Fish Counts Research Articles

Reef fish communities are spooked by scuba surveys and may take hours to recover.

Ecological monitoring programs typically aim to detect changes in the abundance of species of conservation concern or which reflect system status. Coral reef fish assemblages are functionally important for reef health and these are most commonly monitored using underwater visual surveys (UVS) by divers. In addition to estimating numbers, most programs also collect estimates of fish lengths to allow calculation of biomass, an important determinant of a fish’s functional impact. However, diver surveys may be biased because fishes may either avoid or are attracted to divers and the process of estimating fish length could result in fish counts that differ from those made without length estimations. Here we investigated whether (1) general diver disturbance and (2) the additional task of estimating fish lengths affected estimates of reef fish abundance and species richness during UVS, and for how long. Initial estimates of abundance and species richness were significantly higher than those made on the same section of reef after diver disturbance. However, there was no evidence that estimating fish lengths at the same time as abundance resulted in counts different from those made when estimating abundance alone. Similarly, there was little consistent bias among observers. Estimates of the time for fish taxa that avoided divers after initial contact to return to initial levels of abundance varied from three to 17 h, with one group of exploited fishes showing initial attraction to divers that declined over the study period. Our finding that many reef fishes may disperse for such long periods after initial contact with divers suggests that monitoring programs should take great care to minimise diver disturbance prior to surveys.

Microbial load on smoked fish commonly traded in Ibadan, Oyo State, Nigeria

The microbial load on smoked fish sold in Ibadan, Oyo State was studied. 64 of 4 different fish species (Mackerel ( Scomber scombrus ), Sardine ( Sardinela eba ), Panla ( Gadus morhua ) and Cat fish ( Clarias gariepinus )) were sourced from five different market locations. The microbiological analysis was done using standard microbiological procedures. The bacterial count of fish sampled from Ojo market was the highest (0.35±0.11 x 10 3 CFU/g) while the bacteria count of the fish sample from Bodija market was the lowest (0.07±0.04 x 10 3 CFU/g). There was no significant difference (p>0.05) in the microbial load of the various fish species sold within Ibadan metropolis as well as fish sampled from various market locations in Ibadan metropolis. Bacterial isolated on smoked fish studied were: E. coli , Salmonella spp , Klebsiella spp , Staphylococcus aureus , Aerosomonas spp , Pseudomonas spp , Vibrio spp , Serratia spp , Chromobacterium spp , Enterobacteria spp and Shigella spp. While the following fungi were isolated from the study: Aspergillus flavus , Penicillium spp , Fusarium oxysporum , Trrichoderma spp and Ceotrichium albidium . Fish species sold in different markets within Ibadan metropolis is fit for human consumption. Caution should be exercised in consuming smoked-dried fish displayed openly, reheating may be necessary to activate such micro-organisms before consumption. Keywords: bacteria, fungi, market, fish species

MONITORING OF FISH IN THE COASTAL BIOTOPES OF THE SOUTHERN PART OF FAR EASTERN MARINE RESERVE (PETER THE GREAT BAY, JAPAN SEA)

Fish counts by SCUBA visual methods are conducted in the coastal biotopes at Furugelm and Popov Islands and in the Sivuchia, Kalevala, and Pemzovaya Bays in the western Peter the Great Bay in July-August of 2012 and 2014. In total, 23 fish species were registered on transects at Furugelm Island and 11 species at Popov Island in 2012, and in 2014 — 17 fish species at Furugelm Island, 16 at Popov Island, 9 in the Sivuchia Bay, 6 in the Kalevala Bay, and 11 in the Pemzovaya Bay. Species composition of fish had moderate or high similarity between transects (35 pairs with Sorensen-Chekanowski index 0.3–0.5 and 25 pairs with higher values). The species diversity and its similarity were conditioned by bottom structure and presence or absence of sea grasses and algae. The highest fish biomass was observed in the Pemzovaya Bay (29.2 g/m 2 , mainly large-sized Sebastes schlegelii) and at Furugelm Island (21.2 g/m 2 , mainly S. taczanowskii and nesting males of Hexagrammos otakii), but the biomass values < 10 g/m 2 prevailed. Generally, the observed fish diversity, density, and biomass are lower in compare with the mid 1990s because of partial degradation of their habitats (disappearance of eelgrass Zostera marina) and water warming that prevents migrations of some coldwater fishes to the shallows. The most prominent decreasing is noted for Sebastes taczanowskii adults and juveniles, previously high abundant on rocky grounds, and for flounders on sandy grounds. So far as the changes of fish abundance and diversity have natural reasons, there is concluded that the effect of protection regime in the marine reserve is insignificant for fish populations.

Application of image processing to calculate the number of fish seeds using raspberry-pi

Many fish cultivator in Indonesia who suffered losses due to the sale and purchase of fish seeds did not match the agreed amount. The loss is due to the calculation of fish seed still using manual method. To overcome these problems, then in this study designed fish counting system automatically and real-time fish using the image processing based on Raspberry Pi. Used image processing because it can calculate moving objects and eliminate noise. Image processing method used to calculate moving object is virtual loop detector or virtual detector method and the approach used is “double difference image”. The “double difference” approach uses information from the previous frame and the next frame to estimate the shape and position of the object. Using these methods and approaches, the results obtained were quite good with an average error of 1.0% for 300 individuals in a test with a virtual detector width of 96 pixels and a slope of 1 degree test plane.

Camera field-of-view and fish abundance estimation: A comparison of individual-based model output and empirical data

Camera technology is evolving rapidly as computing and sensor technology reduces in size and increases in processing speed. This convergence of high speed computing and optics has resulted in the creation of full-spherical cameras and their application in marine environments has begun. Thus, there is a need to understand how large increases in camera field-of-view (FOV) impacts data collection and statistical inference, particularly when dealing with long-term time-series data. Data collected in this survey consisted of a single year of sampling and were insufficient to describe relationships for single species, therefore we species were grouped based on lineage and behavior into snappers, jacks, and mixed-reef groups. The empirical and theoretical models presented here demonstrate an asymptotic relationship between single-camera MaxN and four-camera MaxN counts for snappers and to a lesser extent the mixed reef groups composed primarily of groupers. In contrast the jack group showed a linear relationship between counts. This result suggests that accuracy of the counts can be improved by increasing camera field-of-view to 360° or full-spherical. Habitat complexity was demonstrated to be positively related to fish counts but had no effect on the relationship between camera FOV and fish counts. This could be the result of several things, 1) fish behavior is more critical in driving aggregative behaviors that modify the relationship between FOV and fish counts, 2) abundances observed in this region are not high enough for habitat effects to have impacted the relationship, or 3) a mixture of these effects. Further exploration of these relationships is needed that would improve sample sizes, more observations at high counts, and that establish species specific relationships. This work provides empirical footing to further develop the relationship between MaxN-type estimators relative to camera FOV and additionally includes insight into the effects of habitat. Critically, this work provides a method to relate counts produced from 360° systems to those produced with restricted FOV.

다중 적외선 센서 기반 어류계수기 개발

다중 적외선 센서 기반 어류계수기 개발

Development and implementation of a fish counter by using an embedded system

The development and implementation of an instrument for the automatic counting of ornamental fish by using an embedded system, is introduced herein. The proposed instrument is tested with two marine species, the Guppies (Poecilia Reticulata) and Mollies (Poecilia Sphenops), under conditions of controlled lighting and specimens whose sizes vary from 0.5 to 2.3 cm. The counting is done by digital image processing obtaining an average accuracy up to 96.64% using different species of fishes and different sizes. The main contributions are the theoretical and experimental study to determine the aquarium background color and the algorithm of the proposed method implemented in a low cost and high performance embedded system, specifically in a Raspberry Pi 2 executing the free GNU Octave Scientific Programming Language, thus, allowing the counting instrument to be reliable, portable and easily migratory to different operating systems. The obtained results demonstrate that the proposed method is competitive with state-of-the-art ones.

Chlorpyrifos-induced biochemical changes in Cyprinus carpio: Ameliorative effect of curcumin

The aim of this study was to determine protective effects of curcumin on some haematological values and oxidant/antioxidant status in Cyprinus carpio exposed to chlorpyrifos. The fish were exposed to two sublethal concentrations of chlorpyrifos (0.040 and 0.080mgL), and curcumin (100mg per kg of fish weight) was simultaneously administered for 14 days. Blood and tissue (liver, kidney, and gill) samples were collected at the end of the experiment and analysed to determine the haematological profile (red blood cell count, white blood cell count, haemoglobin concentration, and haematocrit level) and oxidant/antioxidant status (malondialdehyde level and superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase activities) of the fish. There was a significant decrease in the red blood cell count, the haemoglobin concentration, and the haematocrit level and a increase in the white blood cell count of CPF-treated fish. The results revealed a significant increase in the malondialdehyde levels of the groups that were exposed to CPF. Conversely, the MDA levels were significantly decreased by curcumin. Also, CPF exposure caused a significant increase in the superoxide dismutase and glutathione-S-transferase activities and a significant decrease in the catalase and glutathione peroxidase activities. However, curcumin reversed the superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase activities. In conclusion, this study demonstrated that CPF had a negative effect on the haematological values and the oxidant/antioxidant status of the fish. The simultaneous administration of curcumin was neutralised CPF-induced toxicity.

Comparison of sonar-, camera- and net-based methods in detecting riverine fish-movement patterns

Monitoring of fish movement is important in understanding and optimising the functionality of fishways and in restoring riverine connectivity. This study compared fish monitoring data (ARIS sonar-based and GoPro camera-based), with catches in a multi-mesh stow net following downstream passage in a small river in Bavaria, Germany. In terms of the number of individuals, the sonar-based system (detection rate=62.6% of net-based catches) outnumbered the counts of the camera-based system (45.4%). Smaller specimens of &amp;lt;100 and &amp;lt;150mm were under-represented with the sonar and the camera-based systems respectively. Species identification based on the camera system was similar to that for net-based catch, whereas no proper species identification could be performed with sonar data. In conclusion, the sonar-based system can be recommended for the counting of fish &amp;gt;100mm during night and turbid conditions, unless species identification is necessary. During daylight and with clear water, cameras can be a cheaper and promising option to monitor species compositions of fish &amp;gt;150mm.

Study on the sensor unit for resistivity fish counter for small fish

Study on the sensor unit for resistivity fish counter for small fish

Erratum to: Application of systematic adaptive cluster sampling for the assessment of black sea bass Centropristis striata abundance

In this study, we applied systematic adaptive cluster sampling (SACS) to assess the abundance of black sea bass Centropristis striata on hard bottom habitats in the Mid-Atlantic Bight (MBA; USA). We used a remote underwater video system to obtain video recordings of black sea bass from 25 June to 6 August 2013 within a 25-square nautical mile (nmi2) sampling region. Data in the form of fish counts were collected from video recordings and used to estimate parameters including sample means and population totals of black sea bass for two adaptive cluster sampling estimators and a single systematic sampling estimator. The precision and relative efficiencies of the parameter estimates were also calculated and compared. In total, two adaptive cluster samples were encountered within the sampling region. Sample means and population totals were largest for the systematic sampling (SS) estimator while the adaptive sampling estimators produced parameter estimates with the lowest variances and highest precision. Our results indicated that SACS was more efficient and advantageous with respect to sampling costs [i.e., sampling time (hours) and travel distance (kilometers)] than SS alone for assessing the abundance of clustered populations of C. striata on hard bottom habitats in the MBA.

Multi-scale temporal patterns in fish presence in a high-velocity tidal channel.

The natural variation of fish presence in high-velocity tidal channels is not well understood. A better understanding of fish use of these areas would aid in predicting fish interactions with marine hydrokinetic (MHK) devices, the effects of which are uncertain but of high concern. To characterize the patterns in fish presence at a tidal energy site in Cobscook Bay, Maine, we examined two years of hydroacoustic data continuously collected at the proposed depth of an MHK turbine with a bottom-mounted, side-looking echosounder. The maximum number of fish counted per hour ranged from hundreds in the early spring to over 1,000 in the fall. Counts varied greatly with tidal and diel cycles in a seasonally changing relationship, likely linked to the seasonally changing fish community of the bay. In the winter and spring, higher hourly counts were generally confined to ebb tides and low slack tides near sunrise and sunset. In summer and fall of each year, the highest fish counts shifted to night and occurred during ebb, low slack, and flood tides. Fish counts were not linked to current speed, and did not decrease as current speed increased, contrary to observations at other tidal power sites. As fish counts may be proportional to the encounter rate of fish with an MHK turbine at the same depth, highly variable counts indicate that the risk to fish is similarly variable. The links between fish presence and environmental cycles at this site will likely be present at other locations with similar environmental forcing, making these observations useful in predicting potential fish interactions at tidal energy sites worldwide.

Survival, growth and physiological responses of juvenile Japanese flounder (Paralichthys olivaceus, Temminck &amp; Schlegel, 1846) exposed to different dissolved oxygen concentrations and stocking densities

The aim of this study was to determine to what extent juvenile Japanese flounder can adapt to different stocking densities in captivity and to examine whether growth and some physiological parameters critical for welfare might be affected by different dissolved oxygen levels. Japanese flounder (Paralichthys olivaceus) juveniles (initial weight 1.27 ± 0.04 g/fish) were reared at five stocking densities (500, 1,000, 1,500, 2,000, 2,500 ind/m3) and two levels of dissolved oxygen (DO) concentration (5.5 ± 0.5 mg/L or 14 ± 2 mg/L) with duplicate tanks for each treatment in water-recirculating systems for 40 days. Survival and activity of superoxide dismutase (SOD) were not affected either by stocking density or dissolved oxygen, whereas final body weight, specific growth rate (SGR) and feed conversion efficiency (FCE) of fish under low DO concentration decreased significantly with increasing stocking density. In contrast, growth of fish reared in high DO levels were unaffected by the stocking density. Furthermore, fish in this group had a higher feed intake and, consequently, grew faster (SGR) and achieved a higher final weight than fish reared at the low DO level. A significant reduction in hemoglobin (Hb) concentration and red blood cell (RBC) count of fish were recorded as DO concentration increased. Furthermore, the activity of protease decreased significantly with increasing stocking density and increased significantly with increasing DO concentration. The ventilation frequency results indicate that gill ventilation decreased significantly as DO levels increased. This study demonstrates that stocking density can affect the growth performance and physiological parameters critical for welfare of juvenile Japanese flounder. Also shown is that pure oxygen supplementation is an effective way to improve the growth of juvenile Japanese flounder when reared at a high stocking density.

Dietary Fiber's Contribution to the Energy Needs of the Microbiota

The objective of this research is to address the amount of energy resulting from the total fermentation of an oligosaccharide, resistant maltodextrin (RM), used for the growth of the microbiota (MB). The metabolizable energy (ME) of RM has been previously reported (J. Nutr. 144:1, 2014). Dietary Fiber (DF), intrinsic and intact in plant foods, and Added Fiber, isolated or modified from plant foods or chemically synthesized are now defined (FDA, 2014) as having “beneficial physiological effects for human health (BPEFHH)”. The microbiota (MB) is considered to have strong associations with BPEFHH, but evidence to confirm this association has not been established. While DF can contribute to health benefits, its quintessential properties are to promote laxation and serve as the primary energy source for the MB. However, the energy contribution of DF for MB growth is not known. A randomized placebo controlled double blind crossover study was conducted and all participants were provided all foods for replicated intakes and fed to maintain body weight. As part of the controlled diet, men (n=14) were fed, in in random order, sequence 3‐treatments, of 0 g RM and 50 g digestible dextrin (DD), 25 g RM and 25 g DD, and 50 g RM and 0 g DD. In addition to a MB analysis of feces, total MB counts were accomplished by appropriate dilution of wet fecal samples and MB stained for FISH (counts) cell counting with a light microscope. Total wet and dry fecal weights (g), increased with 25g RM (148,32‐NS) and 50g RM (161,39‐P ≤0.02) compared to the control treatment, 0g RM (118,27), respectively. Total MB counts in wet fecal samples, in counts per g for 0, 25 and 50 g RM/day were 8.6a, 10.1a,b and 10.3b × 109, and for the total feces, total MB counts would be 1.0, 1.5 and 1.2 × 1012, respectively. The ME values for RM fed 25g and 50g/d were 8.2 kJ and 10.4 kJ levels, and net energy (NE) values were 8.2 kJ and 2.0 kJ/g, respectively. It is suggested that totally fermentable DF even in diets currently providing 18–20 g total DF/d, provide approximately 5 to 7 kJ/g for MB growth. Increased total MB in wet fecal weight, increased mass, and with increased MB concentration per g feces is considered as contributing to DF ability to improve BPEFHH, and initially via better laxation.Support or Funding InformationSupport, Matsutani, Co, LTD, USDA, ARS

Detecting a nearshore fish parade using the adaptive resolution imaging sonar (ARIS): An automated procedure for data analysis

Recent developments in sonar imaging provide an efficient way of obtaining near video quality of free-swimming fish in hard to reach areas, e.g., permanent structures like docks and piers, and hard to see environments, e.g., highly turbid waters. However, processing large volumes of data output by sonar imaging systems remains a major challenge. In the present study, we developed an automated image processing procedure to process footage recorded for 59 consecutive hours using an Adaptive Resolution Imaging Sonar, ARIS Explorer 3000 (Sound Metrics INC) deployed at a fixed location. Our approach successfully counted large free swimming fish at a precision rate >94% and estimated sample volume with manual and automatic calculations being highly correlated (r=0.96). An auto-regressive time series model (of the sixth or higher order) with a zero-inflated Poisson distribution was used to estimate local abundance. Fish counts were low to zero during the first 31h of sampling, and a major influx of fish occurred in the last 28h. The observed pattern was co-incidental with local weather patterns: intermittent thunderstorms in the first 32h and relatively calm weather in the last 24h. Though thunderstorms limited our conclusions on fish-pier usage with tidal and diurnal cycles, it is apparent that weather conditions play a role in pier usage by large fish. Overall, the ARIS3000 deployment, automated data processing and statistical analyses used in this study proved successful in studying fish affiliations with piers in shallow habitats.

Farmed fish to supermarket: Testing for price leadership and price transmission in the salmon supply chain

ABSTRACTIn this article, we measure the extent of price transmission and test price leadership in the salmon supply chain. The data represent monthly observations (2005–2014) on export price of fresh salmon from Norway and on retail prices for a variety of salmon products in France and United Kingdom. The contribution is to use a Johansen bivariate time-series approach to quantify the degree of price transmission on a broader set of consumer salmon products than has been previously studied. Of the original 17 retail products examined only 8 cointegrate with export prices. Of these, all but one reject a null of full price transmission and all show price causality from export to retail level. Price transmission to retail prices decreases, as more processing is involved and increases for packaged salmon products compared to salmon sold in the fresh fish counter.

Entry of adult Atlantic salmon into a tributary of the Aberdeenshire Dee, Scotland

AbstractUpstream counts of adult salmon in a tributary to the River Dee during autumn and winter were examined over a 13‐year period using an optical fish counter. Statistical analysis indicated that salmon were mainly primed to enter the tributary at a particular time of year, peaking at early December. However, environmental factors also had a large influence. Entry of salmon was initiated by high flow rates in the main stem of the River Dee. Increases in water level in the tributary itself were not needed to stimulate the entry of salmon. Moreover, a change in flow from 1 day to the next did not result in a response from salmon. Rather, they reacted only after more than a day of flow increase. There was no consistent threshold level of flow that triggered tributary entry. The upstream passage of salmon was reduced at low temperatures (below 3°C). The numbers of salmon migrating upstream showed a gradual increase as the temperatures increased up to 11°C, and then sharply decreased at higher temperatures. Female salmon migrated earlier by about 2 weeks on average than males. Increasingly, counters and traps are being installed on spawning tributaries to examine the state of salmon stocks. Caution should be exercised, however, in using upstream entry data from individual tributaries to provide an overall assessment of salmon abundance, as local conditions in the tributaries may affect the salmon counts in particular years.

AN OUTBREEK OF AFLATOXICOSIS IN CLARIAS GARIEPINUS, A MYCOLOGICAL, BIOCHEMICAL AND HISTOPATHOLOGICAL STUDIES

A total of one hundred and twenty cat fish (Clarias gariepinus) were collected from two private fish farms in Dakahlia governorate during summer, 2016. We collected fifty diseased fish from first farm which suffered from cumulative mortality and seventy healthy fish from second farm. All collected fish were subjected to clinical, postmortem, histopathological and mycological examination. Aflatoxins were extracted and quantitated from feed and musculature of diseased and healthy fish (5 samples for each) using HPLC. Blood samples were collected for biochemical and hematological parameters. The clinical observation revealed that the diseased fish showed opacity of the eyes, paleness of the gills with presence yellowish greenish infiltration, hemorrhagic, yellowish skin and fins, and the fish were slow in motion. The postmortem examination showed enlargement of the gall bladder, distention of the stomach, yellowish enlarged liver, swollen, dark red and friable kidneys. Whereas the histopathological examination revealed a severe degenerative and necrotic changes in most internal organs of diseased fish. On the other hand mycological examination of diseased fish yielded isolation of Aspergillusflavus (42%), A. parasiticus (34.8%), A. niger (12%) and A. fumigatus (10.9%). While no fungi was isolated from any organs of healthy fish. The mean levels of aflatoxins in feed of diseased fish was 108.9±0.77 ppb (46.5±0.75 ppb AFB1, 1.4±0.11 ppb AFB2, 58.9±0.38 ppb AFG1, 2.1±0.24 ppb AFG2), while the mean levels of AFs residues detected in musculature of diseased fish was 20.9±0.39 ppb (11.3±0.25 AFB1, 0.15±0.007 AFB2, 8.9±0.20 AFG1, 0.5±0.44 AFG2). Whereas Aflatoxins not detectable in feed or muscles of healthy fish. Regarding to biochemical and hematological parameters, there were significant decrease in serum protein and albumin also a significant increase in AST, ALT and serum creatinine, as well as there were significant decrease in HB concentration and RBCs count of diseased fish compared to healthy fish.

Seasonal and daily upstream movements of brown troutSalmo truttain an Iberian regulated river

Migrating fish are vulnerable to anthropogenic disturbances and, to assess the impact of human activities in freshwater ecosystems, it is vital to understand their movement patterns. The aim of this study is to describe the upstream movements of potamodromous brown trout Salmo trutta (seasonal and daily) and the potential environmental triggers in a regulated river in the northwest of the Iberian Peninsula (Porma River, Leon, Spain). Data collected in a fishway from October 2011 to January 2013 with a fish counter showed two important migratory periods, one associated with reproduction (October–December) and another one during summer (July–August). Both were significantly correlated with changes in solar radiation, flow and water temperature. Although in all seasons movements were identified throughout the day, they were more frequent early in the morning and in the afternoon during the spawning migration and in the morning during summer. River regulation of the Porma Reservoir significantly influenced movements by providing non-natural high flows during summer, which increased the chance of migration, but also colder water that could delay the thermoregulatory movements. In contrast, it provided lower flows in the spawning season. This highlights how susceptible brown trout movements are to human influence on flow and thermal regimes.

Putinism After Crimea

“The pursuit of national glory,” which M. Steven Fish counts among the features of Vladimir Putin’s “populism,” is emerging as central to the regime’s legitimation. Unlike previous instances of patriotic mobilization (around the Second Chechen War and the 2008 Georgia war), the current one appears to have evolved into a permanent structure sustaining Putin’s regime. As a result, of the two presidential roles that undergird what Kirill Rogov called Putin’s “supermajority”—which safeguards Putin’s popularity even in tough economic times— that of “savior and protector of the nation” has all but supplanted that of “wealth manager.” The most probable threat to Putinism’s survival in the short term lies in the possibility that efforts to bolster the credibility and salience of the “savior and protector” narrative may lead to a foreignpolicy setback.