Distribution Of Fish Schools Research Articles

Fuad Fuad fuad: Thank you for reviewing the copyediting of your manuscript, "The Effectiveness and Distribution of Fishing Light Attractors on the Stationary Lift Net," for Research Journal of Life Science. We look forward to publishing this work. Aminatus Suhriyah Institute of Research and Community Service, University of Brawijaya riris.aminatus@ub.ac.id

A stationary lift net requires an effective fishing light attractor. The intensity and distribution of light are important factors to increase the effectiveness of fishing light attractors. This study aimed to probe the distribution of light intensity and its effect on the effectiveness of fishing light attractors. This research employed a descriptive-comparative method by comparing the effectiveness of LED lights with kerosene lights. The results showed that the concentration of fish school in LED lights was at a depth of 4–10 m with a light intensity of 1x10-8– 10x10-8 W/cm2, while the kerosene lights was deeper than LED lights at a depth of 8–12 meters with a light intensity of 1x10-8– 10x10-8 W/cm2. The distribution of fish schools from LED lights tends to be concentrated and form larger schools than kerosene lights. The optimum light intensity of LED and kerosene lights was almost the same, in the range of 1x10-8– 10x10-8 W/cm2, with concentrations of fish schools reaching 65% and 64%, respectively. The total catch of LED lights fish during eight fishing trips was 168.5 kg or an average of 21.06±2.32 kg/trip, while the total catch of kerosene lights was 139.6 or an average of 17.5±1.98 kg/trip.

Seasonal variation in fish school spatial distribution and abundance under the Kuroshio regular pattern and the large meander in Suzu coastal waters

The Kuroshio Current can take two paths; usually it follows the regular pattern but occasionally it follows a pattern known as the large meander. In this study, we investigated the abundance of fish that migrate to coastal waters and the spatial distribution of fish schools under both Kuroshio patterns in Suzu district, Kochi prefecture, where the set net is the main fishery industry. We clarified the seasonal variation in the density and distribution of fish schools using a quantitative echo sounder. The effects of the Kuroshio large meander (LM) depended on the season. There was no effect of current pattern in summer or autumn, but in winter and spring the LM altered the marine environment and fish distributions. Cold water masses were formed in the survey area during winter and spring during the LM, and the water temperature dropped significantly compared with during the Kuroshio non-large meander (NLM). This altered the fish species and the distribution of fish schools in the survey area. The catches of Japanese horse mackerels (Trachurus japonicus) and Yellowtails (Seriola quinqueradiata) were much higher during the LM compared with those during the NLM. Unlike these two species, the small-sized pelagic fishes in spring has decreased significantly during the LM.

Advances in Methods for Marine Mammal and Fish Stock Assessments: Thermal Imagery and CamTrawl

AbstractNational Oceanic and Atmospheric Administration (NOAA) has adopted an integrated ecosystem research approach to understand climate effects on fish, seabirds, and marine mammals in the Arctic. The integrated ecosystem approach combines traditional oceanography, fisheries, and mammal research techniques to improve scientific understanding of how ecosystems function as a whole. Innovative technologies are being developed to aid in this effort. Two new technologies that NOAA deploys in the Arctic are an advanced thermal imaging technology used to survey ice seal abundance and a high-resolution, nonlethal technology, which integrates cameras and trawls to sample pelagic fishes (CamTrawl). The ice seal surveys relied on thermal imagery to detect warm seal bodies hauled out on cold sea ice. Compared to observer-based surveys, thermal detection surveys require fewer personnel and less postsurvey processing time, can be flown at a higher altitude (reducing disturbance of seals), and yield higher rates of seal detection. The CamTrawl is a self-contained stereo-camera system fitted to the aft end of a trawl at the cod end (i.e., capture bag), which can be left open. By integrating a camera system in the aft portion of a trawl, the CamTrawl concentrates marine organisms and presents this captive group to the cameras without having to recover them for onboard counting, as is done in traditional trawl tows. Compared to traditional survey methods, the CamTrawl more precisely places marine organisms spatially in their environment, which is useful because of small-scale variation in the composition and distribution of fish schools.

A new tool for visualising multi-dimensional datasets: an example of fish schools around artificial reefs

We demonstrated a tool for visualising multi-dimensional datasets, using an example of fish schools around artificial reefs off the coast of Shimonoseki, Yamaguchi prefecture, Japan. The datasets included acoustic surveys of fish schools, water temperature data, descriptions of the artificial reefs, sediment data, and bathymetry and coastal line data. These datasets were integrated into geographic information system software, which can be used to describe the relationship between water temperature and fish schools; fish schools associated with reefs; and the status of the artificial reefs on the classified seabed. This new tool provides a better understanding of the distribution of fish schools based on their spatial location in context with environmental information around artificial reefs.

Three dimensional analysis of distribution and shape of pelagic/mesopelagic fish school using scanning sonar

Sonar images obtained from a scanning acoustical beam are usually two-dimensional sectional images. However, since the sectional images can be easily obtained as an observation vessel moves forward, we can reconstruct three-dimensional images of underwater objects by analyzing stacked two-dimensional sectional images.The echo survey was conducted in Funka Bay aboard the R/V Ushio Maru, which is equipped with a 180-degrees sector scanning sonar (model KCH 1827, Kaijo Co. LTD). The sonar beam was directed downward perpendicularly to the ship's course. Vertical sectional sonar images were digitized every 1.5 seconds while the vessel was cruising at 10 knots. The stacked sectional images were analyzed to determine the spatial distribution and shape of fish schools using the three-dimensional image processing software SLICER.The distribution of fish schools was displayed by simultaneous expression of both horizontal and vertical projections. This expression method enabled us to observe fish avoidance from vessel, which can not be observed using ordinary vertical echo sounders.The reconstructed solid shape of fish schools by volume rendering could be observed by changing the visual point freely. This allowed to determine scale, features, and swimming direction of the fish schools. Three-dimensional display of sector scanning sonar images is a useful tool not only for a commercial fishing, but also for scientific surveys of fish resources and underwater drifters.

Analysis of the summer distribution of fish schools in the Pacific Eastern Boundary Current

The patterns of fish schools, mainly of Pacific hake (Merluccius productus), were studied in the Pacific Eastern Boundary Current during summer 1992. DiVerences between schooling patterns and depth preferenda offish schools in the north and south were elucidated through regression analysis of depth, size, and biomass information aboutfish schools, extracted from acoustic backscatter data. Hake schools appeared to be clustered, based on both visual and statistical evidence. School clusters were larger (more schools) and had more biomass in the north than in the south, but inter-cluster spacing was also larger in the north. Temperature, bottom depth and school depth all significantly aVect the biomass and number of schools in these clusters as the product of their eVect on individual schools and on school density. The eVect of these environmental factors on school cluster biomass and numbers diVers from their eVect on both individual schools and numbers of schools per arbitrary transect length (e.g. 5 nmi segments). School clusters may be a widespread phenomenon for schooling fish. ? 1997 International Council for the Exploration of the Sea

定置網漁場における魚群行動に関する研究 Ｉ 相模湾定置網漁場における魚群性状

定置網漁場における魚群行動に関する研究 Ｉ 相模湾定置網漁場における魚群性状