Use of video monitoring to quantify spatial and temporal patterns in fishing activity across sectors at moored fish aggregating devices off Puerto Rico

A key challenge in small-scale fisheries that use moored fish aggregating devices (mFADs) is the ability to accurately quantify multi-sector fishing activity through fishery-independent methods. Here, we present a novel fishery-independent assessment of multi-sector fishing activity associated with a newly developed open access mFAD programme off San Juan, Puerto Rico. We identified three fishing sectors (recreational, charter and commercial) and 158 individual fishing vessels that routinely operated in the vicinity of the mFADs. The results indicate that daytime fishing activity varied by time of day, day of week, location and sector. During fishing tournaments, the data revealed that fishing activity increased threefold; across monitoring periods, for-hire charter vessels were the most consistent day-to-day user segment, and recreational activity peaked on weekends. Our study represents a new technique for rapidly identifying and detecting multi-sector fishing activity near mFADs and highlights the potential to gather comparable data wherever mFADs are deployed. The results are used to discuss how this technique can be used to assess the performance of mFADs to identify sector overlap and guide management in determining deployment patterns and facilitate the design of cost-effective surveys to estimate mFAD vessel activity, and potentially catch, of mFAD-associated species.

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Detecting anchored fish aggregating devices (AFADs) and estimating use patterns from vessel tracking data in small-scale fisheries

Scientific Reports ◽

10.1038/s41598-021-97227-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ahmad Catur Widyatmoko ◽

Britta Denise Hardesty ◽

Chris Wilcox

Keyword(s):

Fisheries Management ◽

Small Scale ◽

Tracking Data ◽

Use Patterns ◽

Fishing Vessels ◽

Vessel Tracking ◽

Large Numbers ◽

Fish Catch ◽

Tracking Devices ◽

Fish Aggregating Devices

AbstractMonitoring the use of anchored fish aggregating devices (AFADs) is essential for effective fisheries management. However, detecting the use of these devices is a significant challenge for fisheries management in Indonesia. These devices are continually deployed at large scales, due to large numbers of users and high failure rates, increasing the difficulty of monitoring AFADs. To address this challenge, tracking devices were attached to 34 handline fishing vessels in Indonesia over a month period each. Given there are an estimated 10,000–50,000 unlicensed AFADs in operation, Indonesian fishing grounds provided an ideal case study location to evaluate whether we could apply spatial modeling approaches to detect AFAD usage and fish catch success. We performed a spatial cluster analysis on tracking data to identify fishing grounds and determine whether AFADs were in use. Interviews with fishers were undertaken to validate these findings. We detected 139 possible AFADs, of which 72 were positively classified as AFADs. Our approach enabled us to estimate AFAD use and sharing by vessels, predict catches, and infer AFAD lifetimes. Key implications from our study include the potential to estimate AFAD densities and deployment rates, and thus compliance with Indonesia regulations, based on vessel tracking data.

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In the Wrong Place at the Wrong Time: Identifying Spatiotemporal Co-occurrence of Bycaught Common Dolphins and Fisheries in the Bay of Biscay (NE Atlantic) From 2010 to 2019

Frontiers in Marine Science ◽

10.3389/fmars.2021.617342 ◽

2021 ◽

Vol 8 ◽

Author(s):

Helene Peltier ◽

Matthieu Authier ◽

Florence Caurant ◽

Willy Dabin ◽

Pierre Daniel ◽

...

Keyword(s):

Atlantic Coast ◽

Sea Bass ◽

Fishing Effort ◽

Small Scale ◽

Common Dolphin ◽

Bay Of Biscay ◽

The European Union ◽

Fishing Activity ◽

Fishing Vessels ◽

Common Dolphins

The first Unusual Mortality Event (UME) related to fishing activity along the Atlantic coast recorded by the French Stranding Network was in 1989: 697 small delphinids, mostly common dolphins, washed ashore, most of them with evidence of having been bycaught. Since then, UMEs of common dolphins have been observed nearly every year in the Bay of Biscay; unprecedented records were broken every year since 2016. The low and unequally distributed observation efforts aboard fishing vessels in the Bay of Biscay, as well as the lack of data on foreign fisheries necessitated the use of complementary data (such as stranding data) to elucidate the involvement of fisheries in dolphin bycatch. The aim of this work was to identify positive spatial and temporal correlations between the likely origins of bycaught stranded common dolphins (estimated from a mechanistic drift model) and fishing effort statistics inferred from Vessel Monitoring System (VMS) data on vessels >12 m long. Fisheries whose effort correlated positively with dolphin mortality areas after 2016 included French midwater trawlers, French Danish seiners, French gillnetters, French trammel netters, Spanish bottom trawlers, and Spanish gillnetters. For the French fleet only, logbook declarations, sales, and surveys carried out by Ifremer were integrated into fishing effort data. Six fleets were active in common dolphin bycatch areas at least twice between 2016 and 2019: gillnetters fishing hake, trammel netters fishing anglerfish, bottom pair trawlers fishing hake, midwater pair trawlers fishing sea bass and hake, and Danish seiners fishing whiting. Except for changes in hake landings in some fisheries, there were no notable changes in total fishing effort practice (gear or target species) based on the data required by the ICES and Council of the European Union that could explain the large increase in stranded common dolphins recorded along the French Atlantic coast after 2016. Small scale or unrecorded changes could have modified interactions between common dolphins and fisheries, but could not be detected through mandatory data-calls. The recent increase in strandings of bycaught common dolphins could have been caused by changes in their distribution and/or ecology, or changes in fishery practices that were undetectable through available data.

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Identifying fishing grounds from vessel tracks: model-based inference for small scale fisheries

Royal Society Open Science ◽

10.1098/rsos.191161 ◽

2019 ◽

Vol 6 (10) ◽

pp. 191161 ◽

Cited By ~ 1

Author(s):

Tania Mendo ◽

Sophie Smout ◽

Theoni Photopoulou ◽

Mark James

Keyword(s):

Spatial Distribution ◽

Low Cost ◽

Gaussian Mixture ◽

Accurate Estimation ◽

Small Scale ◽

Fishing Activity ◽

Small Vessels ◽

Movement Data ◽

Fishing Vessels ◽

Fishing Fleets

Recent technological developments facilitate the collection of location data from fishing vessels at an increasing rate. The development of low-cost electronic systems allows tracking of small-scale fishing vessels, a sector of fishing fleets typically characterized by many, relatively small vessels. The imminent production of large spatial datasets for this previously data-poor sector creates a challenge in terms of data analysis. Several methods have been used to infer the spatial distribution of fishing activities from positional data. Here, we compare five approaches using either vessel speed, or speed and turning angle, to infer fishing activity in the Scottish inshore fleet. We assess the performance of each approach using observational records of true vessel activity. Although results are similar across methods, a trip-based Gaussian mixture model provides the best overall performance and highest computational efficiency for our use-case, allowing accurate estimation of the spatial distribution of active fishing (97% of true area captured). When vessel movement data can be validated, we recommend assessing the performance of different methods. These results illustrate the feasibility of designing a monitoring system to efficiently generate information on fishing grounds, fishing intensity, or monitoring of compliance to regulations at a nationwide scale in near-real-time.

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Urban pollution control strategy: SBR technology to treat agricultural waste from pig farm in Indonesia

Sains & Teknologi ◽

10.24123/jst.v2i2.2250 ◽

2019 ◽

Vol 2 (2) ◽

pp. 21

Author(s):

Lindawati Lindawati

Keyword(s):

Cost Estimation ◽

Batch Reactor ◽

Agricultural Waste ◽

Cost Effective ◽

Land Application ◽

Pig Manure ◽

Small Scale ◽

Piggery Wastewater ◽

Pig Farm ◽

Number Of Customers

Reduction of food rations and shortages is one of the impacts of the increasing human population. Food sector industries then try to cope with the fast growing number of customers. Agribusiness sector gains its popularity in these recent years, including pig farm. The increase trend of animal farming industry is likely to bring increasing pollution problem unless effective treatment methods are used. The main problems related to the pig farm include odor nuisance and pig manure disposal. The existing land application of piggery wastewater is the traditional way to discharge the wastewater. This may yield in land and water contamination, due to the accumulation of unused nutrients by crop plant. A case study of a large commercial pig farm from Australia is proposed to apply in smaller scale in Indonesia. Operational strategies for the small-scale SBR (Sequencing Batch Reactor) treating piggery effluent were developed based on lab-scale experiments. Due to SBR characteristics, which are money-saving and space-saving, it is very suitable to be applied in urban area. An economic evaluation was made of various process options. The cost estimation showed that SBR is a cost effective process, allowing operational batches to be adjusted to reduce unnecessary aeration cost. A reduction in the aeration cost was achieved by shortening the batch time from 24-h to 8-h. A comparison of three different SBR options showed that smaller size reactors could be more flexible and cost effective when compared with the larger ones.

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Fishers as foragers: Individual variation among small-scale fishing vessels as revealed by novel tracking technology

Fisheries Research ◽

10.1016/j.fishres.2021.105896 ◽

2021 ◽

Vol 238 ◽

pp. 105896

Author(s):

Timothy H. Frawley ◽

Hannah E. Blondin ◽

Timothy D. White ◽

Rachel R. Carlson ◽

Brianna Villalon ◽

...

Keyword(s):

Individual Variation ◽

Small Scale ◽

Fishing Vessels ◽

Tracking Technology

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Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia revealed by advanced InSAR

10.5194/nhess-2018-211 ◽

2018 ◽

Author(s):

Nicholas J. Roberts ◽

Bernhard T. Rabus ◽

John J. Clague ◽

Reginald L. Hermanns ◽

Marco-Antonio Guzmán ◽

...

Keyword(s):

Ground Deformation ◽

Ground Surface ◽

Slope Instability ◽

Small Scale ◽

Spatial And Temporal Patterns ◽

La Paz ◽

Fine Grained ◽

Measured Displacement ◽

Optical Satellite Images ◽

Displacement Patterns

Abstract. We characterize and compare creep preceding and following the 2011 Pampahasi landslide (∼ 40 Mm3 ± 50 %) in the city of La Paz, Bolivia, using spaceborne RADAR interferometry (InSAR) that combines displacement records from both distributed and point scatterers. The failure remobilised deposits of an ancient landslide in weakly cemented, predominantly fine-grained sediments and affected ∼ 1.5 km2 of suburban development. During the 30 months preceding failure, about half of the toe area was creeping at 3–8 cm/a and localized parts of the scarp area showed displacements of up to 14 cm/a. Changes in deformation in the 10 months following the landslide are contrary to the common assumption that stress released during a discrete failure increases stability. During that period, most of the landslide toe and areas near the headscarp accelerated, respectively, to 4–14 and 14 cm/a. The extent of deformation increased to cover most, or probably all, of the 2011 landslide as well as adjacent parts of the slope and plateau above. The InSAR-measured displacement patterns – supplemented by field observations and by optical satellite images – indicate that kinematically complex, steady-state creep along pre-existing sliding surfaces temporarily accelerated in response to heavy rainfall, after which the slope quickly achieved a slightly faster and expanded steadily creeping state. This case study demonstrates that high-quality ground-surface motion fields derived using spaceborne InSAR can help to characterize creep mechanisms, quantify spatial and temporal patterns of slope activity, and identify isolated small-scale instabilities. Characterizing slope instability before, during, and after the 2011 Pampahasi landslide is particularly important for understanding landslide hazard in La Paz, half of which is underlain by similar, large paleolandslides.

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Impact of mechanized clam dredging on the discarded megabenthic fauna on the Catalan coast (NW Mediterranean)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315421000369 ◽

2021 ◽

pp. 1-9

Author(s):

Marc Baeta ◽

Claudia Rubio ◽

Françoise Breton

Keyword(s):

Small Scale ◽

Fishing Activity ◽

Lethal Damage ◽

Catalan Coast ◽

Nw Mediterranean ◽

Chamelea Gallina ◽

Level Scale ◽

Nw Mediterranean Sea ◽

The Impact ◽

Partial Damage

Abstract There is an important small-scale fishery using mechanized dredges and targeting clams (mainly wedge clam Donax trunculus and striped venus clam Chamelea gallina) along the Catalan coast (NW Mediterranean Sea). This study evaluated for the first time the discards and impact of mechanized clam dredging on the Catalan coast. To this end, three surveys were performed on board standard clam vessels (September and November 2016 and January 2017). Surveys were conducted in the three main clam fishing areas (Rosas Bay, South Barcelona and Ebro Delta). The composition of discards and the impact caused to discarded species was assessed using a three-level scale (undamaged; minor or partial damage; and lethal damage). Our study revealed that a large proportion of the catch (between 67–82% weight) is discarded. Even though about 63% of the discarded species were undamaged, 11% showed minor or partial damage and 26% lethal damage. Infaunal and epifaunal species with soft-body or fragile shells were the most impacted by the fishing activity (e.g. the sea urchin Echinocardium mediterraneum (~89%) and the bivalve Ensis minor (~74%)). Our results showed different levels of impact by target species and fishing area.

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Diversity minimization through part combination – a Portuguese railway infrastructure case study

Journal of Computational Design and Engineering ◽

10.1093/jcde/qwaa009 ◽

2020 ◽

Vol 7 (1) ◽

pp. 86-94

Author(s):

Diogo Rechena ◽

Luís Sousa ◽

Virgínia Infante ◽

Elsa Henriques

Keyword(s):

Economies Of Scale ◽

Product Family ◽

Cost Effective ◽

Added Value ◽

Small Scale ◽

Railway Infrastructure ◽

Sustainable Services ◽

Market Needs ◽

Design Diversity ◽

Requirement Changes

Abstract With increasing market needs for product and service variety, companies struggle to provide diversity in cost-effective ways. Through standardization of components with a low perceived added value, companies can take advantage of economies of scale while maintaining product diversity. Railway infrastructure managers face similar challenges of providing economically sustainable services while dealing with the costs of maintaining the system diversity. Typically, unintended design diversity stems from design practices in which existing solutions are not reused for new problems and new solutions are rarely planned considering the dynamics of requirement changes. In this paper we provide a methodology to assess how to standardize different designs to minimize design diversity and to assess design divergence in a product family. The developed methodology is able to take into account any set of standardization compatibility constraints that the user can define. The methodology was applied in the context of a small-scale railway infrastructure manager using a dataset of 223 unique designs of functionally similar components from its electrification system. Depending on the activated compatibility constraints, results indicate that over 60% of components can be reduced to a set of 86 unique designs.

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