Open Water Fish Research Articles

Traditional ecological knowledge and natural resource management: Some examples from Bangladesh

Traditional Ecological Knowledge (TEK) refers to the knowledge, innovations, and practices of indigenous and local communities around the world. As it includes proven technologies for particular situations, its adoption cuts research costs and time. This paper attempts to find out the scoping of some TEKs on different practices ranging from plain land agriculture, hill farming, agro-biodiversity management, open water fish conservation, disaster management, and other aspects in different situations in Bangladesh. It is an outcome of the authors’ field experiences in the study of local flora, plant uses, and natural resource management practices in the community and a review of related literature. Access to modern facilities, urbanization, and land use changes are now causing many threats to TEK. Documentation and codification of this knowledge and its uses for sustainable development are needed for the betterment of local farmers as well as the preservation of cultural heritage. The knowledge is always changing to cope with socio-cultural needs. So, a fusion of TEK and modern scientific knowledge can help solve the problems encountered in the sustainable management of natural resources. It also needs to be incorporated into school curricula and mainstreamed in the local-level natural resource management planning process. The best practices can also be adopted in natural resource management.

Economic valuation of climate induced losses to aquaculture for evaluating climate information services in Bangladesh

Very little research has focused on climate impacts on aquaculture and the potential of climate information services (CIS) for aquaculture to support sustainable development goals 2030 (SDGs).11Resilient aquatic food systems can substantially contribute to SDG 1 to end poverty in all its forms, SDG 2 to end all forms of hunger through food and nutrition security, SDG 3 to ensure healthy lives and promote well-being for all at all ages, SDG 8 to promote inclusive economic growth, employment and decent work for all, SDG 12 to ensure responsible consumption and production patterns, SDG 13 to combat climate change and its impacts, SDG 14 to conserve the oceans, seas and marine resources and SDG 17 to strengthen the means of implementation and revitalize the global partnership. This study represents an effort to bridge this gap by conducting a first ex-ante economic evaluation of CIS for aquaculture in Bangladesh by semi-automating the extraction of data on climate-induced fish losses during 2011 to 2021 from popular online newspaper articles and corroborating them with available government and satellite datasets. During this period, Bangladesh faced an estimated loss of around 140 million USD for hatcheries, open water fish and shrimp. When validated with a year of country-wide official data on climate-induced economic losses to aquaculture, the damage reported from these media sources is approximately 10 percent of actual losses. Given this rule of thumb, the potential economic value of aquacultural CIS could be up to USD14 million a year, if 10 percent of the damage can be offset by appropriate services through a range of multi-sector efforts to establish and extend these services to farmers at scale.

Biological impact of in-situ exposure of catfish (<i>Clarias gariepinus</i> Burchell, 1822) to agricultural pesticide residues in the Tabalak pond

The Tabalak pond is contaminated by residues of agricultural pesticides, used by market gardeners. The present study aims to evaluate the ecotoxicological impact of this contamination on the ichthyofauna of this pond from growth parameters, biometric indices and organs histopathology. An in-situ fish cage experiment was used, compared to controls placed elsewhere and fish in the open water of the pond. Thus, juveniles of Clarias gariepinus were raised in tanks (control) and Tabalak pond for 120 days. The results showed that the survival and growth of the fish were better at the control site than the Tabalak site. The survival rate (SR) was 93.75% for the control, compared to 83.13% at the Tabalak site. The mean final weight (Mfw) was 148.71 g compared to 138.47 g, the weight gain (Wg) was 133.52 g compared to 123.45 g and finally the specific growth rate (SGR) was 1.9% compared to 1.85% for the control and Tabalak sites respectively. Semi-quantitative evaluation of organ tissues showed slight alterations in the organs of the control fish and moderate alterations in the organs of the caged and open water fish. Some of these histological alterations may be detrimental to certain vital functions of these fishes.

Status of Lake Taal Fisheries Amid Volcanic Threat and Covid 19 Pandemic : A Preliminary Study

The status of fishery resources of Lake Taal – the third largest lake in the Philippines was assessed to provide updated information on the capture fisheries following the Taal Volcano eruption and COVID-19 pandemic in 2020. Using the methodology of the National Stock Assessment Program of NFRDI, this study was conducted from January to December 2021 at 15 fish landing sites around the lake. In addition, interview schedules of 100 fisherfolk respondents from 11 coastal municipalities were also conducted to assess the effect of the volcanic eruption and pandemic on the livelihood of fisherfolk. Annual capture fisheries production was estimated at 1,004.14 MT. About 47% percent of these comprised the endangered freshwater sardine Sardinella tawilis while 31% are introduced species, and 22% migratory and/or native species. Current fisheries inventory showed that the number of fishers, fishing gears and fishing boats increased compared to 2018 inventory. The increased number of fisherfolk showed that more residents became dependent on the fishery resources of the lake. In the aftermath of volcanic eruption, reported impacts include reduction of fishing activity due to damaged gear and boat, fear of open water fishing, and reduction in demand for fish due to “unsafe” claims. Though many boats and gear were damaged in the 2020 volcanic eruption, passive or stationary fishing gears such as fish traps and fish corrals noticeably increased. During the peak of the community quarantine due to COVID-19, movement of fisheries products were hindered which led to the disruption of supply chain, and reduction of fishing activities due to lesser demand. Though there were times when fishing activities were halted due to recurring volcanic threat and pandemic, sustaining food and livelihood are what drive the local fisherfolk to learn to live and adjust adaptively to the current situation.

Comparative Study on Proximate Composition and Heavy Metal Concentration of Molacarplet (Amblypharyngodon mola) and Spotted Snakehead (Channa punctatus) Collected from Pond Water and Open Water

A study was conducted on the proximate composition and heavy metal concentration of Amblypharyngodon mola and Channa punctatus collected from pond water and open water in Mymensingh. The proximate composition analysis result showed -protein, lipid, moisture and ash content (%) of pond water A. mola were 20.26±0.63, 6.70±0.17, 66.40±1.51 and 2.55±0.58, respectively and for the fish caught from open water the values were 19.66±0.75, 5.81±0.18, 63.03±0.82 and 2.92±0.15, respectively. On the other hand, protein, lipid, moisture and ash content (%) of pond water C. punctatus found 23.83±1.07, 5.91±0.11, 64.44±1.87 and 3.23±0.11, respectively whereas the values for the fish caught from open water were 22.21±0.66, 5.43±0.19, 62.73±1.65 and 3.67±0.47, respectively. Arsenic (As) concentration of A. mola was higher in open water fishes (0.23±0.05 μg g-1) than the fishes of pond water (0.14±0.03 μg g-1). Cd concentration of pond water C. punctatus was found 0.21±0.04 μg g-1 whereas open water fishes contained 0.28±0.06 μg g-1. Copper (Cu) concentration of pond water and open water A. mola was 0.27±0.07 μg g-1 and 0.32±0.04 μg g-1, respectively. Heavy metal concentration of A. mola and C. punctatus was within permissible limits except Cd. The result revealed that open water fishes had higher concentration of heavy metals in their muscle than the fishes of pond water.
 Environ. Sci. & Natural Resources, 12(1&2): 91-99, 2019

Response of Zooplankton Indices to Anthropogenic Pressure in the Catchment of Field Ponds

As methods for assessing the environmental conditions in ponds are still not well developed, I studied zooplankton to identify a response of community indices to abiotic, biotic, and habitat type in two types of ponds differing in the level of human stress. Ponds of low human alterations (LowHI) harbored generally richer communities and a higher share littoral zooplankton, whose occurrence was associated with higher water transparency and complex macrophyte habitat, particularly the presence of hornworts and charoids. In high human-impact ponds (HighHI) planktonic communities prevailed. Their distribution was mainly related to the open water area and fish presence. Anthropogenic disturbance was also reflected in the frequency of rare species, which were associated with LowHI ponds. Higher diversity of zooplankton increased the chance for rare species to occur. Despite the fact that the majority of rare species are littoral-associated, they had no prevalence towards a certain ecological type of plants, which suggests that any kind of plant cover, even macrophytes typical for eutrophic waters (e.g., Ceratophyllum demersum) will create a valuable habitat for conservation purposes. Thus, it is postulated that a complex and dense cover of submerged macrophytes ought to be maintained in order to improve the ecological value of small water bodies.

Monitoring uncommon and non-indigenous fishes in Italian waters: One year of results for the AlienFish project

Results of the AlienFish project – monitoring and study of rare and non-indigenous fish species in Italian waters – collected through citizen science in 2018 are here reported. Overall, 36 observations of 21 fish species belonging to 17 families were provided from the central and southern sectors of Italian seas. Our findings highlight the effectiveness of involving sea users in the detection of fish species of both indigenous and non-indigenous origin. Professional fishermen were particularly effective in providing information on rare deep-water and open-water fishes.

Assessing the ecological relevance of swimming performance traits: a case study of bluegill sunfish (Lepomis macrochirus)

A variety of fish species show habitat-related variation in traits associated with swimming performance and foraging behavior. This commonly manifests as a distinction between open water and shallow water littoral ecotypes. In bluegill sunfish (Lepomis macrochirus), open water fish exhibit greater energy economy and speed during sustained locomotion than those from the littoral, whereas littoral fish were more maneuverable than their open water counterparts. These distinctions are associated with variation in diet and foraging behavior and may represent a resource polyphenism that enhances fitness through more effective exploitation of particular habitat types. A lack of field data means that polyphenisms have not been placed in context with swimming behavior in the field. We have used 3D videography to quantify bluegill field swimming performance in open water and littoral habitats. This revealed patterns of performance variation that parallel the trait variation previously established in the laboratory. Open water fish utilized faster average swimming speeds than inshore fish, while indicators of nonlinearity and unsteadiness were greater in the littoral fish. There are, however, differences in propulsive behavior between the field and laboratory. Pectoral-fin-powered, median-paired fin swimming is rarely employed by open water fish. Field body-caudal fin swimming involves short sequences of propulsive tail beats interspersed with gliding, rather than the repeated propulsive cycles employed under steady-state conditions. This suggests a need to re-evaluate the applicability of steady-state performance traits to behavior and fitness in the field and highlights the general importance of obtaining field performance data.

Study on heavy metal content of Oreochromis niloticus, Heteropneustes fossilis and Pangasius sutchi collected from pond and open water

Present studies were conducted on the study of heavy metal content of three popular freshwater fish, tilapia Oreochromis niloticus, shing, Heteropneustes fossilis and pangus, Pangasius sutchi collected from pond and open water in Mymensingh. All samples were evaluated by studying unwanted heavy metal concentrations. Cadmium (Cd) concentration (μg/g) of pond water O. niloticus, H. fossilis and P. sutchi was found to be 0.21±0.02, 0.20±0.01 and 0.22±0.02 respectively and open water was 0.28±0.03, 0.25±0.02 and 0.29±0.03, respectively. Copper (Cu) concentration (μg/g) of pond water O. niloticus, H. fossilis and P. sutchi was 0.25±0.02, 0.29±0.03 and 0.21±0.02 respectively whereas open water had 0.28±0.01, 0.59±0.04 and 0.35±0.01 respectively. Lead (Pb) concentration (μg/g) of pond water O. niloticus and H. fossilis contained 0.07±0.01 and 0.08±0.01, respectively whereas the open water had 0.15±0.02 and 0.15±0.01, respectively. Pb concentration both in pond and in open water P. sutchi was nil. Pb concentration of O. niloticus was higher in open water fishes (0.15±0.02 μg/g) than the fishes of pond water (0.07±0.01 μg/g). Heavy metal concentration of O. niloticus, H. fossilis and P. sutchi was within permissible limits except Cd of open water fishes. The result revealed that open water fishes have higher concentration of heavy metals in their muscle than the fishes of pond water. The results indicate that the open water environment is polluted by various chemical composition as well as various toxic heavy metal pollutants.Res. Agric., Livest. Fish.5(1): 117-126, April 2018

Comparative Study of Catch in Open Water Fish Habitats Both Inside and Outside the Embankment of Meghna Dhonagoda Irrigation Project

A comparative study of production /catch in open water fish habitats was conducted both inside and outside the embankment of Meghna Dhonagoda Irrigation Project (MDIP). Very low production was observed in the khal/canal (24.32 kg /ha and 26.45 kg /ha), inundated paddy field/ floodplain (1.99 kg / ha and 2.24kg / ha) in inside the embankment in 2003-2004 and 2004-2005, where the production/Catch per unit area was higher in khal (531.56 kg /ha and 528.77kg /ha), floodplain (38.18 kg /ha and 33.84 kg /ha) in outside during the same years. Beside these, the production/catch was recorded in irrigation canal (13.90 kg /ha and 21.94 kg /ha) in inside the embankment of both the years. On the other hand, the catch was recorded in Meghna river (137.87 kg /ha and 96.27 kg /ha) and in Dhonagoda river (124 kg /ha and 85.92 kg /ha) in outside the embankment of both the years respectively. The production was little bit higher in inside open water habitats in 2004-2005, escaped fishes from the ponds were also caught in the inside open water habitats in 2004-2005 due to the over flooding of ponds caused by excess rainfall in September 2004. In both the years, the highest production of inside habitats was in khal, followed by irrigation canal and inundated paddy field/ floodplain. In case of outside habitats, the highest production was in khal, followed by Meghna river, Dhonagodariver and floodplain during both the years of study. Monthly estimated catch regarding the production of the equal sample area of the same habitats between the two zones are statistically significant (p<0.05) in both 2003-2004 and 2004-2005.
 Asiat. Soc. Bangladesh, Sci. 43(2): 245-257, December 2017

Terminal Pleistocene subsistence strategies and aquatic resource use in southern Greece

In many parts of the Mediterranean Basin, the Late Glacial was a dramatic time in terms of demographic, cultural, and technological change. One region that illustrates this especially well is southern Greece, where Upper Paleolithic lifeways transitioned to the Mesolithic with the onset of the Holocene. Previous archaeological research in this area has documented an intensification of meat resources as foragers widened their diet breadth to include more low-return prey animals, eventually shifting their focus to the Mediterranean Sea. In this paper, we synthesize and expand on these previous analyses by combining new data from Kephalari Cave with two other published sites in the Argolid (Peloponnese), Franchthi Cave and Klissoura Cave 1. These three sites provide an ideal case study for examining changes in meat procurement strategies because they have overlapping Upper Paleolithic and Mesolithic chronologies and are located within about 45 km of one another. We consider each of the sites within their local environmental contexts, including the contraction of the coastal plain and moving shorelines after the Last Glacial Maximum. Changes in the composition of ungulate prey track local environmental and ecological conditions. The use of low-return species supports an overall picture of resource intensification in the region over time. At Klissoura, the most inland of the three sites, small terrestrial prey increases over the course of the Upper Paleolithic, particularly in the Late Glacial, and until the site was abandoned in the Mesolithic. At both Franchthi and Kephalari, small game are abundant in all Upper Paleolithic layers, but there is no overall trend. However, fishing appears in the Upper Paleolithic (most likely the Gravettoid phase) of Kephalari and during the Epigravettian at Franchthi. Fishing increases dramatically in later layers at both sites. At Franchthi, this trend culminates in open-water fishing of large-bodied tunny in the Upper Mesolithic. Interestingly, the use of Klissoura declined at about the time that fishing became a critical part of the economy at Franchthi, and possibly Kephalari. These subsistence shifts reflect a combination of factors, including growing human populations on a regional level and local responses that included changes in mobility patterns and site use, and more diverse toolkits, as well as changes in Pleistocene shorelines that brought an additional ecosystem closer to two of the sites. These internal and external factors allowed foragers in southern Greece to successfully move into a new ecological niche at the end of the Pleistocene.

Effect of heavy metal pollution on the incidence of antibiotic resistance in Aeromonas hydrophila isolates obtained from the surface of fish

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 79:197-207 (2017) - DOI: https://doi.org/10.3354/ame01828 Effect of heavy metal pollution on the incidence of antibiotic resistance in Aeromonas hydrophila isolates obtained from the surface of fish J. Vaun McArthur1,*, R. Cary Tuckfield2, Dean E. Fletcher1, Angela H. Lindell1 1Savannah River Ecology Laboratory, University of Georgia, Drawer E, Aiken, South Carolina, 29802, USA 2Ecostatys LLP, Aiken, South Carolina 29803, USA *Corresponding author: mcarthur@srel.uga.edu ABSTRACT: A large collection of aquatic Aeromonas obtained from the surfaces of 5 species of fish in 2 streams with different contamination histories were examined to test hypotheses on the effects of contaminant history, stream habitat and longitudinal location on the incidence of antibiotic resistance (AR) towards 6 antibiotics and levels of multiple antibiotic resistance (MAR). Fish species included an open-water species (Micropterus salmoides), 2 mid-water species of centrarchids (Lepomis auritus and L. punctatus) and 2 species of bottom-dwelling fish (Ameiurus natalis and A. platycephalus). Metal analysis of the sediments indicated that there was a strong downstream contamination gradient in one stream but not in the other. However, we found that the average MAR level was similar between the 2 streams. Comparisons among fish species found the highest levels of resistance in bacteria isolated from bottom-dwelling fish in the least-contaminated stream. However, there were clear differences in levels of resistance between bacteria isolated from the 2 bottom-dwelling fish, with those isolated from A. natalis having significantly higher levels than those isolated from A. platycephalus. We suggest that these differences relate to higher concentrations of metals and other contaminants in habitats where A. natalis is normally found. For some antibiotics, there was a clear pattern of decreasing resistance among bacteria isolated from bottom-dwelling, mid-water and open-water fish. Unlike culturable sediment bacteria from the same streams in previous studies, these commensal aeromonads did not show the same expected patterns of increasing antibiotic resistance in metal-contaminated vs. uncontaminated streams. KEY WORDS: Antibiotic resistance · Aeromonas · Commensal · Fish · Industrial pollution · Habitat partitioning Full text in pdf format Supplementary material PreviousNextCite this article as: McArthur JV, Tuckfield RC, Fletcher DE, Lindell AH (2017) Effect of heavy metal pollution on the incidence of antibiotic resistance in Aeromonas hydrophila isolates obtained from the surface of fish. Aquat Microb Ecol 79:197-207. https://doi.org/10.3354/ame01828 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 79, No. 3. Online publication date: June 12, 2017 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2017 Inter-Research.

Recent reconstruction of deep-water macrofaunal communities recorded in Continental Margin sediments in the Balearic Basin

We present an initial reconstruction of recent (last few centuries) mud-bottom faunal communities on the upper slope (398–667m) of the continental margin off Catalonia (western Mediterranean), including periods free of any trawling impact. Radiometric dating of marine sediments and identification of faunal remains (e.g., fish otoliths, pteropod shells, coral sclerites) were performed to obtain a sediment geochronology in a 56cm sediment core (MC4) taken at 398m off the Ebro Delta in 2011. Core MC4 was especially rich in faunal remains, including, for example, 247 identifiable otoliths. A fine-scale chronology of MC4 was not possible due to sediment mixing. However, the depth of 210Pbxs penetration (20–22cm) identified sediments older (below 22cm depth) and younger (from core top to 22cm) than ca. 100 years. Mass Accumulation Rate (MAR) from the 210Pbxs profile was estimated as 0.23±0.02gcm−2 y−1. A significant peak of sclerites of the bamboo coral Isidella elongata was found between 4 and 8cm in MC4, with remains of the axes and bases of Isidella colonies exclusively found at core depths >8–10cm, which would correspond (MAR results) to the period 1980–1985. Such structures were not found in the 0–8cm layer, likely an effect of trawling that started in the area in the 1980s. Other changes both in benthos (corals and cirripedes) and zooplankton (pteropods) seemed to be related with Ebro river discharge, with changes coinciding with massive damming of the Ebro and tributary rivers in the 1950s and until 1965. Mesopelagic fish also showed temporal oscillations in MC4. Abundance of some myctophid remains (Lampanyctus croccodilus and Benthosema glaciale) was related with positive NAO periods and with rather high temperature in Levantine Intermediate Waters. By contrast, periods of higher dominance of Ceratoscopelus maderensis off Catalonian coasts could indicate lower salinity during the past and a progressive degree of eutrophication in intermediate waters in recent decades. A general decline in myctophids otolith abundance during the last ca. 100 years could be related to changes in the temperature and salinity of deep-water masses and a decline in ocean productivity that would also have affected open-water fish stocks.

Temporal variations in suspended particulate waste concentrations at open-water fish farms in Canada and Norway

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 8:437-452 (2016) - DOI: https://doi.org/10.3354/aei00190 Temporal variations in suspended particulate waste concentrations at open-water fish farms in Canada and Norway Lindsay M. Brager1, Peter J. Cranford1,*, Henrice Jansen2, Øivind Strand3 1Department of Fisheries and Oceans, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, Nova Scotia B2Y 4A2, Canada 2Wageningen IMARES–Institute for Marine Resources and Ecosystem Studies, Korringaweg 5, 4401 NT Yerseke, The Netherlands 3Institute of Marine Research, Nordnesgaten 50, 5005 Bergen, Norway *Corresponding author: peter.cranford@dfo-mpo.gc.ca ABSTRACT: The co-cultivation of finfish and bivalve filter feeders, with the purpose of recycling solid waste effluents and enhancing aquaculture revenues, has stimulated efforts to characterize particulate waste dynamics at open-water fish farms. Temporal variability in waste concentrations in the water column was studied at Atlantic salmon Salmo salar farms in eastern Canada and Norway, and at a sablefish Anoplopoma fimbria farm in western Canada. Turbidity and chlorophyll a (chl a) sensors were used to continuously monitor suspended particulate matter (SPM) and chl a concentrations at various depths and distances to the net-pens. Time-series analysis of these data indicated that SPM fluctuations at the study sites corresponded largely with tidal periodicity and variations in phytoplankton biomass (chl a). ANOVA comparisons of mean SPM levels in water flowing from the direction of net-pens (potential farm influence) and towards the farm (control) generally indicated insignificant effects of fish wastes on SPM levels at the farms (p > 0.05). A significant effect of the farm was detected by an ANOVA comparison of SPM concentrations collected at 5 m depth at farm and reference stations in an oligotrophic fjord, but the calculated level of waste enhancement over the sampling period was extremely small (0.02 mg l-1). Results indicate that temporal variations in SPM concentrations around the open-water fish farms were largely driven by natural processes and that the addition of fish wastes had a negligible effect. Consequently, there is little rationale for introducing commercial extractive species (e.g. bivalves) in open-water integrated multi-trophic aquaculture systems to mitigate the horizontal flux of particulate fish wastes. KEY WORDS: Aquaculture wastes · Suspended particulate matter · Integrated multi-trophic aquaculture · Salmo salar · Anoplopoma fimbria Full text in pdf format PreviousCite this article as: Brager LM, Cranford PJ, Jansen H, Strand Ø (2016) Temporal variations in suspended particulate waste concentrations at open-water fish farms in Canada and Norway. Aquacult Environ Interact 8:437-452. https://doi.org/10.3354/aei00190 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 8. Online publication date: August 11, 2016 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2016 Inter-Research.

Seasonal variation of water quality parameters, clinical and histological observation of some small endangered open water fishes from Mymensingh and Sylhet region

Seasonal variation of water quality parameters and health condition of some small endangered open water fishes are Baila (Glossogobius giuris), Gutum (Lepidocephalichthys guntea) and Tara baim (Macrognathus aculeatus) was carried out through clinical and histological observation from Kailla beel of Ishargonj upazila, Mymensingh and Surma river, Gobindogonj upazila, Sunamgonj district, Sylhet region for a period of eight months from September 2014 to April 2015. Water quality parameters like water temperature, dissolved oxygen, pH, ammonia, alkalinity, hardness, and nitrate were recorded. Water temperature, pH, alkalinity and hardness were found at unfavorable level for fish in mid November and January. Clinical examinations of the fish were carried out at monthly intervals and any kind of abnormalities were recorded. Clinically it was observed that, fish was affected with fin and tail rot, gill rot, parasitic infestation, nutritional deformities, numerous red spots and patches in lateral and ventral regions, large deep whitish ulcers reached up to deep ulcers especially in December and January in both region. Samples of skin, muscle, gill, liver and kidney were collected and processed for histological observations. Major pathology in the skin and muscle were epidermis separated from dermis, presence of fungal granuloma, vacuums, hemorrhage and necrosis. Loss of primary and secondary gill lamellae, hypertrophy and primary gill lamellae separated, necrosis and hemorrhage were found in the gill. Large vacuums, necrosis and hemorrhage were observed in liver and kidney. Among the affected fish organs skin and muscle, gills were more affected than the internal organs like liver and kidney. Overall, clinical and histological observations of fishes were found to be more affected in December and January. Whereas, in the months of mid February to April, the pathological condition of fish gradually healed up to normal except few vacuums and hemorrhage. Under histopathological observations, fishes of Kailla beel were more affected than the fishes of surma river. In clinical and histopathological observation open water fishes were more susceptible due to EUS.Asian J. Med. Biol. Res. June 2015, 1(1): 95-102

Management of marine resources through a local governance perspective: Re-implementation of traditions for marine resource recovery on Easter Island

Easter Island (Rapa Nui) is one of the most isolated places in the world. The local Rapanui people have noticed an extreme decline in marine resources, which is due to the exploitation of these resources. Top-down regulations (e.g. fisherman and boat registrations and restrictions on catch-length and fishing season and location) implemented by the central fishery authorities located ∼4000 km from the island do not represent the cultural heritage and interests of the Rapanui people. According to the local people, one of the traditional ways to protect marine resources was the taboo (or tapu in Rapa Nui) that regulated the fish harvest. Key informants were interviewed to assess what they knew about the tapu in fisheries and so that the feasibility of its implementation could be assessed based on current local conditions. The tapu that had the greatest potential impact on regulating open water resources, especially tuna, was the traditional belief that consumption of open-water fish during winter months would cause asthma. According to the interviewees, the real reason for this tapu was to protect the fish during its reproductive period, and the asthma threat was only a way to enforce the restriction. At present, tapu is not respected because of the high economic activity related to the tourism that demands fish like tuna all year. Even though many Rapanui people agree that tapu re-implementation would be the best alternative to recover marine resources, people also think it is difficult to implement under modern conditions. We propose to promote a participatory process for development of a local governance structure that will use local traditions and beliefs, including tapu, to support the local decision-making process for reverting the decline of marine resources.

An overview of Fisheries sector of Bangladesh

Bangladesh is endowed with a vast expanse of inland open waters characterized by rivers, canals, natural and man-made lakes, freshwater marshes, estuaries, brackish water impoundments and floodplains. The potential fish resources resulting from these are among the richest in the world; in production, only China and India outrank Bangladesh. The inland fish diversity of is attributed to the habitats created by the Bengal Delta wetlands and the confluence of the Brahmaputra, Ganges and Jamuna rivers that flow from the Himalayan Mountains into the Bay of Bengal. There are, however, serious concerns surrounding the slow decline in the condition of open water fish stocks which have been negatively impacted upon through a series of natural and anthropogenic induced changes including large scale abstraction of water for irrigation and the construction of water barrages and dams, human activity resulting in the overexploitation of stocks, the unregulated introduction of exotic stocks and pollution from industry. Also, natural phenomena, regular flooding etc. cause rivers to continually change course creating complications of soil erosion or over siltation of waterways. As a consequence, many Bangladeshi species are either critically endangered or extinct. Aquaculture has increasingly been playing a major role in total fish production of the country and presently more than half of the total production comes from aquaculture. The sector provides living and livelihood for more than 11% people of the country. If the available resources are used sustainably with proper technological assistance, fish produced from aquaculture would efficiently meet the protein demand of growing population of the country. The needs of Bangladesh’s poor fisher community to eat what they catch and lack of a legal legislative framework means the situation can only worsen. Hope, however, is offered through several new conservation initiatives including the establishment of fish sanctuaries at strategic points in rivers and floodplains, concerted breeding programmes and the maintenance of captive stocks and cryogenically stored materials. DOI: http://dx.doi.org/10.3329/ralf.v1i1.22375 Res. Agric., Livest. Fish.1(1): 109-126, Dec 2014

Spatial distribution of suspended particulate wastes at open-water Atlantic salmon and sablefish aquaculture farms in Canada

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 6:135-149 (2015) - DOI: https://doi.org/10.3354/aei00120 Spatial distribution of suspended particulate wastes at open-water Atlantic salmon and sablefish aquaculture farms in Canada Lindsay M. Brager1, Peter J. Cranford1,*, Jonathan Grant2, Shawn M. C. Robinson3 1Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Dr., Dartmouth, Nova Scotia B2Y 4A2, Canada 2Department of Oceanography, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada 3Fisheries and Oceans Canada, St. Andrews Biological Station, 531 Brandy Cove Rd., St. Andrews, New Brunswick E5B 2L9, Canada *Corresponding author: peter.cranford@dfo-mpo.gc.ca ABSTRACT: Finfish aquaculture results in the production of particulate waste products that include uneaten feed and faeces. The impact of these wastes on the suspended particle field at 4 open-water fish farms in Canada was studied using high-resolution in situ particle sensors. Within-pen sampling at a sablefish Anoplopoma fimbria farm in British Columbia provided some evidence of the release of low levels (mean effect <0.2 mg l-1) of waste feed near the surface (1-3 m depth), but no waste signal was detectable in surface waters outside this farm. Enhancement of the particle field was also not apparent in surface waters (0.5-2 m depth) within the boundaries of an Atlantic salmon Salmo salar farm in the Bay of Fundy. However, data collected outside 2 adjacent farms indicated periodic, low-level particle enhancement (significant mean effect of <1.0 mg l-1; p < 0.001) near the surface immediately down-current from the net-pens. Despite the large sample numbers obtained, consistent detection of waste particle enhancement was confounded by the apparently small effect size and natural seston patchiness. These results suggest that any farm-induced effect on the surrounding particle field at the study sites would be highly localized and episodic. Consequently, the potential for enhanced production by co-cultured bivalve filter-feeders at these integrated multi-trophic aquaculture farms is limited by available space close to net-pens and the periodic availability of low levels of suspended particulate fish wastes. KEY WORDS: Aquaculture wastes · Suspended particulate matter · Biomitigation · Integrated multi-trophic aquaculture · Salmo salar · Anoplopoma fimbria Full text in pdf format PreviousNextCite this article as: Brager LM, Cranford PJ, Grant J, Robinson SMC (2015) Spatial distribution of suspended particulate wastes at open-water Atlantic salmon and sablefish aquaculture farms in Canada. Aquacult Environ Interact 6:135-149. https://doi.org/10.3354/aei00120 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 6, No. 2. Online publication date: January 13, 2015 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2015 Inter-Research.

Has the Hudson River fish community recovered from the zebra mussel invasion along with its forage base?

In the first decade after zebra mussels (Dreissena polymorpha) appeared in the Hudson River, the biomass of zooplankton and deepwater macrobenthos fell by ∼50%, while the biomass of littoral macrobenthos rose by &gt;10%. These changes in the forage base were associated with large, differential changes in the abundance, geographic distribution, and growth rates of openwater and littoral fish. In recent years, populations of zooplankton and deepwater macrobenthos have risen towards pre-invasion levels, while littoral macrobenthos remained unchanged. We therefore hypothesized that the abundance, distribution, and growth rates of openwater fish species would shift back towards pre-invasion levels, while littoral fish species would not change. Our analysis of large data sets for young-of-year fishes found no systematic change in the abundance or geographic distribution of either group of fish in the Hudson. We did find a marked increase in growth rates of openwater fish, but no change in growth rates of littoral fish, in support of our hypothesis. Our study shows that the ecological effects of a biological invasion may change over time.

Máximo térmico crítico en peces argentinos de agua dulce, Sudamérica

Using the critical thermal maximum technique with heating at 18°C /hour and from very different temperatures acclimation, the lethal temperature values and loss of equilibrium temperatures in eight pampasic species were identified. The results show a physiological relationship with the various “ecological types” in relation to temperature. The open-water fish and shore fish show greater tolerance than lower bottom fish, according to the stability of the environment.