Fortification of <Emphasis Type="Italic">niboshi</Emphasis> with histidine prepared from <Emphasis Type="Italic">katsuobushi</Emphasis> protein digest

ABSTRACT:   Free and total histidine contents in the muscle of various fishes and invertebrates caught in the Seto Inland Sea were estimated. These contents were higher in the muscles from skipjack, yellowfin tuna, yellowtail and mackerel than in those from lizard fish, sea bream and hairtail. Invertebrate muscles, except squid, contained low free and total histidine. Boiled and dried anchovy ( niboshi ) contained lower free histidine than that of dried anchovy (suboshi). To prepare free histidine-rich extracts, the waste residue of soup stock from smoke-dried and shaved skipjack ( katsuobushi ) was digested with proteases. The extract of the enzyme digest contained high free histidine and was used to fortify niboshi with free histidine. If taken, the fortified niboshi may suppress food intake, and prevent obesity.     

China's distant‐water fisheries in the 21st century

We conservatively estimate the distant‐water fleet catch of the People's Republic of China for 2000–2011, using a newly assembled database of reported occurrence of Chinese fishing vessels in various parts of the world and information on the annual catch by vessel type. Given the unreliability of official statistics, uncertainty of results was estimated through a regionally stratified Monte Carlo approach, which documents the presence and number of Chinese vessels in Exclusive Economic Zones and then multiplies these by the expected annual catch per vessel. We find that China, which over‐reports its domestic catch, substantially under‐reports the catch of its distant‐water fleets. This catch, estimated at 4.6 million t year^?1 (95% central distribution, 3.4–6.1 million t year^?1) from 2000 to 2011 (compared with an average of 368 000 t·year^?1 reported by China to FAO), corresponds to an ex‐vessel landed value of 8.93 billion € year^?1 (95% central distribution, 6.3–12.3 billion). Chinese distant‐water fleets extract the largest catch in African waters (3.1 million t year^?1, 95% central distribution, 2.0–4.4 million t), followed by Asia (1.0 million t year^?1, 0.56–1.5 million t), Oceania (198 000 t year^?1, 144 000–262 000 t), Central and South America (182 000 t year^?1, 94 000–299 000 t) and Antarctica (48 000 t year^?1, 8 000–129 000 t). The uncertainty of these estimates is relatively high, but several sources of inaccuracy could not be fully resolved given the constraints inherent in the underlying data and method, which also prevented us from distinguishing between legal and illegal catch.     

Quantifying the effects of bycatch reduction devices in Queensland''s (Australia) shallow water eastern king prawn (Penaeus plebejus) trawl fishery

This study presents results from an experimental 10-day research charter that was designed to quantify the effects of (a) a turtle excluder device (TED), (b) a radial escape section bycatch reduction device (BRD) and (c) both devices together, on bycatch and prawn catch rates in the Queensland shallow water eastern king prawn (Penaeus plebejus) trawl fishery. The bycatch was comprised of 250 taxa, mainly gurnards, whiting, lizard fish, flathead, dragonets, portunid crabs, turretfish and flounders. The observed mean catch rates of bycatch and marketable eastern king prawns from the standard trawl net (i.e., net with no TED or BRD) used during the charter were 11.06 kg/hectare (ha⁻¹) (S.E. 0.90) swept by the trawl gear and 0.94 kg ha⁻¹, respectively. For the range of depths sampled (20.1–90.7 m), bycatch rates declined significantly at a rate of 0.14 kg ha⁻¹ for every 1 m increase in depth, while prawn catch rates were unaffected. When both the TED and radial escape section BRD were used together, the bycatch rate declined by 24% compared to a standard net, but at a 20% reduction in marketable prawn catch rate. The largest reductions were achieved for stout whiting Sillago robusta (57% reduction) and yellowtail scad Trachurus novaezelandiae (32% reduction). Multidimensional scaling and analysis of similarities revealed that bycatch assemblages differed significantly between depths and latitude, but not between the different combinations of bycatch reduction devices. Despite the lowered prawn catch rates, the reduced bycatch rates are promising, particularly for S. robusta, which is targeted in another fishery. Prawn trawl operators are not permitted to retain S. robusta and the devices examined herein offer the potential to significantly reduce the incidental fishing mortality that this species experiences.     

Effect of towing speed and net mouth size on catch efficiency in framed midwater trawls

ABSTRACT:   To investigate fish density using rigid-mouth, towed net gear, such as a framed midwater trawl (FMT), it is necessary to know the catch efficiency. The catch efficiency with an FMT is described as the rate of fish entering the net (entering rate) versus the rate of fish retention, i.e. the mesh selectivity. This study investigated the change in the catch efficiency under several towing conditions using three types of FMT of different net mouth areas (4.0, 12.3, and 16.0 m²) with the same mesh size. The catch efficiency of the FMT was evaluated by comparing catch per unit effort obtained from each towing condition. The catch efficiency of FMT varied with towing speed and net mouth area. Particularly, the effect of net mouth area on the catch efficiency was greater than that of towing speed. Additionally, under the same towing condition, the catch efficiency for large length fish was lower than that for small length fish.     

Effects of entrance design on catch efficiency of arabesque greenling traps: a field experiment in Matsumae, Hokkaido

ABSTRACT:   A field experiment was conducted in the Matsumae area of Hokkaido, Japan, during June and July 2002, to investigate the effects of different entrance designs on the catch efficiency of fish traps by fishing with commercial traps (entrance inclination angle [α] = 37°; funnel length of entrance [ L _f ] = 22 cm) and experimental traps. The experimental traps were of the same size and similar design as commercial traps, with different entrance inclination angles (trap E1: α = 46°; E2: α = 27°; E3: α = 0°; all L _f  = 22 cm) or funnel lengths (E4: α = 37°, L _f  = 8 cm). In total, 2200 fish during 200 trap hauls were captured. The catch was significantly higher using both traps E2 and the commercial trap than with trap E3 ( P  < 0.05), and the catch of trap E2 was higher than that of the commercial trap. There were no significant differences in mean fish body length or the frequency distributions of body length among trap types (E1, E2, E3 and commercial). The funnel length of the entrance also affected the catch of traps. Trap E4 had significantly higher catches than the commercial trap ( P  = 0.04) when traps were deployed for a 1-day soak time. Fish body length frequency distributions did not differ between trap E4 and the commercial trap. The results showed that catch can be greatly affected by trap entrance designs.     

Relationship between sea-surface temperature and catch fluctuations in the Pacific stock of walleye pollock in Japan

ABSTRACT:   This paper investigates the relationship between sea-surface temperature (SST) and catch fluctuations in the Pacific stock of walleye pollock Theragra chalcogramma in Japan. Incorporating time lags between years of birth and harvest, the correlation coefficients between the catch and SST in two regions off the east coast of Hokkaido were calculated. The catch in year t had a high negative correlation with the SST during January–April and November–December of the years t- 2 and t- 3 in the spawning area. These results coincided well with the correlation observed in the northern 'Sea of Japan' stock. Both analyses suggested that the long-term catch fluctuations of the two stocks could be explained by the same mechanism, that is, the fluctuations would be explained by the SST in their spawning area during the spawning season using 2–3 or 3–5 years time lags, which corresponded to the dominant age of the catch within these two stocks.     

The first detection of okadaic acid and its derivatives in Korean bivalves by liquid chromatography-mass spectrometry

ABSTRACT:   Lipophilic toxin profiles associated with diarrhetic shellfish poisoning in Korean bivalves were investigated by liquid chromatography-mass spectrometry (LC-MS). Okadaic acid (OA), dinophysistoxins (DTX), pectenotoxins (PTX) and yessotoxin (YTX) in bivalves were quantified by LC-MS. Thirty-eight bivalve samples were collected from five different areas on the south coast of Korea during January to June 2006. Dinophysistoxin-1 (DTX1) and OA were found in some samples of both mussel Mytilus edulis and oyster Crassostrea gigas . The levels of DTX1 and OA found in the hepatopancreas of the samples were 0.04–0.23 µg/g and 0.03–0.08 µg/g, respectively. Dinophysistoxin-3 was found in the hepatopancreas of the short-necked clam Ruditapes philippinarum at a concentration of 0.06 µg/g. PTX and YTX were not detected from all of the samples examined. This is the first report of the unambiguous identification of OA and its derivatives, by LC-MS, in Korean bivalves.     

Incidental catch and discard of red drum, Sciaenops ocellatus, in a large mesh Paralichthyidae gillnet fishery: experimental evaluation of a fisher's experience at limiting bycatch

Abstract  The ability of a commercial fisher to limit red drum, Sciaenops ocellatus (Linnaeus), bycatch was evaluated by comparing the catch of directed sets (net site chosen by the commercial fisher) vs randomly placed gillnets during 70 days of gillnetting ( n  = 691 sets). Catch rate did not differ between directed sets and nets set randomly. Thus, fisher experience did not lead to reduced bycatch; however, this may have been influenced by overall low red drum bycatch (0.41 fish net⁻¹ for 12 h sets and 0.59 fish net⁻¹ for 24 h sets). Catch rates of southern flounder were much higher at 3.97 and 3.37 fish net⁻¹ for 12 h and 24 h sets, respectively. Fishing 10 nets per day, the catch of red drum exceeded the daily bag limit of seven red drum on 23% of the days. Of the 326 red drum retrieved from gillnets, 32.5% were dead at the time of retrieval; but only 15 of the 106 dead red drum had to be discarded due to size limits, and six were discarded dead based on bag limits. Current fisheries management regulations (bag limit and window limit of 457–686 mm) are supported by these findings given the conditions (e.g. red drum densities) at which the study was performed.     

Comparative analysis of artisanal and recreational fisheries for Dentex dentex in a Marine Protected Area

The common dentex, Dentex dentex (L.), is an iconic marine coastal fish in the Mediterranean Sea. This study was performed in the Bonifacio Strait Natural Reserve (BSNR), (NW Mediterranean Sea). The aims were to: (1) evaluate temporal variation of the artisanal fishing of common dentex (2000–2012); (2) compare and quantify catch rates, fishing techniques and catch composition for artisanal and recreational fisheries, and determine the influence of management measures by both activities; and (3) estimate the production of both artisanal and recreational fisheries. Fishery data were collected from different artisanal fishing surveys (onboard fishing vessels and landings) and recreational fishing surveys (roving). The gears with the highest rates of exploitation were longline (3554 g per 100 hooks) and Trolling (351 g boat^?1 h^?1 ±SE), respectively, for artisanal and recreational fishing. This study showed that catches by both activities were quantitatively higher in partially protected areas than outside them. Production estimations suggest that the recreational fishery contributes significantly to fishing mortality and that it can magnify the negative effects of artisanal fisheries. Specific measures are needed for the sustainable fishery management of common dentex.     

Confidence interval estimation of CPUE year trend in delta-type two-step model

Abstract:   A procedure is suggested for estimation of the approximate confidence intervals of the extracted catch per unit effort (CPUE) year trend in the delta-type two-step model used for CPUE standardization with a lot of zero-catch data. This method is a simple way to combine the Taylor expansion and delta method and is suitable for practical use. This model was applied to the catch and effort data with more than 80% zero catch for silky shark in the North Pacific Ocean caught by Japanese training vessels. As a result, realistic values of the 95% confidence interval of CPUE year trend are obtained. A method for left–right unsymmetrical interval estimation based on the asymptotic normality of the natural logarithm of CPUE is also suggested. In the example of silky shark, both CPUE year trends obtained from these two methods are similar.     

cDNA clonings of shell matrix proteins from scallop shell

ABSTRACT:   A cDNA encoding the matrix shell protein from scallop (MSP-2) has been cloned. Comparison of the sequence of MSP-2 with the GenBank database revealed the sequence displays a high degree of homology with MSP-1, which was recently identified in the shell of the scallop Patinopecten yessoensis . Matrix shell protein-2 contains only 323 amino acids, while MSP-1 comprises 824 amino acids. The structural difference between MSP-1 and MSP-2 is mainly the presence or absence of the tandem repeat arrangement. In addition, multiple isoforms of MSP-2 were found. These isoforms share a high degree of sequence similarity to each other, suggesting that the MSP-2, MSP-2 isoforms and MSP-1 may constitute the same family. The MSP-2 isoforms in scallop shell may be responsible for the formation of molluscan shells.     

Influence of episodic upwelling on capelin, Mallotusvillosus, and Atlantic cod, Gadusmorhua, catches in Newfoundland coastal waters

Wind-induced upwelling in the north-west Atlantic has been hypothesized to influence catch rates of fish by gear fishing at fixed locations. Passive movement to shallow depths during upwelling has been proposed to increase encounter rates of fish with net leaders set at the coast. However, supporting evidence is not conclusive, possibly because fish respond to strong events rather than all events. We investigated whether catch rates of capelin, Mallotusvillosus, and Atlantic cod, Gadusmorhua, were related to the strength of upwelling, as measured by the rates of water temperature change, or to stage of upwelling. Capelin trap catches were positively related to increases in water temperature, representing the relaxation phase. This result was due primarily to increases in catch after strong (> 4°C change) rather than after typical (< 4°C change) upwelling events. Cod trap catches were not related to upwelling strength but did increase 1–2 days after typical events. The data suggest that upwelling increases capelin movement, while the return of warmer surface water after an upwelling event increases cod movement.     

Comparing three indices of catch per unit effort using Bayesian geostatistics

In assessing a fish stock, indices based on catch per unit effort (CPUE) are frequently used. Estimates of three indices of catch per unit effort were compared here (CPUE₁, CPUE₂ and CPUE₃), considering the fitting of two models: (i) a bivariate geostatistical model for catch and effort; (ii) a bivariate model where catch and effort were considered spatially independent. For comparing the estimates of the three indices after the fitting of the two models, catch and effort data were simulated in different scenarios. The simulation study showed that, in general, the estimates of CPUE₁ expressed by the ratio of the means of catch and effort, present better results for different scenarios and that the estimates from (i) are better than (ii), mainly when there is a correlation between catch and effort and an additional spatial correlation.     

Effect of water temperature and diet on growth and mortality of Neptunea arthritica juveniles

The growth and mortality of Neptunea arthritica juveniles hatched from different egg masses (controlled conditions and field) reared at 10 and 15 °C, and provided with sardine (D1) and polychaete (D2) as foods were evaluated. Results showed that diet type and water temperature significantly affect the growth and mortality. Interaction between these factors reflected robust relationship among them, but restricted exclusively to growth. Through the study period, juveniles treated at 10 °C showed maximum increments of 2.5 mm (shell length), 2.3 mm (shell width) and 0.25 g (body weight) from their initial size. While maximum values of those treated at 15 °C for the above-mentioned parameters were 7.6 mm, 5.5 mm and 1 g respectively. In both cases, these increments were recorded for individuals fed with sardine. Mortality was significantly affected by diets and water temperature, which significantly increased under D2 [10 °C (20–67%), 15 °C (70–87%)] or 15 °C [D1 (30–83%), D2 (70–87%)]. According to the results, juveniles of N. arthritica could be maintained under controlled conditions, which allows growth improvement. Mortality appears to be the limiting factor, but this could be improved by the implementation of efficient culture method, basically oriented to increase the water quality.     

The influence of warp length on trawl dimension and catch of walleye pollock <Emphasis Type="Italic">Theragra chalcogramma</Emphasis> in a bottom trawl survey

ABSTRACT:   Variations in trawl dimension, bottom contact, and catch with differing warp lengths during walleye pollock surveys conducted by the Fisheries Research Agency were examined. The ratio of warp length to fishing depth (scope ratio) was set at 2.5, 3.0 and 3.5 at depths of 110 m. At a 2.5 scope ratio, the net mouth shape and footgear contact fluctuated, as the trawl door did not contact the bottom. Footgear contact was complete when the scope ratio was 3.0 or more. Walleye pollock, sculpins and flatfishes were the main catch in all tows, and the catch increased with scope ratio. There was no difference in the length frequency of walleye pollock ( n  = 300) captured at 2.5 and 3.0 scope ratio. However, the length frequency at 3.5 was significantly different from that of other scope ratios. These results suggest that at a scope ratio of 3.0 or more, the trawl door will not leave the bottom at any depths. To compliment echo surveys for walleye pollock, a 3.0 scope ratio would be optimal, since the catch data for a 3.5 scope ratio was dissimilar from that of scope ratios.     

Population assessment of sockeye salmon Oncorhynchus nerka caught by recreational angling and commercial fishery in Lake Toya, Japan

ABSTRACT: We carried out mail and access point surveys to estimate the catch numbers, angling effort of recreational angling and the population of sockeye salmon Oncorhynchus nerka in Lake Toya in 1998 and 1999. The mail survey questions in questionnaires distributed to anglers with a recreational angling license included date of angling, caught fish species and size, and catch number. In the access point survey we also asked anglers if they had a license. We measured the fork length and weight of caught fish. The catch rate (catch number in a day by each angler) from both surveys showed no significant difference, suggesting no bias for the catch rate between surveys. The estimated total angling effort was 1760 people (1998), and 1516 people (1999). The estimated recreational catch was 28 889 (1998) and 5455 (1999), that is, two or three times larger than the commercial catch. The fish population was estimated by using the DeLury method as 60 262 (1998) and 10 806 (1999). The total exploitation rate was 62% (1998) and 78% (1999). The size of caught fish was much larger in 1999 than 1998 because of the difference in age composition.     

Post-release mortality of bonefish, Albula vulpes, exposed to different handling practices during catch-and-release angling in Eleuthera, The Bahamas

Abstract  Bonefish, Albula spp., are popular sportfish that inhabit shallow nearshore environments in tropical and subtropical seas. Although catch and release is a common voluntary practice for anglers seeking bonefish, the post-release fate of bonefish is poorly understood. Gastrically implanted acoustic transmitters were used to assess the short-term (<48 h) and long-term (>48 h) post-release mortality of bonefish, Albula vulpes (Linnaeus), in Eleuthera, The Bahamas, subjected to gentle handling (quick retrieval, 0–15 s of air exposure and brief handling time) or rough handling (longer retrieval, 30–60 s of air exposure and extended handling time). Of the 12 fish captured and released, one was preyed upon by two lemon sharks, Negaprion brevirostris (Poey), within the first hour post-release, and this fish was handled roughly. The transmitter from another bonefish was found on the substratum 2 days post-release near the site at which the fish was originally caught. Of the remaining 10 fish, all were tracked and alive for at least 13 days and up to 24 days, suggesting that the negative impacts of catch-and-release angling that lead to mortality for bonefish likely occur within minutes post-release.     

C-protein (MyBP-C) isoforms from carp ordinary and dark muscles and muscle type-specific binding to myosin

ABSTRACT:   C-protein is a myosin-associated protein of vertebrate striated muscle, and its function and properties have been extensively examined. However, there has been no report of C-protein of fish skeletal muscle so far. C-protein was identified in carp skeletal muscle by immunoassay using antibody against chicken C-protein, and the muscle-type specific C-protein was purified from carp ordinary and dark muscles for the first time. Although C-protein could be prepared from crude myosin by the reported procedure, C-protein degraded appreciably during the purification steps. Accordingly, C-protein was selectively extracted from the muscle with 0.15 M K-phosphate buffer (pH 5.8), and purified by ammonium sulfate fractionation, followed by AF-blue chromatography. Myosin free from the accessory proteins was obtained by diethylaminoethyl (DEAE) chromatography and used to assay the binding of C-protein with myosin. Ordinary muscle C-protein bound to ordinary muscle myosin in a saturable manner, but its maximum amount of binding was approximately twice that of dark muscle myosin. Similarly, dark muscle C-protein bound to dark muscle myosin much more than to ordinary muscle myosin. These results suggest that C-protein isoforms specifically bound with myosin isoforms originated from the same type of muscle.     

Effects of Reduced Fishing for Feeding Salmon (Salmo salar L.) in the Baltic on Home Water Fisheries according to Simulations with the Carlin-Larsson Population Model

The Carlin-Larsson population model of Baltic salmon was used to simulate reduced effort in an offshore fishery for feeding salmon and its effect on home water fisheries. Some simplifying assumptions had to be made; no changes in seasonal mean weight or exploitation rate in the home water fisheries were assumed. With a simulated termination of the offshore fishery, seasonal mean weights from the time before the excessive offshore fishery started were also applied to give a maximum effect on the catches. The total non-catch fishing mortality in the offshore fishery was estimated at 5% per season (total M = 10% per season). A total ban on the offshore fishery would mean a sixfold increase in catch-value for home water fisheries and a total value twice that in the present situation with the present seasonal mean weights. With the higher mean weights the simulated catch would be 87% and its value 182% higher than at present.     

Assessment of catch, effort and species changes in the pair-trawl fishery of southern Lake Malawi, Malawi, Africa

Abstract  Catch per unit effort (CPUE) and species composition in the pair-trawl fishery in commercial Area A of southern Lake Malawi were assessed from 1991 to 2001. CPUE declined from 1.7 t day⁻¹ in 1995 to 0.5 t day⁻¹ in 2001 and the fishery is considered depleted. In 2000/2002, catch composition differed significantly from a 1991 survey, and was dominated by haplochromine cichlids (92% by weight). Of 98 haplochromine cichlid taxa identified in the catch, 18 contributed ≥1% by weight. The artisanal fishery targeted similar species of a similar size. It was recommended that: (1) renewed investment and increased effort in the pair-trawl fishery is not advisable; (2) there was a need for effort limitation in Area A and (3) the pair-trawl fishery should not be managed in isolation of the artisanal fishery.