Academic literature on the topic 'Discarded fish'
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Journal articles on the topic "Discarded fish"
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Wassenberg, TJ, and BJ Hill. "Partitioning of material discarded from Prawn Trawlers in Morton Bay." Marine and Freshwater Research 41, no. 1 (1990): 27. http://dx.doi.org/10.1071/mf9900027.
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Prawn trawlers in Moreton Bay, Queensland, discard about 3000 t of material each year. About 3% floats, and the rest sinks. The floating component is almost entirely fish. At night, floating discards are eaten by silver gulls (Larus novaehollandiae), crested terns (Sterna bergii) and, to a lesser extent, dolphins (Tursiops truncatus). There is little trawling during the day but the last discards are dumped overboard around dawn. At this time cormorants (Phalacrocorax varius) join the scavengers. Birds and dolphins scavenged only fish and cephalopods, and not crustaceans nor echinoderms. Birds are selective as to the size of fish they will eat, but most of the whole fish in the discards are below 50 g, and the largest fish that crested terns ate was 100 g. Dolphins are capable of taking the largest of the discarded fish. Most of the material that sinks is crustaceans (54%) and echinoderms (18%); the rest is elasmo- branchs and rubble. At night, about half of the fish that sink are eaten by diving birds and by dolphins. There was no indication of mid-water scavenging of sinking discards, except for cormorants and dolphins in the upper water column. Approximately 11% of the discards that reach the bottom comprise fish and crustaceans, which are eaten by crabs (Portunus pelagicus) and fish. The remainder- chiefly crabs, echinoderms and elasmobranchs-reach the bottom alive. Altogether, about 20% of discards are eaten by surface and bottom scavengers. Discards are probably important in maintaining populations of the major scavengers.
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Díaz, Paz, Juan Santos, Francisco Velasco, Alberto Serrano, and Nélida Pérez. "Anglerfish discard estimates and patterns in Spanish Northeast Atlantic trawl fisheries." ICES Journal of Marine Science 65, no. 7 (August 7, 2008): 1350–61. http://dx.doi.org/10.1093/icesjms/fsn127.
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Abstract Díaz, P., Santos, J., Velasco, F., Serrano, A., and Pérez, N. 2008. Anglerfish discard estimates and patterns in Spanish Northeast Atlantic trawl fisheries. – ICES Journal of Marine Science, 65: 1350–1361. Estimates of Spanish bottom trawl discards of anglerfish Lophius budegassa and Lophiuspiscatorius in the Northeast Atlantic Ocean are presented. Both species are commercially valuable in ICES Subareas VI and VII, and Divisions VIIIc and IXa. Information was obtained from observers on board during discard-monitoring programmes. Raising by effort, rather than by landings and target species, was used to determine the total annual discards by weight and number, the discard percentage, and the discard length distribution by stock throughout the dataseries. By weight and number, discards varied interannually, ranging from 4 to 600 t (∼28 000–7 000 000 fish) in northern stocks of anglerfish, and from 1 to 100 t (∼20 000–400 000 fish) in southern stocks. The discard percentage for both species and northern and southern stocks therefore ranged between 2 and 76% by number. Length distributions of the discarded anglerfish show that most were juveniles, although the pattern differed in years with high or with low rates of discarding. The number of juveniles caught apparently increased in most areas after 2000. Correlations between the quantities discarded and recruitment indices from French and Irish trawl surveys were found for northern stocks and with Spanish trawl survey indices for southern stocks.
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Borges, Lisa, Olvin A. van Keeken, Aloysius T. M. van Helmond, Bram Couperus, and Mark Dickey-Collas. "What do pelagic freezer-trawlers discard?" ICES Journal of Marine Science 65, no. 4 (April 3, 2008): 605–11. http://dx.doi.org/10.1093/icesjms/fsn050.
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Abstract Borges, L., van Keeken, O. A., van Helmond, A. T. M., Couperus, B., and Dickey-Collas, M. 2008. What do pelagic freezer-trawlers discard? – ICES Journal of Marine Science, 65: 605–611. Estimates of discards by the Dutch pelagic freezer-trawler fleet were derived based on data from observers on board commercial vessels. In all, 27 fishing trips of duration 2–5 weeks each were sampled between 2002 and 2005, covering the North Sea and the western waters of the British Isles. Different methods to estimate discards were compared, and raising these estimates by number of trips or by total landings did not greatly influence the annual estimates of total discards. Some 30 000 t of fish were discarded annually by the fleet, the commercial target species mackerel, herring, and horse mackerel being discarded most, with 41%, 19%, and 15% of the total discards by weight, respectively. The most commonly discarded non-commercial species was boarfish, accounting for 5% of total discards. Slippage accounts for 10% of all discards, and the most common species slipped is herring. There is extensive discarding of juvenile mackerel in the horse mackerel fishery, and to a lesser extent highgrading of mackerel in the same fishery.
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Davis, Michael W. "Key principles for understanding fish bycatch discard mortality." Canadian Journal of Fisheries and Aquatic Sciences 59, no. 11 (November 1, 2002): 1834–43. http://dx.doi.org/10.1139/f02-139.
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The mortality of discarded fish bycatch is an important issue in fisheries management and, because it is generally unmeasured, represents a large source of uncertainty in estimates of fishing mortality worldwide. Development of accurate measures of discard mortality requires fundamental knowledge, based on principles of bycatch stressor action, of why discarded fish die. To date, discard mortality studies in the field have focused on capture stressors. Recent laboratory discard experiments have demonstrated the significant role of environmental factors, size- and species-related sensitivity to stressors, and interactions of stressors, which increase mortality. In addition, delayed mortality was an important consideration in experimental design. The discard mortality problem is best addressed through a combination of laboratory investigation of classes of bycatch stressors to develop knowledge of key principles of bycatch stressor action and field experiments under realistic fishing conditions to verify our understanding and make predictions of discard mortality. This article makes the case for a broader ecological perspective on discard mortality that includes a suite of environmental and biological factors that may interact with capture stressors to increase stress and mortality.
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Uhlmann, Sebastian S., Aloysius T. M. van Helmond, Elísabet Kemp Stefánsdóttir, Sigríður Sigurðardóttir, John Haralabous, Jose Maria Bellido, A. Carbonell, et al. "Discarded fish in European waters: general patterns and contrasts." ICES Journal of Marine Science 71, no. 5 (April 14, 2013): 1235–45. http://dx.doi.org/10.1093/icesjms/fst030.
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Abstract To reduce the practice of discarding commercially fished organisms, several measures such as a discard ban and extra allowances on top of landings quotas (“catch quota”) have been proposed by the European Commission. However, for their development and successful implementation, an understanding of discard patterns on a European scale is needed. In this study, we present an inter-national synthesis of discard data collected on board commercial, towed-gear equipped vessels operating under six different national flags spanning from the Baltic to the Mediterranean Seas mainly between 2003 and 2008. We considered discarded species of commercial value such as Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), European hake (Merluccius merluccius), and European plaice (Pleuronectes platessa). Comparisons of discard per unit effort rates expressed as numbers per hour of fishing revealed that in the Mediterranean Sea minimum size-regulated species such as hake are generally discarded in much lower numbers than elsewhere. For most species examined, variability in discard rates across regions was greater than across fisheries, suggesting that a region-by-region approach to discard reduction would be more relevant. The high uncertainty in discard rate estimates suggests that current sampling regimes should be either expanded or complemented by other data sources, if they are to be used for setting catch quotas.
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Tsagarakis, K., A. Machias, M. Giannoulaki, S. Somarakis, and I. Karakassis. "Seasonal and temporal trends in metrics of fish community for otter-trawl discards in a Mediterranean ecosystem." ICES Journal of Marine Science 65, no. 4 (March 3, 2008): 539–50. http://dx.doi.org/10.1093/icesjms/fsn023.
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Abstract Tsagarakis, K., Machias, A., Giannoulaki, M., Somarakis, S., and Karakassis, I. 2008. Seasonal and temporal trends in metrics of fish community for otter-trawl discards in a Mediterranean ecosystem. – ICES Journal of Marine Science, 65: 539–550. Trends in discard to marketed ratios, size spectra, diversities, and trophic levels of the demersal fish community were examined using data from a seasonally closed commercial trawl fishery in the eastern Mediterranean Sea (Ionian Sea), over a period of about 10 years. Trends were also examined for the artificial fractions derived from the discarding process (the marketed, the discarded, and the non-marketed clusters of the catch), as well as for the “big” and “small” fractions (defined by the size at which 50% of all specimens were discarded). The ratio of the discarded/marketed catch fluctuated greatly. Two commercial (Merluccius merluccius, and Mullus barbatus) and two non-marketed species (Lepidotrigla cavillone, and Argentina sphyraena) were the characteristic species of the fractions. A declining trend with time was observed for the examined time-series for species richness (S), Margalef’s d, and average taxonomic distinctness (Δ+), whereas the variation in taxonomic distinctness (Λ+) increased. The composition and/or trophic level of discards in relation to the marketed catch seemed to be indicative of the exploitation state of the demersal community: differences between the discarded and marketed fractions were high at the beginning of the fishing season (autumn), but the values of the indices converged at the end of the fishing season (spring). These changes could be attributed to alternative discarding strategies for certain species in response to increased cumulative fishing mortality towards the end of the period.
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Catchpole, T. L., J. P. Feekings, N. Madsen, A. Palialexis, V. Vassilopoulou, J. Valeiras, T. Garcia, N. Nikolic, and M. J. Rochet. "Using inferred drivers of discarding behaviour to evaluate discard mitigation measures." ICES Journal of Marine Science 71, no. 5 (October 18, 2013): 1277–85. http://dx.doi.org/10.1093/icesjms/fst170.
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Abstract Discards refer to the part of the catch not retained on board during commercial fishing operations, but returned to the sea. The proposed European Union Common Fisheries Policy reform, to be implemented in 2014, sets out a gradual elimination of discards by reducing unwanted catches and ensuring that all catches are landed. To develop successful discard mitigation measures, it is necessary to identify the reasons for discarding. Here, we have developed a simple model that can be applied to data from observer programmes (ObsPs) to establish the contribution of different drivers of discarding behaviour. The analysis makes inferences on the causes of discarding by partitioning discards into four categories based on the length of the fish and the associated regulatory restrictions. The drivers are defined as: fish discarded below the legal minimum landing size; fish for which there is no market and that do not have a minimum landing size; fish for which there are inconsistencies in market and sorting practices; and discards that can be attributed to fishers' responses to quota restrictions. The approach is applied to data generated from ObsPs from five European Member States. All the inferred drivers contribute to the total discard quantity. Their relative contributions vary widely across countries, areas, gears, and species.
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Borges, Lisa, Alain F. Zuur, Emer Rogan, and Rick Officer. "Modelling discard ogives from Irish demersal fisheries." ICES Journal of Marine Science 63, no. 6 (January 1, 2006): 1086–95. http://dx.doi.org/10.1016/j.icesjms.2006.03.017.
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Abstract Annual discard ogives were estimated using generalized additive models (GAMs) for four demersal fish species: whiting, haddock, megrim, and plaice. The analysis was based on data collected on board commercial vessels and at Irish fishing ports from 1995 to 2003. For all species the most important factors influencing annual discard ogives were fleet (combination of gear, fishing ground, and targeted species), mean length of the catch and year, and, for megrim, also minimum landing size. The length at which fish are discarded has increased since 2000 for haddock, whiting, and plaice. In contrast, discarded length has decreased for megrim, accompanying a reduction in minimum landing size in 2000.
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Uhlmann, Sebastian S., Stijn M. Bierman, and Aloysius T. M. van Helmond. "A method of detecting patterns in mean lengths of samples of discarded fish, applied to the self-sampling programme of the Dutch bottom-trawl fishery." ICES Journal of Marine Science 68, no. 8 (June 8, 2011): 1712–18. http://dx.doi.org/10.1093/icesjms/fsr066.
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Abstract Uhlmann, S. S., Bierman, S. M., and van Helmond, A. T. M. 2011. A method of detecting patterns in mean lengths of samples of discarded fish, applied to the self-sampling programme of the Dutch bottom-trawl fishery. – ICES Journal of Marine Science, 68: 1712–1718. In 2009, a self-sampling programme was organized in the Netherlands, fishers sampling ca. 80 kg of discards from randomly selected bottom trawls in the North Sea. A statistical procedure is proposed to highlight samples, trips (with multiple samples), or vessels (which may have multiple trips within a year) where extreme mean lengths of discarded fish were observed. Randomization methods were used to test for evidence of non-randomness in patterns of highlighted discard samples, e.g. repeated observations of extreme mean lengths for consecutive discard samples across trips from the same vessel. European plaice (Pleuronectes platessa), common dab (Limanda limanda), grey gurnard (Eutrigla gurnardus), and whiting (Merlangius merlangus) were considered because these were the most abundant species in most of the discard samples. A linear mixed model was used to estimate random-sample effects on the estimated mean lengths by species. These random effects were incorporated into uni- and bivariate procedures to identify extreme samples that were summed for each vessel, and the probability of observing such numbers was estimated. Excluding these samples from the dataset had marginal effects on estimated size distributions of fish.
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Leitão, Francisco, Vânia Baptista, and Karim Erzini. "Reconstructing discards profiles of unreported catches." Scientia Marina 82, S1 (December 20, 2018): 39. http://dx.doi.org/10.3989/scimar.04723.08a.
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In Portugal it has been estimated that unreported catches represent one third of total catches. Herein, information on landings and total unreported catches (discards) by commercial métier were disaggregated into high taxonomic detail using published scientific studies. Fish accounted for 93.5% (115493 t) of overall unreported catches per year, followed by cephalopods (2345 t, 1.9%) and crustaceans (1754 t, 1.4%). Sharks accounted for 1.3% of total unreported catches in weight (1638 t/y). Unreported taxa consisted mostly of the commercial landed fish species: Scomber colias, Boops boops, Trachurus picturatus, T. trachurus, Merluccius merluccius, Sardina pilchardus, Liza aurata and Micromesistius poutassou, which together accounted for 70% of the unreported discarded catches. The number of unreported/discarded species was highest in artisanal fisheries, followed by trawl and purse seine. In artisanal fisheries, L. aurata, S. colias, S. pilchardus, Trachinus draco and B. boops accounted for 76.4% of the unreported discards. B. boops, S. colias and S. pilchardus were also among the most discarded purse seine species, together with Belone belone accounting for 79% of the unreported catches. In trawl fisheries, T. picturatus (16%), M. merluccius (13%), S. colias (13%) and M. poutassou (13%) accounted for 55% of the trawl discarded unreported catches. The discarded species that most contribute to overall unreported catches are those that are most frequently landed and that most contribute to overall landings in weight.
Dissertations / Theses on the topic "Discarded fish"
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Stratoudakis, Yorgos. "A study of fish discarded by Scottish demersal fishing vessels." Thesis, University of Aberdeen, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339907.
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This study focuses on fish discards generated by demersal vessels fishing in Scottish waters (North Sea and West of Scotland). The analysis is based on data collected by scientific observers onboard commercial vessels during the past two decades (1975 - 1993). Chapter 1 introduces the problem of discarding, describes its implications for fisheries and the marine environment, and gives a brief overview of the sampling scheme. Chapter 2 uses generalised additive models (GAMs) and regression trees to investigate the main reasons that lead Scottish fishers to discard commercially important species (haddock - Melanogrammus aeglefinus, whiting - Merlangius merlangus and cod - Gadus morhua). Different discarding patterns are observed in inshore and offshore areas, with vessels fishing offshore discarding larger fish, irrespective of gear type. In inshore areas, discarding decisions are mainly driven by legal landing size, whereas offshore, high grading decisions due to market pressures and, possibly, quota limitations prevail. Chapter 3 explores the performance of several estimators of total discards and their variances in a simulated population of fishing trips. The simulated population is generated from the residuals of temporal models fitted to the catch and discards observations from the trips sampled under the Scottish discards monitoring scheme. The estimator currently applied to obtain annual estimates of total discards in Scotland is shown to be biased and imprecise, whereas several other estimators perform better under limited sampling coverage. The best estimators from chapter 3 are used in chapter 4 to estimate the total discards and their variances for species that were regularly discarded by Scottish vessels in the period 1988 - 1993. Overall, it is estimated that Scottish vessels generate annually around 100,000 tonnes of demersal fish discards in the North Sea and 30,000 tonnes in the West of Scotland. This suggests that close to 40% of the total demersal catch of Scottish vessels is annually wasted through discarding.
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Cotterell, Stephen Paul. "Fish landings, discards and benthic material from demersal trawling in the western English Channel (ICES VIIe)." Thesis, University of Plymouth, 2006. http://hdl.handle.net/10026.1/2751.
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This study examined the impact of inshore single boat otter trawling from Newlyn, Looe, Plymouth and Salcombe and pair boat demersal trawling from Looc and Plymouth on the benthic environment off the SW peninsula of the UK between 1998 and 2000. Fish and shellfish species (54 and 11 species respectively) were measured at sea and the non-fish material (124 species) was analysed later. Overall 79.8 % of the sample was landed fish and shellfish, 15.8 % was discarded fishes and 4.4 % was invertebrates and other material (by weight). Related information about the substrate and tide were generated from British Geological Survey data and a computer simulation of the maximum mean tidal strength. In agreement with the different abiotic regime, the dominant fishes were different in Newlyn and the other ports. According only to port, the Looe and Plymouth samples were not significantly different, either as full samples or for their fish and non-fish components. The Salcombe samples were not significantly different to those from Looc or Plymouth for the non-fish part of the sample. Including the type of trawling meant that the greatest similarity was for the non-fish part of the sample although the relative amounts of the components varied. The pair trawling samples contained more landed, less discarded and less non-fish material than their single boat equivalents. Pair trawl samples also contained fewer examples of large invertebrate species. Several within and between-species relationships were explored to assess the wider interpretation of the fish community data. This examined size of Raja spp., several predator-prey relationships and the utility of Marlhasterias glacialis as an indicator of fishing disturbance. Disturbance as measured by Abundance Biomass Comparison was similar whether according to the non-fish or full sample, and suggested that the whole region was relatively undisturbed (with Newlyn apparently the most impacted area). Analysis of the relative contribution of selected groups to taxonomic diversity showed the derived conservation priorities for 'orders' of fishes were Elasmobranches > Pleuronectiformes > Gadiformes. In general, the fact of 'losing' orders of fishes was more important for single rather than pair trawl samples, which suggests that single boat samples were collected from structurally more complex areas supporting a wider taxonomic diversity. The analysis of groups for conservation priority was also carried into the invertebrates with echinoderms being highly influential for Newlyn. Taxonomic diversity (A+ and A) was also proposed as an addition to the definition of 'Good Environmental Status' according to the proposed EU Marine Strategy Directive. When examining the abiotic and biotic data sets, the fish species bore the closest similarity to the abiotic data suggesting that much of the study area was dominated by similar invertebrate species that tended to be scavengers and in most analyses the positive influence of the voluntary Inshore Potting Agreement management regime was evident. In a novel analysis, there was broad agreement between the data and literature sources for the location of the fishes in relation to the substrates and for eight of the most commonly occurring species it was possible to be more precise in their substrate preferences than suggested from the literature. The landed fish part of the sample was shown to be a statistically good approximation of the landed part of the haul (for which the commercial data was known) in > 95 % of the hauls. Finally, data on the commercial landings for each port show that the boats sampled in this study were representative of these ports.
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Sauls, Beverly J. "Relative Survival of Gags Mycteroperca microlepis Released Within a Recreational Hook-and-Line Fishery: Application of the Cox Regression Model to Control for Heterogeneity in a Large-Scale Mark-Recapture Study." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4940.
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The objectives of this study were to measure injuries and impairments directly observed from gags Mycteroperca microlepis caught and released within a large-scale recreational fishery, develop methods that may be used to rapidly assess the condition of reef fish discards, and estimate the total portion of discards in the fishery that suffer latent mortality. Fishery observers were placed on for-hire charter and headboat vessels operating in the Gulf of Mexico from June 2009 through December 2012 to directly observe reef fishes as they were caught by recreational anglers fishing with hook-and-line gear. Fish that were not retained by anglers were inspected and marked with conventional tags prior to release. Fish were released in multiple regions over a large geographic area throughout the year and over multiple years. The majority of recaptured fish were reported by recreational and commercial fishers, and fishing effort fluctuated both spatially and temporally over the course of this study in response to changes in recreational harvest restrictions and the Deepwater Horizon oil spill. Therefore, it could not be assumed that encounter probabilities were equal for all individual tagged fish in the population. Fish size and capture depth when fish were initially caught-and-released also varied among individuals in the study and potentially influenced recapture reporting probabilities. The Cox proportional hazards regression model was used to control for potential covariates on both the occurrence and timing of recapture reporting events so that relative survival among fish released in various conditions could be compared.
A total of 3,954 gags were observed in this study, and the majority (77.26%) were released in good condition (condition category 1), defined as fish that immediately submerged without assistance from venting and had not suffered internal injuries from embedded hooks or visible damage to the gills. However, compared to gags caught in shallower depths, a greater proportion of gags caught and released from depths deeper than 30 meters were in fair or poor condition. Relative survival was significantly reduced (alpha (underline)<(/underline)0.05) for gags released in fair and poor condition after controlling for variable mark-recapture reporting rates for different sized discards among regions and across months and years when individual fish were initially captured, tagged and released. Gags released within the recreational fishery in fair and poor condition were 66.4% (95% C.I. 46.9 to 94.0%) and 50.6% (26.2 to 97.8%) as likely to be recaptured, respectively, as gags released in good condition. Overall discard mortality was calculated for gags released in all condition categories at ten meter depth intervals. There was a significant linear increase in estimated mortality from less than 15% (range of uncertainty, 0.1-25.2%) in shallow depths up to 30 meters, to 35.6% (5.6-55.7%) at depths greater than 70 meters (p < 0.001, R2 = 0.917). This analysis demonstrated the utility of the proportional hazards regression model for controlling for potential covariates on both the occurrence and timing of recapture events in a large-scale mark-recapture study and for detecting significant differences in the relative survival of fish released in various conditions measured under highly variable conditions within a large-scale fishery.
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Husein, Yara. "Application of the Mechanical Separation Process in Different Fish Species for the Development of a New Product Based on Fish." Doctoral thesis, 2018. http://hdl.handle.net/2158/1152714.
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This PhD thesis is based on three main trials. The overall aim was to investigate the feasibility of using discard fish by adopting mechanical separation process to different fish species for creating new fish products (fish burgers). Different formulae of fish burgers were evaluated physically, chemically, nutritionally, and sensorily.
The first research was conducted in order to investigate the impact of exploiting fish waste by mechanical separation process (MS) in order to produce ready-to-eat/cook foods based on fish. The aim was to evaluate the effect of MS process on physical and chemical characteristics, and on the nutritional value of the three farmed species: the European sea bass (Dicentrarchus labrax), gilthead sea bream (Sparus aurata), and rainbow trout (Oncorhynchus mykiss). Specifically, mechanically separated meat (MSM) burgers were compared with manual minced-burgers and whole fillets by evaluating yield, colour, pH, dienes, proximate composition, fatty acid profiles, and mineral composition. Results revealed that rainbow trout showed the highest yield for both manually and mechanically separated meat (53 and 50 g/100 g, respectively). The yield of MS process of sea bass and sea bream was higher than the manual operation yield (42 and 45 g/100 g, respectively against 39 and 40 g/100 g). The proximate composition, pH, colour, and mineral compositions are differently affected by MS process in the different fish species. However, MS slightly increased water content in sea bream and trout (71.12, and 70.65 g/100 g, respectively against 68.05, and 68.11 g/100 g of fillets) and decreased minerals, especially in trout, which showed loss of Ca, Mg, Na, and P. Interestingly, the fatty acid profiles of whole fillet, MS burger, and minced burger did not change. In conclusion, the MS process enabled manufacturing products with good characteristics in terms of yield and maintained nutritional value.
In the second research, non-directly marketable specimens of European sea bass (Dicentrarchus labrax) and rainbow trout (Oncorhynchus mykiss) were used in order to produce healthy clean label products, and to examine the instrumental, chemical and sensory properties of raw and cooked fish burger recipes obtained from MSM characterized by differences in the recipe composition. Consumer attention towards healthy and more natural foods and producer attempts to reduce food loss have become more popular nowadays. For this reason, shear stress, proximate composition, fatty acid composition, and sensory characteristics of four formulations of fish burgers were examined. The four formulae differed in the ratios of European sea bass to rainbow trout (50:50 and 30:70) and the ratios of fish to potato flakes (dry matter ratio, DMR: 2.5:1 and 1.5:1). Results showed that the sensory attributes were affected mostly by the potato content of fish burger, whereas the effect of sea bass to trout ratio was negligible. The recipes with higher DMR were related to sandy, crusty, and dry
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features, salty taste and the flavour of raw fish, while the lower DMR recipes were distinguished by soft texture, and a starchy flavour and a flavour of fish cooked in the oven. Moreover, shear stress was unaffected by the different ratios of fish or potato flakes in raw and cooked burgers. However, raw burgers with lower DMR had higher moisture and ash, and lower protein content, while cooked burgers with lower DMR had higher moisture and lower protein content. Interestingly, the fatty acid profiles of the four cooked burger recipes were not significantly different, and a quantity of 100 g of burger provided more than the recommended daily intake of the essential fatty acids. In brief, development of ready-to-cook products based on under-utilized fish through four clean label recipes of high nutritional value and good sensory attributes was attained, irrespective of prevalence of rainbow trout over the more expensive sea bass, or using higher ratio of potato flakes.
In the third study instead, two mechanically separated meat from two fish species, the European sea bass (Dicentrarchus labrax), and rainbow trout (Oncorhynchus mykiss), were used for obtaining fish burgers submitted to a frozen storage. Recently ready-to-cook fish products, which are generally marketed as frozen and need some culinary preparation, stimulated the fish consumption. Therefore, the target of this research was to study the effect of two recipes, distinguished by the ratios of European sea bass to rainbow trout (50:50 and 30:70), and storage duration at sub-zero temperatures for obtaining convenient, easy-to-prepare, and good quality products. Particularly, the physical, chemical, and nutritional properties of raw and cooked fish burger of different formulations were assessed during storage. Results revealed that raw recipes with more trout have higher moisture, shear stress, yellowness, and intense colour. Conversely, they have lower values of primary (conjugated dienes) and secondary (TBARS) oxidation products. On the other hand, cooked recipes with more trout have more moisture, but lower protein content, and higher water holding capacity, yellowness, and intense colour. Furthermore, storage was found to significantly affect the shear stress, water-holding capacity and colour in raw and cooked fish burgers, causing their values to decline at the end of the storage. Excitingly, the nutritional value of raw and cooked fish burgers was decent and was not altered by the different formulae and storage durations. The highest oxidative stability was obtained in fish burger containing a high proportion of rainbow trout, which could be a matter of importance for the seafood industry because to the lower economical value of this species than sea bass.
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Ηλιοπούλου, Νικολία. "Τροποποιήσεις των τεχνικών χαρακτηριστικών των ιχθυοπαγίδων και μελέτη των επιπτώσεών τους στην αλιευτική διαχείριση της λιμνοθάλασσας Μεσολογγίου." Thesis, 2013. http://hdl.handle.net/10889/8162.
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Το πρόβλημα της αυξημένης σύλληψης υπομεγεθών ατόμων τσιπούρας (Sparus aurata, Linnaeus 1758) στις ιχθυοσυλληπτικές εγκαταστάσεις της λιμνοθάλασσας Μεσολογγίου-Αιτωλικού τις τελευταίες δεκαετίες έχει αποκτήσει σοβαρές διαστάσεις. Το φαινόμενο αυτό εκτός του ότι συνιστά περιβαλλοντική απειλή έχει επιφέρει σημαντική μείωση της εμπορικής αξίας του αλιεύματος με αποτέλεσμα τη συρρίκνωση του εισοδήματος των αλιέων.
Η παρούσα εργασία μελετά την επιλεκτικότητα νέων τροποποιημένων ιχθυοπαγίδων που έχουν εγκατασταθεί στη λιμνοθάλασσα στο πλαίσιο μιας πρωτοβουλίας για την αντιμετώπιση του συγκεκριμένου προβλήματος. Η παρακολούθηση αυτής της πρωτοβουλίας έδειξε ότι οι νέες ιχθυοπαγίδες συμβάλλουν στη διαφυγή των υπομεγεθών ψαριών, οπότε και στη μείωση των ποσοτήτων των απορριπτόμενων ψαριών διασφαλίζοντας έτσι τη βιωσιμότητα του ιχθυοπληθυσμού. Επίσης, αυξάνονται τα έσοδα της αλιευτικής εκμετάλλευσης και βελτιώνεται η καθημερινότητα των αλιέων δεδομένου ότι δε μεσολαβεί το στάδιο του διαχωρισμού των μη εμπορεύσιμων από τα εμπορεύσιμα ψάρια. Οι διαφυγές των ψαριών από τις ιχθυοπαγίδες φάνηκε να επηρεάζονται από την αφθονία του αλιεύματος και πιο συγκεκριμένα σε περιπτώσεις μεγάλης αφθονίας παρατηρήθηκε να δυσχεραίνεται η διαφυγή των υπομεγεθών ψαριών από τις ιχθυοπαγίδες. Ενδεχομένως, αυτό να δημιουργεί την ανάγκη επέκτασης της τροποποιημένης επιφάνειας των ιχθυοπαγίδων.
Η παρούσα εργασία αποτελεί πηγή σημαντικών πληροφοριών στη λήψη μέτρων με στόχο τη βελτίωση του προτύπου της αλιευτικής εκμετάλλευσης της λιμνοθάλασσας.The problem of increased capture of undersized individuals of gilthead seabream (Sparus aurata, Linnaeus, 1758) at the Messolonghi - Etoliko lagoon fish traps, the last decades has become serious. This phenomenon apart from the ecological threat has decreased the commercial value of the catch thus leading to a reduction of the fishermen income. The present study investigates the selectivity of new fish traps installed in the lagoon in order to deal with this problem. It was found that modified traps contribute to the escapement of undersized individuals thus decreasing the discards as well as ensuring the sustainability of fish population. Furthermore, new traps exploitation leads to an increase of the income. Also, there is no need to sort undersized fish from the catch thus improving the daily lives of the fishermen. Fish escapement was found to be affected by the abundance of fish catch. In more details, high abundance was observed to make fish escapement difficult. Perhaps, this highlights the need of modified area extension. The present study reflects a source of useful information to take into consideration for the improvement of the lagoon fishery exploitation.
Books on the topic "Discarded fish"
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(2002-2003), New England Bycatch Workshops. Proceedings of the New England Bycatch Workshops. Narragansett, R.I: Rhode Island Sea Grant, 2003.
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Robertson, Jack. Minimising Discards to Improve Global Fish Stocks. Fishing News Books, 2003.
Find full textBook chapters on the topic "Discarded fish"
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Gasco, Laura, Francesco Gai, Giulia Maricchiolo, Lucrezia Genovese, Sergio Ragonese, Teresa Bottari, and Gabriella Caruso. "Fishery Discard as a Source of Food for Reared or Wild Fish? The Bottom Trawling in the Mediterranean Sea as a Case Study." In SpringerBriefs in Molecular Science, 29–48. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-77941-6_2.
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"The Angler in the Environment: Social, Economic, Biological, and Ethical Dimensions." In The Angler in the Environment: Social, Economic, Biological, and Ethical Dimensions, edited by Eric N. Powell, Eleanor A. Bochenek, John DePersenaire, and Sarah E. King. American Fisheries Society, 2011. http://dx.doi.org/10.47886/9781934874240.ch10.
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<i>Abstract</i> .—Summer flounder <i>Paralichthys dentatus </i> supports an important recreational fishery along the northeastern coast of the United States. Successful rebuilding of the stock and the need to constrain landings within total-allowable-landing targets has resulted in declining bag limits, increasing size limits, higher discarding, and a reduction in satisfaction derived from recreational fishing trips. A series of fishing trips were observed in which alternative regulatory scenarios were tested to identify approaches to better optimize bag limits and size limits. The alternatives included a slot limit in which some smaller fish were allowed to be landed, a reduced minimum size, and a cumulative size, in which the bag limit and size limit were conflated such that fish take was controlled by the cumulative size of the landed fish. Comparisons were made to fishing trips conducted under 2006 regulations that produced higher injury frequencies than other regulatory scenarios due to discarding of larger fish that tended to be gut-hooked. Two alternatives performed significantly better in terms of reducing the potential for discard mortality among discarded fish, the slot-limit and the cumulative-size scenarios. An intermediate performance of the reduced-minimum-size scenario was due to an increased proportion of dead fish, but this association was unexplained. Fish uninjured save for minor hook damage were common on all vessels and in all fishing approaches. Injury frequency was, in fact, remarkably low, less than half of the assumed discard mortality rate in presentday stock assessments. The study supports the use of size-specific mortality rates for fish discarded recreationally. The study offers no support for the efficacy of the 2006 regulatory system in controlling discard mortality rate. Any of the alternative plans is an improvement, but the slot-limit and cumulative-size scenarios are deserving of the most scrutiny.
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"Paddlefish Management, Propagation, and Conservation in the 21st Century." In Paddlefish Management, Propagation, and Conservation in the 21st Century, edited by JANICE A. KERNS, PHILLIP W. BETTOLI, and GEORGE D. SCHOLTEN. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874127.ch20.
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<em>Abstract</em>.—We present information on delayed mortality of commercially exploited paddlefish <em>Polyodon spathula </em>released as bycatch in Kentucky Lake, Tennessee–Kentucky, an impoundment on the lower Tennessee River. Minimum size limits enacted in 2002 (864 mm eye-to-fork length [EFL]) and 2005 (914 mm EFL) sought to protect paddlefish from overfishing. In 2005, bycatch of sublegal paddlefish represented 75% of the total catch, and releasing undersized fish will not reduce fishing mortality unless those fish survive. Paddlefish caught and released by commercial fishers in 2005 and 2006 were externally tagged with radio transmitters and tracked a minimum of 2 weeks to estimate delayed mortality. Four of the 104 tagged paddlefish died following release, 94 survived, and 6 were censored because their fate could not be determined. Paddlefish that survived moved rapidly from release locations. Net movements of the 94 fish that survived averaged 12.0 km (SE = 5.3) upriver and ranged from 91.5 km downriver to 390.0 km upriver. Fish that died could not be distinguished from fish that lived on the basis of mean water temperature, fish length, net-soak time, or handling time. Given the low delayed mortality of discarded paddlefish, imposing minimum size limits is a reasonable approach to reduce fishing mortality of juveniles and reduce the likelihood of overfishing. Efforts to reduce fishing mortality should focus on avoiding fishing gear and seasons (e.g., early fall and late spring) that cause high initial bycatch mortality.
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"Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries." In Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries, edited by David M. Clausen. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874004.ch23.
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<em>Abstract.</em>—This report summarizes biological, fishery, and survey information on giant grenadier, <em>Albatrossia pectoralis</em>, in Alaskan waters. Catch estimates of giant grenadier in Alaska for the years 1997–2005 have averaged over 16,000 metric tons (mt), and most of this catch has been taken as bycatch in longline fisheries for sablefish, <em>Anoplopoma fimbria</em>, and Greenland halibut, <em>Reinhardtius hippoglossoides</em>. The giant grenadier catch is all discarded, and none of the fish survive due to the pressure change when they are brought to the surface. Most of the catch is from the Gulf of Alaska. Data from bottom trawl and longline surveys in Alaska indicate that giant grenadier are extremely abundant in depths 300–1,000 m, and it appears this species is very important ecologically in this environment. Greatest abundance is in the western Gulf of Alaska, eastern Aleutian Islands, and in some areas of the eastern Bering Sea; abundance declines in the eastern Gulf of Alaska. Relative abundance of giant grenadier is much higher off Alaska than off the U.S. West Coast. Fish in the eastern Bering Sea and Aleutian Islands were consistently larger than those in the Gulf of Alaska. Mean size of females was larger in shallower water, and decreased with depth. Females and males appear to have different depth distributions, with females greatly predominating in depths less than 800 m. Although sex composition of giant grenadier caught in the fishery is unknown, nearly all the fishing effort is believed to be in waters less than 800 m, which indicates females are disproportionately harvested. Because of the great abundance of giant grenadier in Alaska and the relatively modest catch, overfishing of giant grenadier does not appear to be a problem at present. However, because information on the population dynamics of giant grenadier is very sparse, and because of the 100% discard mortality, the disproportionate harvest of females, and the general susceptibility of deep-sea fish to overharvest, fishery managers should monitor this species closely if catches increase in the future.
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"Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries." In Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries, edited by David M. Clausen. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874004.ch23.
Full textAbstract:
<em>Abstract.</em>—This report summarizes biological, fishery, and survey information on giant grenadier, <em>Albatrossia pectoralis</em>, in Alaskan waters. Catch estimates of giant grenadier in Alaska for the years 1997–2005 have averaged over 16,000 metric tons (mt), and most of this catch has been taken as bycatch in longline fisheries for sablefish, <em>Anoplopoma fimbria</em>, and Greenland halibut, <em>Reinhardtius hippoglossoides</em>. The giant grenadier catch is all discarded, and none of the fish survive due to the pressure change when they are brought to the surface. Most of the catch is from the Gulf of Alaska. Data from bottom trawl and longline surveys in Alaska indicate that giant grenadier are extremely abundant in depths 300–1,000 m, and it appears this species is very important ecologically in this environment. Greatest abundance is in the western Gulf of Alaska, eastern Aleutian Islands, and in some areas of the eastern Bering Sea; abundance declines in the eastern Gulf of Alaska. Relative abundance of giant grenadier is much higher off Alaska than off the U.S. West Coast. Fish in the eastern Bering Sea and Aleutian Islands were consistently larger than those in the Gulf of Alaska. Mean size of females was larger in shallower water, and decreased with depth. Females and males appear to have different depth distributions, with females greatly predominating in depths less than 800 m. Although sex composition of giant grenadier caught in the fishery is unknown, nearly all the fishing effort is believed to be in waters less than 800 m, which indicates females are disproportionately harvested. Because of the great abundance of giant grenadier in Alaska and the relatively modest catch, overfishing of giant grenadier does not appear to be a problem at present. However, because information on the population dynamics of giant grenadier is very sparse, and because of the 100% discard mortality, the disproportionate harvest of females, and the general susceptibility of deep-sea fish to overharvest, fishery managers should monitor this species closely if catches increase in the future.
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Moosavi-Nasab, Marzieh, Najme Oliyaei, Jong-Bang Eun, and Armin Mirzapour-Kouhdasht. "Innovation in the Seafood Sector through the Valorization of By-Products." In Innovation in the Food Sector Through the Valorization of Food and Agro-Food By-Products [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.95008.
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Aquatic, marine and algae, is reservoir of bioactive compounds, which have considerable potential to supply novel ingredients toward the development of commercial functional food products. Meanwhile, several valuable by-products generate during the manufacturing process. Seafood is still an intact reservoir of valuable compounds with significant potential to provide unique compounds applicable in functional food development. Seafood, as an important part of the diet all around the world, can be used as a source of functional components that are positively affecting the human health. Annually, 50–80 percent of the seafood processing is discarded as waste every year. Algae are also the novel natural resources for their biological and pharmacological properties. This chapter will be discussing the innovations in seafood and algae sector through the valorization of their by-products. Firstly, protein production, its characterization and the protein hydrolysates derived from seafood will be reviewed. Subsequently, bioactivity of the peptides obtained from these protein hydrolysates and other bioactive compounds such as carotenoid compounds derived from seafood including fish, shrimp, alga, and so on will be included. Finally, the main components of algae including sulfated polysaccharides, pigments and proteins will be surveyed.
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Moosavi-Nasab, Marzieh, Najme Oliyaei, Jong-Bang Eun, and Armin Mirzapour-Kouhdasht. "Innovation in the Seafood Sector through the Valorization of By-Products." In Innovation in the Food Sector Through the Valorization of Food and Agro-Food By-Products. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95008.
Full textAbstract:
Aquatic, marine and algae, is reservoir of bioactive compounds, which have considerable potential to supply novel ingredients toward the development of commercial functional food products. Meanwhile, several valuable by-products generate during the manufacturing process. Seafood is still an intact reservoir of valuable compounds with significant potential to provide unique compounds applicable in functional food development. Seafood, as an important part of the diet all around the world, can be used as a source of functional components that are positively affecting the human health. Annually, 50–80 percent of the seafood processing is discarded as waste every year. Algae are also the novel natural resources for their biological and pharmacological properties. This chapter will be discussing the innovations in seafood and algae sector through the valorization of their by-products. Firstly, protein production, its characterization and the protein hydrolysates derived from seafood will be reviewed. Subsequently, bioactivity of the peptides obtained from these protein hydrolysates and other bioactive compounds such as carotenoid compounds derived from seafood including fish, shrimp, alga, and so on will be included. Finally, the main components of algae including sulfated polysaccharides, pigments and proteins will be surveyed.
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"Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives." In Marine Artificial Reef Research and Development: Integrating Fisheries Management Objectives, edited by Ahmad Ali, Nur Iskandar Tajudin, and Rafezi Hazizi. American Fisheries Society, 2018. http://dx.doi.org/10.47886/9781934874516.ch18.
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<em>Abstract</em>.—Research and development (R&D) on the design and construction of artificial reefs in Malaysia was initiated by researchers from the Fisheries Research Institute, Department of Fisheries Malaysia (DoFM) based in Penang in 1975. Initially, R&D only focused on simple designs and construction using discarded tires, wooden fishing boats, polyvinyl chloride (PVC) pipe, reinforced concrete, and ceramic sewerage pipe. These reefs were used in fisheries management to maximize resource enhancement, resource conservation, and habitat rehabilitation and mitigation, as well as being an aid to alleviate the problem of depleting fish resources in coastal waters. However, in 2006, the DoFM made a major policy change in the design and construction materials of artificial reefs in the country. The focus was to construct large, heavy, and robust artificial reefs using durable materials such as reinforced concrete and steel to deter the encroachment of destructive fishing gears, especially trawlers, along the coastal and in marine protected areas. These new artificial reefs addressed several issues, such as fish behavior, target species, physical oceanography, and marine engineering, in their design. The reinforced concrete artificial reefs were built according to the British Standard 8110 under the supervision of officers from the Engineering Division and Research Division of the DoFM. Presently, the DoFM has designed 21 types of artificial reefs that have been deployed at 130 selected locations in Malaysia. This paper reviews the progress of R&D on the design and construction of artificial reefs using tires, wooden fishing boats, reinforced concrete, PVC pipe, ceramic materials, and steel in Malaysia between 1975 and 2017.
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"Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries." In Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries, edited by Alexei M. Orlov and Alexei M. Tokranov. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874004.ch16.
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<em>Abstract</em>.—The giant grenadier <em>Albatrossia pectoralis </em>and popeye grenadier <em>Coryphaenoides cinereus </em>are among the most abundant continental slope fish species of the North Pacific. Their high biomass constitutes about 2 million metric tons and they comprise a large portion of by-catch in deepwater bottom trawl and longline fisheries. However, these species are mostly discarded and their specialized fisheries are currently only in the initial stage. The ecology and biology of giant and popeye grenadiers in the Pacific off the northern Kuril Islands and southeastern Kamchatka are still poorly understood. This paper is based on results of studies conducted in 1992–2002 aboard Japanese trawlers in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka. It describes seasonal changes of spatial and vertical distributions and bottom temperature preferences, provides data on their lengths and weights, length-weight relationships, sex ratios, and multi-annual, seasonal, and diurnal variations of catch rates. Relationships between mean body weight and capture depth are presented for different seasons. Data on composition of species co-occurring in catches are given for both grenadiers in respect to different times of year.
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"Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries." In Grenadiers of the World Oceans: Biology, Stock Assessment, and Fisheries, edited by Alexei M. Orlov and Alexei M. Tokranov. American Fisheries Society, 2008. http://dx.doi.org/10.47886/9781934874004.ch16.
Full textAbstract:
<em>Abstract</em>.—The giant grenadier <em>Albatrossia pectoralis </em>and popeye grenadier <em>Coryphaenoides cinereus </em>are among the most abundant continental slope fish species of the North Pacific. Their high biomass constitutes about 2 million metric tons and they comprise a large portion of by-catch in deepwater bottom trawl and longline fisheries. However, these species are mostly discarded and their specialized fisheries are currently only in the initial stage. The ecology and biology of giant and popeye grenadiers in the Pacific off the northern Kuril Islands and southeastern Kamchatka are still poorly understood. This paper is based on results of studies conducted in 1992–2002 aboard Japanese trawlers in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka. It describes seasonal changes of spatial and vertical distributions and bottom temperature preferences, provides data on their lengths and weights, length-weight relationships, sex ratios, and multi-annual, seasonal, and diurnal variations of catch rates. Relationships between mean body weight and capture depth are presented for different seasons. Data on composition of species co-occurring in catches are given for both grenadiers in respect to different times of year.
Conference papers on the topic "Discarded fish"
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Sini, Valeria, Angela Carluccio, Mariella Marangi, Roberta Ragni, Gianfranco D'Onghia, and Pietro Cotugno. "Green production of biofuels from fish discards using supercritical Carbon Dioxide as the extraction solvent." In 2022 IEEE International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea). IEEE, 2022. http://dx.doi.org/10.1109/metrosea55331.2022.9950807.
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