished over time suggesting that the association between scallop abundance and bottom type may not have been as strong or constant as first assumed. Modelling of the association between scallop abundance and bottom type and depth using a Bayesian hierarchical approach confirms this diminishing relationship. Comparison of the results from the model with spatial measures of fishing effort based on satellite vessel monitoring data suggests that increasing exploitation may be masking the relationships as scallop beds are targeted and fished down. These results could have implications on the interpretation of species habitat associations from areas where data are only available from periods when the populations have been exploited over a long time. In these cases, the spatial distribution of fishing effort may be a better indicator of species habitat associations than the estimates from surveys.

Spatial and Temporal Overlap of the American Lobster (Homarus americanus) and Sea Scallop (Placopecten magellanicus) as Related to the impact of Inshore Scallop Dragging

1992 ◽  
Vol 49 (7) ◽  
pp. 1486-1492 ◽  
Author(s):  
D. L. Roddick ◽  
R. J. Miller
Keyword(s):  
Nova Scotia ◽  
Homarus Americanus ◽  
Fishing Effort ◽  
The Other ◽  
American Lobster ◽  
Placopecten Magellanicus ◽  
Time And Space ◽  
Sea Scallop ◽  
The Impact ◽  
Temporal Overlap

Assessment of the damage of one fishery by another requires knowledge of the overlap, in time and space, of the damaging fishing effort and the abundance of the damaged species, as well as a measure of the rate of damage. This approach was used to measure the impact of inshore scallop dragging on lobsters in Nova Scotia. Areas of reported co-occurrence of lobster and scallop grounds were surveyed by divers to determine the extent of overlap. Only 2 of 52 sites surveyed had lobsters on scallop grounds that could be dragged. Divers surveyed one site six times during 1987 and 1988 and found lobsters most abundant during August and September. Only 2% of the lobsters in the path of scallop drags were either captured or injured. The estimated value of lobsters destroyed by dragging for scallops during periods of peak lobster abundance was minor: $757 at one site and $176 at the other. Restricting dragging to periods of low lobster abundance significantly reduces this cost.

Benthic Habitats and the Effects of Fishing

2005 ◽  
Keyword(s):  
Habitat Type ◽  
High Energy ◽  
Benthic Habitat ◽  
Commercial Fishing ◽  
Placopecten Magellanicus ◽  
Benthic Species ◽  
Habitat Types ◽  
Closed Area ◽  
Sea Scallops ◽  
Moderate Complexity

<strong><em>Abstract. </em></strong>In late 1994, substantial portions of Georges Bank were closed to commercial fishing to assist with stock rebuilding. These areas were Closed Area I (CAI), located on the western portion of the bank, and Closed Area II (CAII), on the eastern portion. After about 5 years of closure, the southern portion of CAII and the central portion of CAI, having exhibited substantial increases in biomass and density of sea scallops <em>Placopecten magellanicus</em>, were reopened to scallop fishing. Before the industry was allowed entry, we conducted surveys to monitor the recovery of benthic habitat and fauna inside both areas. Sampling sites were selected in a paired station design for an inside–outside comparison representative of major habitat types in each closed area; other stations were chosen to survey the remainder of the closed areas. At each station, we examined a suite of biotic and abiotic variables ranging from substrate type to benthos to nekton. Our results suggest few differences between the inside–outside paired stations in both closed areas for nekton and benthic species composition and species richness. Fish abundance and biomass were similar inside and outside the closed areas. However, individuals of species such as skates (<em>Raja </em>spp.), haddock <em>Melanogrammus aeglefinus</em>, and flounders (Pleuronectiformes) were generally larger inside than outside the closed areas. Additionally, habitat type was important in determining the distribution, abundance, biomass, size, and feeding ecology for some of the more benthic-oriented species studied. In CAI, the differences we observed in the suite of biotic metrics are likely a result of the high diversity of habitat types, with many of the habitat types composed of higher-relief material (e.g., cobble, gravel, etc.) in the region. The seabed in the southern portion of CAII is a relatively high-energy sand habitat of low to moderate complexity and has a relatively low vulnerability to trawling and dredging, which may explain why there were less pronounced differences in abundance or biomass across habitat types in that closed area as compared to CAI. Other parts of closed areas on the northeastern shelf may exhibit more obvious changes in the same biological metrics due to the presence of more complex habitats and increased vulnerability to bottom tending fishing gear. Those differences we observed for CAI and CAII may have implications for the population dynamics of commercially valuable benthic species, yet that question remains a major challenge.

Biological reference points for sea scallops (Placopecten magellanicus): the benefits and costs of being nearly sessile

2004 ◽  
Vol 61 (8) ◽  
pp. 1338-1354 ◽  
Author(s):  
Stephen J Smith ◽  
Paul Rago
Keyword(s):  
Management Strategies ◽  
Fishing Effort ◽  
Reference Points ◽  
Placopecten Magellanicus ◽  
Nonlinear Mixed Effects Models ◽  
Lower Productivity ◽  
Boom And Bust ◽  
Sea Scallops ◽  
Habitat Damage ◽  
Definition Of

In this paper, we concentrate on spatial aspects of growth and reproduction for sea scallops (Placopecten magellanicus) to advance the general theory for development of reference points for sessile animals and to illustrate the general points with several specific examples. Nonlinear mixed effects models can be used to define the spatial distribution of growth rates and their implications for the definition of growth overfishing. We develop a basin model to illustrate that the typical "boom and bust" effects, often attributed to environmental factors, are explained equally well by spatial variations in habitat quality, spatial concentration of fisheries, and dispersal of larvae among areas. Results suggest that incentives to concentrate fishing effort in lower productivity areas may be an effective tool for reducing recruitment variation and improving yields. Reductions in fishing mortality might be possible with closed areas as they can be used to reduce the concentration of effort on high scallop densities. Further, rotational area management strategies can offer the promise of balancing demands for increased yield, prevention of recruitment overfishing, maintaining spawning reserves, and reducing habitat damage and bycatch.

Investigating the Impact of Multiple Factors on Gray Meats in Atlantic Sea Scallops (Placopecten magellanicus)

2019 ◽  
Vol 38 (2) ◽  
pp. 233
Author(s):  
Liese A. Siemann ◽  
Luisa M. Garcia ◽  
Carl J. Huntsberger ◽  
Ronald J. Smolowitz
Keyword(s):  
Placopecten Magellanicus ◽  
Multiple Factors ◽  
Sea Scallops ◽  
The Impact

scholarly journals Length-based indicators for the management of sport fishery in Yucatan, Mexico

2020 ◽  
Vol 48 (4) ◽  
pp. 637-648
Author(s):  
Jorge A. López-Rocha ◽  
Laura Vidal-Hernández ◽  
Arturo Bravo-Calderón
Keyword(s):  
Fishing Effort ◽  
Commercial Fishing ◽  
Sport Fishing ◽  
Optimal Length ◽  
Monitoring Method ◽  
Priority Level ◽  
Sport Fishery ◽  
Mycteroperca Bonaci ◽  
Sphyraena Barracuda ◽  
The Impact

Sportfishing is an activity of increasing popularity that involves a large number of users and high levels of fishing effort. In Yucatan, most of the target species in sport fishing are the same as those of commercial fisheries. However, there is no record of fishing effort or catch volumes. Thus the impact of sport fishing on these populations is unknown. This study analyzes the catches made by users of sport fisheries of nine species (Epinephelus morio, Haemulon plumieri, Seriola dumerili, Lutjanus synagris, Ocyurus chrysurus, Calamus bajonado, Sphyraena barracuda, S. guachancho and Mycteroperca bonaci) through length-based indicators. Samples of species’ sizes were obtained from the catches made during 10 fishing tournaments held in Yucatan's three-port towns (Sisal, Yucalpeten, and Telchac) between 2015 and 2016. The catch variables that were evaluated included: the number of mature individuals Pmat, optimal length Popt, and the number of mega-spawners Pmega. Length measures were derived from 1,252 individuals. Only H. plumieri, L. synagris, and S. guachancho exhibited sustainable indicator values, while E. morio and C. bajonado demonstrated extremely low values. In most species, sport fishing affects a high proportion of juveniles. The results suggest that sportfishing contributes to the fishing pressure of a species and commercial fishing, due to the capture of juveniles of economically important fish. It is essential to establish a systematic monitoring method of such activities and increase the priority level of the evaluation and management of this fishery.

Assessment of sensitivity of the efficiency of regional tax spending towards investment attractiveness of the types of economic activity carried out by the residents of advanced development territory

2020 ◽  
pp. 98-110
Author(s):  
Evgeniya Mikhailovna Popova ◽  
Guzel Mukhtarovna Guseinova ◽  
Sergei Borisovich Milov
Keyword(s):  
Economic Activity ◽  
Socioeconomic Development ◽  
Federal District ◽  
Tax Incentives ◽  
Capital Investments ◽  
The Subject ◽  
Investment Process ◽  
The Impact ◽  
Advanced Development

The deficit of subnational budgets and deceleration capital investments in multiple Russian regions increase the relevance of research aimed at improvement of tax incentivizing practice of the regional investment process. The studies focused on determination of the impact of socioeconomic and institutional factors upon the efficiency of investment tax expenses obtained wide circulation within the foreign scientific literature. The subject of this article is the assessment of sensitivity of the efficiency of regional tax expanses towards investment attractiveness of the types of economic activity carried out by the residents of territories of advanced socioeconomic development, created in the subjects of Far Easter Federal District. The scientific novelty and practical values of this research consists in substantiation of the reasonableness of assessment of investment attractiveness of the types of economic activity that are stimulated by tax incentives. Methodology for assessing investment attractiveness is proposed and tested. The conclusion is made that in case of low investment attractiveness of the type of economic activity, which was planned to support by tax incentives, it is required to conduct and additional analysis to avoid unjustified tax expanses.

Method development for the determination of textural properties of sugar beet roots

2019 ◽  
pp. 392-400 ◽  
Author(s):  
Gunnar Kleuker ◽  
Christa M. Hoffmann
Keyword(s):  
Sugar Beet ◽  
Compression Test ◽  
Storage Period ◽  
Textural Properties ◽  
Small Sample ◽  
Root Tip ◽  
Flexural Test ◽  
Sample Distribution ◽  
The Impact

The harvest of sugar beet leads to root tip breakage and surface damage through mechanical impacts, which increase storage losses. For the determination of textural properties of sugar beet roots with a texture analyzer a reliable method description is missing. This study aimed to evaluate the impact of washing, soil tare, storage period from washing until measurement, sample distribution and number of roots on puncture and compression measurements. For this purpose, in 2017 comprehensive tests were conducted with sugar beet roots grown in a greenhouse. In a second step these tests were carried out with different Beta varieties from a field trial, and in addition, a flexural test was included. Results show that the storage period after washing and the sample distribution had an influence on the puncture and compression strength. It is suggested to wash the roots by hand before the measurement and to determine the strength no later than 48 h after washing. For reliable and comparable results a radial distribution of measurement points around the widest circumference of the root is recommended for the puncture test. The sample position of the compression test had an influence on the compressive strength and therefore, needs to be clearly defined. For the puncture and the compression test it was possible to achieve stable results with a small sample size, but with increasing heterogeneity of the plant stand a higher number of roots is required. The flexural test showed a high variability and is, therefore, not recommended for the analysis of sugar beet textural properties.

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