scholarly journals Incidental seabird mortality and discarded catches from trawling off far southern Chile (39–57°S)

2019 ◽  
Vol 76 (4) ◽  
pp. 848-858
Author(s):  
Luis M Adasme ◽  
Cristian M Canales ◽  
Nicolás A Adasme
Keyword(s):  
Monitoring Systems ◽  
Breeding Period ◽  
Southern Chile ◽  
Target Species ◽  
Fishing Activity ◽  
Important Species ◽  
Probable Relationship ◽  
Trawl Fishing

AbstractIn world fisheries, incidental non target species mortality have turned in a permanent debate issue. Although many studies have dealt with these interactions from a descriptive overview, there is little information based on fishing operations data. One of the most important species that have awakened scientific concern are seabird, being southern Chile one of the areas with the highest levels in this kind of interactions. In order to improve our understanding on these relationships, we analyze records of fishing hauls of industrial trawlers off the coast of Chile between 39 and 57°S. The results showed that incidental seabird mortality appears to be affected mainly by the collisions with net monitoring systems (net-sonde cable), the duration of fishing hauls, the year period, and the fishing zones, these last related to the breeding period and areas of albatross colonies. We indirectly address a probable relationship between seabird mortality and fishing discards, and some hypothesis are proposed to explain the results. Finally, we demonstrated that longer fishing hauls are less efficient for fishing, beside to a high seabird mortality. Our findings suggest mitigation actions that would harmonize fishing activity with the ecosystem, in particular, for trawl fishing management and operations off far southern Chile.

scholarly journals Correlation-Centric Network (CCN) representation for microbial co-occurrence patterns: new insights for microbial ecology

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Pengshuo Yang ◽  
Chongyang Tan ◽  
Maozhen Han ◽  
Lin Cheng ◽  
Xuefeng Cui ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Large Scale ◽  
Network Connectivity ◽  
Small Range ◽  
Environmental Disturbance ◽  
Target Species ◽  
Important Species ◽  
Metagenome Analysis ◽  
Occurrence Patterns ◽  
Edge Networks

Abstract Mainstream studies of microbial community focused on critical organisms and their physiology. Recent advances in large-scale metagenome analysis projects initiated new researches in the complex correlations between large microbial communities. Specifically, previous studies focused on the nodes (i.e. species) of the Species-Centric Networks (SCNs). However, little was understood about the change of correlation between network members (i.e. edges of the SCNs) when the network was disturbed. Here, we introduced a Correlation-Centric Network (CCN) to the microbial research based on the concept of edge networks. In CCN, each node represented a species–species correlation, and edge represented the species shared by two correlations. In this research, we investigated the CCNs and their corresponding SCNs on two large cohorts of microbiome. The results showed that CCNs not only retained the characteristics of SCNs, but also contained information that cannot be detected by SCNs. In addition, when the members of microbial communities were decreased (i.e. environmental disturbance), the CCNs fluctuated within a small range in terms of network connectivity. Therefore, by highlighting the important species correlations, CCNs could unveil new insights when studying not only the functions of target species, but also the stabilities of their residing microbial communities.

scholarly journals Influencia de la proporción sexual y del ambiente en la tasa de crecimiento poblacional de Callinectes bellicosus (Decapoda: Portunidae) del Golfo de California

2016 ◽  
Vol 64 (3) ◽  
Author(s):  
Demetrio Angel Rodríguez-Felix ◽  
Miguel Angel Cisneros-Mata ◽  
Eugenio Alberto Aragón-Noriega ◽  
José Alfredo Arreola-Lizárraga
Keyword(s):  
Sex Ratio ◽  
Gulf Of California ◽  
Sensitivity Analyses ◽  
Swimming Crab ◽  
Linear Regression Models ◽  
Habitat Size ◽  
Positive Dependence ◽  
Fishing Activity ◽  
Important Species ◽  
Spawning Period

The brown swimming crab (Callinectes bellicosus) is an economically important species in the Gulf of California, and its fishing activity, held in Sonora from 1986, has been affected by a 20-year declining trend in its biomass. With the aim to understand the possible reasons of this species population changes along time, we estimated population growth rate (r) and sex ratio of C. bellicosus, and combined them with three parameters describing its habitat: sea temperature, wetland extension and habitat size in four areas along the coast of Sonora. For this, monthly mean sex ratio was estimated from crabs samples obtained from commercial catches during 1998-2002 and 2012; mean sea surface temperature for the spawning period (May-August) were derived from remote sensors for the same years; while wetland coverages were obtained from published reports, and habitat size was estimated as the fishing surface. For each area, r was estimated using a method developed for limited data situations using commercial landings (t) from 1986-2013. With data from the four areas, simple and multiple linear regression models were developed to ascertain theoretical sensitivities of r to variations in sex ratio and environmental parameters. A total of 24 556 crabs were sampled; males dominated (68.8 %) over females during the study period and in all areas; a cluster analysis identified two groups according to sex ratio: a Northern group with zones 1 and 2, and a Southern group with zones 3 and 4. r values were different in all zones (P<0.001) as was sex ratio (P=0.037); no differences in temperature were identified within the study years (P>0.995). Both the estimated data and sensitivity analyses suggest the existence of a direct and positive dependence of r on the proportion of female crabs and wetland size. We hypothesize that excess fishing of females caused the declining biomass trend of the brown swimming crab in Sonora, and concluded on the convenience of implementing harvest refugia inside coastal wetlands to protect females during the spawning season. 

Elastomeric Risers in the Offshore Wind Industry

2020 ◽  
Vol 54 (6) ◽  
pp. 77-83
Author(s):  
David G. Aubrey ◽  
Jennifer Wehof ◽  
Stephen O'Malley ◽  
Rajai Aghabi
Keyword(s):  
Environmental Monitoring ◽  
Fiber Optic ◽  
Power Transmission ◽  
Autonomous Underwater Vehicle ◽  
Data Transfer ◽  
Benthic Communities ◽  
Underwater Vehicle ◽  
Offshore Wind ◽  
Monitoring Systems ◽  
Fishing Activity

AbstractFloating LiDAR systems (FLS) and other moored environmental monitoring systems are used extensively for wind and environmental assessments in offshore wind projects. In addition, wave energy converters (WECs) are being evaluated for more extensive use in coastal and deeper waters, most of which also require anchoring to the seabed. Since these systems must be moored, heavy anchors and typically heavy chain are used to secure the mooring and measurement/WEC buoy to the seabed. Disadvantages of present mooring technology include 1) damage to the seabed and benthic communities in vicinity of the mooring, as chain sweeps over the sea bottom; 2) an unnecessarily large watch circle at the water's surface; 3) slightly increased likelihood of marine mammal entanglement; 4) mooring damage from nearby fishing activity; and 5) likelihood of mooring failure due to self-entanglement within the mooring itself. This study presents an alternative mooring using mechanically compliant, elastomeric hoses to connect the buoyed system to the bottom anchor. Modeling the two mooring types with a typical buoy used in wind resource assessments shows a significant decrease in anchor drag area and surface watch circle with the use of the elastomeric hose versus the traditional chain and polyethylene line mooring. The hose also is equipped with copper conductors and/or fiber-optic conductors, providing power and data transmission between the bottom and the surface. For WEC solutions, the elastomeric hose provides similar benefits as for FLS and environmental monitoring systems, with the added advantage of being able to transmit power to the seafloor for distribution. For one WEC application, we have developed an elastomeric solution containing not only larger copper conductors to enable power transmission but also fiber-optic conductors to permit data transfer from a garage mounted on the bottom (servicing an autonomous underwater vehicle [AUV] or unmanned underwater vehicle [UUV], for instance) to the surface buoy for onward transmission to shore.

Managing Atlantic marlin as bycatch under ICCAT. The fork in the road: recovery or collapse

2003 ◽  
Vol 54 (4) ◽  
pp. 575 ◽  
Author(s):  
Ellen Peel ◽  
Russell Nelson ◽  
C. Phillip Goodyear
Keyword(s):  
Primary Source ◽  
Maximum Sustainable Yield ◽  
Extinction Rate ◽  
Fishing Mortality ◽  
Target Species ◽  
Important Species ◽  
The Road ◽  
Wild Fauna ◽  
Target Fish ◽  
Longline Fisheries

Atlantic billfish (marlin, sailfish and spearfish) are managed under the jurisdiction of the International Commission for the Conservation of Atlantic Tunas (ICCAT). Because they are not commonly a target species, most fishing mortality is generated as a function of bycatch in various commercial fisheries. Billfish are very important species for recreational fisheries. The record indicates that ICCAT has placed its greatest emphasis on managing target fish to maximize their catch for ‘food purposes’ and has not placed the same level of emphasis on maximizing catch for ‘other purposes’, such as for the benefit of recreational fisheries.Stock assessments indicate Atlantic marlin are severely overexploited, with the rates of decline showing no signs of slowing. The primary source of billfish mortality is as bycatch in pelagic longline fisheries for tuna and swordfish. Simultaneous fishing mortality rates that will produce maximum sustainable yield (MSY) for at least one targeted tuna species is near the extinction rate for blue marlin. Failure to significantly reduce fishing mortality on marlin by restraining effort on target species has led to the collapse of both blue and white marlin stocks and, if continued indefinitely, may lead to extinction of either species. Although ICCAT's charter does not prioritize management between different types of fisheries, commercial or recreational, or among different species of fish within its authority, the de facto result of ICCAT's actions to date has relegated billfish to the role of bycatch species. The needs of the directed recreational billfish industry have been largely ignored.In the absence of responsible action by ICCAT to reduce fishing mortality on marlin, those concerned with the conservation of billfish will be forced to seek alternative conservation and management assistance through The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and other protected species options. Compatible management solutions now must be identified and implemented by ICCAT if diverse fishing interests are to coexist and the stocks are to return to MSY. Time and area closures and live releases, coupled with some restraints on targeted effort, may offer a solution most acceptable to all fishing interests.

scholarly journals Evaluating marine reserves as a management policy in the central-southern anchovy (Engraulis ringens) fishery of Chile

2021 ◽  
Vol 49 (2) ◽  
pp. 212-226
Author(s):  
Juan Pablo Díaz Vega ◽  
Yarela Flores Arévalo
Keyword(s):  
Marine Reserves ◽  
Marine Reserve ◽  
Fishing Effort ◽  
Management Policy ◽  
Decision Variable ◽  
Southern Chile ◽  
Artisanal Fishing ◽  
Fishing Activity ◽  
Engraulis Ringens ◽  
The Impact

The anchovy (Engraulis ringens) fishery in central-southern Chile, like many fisheries worldwide, is overexploitation mainly due to poor and short-term management by fishing authorities and communities. This study proposes and evaluates marine reserves as a possible tool to apply since there is a current marine reserve law in Chile. The study's methodology is the simulation of a bioeconomic model that includes two areas: one is the protected, and the other is the artisanal fishing, in which the protected area transfers biomass to the artisanal fishing area. The reserve is incorporated as a decision variable in the management of this resource. It is determined as a percentage of protection of the total fish population related to fishing effort, which quantifies and evaluates the impact of protecting a stock of parental fish on the fishery's sustainability. Biomass data used is from 2000-2006, during which the anchovy fishery was fully exploited. The carrying capacity and intrinsic growth rate are estimated, and biomass is projected at different protection and effort levels. Results show that if a marine reserve with a protection level of 30% had been applied as a management policy in the anchovy fishery of central-southern Chile in the early 2000s, the fishing activity would be in a state of full exploitation rather than overexploitation as it is today. This model's fundamental contribution is that it makes possible fishery evaluation with real data from the same fishing activity.

scholarly journals POTENTIAL FISHING GROUND MAPPING BASED ON GIS HOTSPOT MODEL AND TIME SERIES ANALYSIS: A CASE STUDY ON LIFT NET FISHERIES IN SERIBU ISLAND

2017 ◽  
Vol 9 (1) ◽  
pp. 337-356
Author(s):  
Andi Alamsyah Rivai ◽  
Vincentius P. Siregar ◽  
Syamsul B. Agus ◽  
Hiroki Yasuma
Keyword(s):  
Time Series ◽  
Fisheries Management ◽  
Fishing Ground ◽  
Effective Management ◽  
Target Species ◽  
Fishing Activity ◽  
Fishing Season ◽  
Spatio Temporal ◽  
West Monsoon

Information on the spatial and temporal of fishing activity can optimize a fisheries management and increase their economical and biological benefit. For effective management and good understanding of fishing activities, information about fishing ground is crucial. In this study, we aimed to analyze the spatio-temporal of lift net fisheries in Kepulauan Seribu by analyzing their fishing season, investigating their hotspot of fishing ground using GIS-based hotspot model, and mapping the potential fishing ground of each target species. We found that anchovy and scad could be caught throughtout the year, while sardine and squid had high fishing season in west monsoon. Hotspot of fishing ground of lift net fisheries in Kepulauan Seribu waters generally was concentrated around Lancang Island and in southern part of Kotok Island. Potential fishing ground for sardines was located in around Lancang Island on west monsoon. Squids were highly distributed around Lancang Island in December to January and around Lancang and Rambut Islands in November. Anchovy and scad had more potential fishing ground in around Kepulauan Seribu waters.  Keywords: fishing ground, lift net, hotspot, fishing season 

scholarly journals Integrating vessel monitoring systems (VMS) data with daily catch data from logbooks to explore the spatial distribution of catch and effort at high resolution

2010 ◽  
Vol 68 (1) ◽  
pp. 245-252 ◽  
Author(s):  
Hans Gerritsen ◽  
Colm Lordan
Keyword(s):  
Spatial Distribution ◽  
High Resolution ◽  
Practical Method ◽  
Monitoring Systems ◽  
Catch Per Unit Effort ◽  
Fishing Activity ◽  
Distribution Maps ◽  
Catch Data ◽  
Fishing Vessels ◽  
Logbook Data

Abstract Gerritsen, H., and Lordan, C. 2011. Integrating vessel monitoring systems (VMS) data with daily catch data from logbooks to explore the spatial distribution of catch and effort at high resolution. – ICES Journal of Marine Science, 68: 245–252. Vessel monitoring systems (VMS) automatically collect positional data from fishing vessels, and the data can be linked to catch data from logbooks to provide a census of spatially resolved catch-and-effort data. The most appropriate and practical method for integrating Irish VMS and logbook data is explored and validated. A simple speed rule is applied to identify VMS records that correspond to fishing activity. The VMS data are then integrated with the catch data from logbooks using date and vessel identifier. Several assumptions were investigated, and the resulting distribution maps of catch and effort appear to be unbiased. The method is illustrated with an example of a time-series of spatially explicit estimates of catch per unit effort. The proposed method is relatively simple and does not require specialist software or computationally intensive methods. It will be possible to generalize this approach to similar datasets that are available within the EU and many other regions. Analysis of integrated VMS and logbook data will allow fisheries data to be analysed on a considerably finer spatial scale than was possible previously, opening up a range of potential applications.

scholarly journals Technical and economic efficiency analysis of the Portuguese artisanal dredge fleet

2010 ◽  
Vol 67 (8) ◽  
pp. 1811-1821 ◽  
Author(s):  
Manuela M. Oliveira ◽  
Ana S. Camanho ◽  
Miguel B. Gaspar
Keyword(s):  
Economic Efficiency ◽  
Efficiency Analysis ◽  
Target Species ◽  
Wholesale Market ◽  
Fishing Activity ◽  
Efficiency Assessment ◽  
Stock Biomass ◽  
Using Data ◽  
Analysis Models ◽  
Revenue Efficiency

Abstract Oliveira, M. M., Camanho, A. S., and Gaspar, M. B. 2010. Technical and economic efficiency analysis of the Portuguese artisanal dredge fleet. – ICES Journal of Marine Science, 67: 1811–1821. An efficiency analysis of the commercial dredge fleet operating along the south coast of Portugal between 2005 and 2007 sought to determine the efficiency of the vessels using data envelopment analysis models, considering fixed inputs (vessel power, length, tonnage, and an indicator of stock biomass) and a variable input (number of days at sea). The annual quota per vessel was also included in the model as a contextual factor. In the technical-efficiency (TE) analysis, outputs were defined by the catch weight for each of the three target species (bivalves). Using price data for each species in the wholesale market, revenue efficiency was also estimated to complement the TE analysis. The advantage of the approach lies in the ability to separate technical aspects from allocative aspects in the efficiency assessment, allowing two-dimensional graphic representation of vessel performance. The procedure allows the identification of benchmark vessels, which maximized the catch weight of the species landed, given their inputs, as well as the vessels that selected the appropriate target species to maximize the revenue of the fishing activity, given output prices. The approach also allowed the specification of targets for inefficient vessels that correspond to the catch by species, permitting revenue maximization from fishing.

scholarly journals Komposisi dan distribusi ukuran hasil tangkapan sampingan bubu ekor kuning di Perairan Kepulauan Seribu

DEPIK ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 516-524
Author(s):  
Mokhamad Dahri Iskandar ◽  
Sugeng Hariwisudo ◽  
Budi Hascaryo Iskandar ◽  
Mulyono S Baskoro
Keyword(s):  
Size Distribution ◽  
Weight Ratio ◽  
Total Weight ◽  
Fish Stock ◽  
Total Catch ◽  
Target Species ◽  
High Demand ◽  
Fishing Activity ◽  
Composition Ratio ◽  
Stock Depletion

Bycatch is non-target species which mostly caught at fishing operation. High quantity of bycatch mortality was predicted as one factor of fish stock depletion. Additionally, the high demand to improve fisheries production will be able to lead over fishing. This situation will affect improvement of bycatch and discarded species which will endanger the fish stock. The objective of this research was to identify bycatch composition, ratio between target species and bycatch and size distribution of dominant bycatch at yellow tail fishing operation in Seribu Islands. The research was carried out at Seribu Islands on July-August 2020. The fishing activity used pot with size length x width x height : 100 x 75 x 32.5 cm. Result of research indicated that yellow tail pot bycatch was dominated by brownstripe snapper (Lutjanus vitta) with catch amount of 330 fishes ( 15.9% of total catch) and weight of 50,861 kg (11.5% of total catch weight) followed by squirrelfishes (Sargocentron rubrum) with catch amount of 324 fishes (15.6 % of total catch) and weight of 51,181 kg (11.6%). Another dominant bycatch was striped spinecheek (Scolopsis margaritiferus) with catch amount of 289 fishes (13.9% of total catch) and weight of 40,042 kg (9.1% of total weight). Ratio of target of catch : bycatch in weight was 42.6% : 57.4%. It means, to catch 1 kg of yellow tail there will be caught 1.7 kg bycatch. Total length size of brownstripe snapper at range of 12-27 cm, squirrelfishes at range of 9-27 cm and striped spinecheek at range of 11-29 cm.Keywords:BycatchPotDiscard speciesYellow tailCatch compositionABSTRAKHasil tangkapan sampingan merupakan spesies hasil tangkapan non target yang relatif tinggi tertangkap pada operasi penangkapan. Tingginya jumlah kematian hasil tangkapan sampingan diduga menjadi salah satu penyebab menurunnya stok sumberdaya ikan di seluruh penjuru dunia. Adanya permintaan yang tinggi untuk meningkatkan produksi perikanan dapat memicu peningkatan upaya penangkapan secara berlebihan. Kondisi ini mengakibatkan hasil tangkapan sampingan akan meningkat dengan meningkatnya upaya penangkapan sehingga membahayakan stok dan populasi sumberdaya ikan. Penelitian ini bertujuan untuk mengidentifikasi komposisi hasil tangkapan sampingan, rasio antara hasil tangkapan utama dengan hasil tangkapan sampingan dan ukuran hasil tangkapan sampingan dominan yang tertangkap pada operasi penangkapan ikan ekor kuning di Perairan Kepulauan Seribu. Penelitian dilakukan di Perairan Kepulauan Seribu pada bulan Juli-Agustus 2020 dengan menggunakan bubu ekor kuning (ukuran p x l x t : 100 x 75 x 32,5 cm). Hasil penelitian menunjukan bahwa hasil tangkapan sampingan bubu ekor kuning didominasi oleh ikan kakap (Lutjanus vitta) dengan total jumlah hasil tangkapan mencapai 330 ekor ( 15,9%) dengan total bobot mencapai 50.861 kg (11,5%) disusul oleh ikan swanggi (Sargocentron rubrum) mencapai 324 ekor (15,6 %) dengan total bobot hasil tangkapan sebesar 51.181 kg (11,6%) dan ikan serak (Scolopsis margaritiferus) dengan jumlah hasil tangkapan mencapai 289 ekor (13,9%) dan bobot sebesar 40.042 kg (9,1%) dari total bobot hasil tangkapan bubu ekor kuning. Proporsi bobot hasil tangkapan utama dibanding dengan hasil tangkapan sampingan adalah 42,6% : 57,4%. Hal ini berarti untuk menangkap 1 kg ekor kuning maka akan tertangkap 1,354 kg hasil tangkapan sampingan. Ukuran hasil tangkapan sampingan dominan yang tertangkap pada bubu ekor kuning meliputi ikan kakap yang tertangkap pada selang ukuran panjang total 12-27 cm, ikan swanggi dengan selang ukuran panjang total berkisar 9-27 cm dan ikan serak dengan selang ukuran panjang total berkisar antara 11-29 cm.Kata kunci:Hasil tangkapan sampinganBubuDiscard spesiesIkan ekor kuningKomposisi hasil tangkapan

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