Some Aspects of the Ecology of Lake Macquarie, N.S.W., with Regard to an Alleged Depletion of Fish. VIII. Trends of the Commercial Fish Catch and Management of the Fishery

1959 ◽  
Vol 10 (3) ◽  
pp. 354 ◽  
Author(s):  
JM Thomson
Keyword(s):  
Commercial Fishing ◽  
Total Catch ◽  
Commercial Fish ◽  
Injurious Effect ◽  
Nursery Grounds ◽  
Fish Catch

Although the total catch has fallen since 1922 the abundance of fish as measured by the catch per man has not. The total catch has dropped because fewer men are fishing. A red drop in the abundance of certain species, namely flathead, bream, luderick, and sea mullet, occurred between 1945 and 1947; the algal-feeding luderick and mullet regained their abundance by 1951, but the three ground fish had not regained their former abundance by 1957. The trends of the monthly catch are similar in all years, the catch expectation being least reliable in November and most predictable in February. Closing of the northern end of the lake to commercial fishing has resulted in a loss to the consumer of quantities of sea mullet and tailor, species which are fished ineffectively by amateur anglers. During the winter months netting in the northern part of the lake, except in certain bays which form nursery grounds for the young of several species, would have no injurious effect on the stocks.

scholarly journals EVALUACIÓN EXPERIMENTAL DE DISPOSITIVOS EXCLUIDORES DE FAUNA ACOMPAÑANTE EN REDES DE ARRASTRE PARA CAMARÓN DE AGUAS SOMERAS EN EL PACÍFICO COLOMBIANO

2016 ◽  
Vol 39 (2) ◽  
Author(s):  
Alexander Girón ◽  
Farit Rico ◽  
Mario Rueda
Keyword(s):  
Length Distribution ◽  
Marine Biodiversity ◽  
Commercial Fishing ◽  
Chi Square ◽  
Commercial Fish ◽  
Fishing Sector ◽  
Fish Catch ◽  
Chi Square Test ◽  
Overall Ratio ◽  
The Impact

The effects of the introduction of bycatch reduction devices in the shrimp trawling fleet in shallow waters of the Colombian Pacific, were tested through an experiment fishing involving the industrial fishing sector. Following the commercial fishing conditions, we evaluated the turtle excluder device (TED), the "fish eye" fish excluder device (OP) and the combination of both devices (DET + OP). The variables used to assess the effects of the devices on the different components of the catch [target catch (CO), bycatch (CI) and discard (D)] were the relative abundance and length distribution of individuals. The effects of device type, fishing areas and their interaction were assessed by two-way ANOVA, while the effect of the devices on the length structure of catches was evaluated by comparison of size distributions using the Chi-square test. The overall ratio between the target catch (shrimp) and bycatch was 1:14. Groups of species caught were fish (83 %), crustaceans (13 %), molluscs (1.1 %), cnidarians (1.3 %), reptiles (1 %) and echinoderms (0.6 %), which together included 216 taxa. The variables TCO, CI (commercial fish) and D (discards) all varied significantly between fishing grounds. The devices did not affect shrimp catch in trawl nets, but fish catch did depending on the fishing grounds. The performance of devices showed with respect to the CI that DET excluded 45 %, the OP 36 % and OP+DET 78 %, while the discard was reduced by 22 % with the DET, 39 % with OP and 58 % in the DET + OP. The length distributions of the trawl-net with devices did differ significantly from the control net. The devices tested reduced the impact of trawling on marine biodiversity by allowing the escape of many species. However, the escape of commercial size fish could affect the income of fishermen.

scholarly journals On estimating the age composition of the commercial catch of Northeast Arctic cod from a sample of clusters

2003 ◽  
Vol 60 (2) ◽  
pp. 297-303 ◽  
Author(s):  
Aanes Sondre ◽  
Michael Pennington
Keyword(s):  
Age Structure ◽  
Age Distribution ◽  
Significant Loss ◽  
Effective Sample Size ◽  
Commercial Fishing ◽  
Total Catch ◽  
Intracluster Correlation ◽  
Age Composition ◽  
Commercial Catch ◽  
Arctic Cod

Abstract Assessment of Northeast Arctic cod is based on estimates of the commercial catch in numbers at age. The age structure of the catch is estimated by sampling fish from commercial fishing trips. Although it is commonly assumed that a sample of individuals is a random sample from the population, fish sampled from the same trip (i.e. from a “cluster” of fish) tend to be more similar in age than those in the total catch. For Northeast Arctic cod, the intracluster correlation for age is positive, and therefore the effective sample size is much smaller than the number of fish aged. Given the number of fish aged, the precision of the estimated age distribution is rather low, and the number of fish aged from each trip could be reduced from approximately 85 to 20 without a significant loss in precision.

scholarly journals Mapping and Assessing Commercial Fisheries Services in the Lithuanian Part of the Curonian Lagoon

Fishes ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Edgaras Ivanauskas ◽  
Andrius Skersonas ◽  
Vaidotas Andrašūnas ◽  
Soukaina Elyaagoubi ◽  
Artūras Razinkovas-Baziukas
Keyword(s):  
Spatial Distribution ◽  
Residence Time ◽  
Fish Species ◽  
Circulation Model ◽  
Curonian Lagoon ◽  
Water Residence Time ◽  
Total Catch ◽  
Catch Per Unit Effort ◽  
Commercial Fish ◽  
The Impact

The spatial distribution of biomass of main commercial fish species was mapped to estimate the supply of a provisioning fishery service in the Curonian lagoon. Catch per unit effort (CPUE) was used as a proxy to estimate the efficiency of commercial fishing and, subsequently, the potential biomass of fishes. The relationship between distinctive characteristics of the fishing areas and corresponding commercial catches and CPUE was analyzed using multivariate analysis. The total catch values and CPUE used in the analyses were derived from the official commercial fishery records. RDE analysis was used to assess the variation of both catch and CPUE of commercial fish species, while the percentages of bottom sediment type coverage, average depth, annual salinity, and water residence time in each of the fishing squares were used as explanatory variables. This distance e-based redundancy analysis allowed for the use of non-Euclidean dissimilarity indices. Fisheries data spatial distribution map indicated the lack of coherence between the spatial patterns of commercial catches and CPUE distribution in the northern part of the lagoon. Highest CPUE values were estimated in the central-eastern part of the lagoon as compared to the western part of the lagoon where CPUE values were substantially lower. Both total catch and CPUE appeared not to be related to the type of bottom habitats statistically while being spatially correlated in-between. However, the impact of salinity and water residence time calculated using the 3D hydraulic circulation model on the distribution of both CPUE and commercial catches was statistically significant.

scholarly journals PENGEMBANGAN LAMPU BAWAH AIR SEBAGAI ALAT BANTU PADA BAGAN TANCAP DI DESA TAMBAK LEKOK KECAMATAN LEKOK PASURUAN

2016 ◽  
Vol 9 (1) ◽  
pp. 7
Author(s):  
F Fuad ◽  
S Sukandar ◽  
Alfan Jauhari
Keyword(s):  
Fishing Gear ◽  
Total Catch ◽  
Fish Catch ◽  
To Come ◽  
Almost All

<p><em>DEVELOPMENT OF UNDER WATER LAMP AS A TOOL TO LIFT NET IN TAMBAK LEKOK VILLAGE PASURUAN</em></p><p><em><br /></em></p><p><em>Bagan is one type of fishing gear that uses light to collect fish. The lights are expected to stimulate the fish to come and stay around the light and than arrested with net. The use of light for fishing is growing rapidly, almost all fishing gear to use light as a tool for collecting fish. Application of this technology aims to increase fish catch fishermen in District Lekok through the application of technology underwater lamp with LED. Underwater lamp applied to the bagan tancap with a certain intensity and color to find the intensity of light and color that give the best catches. Best catches in the light of 450 lux is capable of delivering the highest total catch of 254 kg, it is supported by the values of illumination of 1.5 lux at a distance of 5 m. Types of fish that were caught on as much as 23 step chart types where the type of Stolephorus spp, Selaroides spp, Leiognathus spp, Loligo sp, Rastrelliger spp is a type of fish that always caught each fishing operation.</em></p><p> </p><p><strong>Keywords</strong>:<em> auxilary, development, lamp, Lekok, lift net </em></p><p align="center"><strong> </strong></p><p align="center"><strong>ABSTRAK</strong></p><p align="center"><strong> </strong></p><p><em>Bagan merupakan salah satu jenis alat tangkap yang menggunakan lampu sebagai alat bantu pengunpul ikan. Cahaya lampu diharapkan </em><em>dapat merangsang ikan untuk datang dan berkumpul disekitar sumber cahaya sampai pada suatu catchable area tertentu, lalu penangkapan dilakukan dengan alat jaring maupun pancing. Penggunaan lampu untuk penangkapan ikan saat ini berkembang pesat, hampir semua alat tangkap menggunakan lampu sebagai alat bantu pengumpul ikan. </em><em>Aplikasi teknologi ini bertujuan untuk meningkatkan hasil tangkapan ikan nelayan bagan tancap di Kecamatan Lekok melalui penerapan teknologi lampu celup bawah air berbasis lampu LED. Lampu celup bawah air diterapkan pada bagan tancap dengan intensitas dan warna tertentu untuk mencari intensitas cahaya dan warna yang memberikan hasil tangkapan yang terbaik. </em><em>Hasil tangkapan ikan yang terbanyak adalah pada lampu 450 lux yang mampu memberikan total tangkapan terbanyak 254 kg, hal ini didukung dengan nilai nilai illuminasi sebesar 1,5 lux pada jarak 5 m. Jenis ikan yang tertangkap pada bagan tancap sebanyak 23 jenis dimana jenis ikan teri (</em><em>Stolephorus</em><em> spp), ikan selar (Selaroides spp), ikan pepetek (Leiognathus spp ), cumi – cumi (Loligo sp), ikan kembung (Rastrelliger spp) merupakan jenis ikan yang selalu tertangkap disetiap operasi penangkapan.</em> <em></em></p><p> </p><p><strong>Kata kunci</strong>: a<em>lat bantu, bagan tancap, lampu, Lekok, pengembangan</em></p>

scholarly journals The effect of escape gaps of cylinder folding traps on fish catch at the coastal waters of Tuban Regency

2021 ◽  
Vol 322 ◽  
pp. 03002
Author(s):  
Farrel Nafis Adyatama ◽  
Ghassan Nurul Huda ◽  
Nahla Alfiatunnisa ◽  
Faizal Rachman ◽  
Supardjo Supardi Djasmani ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Marine Organisms ◽  
Total Weight ◽  
Total Catch ◽  
Catch Per Unit Effort ◽  
Unit Effort ◽  
Significant Difference ◽  
Fish Catch ◽  
Swimming Crabs

The purpose of this study is to determine the effect of the escape gap of cylinder folding trap on catch per unit effort (CPUE), trap rate, composition, and size of fish caught in the coastal waters of Tuban Regency. The research was conducted in November 2019 by deploying 60 units in ten experimental fishing trips at different locations. The traps were 20 units without escape gap, 20 units with an escape gap of 3 cm x 6 cm, and 20 units with an escape gap of 4 cm x 7 cm. Overall, the experiments resulted in a collection of 22 species of marine organisms, such as swimming crabs (33% of total weight), snails, shrimps, crabs, fishes (55% of total weight), and cuttlefish. The highest CPUE was found for the traps with escape gaps of 4 cm x 7 cm, i.e., 9.18 gr/trap/trip. There was no significant difference in the total catch, the weight of catches, trap rate, and catch per unit effort (CPUE) among the three types of traps.

scholarly journals Preparation for the Final Testing of the Sprayed Bentonite Sealing Layer of a Pond Dam

2018 ◽  
Vol 65 ◽  
pp. 02008
Author(s):  
Jiri Stastka ◽  
Vaclav David ◽  
Katerina Cernochova
Keyword(s):  
Preferential Flow ◽  
Experimental Testing ◽  
Commercial Fishing ◽  
Fish Ponds ◽  
Flow Paths ◽  
Commercial Fish ◽  
Suitable Material ◽  
Preferential Flow Paths ◽  
Earth Structures ◽  
Sealing Layer

This paper presents research conducted on the development of a bentonite material suitable for the sealing of the dams of large ponds used for commercial fishing purposes. It is intended that the material will be applied using spray technology. The research was motivated by the large number of very old commercial fish ponds in the Czech Republic of which some are nearly a thousand years old. With the passage of time, leakage through the dams leads to the creation of caverns and preferential flow paths which may eventually result in a breach in the dam wall. An efficient technological approach to the sealing of these earth structures may, therefore, help to mitigate the risk of their failure and destruction. A potentially suitable material for this purpose has been researched and developed at the Czech Technical University and is now ready for the experimental testing phase involving the construction and study of a physical model of such a dam constructed according to the geometry of traditional commercial fish ponds.

scholarly journals Temporal Dynamics of Fish Assemblages as a Reflection of Policy Shift from Fishing Concession to Co-Management in One of the World’s Largest Tropical Flood Pulse Fisheries

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2974 ◽  
Author(s):  
Bunyeth Chan ◽  
Peng Bun Ngor ◽  
Zeb S. Hogan ◽  
Nam So ◽  
Sébastien Brosse ◽  
...  
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Temporal Dynamics ◽  
Flood Pulse ◽  
Commercial Fishing ◽  
Fish Assemblage Structure ◽  
Policy Reforms ◽  
Fisheries Governance ◽  
Inland Fisheries ◽  
Fish Catch

Inland fisheries management in Cambodia has undergone two major policy reforms over the last two decades. These reforms led to the abolishment of a century-old commercial fishing lot system in 2012 and the establishment of new fish sanctuary and community fishing areas. However, the status of fisheries and fish assemblages following the reforms is not well understood. Here, we investigated the temporal changes in fish catch weight and fish assemblage structure for the period 1995–2000 before fishing lot abolishment (BLA) and for the period 2012–2015 after the removal of all fishing lots (after lot abolishment-ALA) using time-series fish catch data recorded from the Tonle Sap Lake (TSL), one of the world largest inland fisheries. We found (i) mean catch trends vary seasonally, with stable catch trends during the BLA and decreasing catch trends during the ALA and (ii) significant shifts in fish assemblage composition, notably a shift from large-bodied, migratory, and/or predatory species during the BLA toward more short-distance migratory and/or floodplain, small-bodied species during the ALA. Fishing lot abolishment coincided with substantial changes to floodplain habitats and increases in fishing pressure, threatening TSL fish stocks. Flow alterations caused by dams and climate change may exacerbate the problem. Therefore, to realize the fisheries reform objectives, it is imperative to strengthen the fisheries’ governance and management system, including effective law enforcement, institutional strengthening, improved planning, cooperation, and coordination as well as clearly defined roles and responsibilities among concerned stakeholders at all levels.

scholarly journals The value of commercial fish size distribution recorded at haul by haul compared to trip by trip

2020 ◽  
Author(s):  
Kristian S Plet-Hansen ◽  
François Bastardie ◽  
Clara Ulrich
Keyword(s):  
Fishing Effort ◽  
Fish Distribution ◽  
Minimum Size ◽  
Dependent Data ◽  
Commercial Fishing ◽  
Commercial Fish ◽  
Traceability System ◽  
Fishing Vessels ◽  
Set Up ◽  
Abundance And Distribution

Abstract Data from commercial fishing vessels may enhance the range of observations available for monitoring the marine environment. However, effort and catch data provide information on fish distribution with a bias due to spatial targeting and selectivity. Here, we measured the shortcomings of standard fishery-dependent data and advocate for the utilization of more precise datasets indirectly collected by the commercial fishery. Data from a Danish traceability system, which records size of commercial fish at the haul level, are held against the set-up of current eLog and sales slips’ data collected for the Danish fisheries. We showed that the most accurate mapping of the spatial distribution of catches per size group is not only possible through size records collected at the haul level but also by high resolution on fishing effort data. In Europe, the regulation to land all catches with a quota or minimum size limit, including unwanted, has increased the focus on avoidance and discards; we show the potential of such data sources to inform on fish abundance and distribution, especially of importance where fishery-dependent data are the only source of information.

scholarly journals ON THE QUESTION OF FISHERY REGIME REGULATION IN THE VOLGA-CASPIAN BASSIN (ASTRAKHAN REGION) BY THE EXAMPLE OF NORTH-CASPIAN ROACH

2018 ◽  
pp. 41-48
Author(s):  
Vitaliy Victorovich Barabanov ◽  
Sergey Yurievich Nikiforov
Keyword(s):  
Hydrological Regime ◽  
Fishing Effort ◽  
Major Purpose ◽  
Spawning Grounds ◽  
Commercial Fish ◽  
Factors Affecting ◽  
Fish Catch ◽  
And Gender ◽  
Negative Factors ◽  
Caspian Roach

The article shows the assessment of fishing conditions of roach catches (the number of fishing grounds, fishing gears, catches, catches per unit of fishing effort, fishing intensity, etc.) at the main fishery objects of the Volga delta. There has been made the analysis of structure of size and gender composition of roach from commercial and amateur catches. The results have shown a depression of the population with negative dynamics in future. There have been determined main negative factors affecting the state of roach stock: unfavorable hydrological regime, incoordination in terms of commercial and amateur catches, limits of catch and size. In such circumstances the major purpose is to create a fishing regime, when maximum pass of fish spawners to spawning grounds is provided. The article proposes organizing a special regime of fishing roach with the aim to introduce additional limitations to the commercial fish catch, the main point of which is a transition from fine-meshed seines to medium-meshed seines in the day, when the water level in the Astrakhan region achieves an index mark as 350 cm. This measure will allow assuring a maximum pass of roach spawners to spawning grounds. A similar interdiction must be valid for amateur fishing. It should be noted that this interdiction is a provisional measure allowing to preserve and reproduce roach population.

scholarly journals Fish Corral Composition, Abundance, and Distribution in the Reef Flat of Palompon, Leyte, Philippines

2011 ◽  
pp. 62-84
Author(s):  
Jerome Benedict Cabansag ◽  
Arriane Krisna Rose Tuazon ◽  
Liezel Paraboles
Keyword(s):  
Reef Flat ◽  
Structural Complexity ◽  
Total Catch ◽  
Future Studies ◽  
Spatial Trends ◽  
Fish Catch ◽  
Temporal And Spatial ◽  
Catch Composition ◽  
Abundance And Distribution ◽  
Distribution Of Fish

There is paucity of studies relating to fish corral fishery and its management particularly those operated on reef flats. This study was conducted to evaluate the fish catch composition of fish corrals situated in the reef flat of Palompon, Leyte from July 2009 to January 2010. During the monitoring, two sets of data were utilized: the semimonthly field intercept samplings and the daily fish landing data. Field intercept samplings enabled the researchers to approach fishers as they were gathering their fish catch that was eventually identified, sorted, measured, and weighed. Fish landing data recorded by local enumerators included the fish’s local name and corresponding weight. From 27 fish corrals, the intercept samplings yielded a total catch of 23.9 kg, which was composed of 81 identified species under 47 genera from 31 families. The most abundant family was Siganidae comprising 44% of the total catch, followed by Apogonidae (18%) and Pomacentridae (9%). This composition was corroborated by the fish landed data. The temporal and spatial trends of the catch composition showed that Fam. Siganidae was most abundant in the months of July, October, and December, while Apogonidae in the months of August and November. It was observed that there was an unequal spatial distribution of fish species in the study area. Of the four sampling areas, Area 2 on the northeastern part of Palompon was the most diverse due partly to the high number of fish corral units and the area’s structural complexity wherein seagrass and algal beds were most extensive interspersed with coral patches. Results of this study could serve as reference for future studies dealing with monitoring and managing fish corral fishery.

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