scholarly journals Crustacean fishery with bottom traps in an area of the southern Tyrrhenian Sea: species composition, abundance and biomass

2004 ◽  
Vol 5 (2) ◽  
pp. 15 ◽  
Author(s):  
L. CASTRIOTA ◽  
M. FALAUTANO ◽  
T. ROMEO ◽  
J. FLORIO ◽  
P. PELUSI ◽  
...  
Keyword(s):  
Species Composition ◽  
Eastern Coast ◽  
Tyrrhenian Sea ◽  
Bathymetric Range ◽  
Important Species ◽  
Trawl Fishery ◽  
The North ◽  
Student’S T ◽  
One Year ◽  
Post Hoc

The north-eastern coast of Sicily is characterized by deep, steep bottoms, not easily exploitable by trawl fishery. In this area few fishermen use bottom traps to catch shrimps and Norway lobsters. Our studies were aimed at identifying the species’ composition, abundance and biomass of crustaceans exploitable by bottom traps in this area. Monthly samples over one year were obtained from two lines of 30 baited traps each, at depths between 100 and 500 m. One line was placed in an area usually exploited by this fishery; the other line was used in the unexploited deepest bottoms. Trapped specimens were counted and weighed. ANOVA test, post hoc multiple comparisons and Student’s t test were applied on abundance and biomass data, for testing differences between areas, among seasons and species. During 22 fishing days, 23 species characteristic of the bathyal mud assemblage were caught, 8 of which were not considered commercial. Plesionika edwardsii was the most important species, recorded in the whole bathymetric range investigated; Nephrops norvegicus was significantly higher in terms of biomass in the unexploited area. The discard, of slight importance, was mostly represented by the crab Liocarcinus depurator. Spring season yielded the best catches in both areas, showing the highest values for both abundance and biomass

Feeding habits of the bullet tuna Auxis rochei in the southern Tyrrhenian Sea

2007 ◽  
Vol 87 (4) ◽  
pp. 1007-1012 ◽  
Author(s):  
E. Mostarda ◽  
D. Campo ◽  
L. Castriota ◽  
V. Esposito ◽  
M.P. Scarabello ◽  
...  
Keyword(s):  
Diet Composition ◽  
Fish Larvae ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Hierarchical Cluster ◽  
Eastern Coast ◽  
Tyrrhenian Sea ◽  
Monthly Basis ◽  
The North ◽  
Important Prey

A total of 235 bullet tunas (Auxis rochei) was caught off the north-eastern coast of Sicily between March 2003 and March 2004 for the purpose of studying their feeding habits. The fish were caught by means of an experimental surface gill-net during fishing surveys carried out on a monthly basis. The stomach contents were analysed and the prey identified, counted and weighed. The importance of the different prey types was assessed utilizing several feeding indices while possible size-related changes of the diet composition were highlighted by means of hierarchical cluster analysis, nMDS and SIMPER analysis. The results of this study showed that the bullet tuna is an epipelagic off-shore predator feeding on whatever abundant resource is available in the environment with a preference for planktonic crustaceans, small cephalopods and fish larvae. Among crustaceans, hyperiidean amphipods were the most important prey, with Anchylomera blossevillei as the dominant species, followed by the euphausiacean Stylocheiron maximum. Among cephalopods, Heteroteuthis dispar was recorded frequently while fish larvae showed high values of all indices. All prey were pelagic organisms. A size-related change in the diet composition was observed, even if it seemed related to the temporal fluctuations of the zooplanktonic assemblage in the environment. The average prey weight per stomach increased significantly in the larger predators which mostly fed on fish larvae belonging to several commercially important demersal and pelagic species.

A study on phytoplankton following ‘Volgoneft-248’ oil spill on the north-eastern coast of the Sea of Marmara

2010 ◽  
Vol 91 (3) ◽  
pp. 715-725 ◽  
Author(s):  
Seyfettin Taş ◽  
Erdoğan Okuş ◽  
Selma Ünlü ◽  
Hüsne Altiok
Keyword(s):  
Surface Water ◽  
Species Composition ◽  
Oil Spill ◽  
Oil Pollution ◽  
Sampling Period ◽  
Natural Variability ◽  
Total Petroleum Hydrocarbons ◽  
Eastern Coast ◽  
Secchi Disc ◽  
The North

Following the ‘Volgoneft-248’ oil spill, phytoplankton distribution within the affected area was investigated for two years. Simultaneously measured physical variables such as salinity, temperature, Secchi disc, current speed and direction, and total petroleum hydrocarbons (TPH) were evaluated together with phytoplankton data. At the time of the accident, the TPH concentration in surface water was measured as 2.17 mg l−1 and decreased to 88.5 µg l−1 after five days. In the first sampling period, no diatoms were detected in surface water, while dinoflagellates were dominant in the phytoplankton community. The species composition of phytoplankton changed rapidly in two months and the diatoms increased in terms of abundance and diversity. This indicated that the diatoms might be more sensitive to oil pollution than the dinoflagellates. In comparison with the historical datasets, the low phytoplankton abundance following the oil spill should be considered as the small effect of oil on the phytoplankton rather than natural variability of the ecosystem. High oil concentration in the water column caused stress on the phytoplankton and influenced the species composition negatively depending on the sensitivity of groups and the natural variability of the ecosystem.

The New South Wales Tiger Flathead, Neoplatycephalus macrodon (Ogilby). I. Biology and Age Determination

1951 ◽  
Vol 2 (2) ◽  
pp. 117 ◽  
Author(s):  
WS Fairbridge
Keyword(s):  
Age Groups ◽  
Age Determination ◽  
Sampling Technique ◽  
Final Analysis ◽  
Point Of View ◽  
Fish Length ◽  
Important Species ◽  
Trawl Fishery ◽  
The North ◽  
Catch Statistics

In a previous paper the catch statistics of the east Australian trawl fishery (Fairbridge 1948) were discussed, and in the present work, the biology of the most important species, the tiger flathead, is examined in greater detail. An age determination technique is developed for this species, and the age composition of the catch of recent years is analysed. The sampling technique carried out at the Sydney Fishmarkets is described and tested. The results are given of the first experimental trawling in Australian waters using a fine-meshed cover on the codend. The biology of the species is studied, chiefly from the point of view of establishing the age determination technique and the final analysis of the catch. Spawning is protracted, lasting throughout the six warmer months, and takes place throughout the geographical range of the species. The males spawn first in their second year, the females in their third or fourth. The "condition" (K) of the gutted fish is lowest in February, after spawning. It is probable that there is a single, genetically uniform stock, with a single centre of maximum occurrence. The younger age-groups probably do not undertake extensive coastwise movement; as a result, local areas are liable to become relatively depopulated by heavy fishing. The method of collecting and reading the flathead otolith is described. The otolith is found to grow isauxetically above a fish-length of 10 cm., and the technique of back-calculation is therefore used as an aid in age determina- tion. The otolith in this species is certainly not as clear to interpret as that of the North Sea plaice, but is probably comparable with that of the cod or hake.

Age and growth of the Japanese butterfish Psenopsis anomala in the waters off north-eastern Taiwan

2020 ◽  
Vol 100 (3) ◽  
pp. 427-433 ◽  
Author(s):  
Shyh-Bin Wang ◽  
Li-Yu Hung ◽  
Kwang-Ming Liu
Keyword(s):  
Growth Parameters ◽  
Linear Method ◽  
Growth Function ◽  
Age And Growth ◽  
Trawl Fishery ◽  
Age Class ◽  
The North ◽  
North Eastern ◽  
Marginal Increment ◽  
One Year

AbstractThe catch of Japanese butterfish, Psenopsis anomala in Taiwan is greater than those of any other nation; however, the biology, particularly the age and growth, of this economically important fish species is little known. This study describes the age and growth of P. anomala based on 734 specimens (340 females, 363 males, 31 unsexed) caught by trawl fishery in the north-eastern waters off Taiwan from March 2007 to July 2008. The age of specimens was estimated by counting the growth annuli in sagittal otoliths. The periodicity of annulus deposition on otolith was estimated to be one year with opaque zone deposited between July and August based on marginal increment analysis. The maximum age for both sexes was estimated to be ~4. The female portion of the population was dominated by the 3+ age class, while the male portion was dominated by the 2∞ age class. The parameters of the von Bertalanffy growth function with standard error estimated based on the observed length at age using a non-linear method are as follows: L∞ = 25.47 ± 0.65 cm, k = 0.30 ± 0.03 year−1, and t0 = −1.84 ± 0.16 year for females (n = 350), and L∞ = 22.39 ± 0.45 cm, k = 0.46 ± 0.04 year−1, and t0 = −1.38 ± 0.13 year for males (n = 378). The growth performances of P. anomala reported from different geographic regions were compared, and the potential influences of sample size distribution on the estimated growth parameters were further discussed.

scholarly journals Estimating selectivity of experimental diamond (T0) and turned mesh (T90) codends in multi-species Mediterranean bottom trawl

2020 ◽  
Author(s):  
ANDREA PETETTA ◽  
BENT HERRMANN ◽  
MASSIMO VIRGILI ◽  
ROCCO De MARCO ◽  
GIOVANNI CANDUCI ◽  
...  
Keyword(s):  
Mesh Size ◽  
Bottom Trawl ◽  
Size Selectivity ◽  
Important Species ◽  
Trawl Fishery ◽  
The North ◽  
Common Squid ◽  
Commercially Important ◽  
The Mediterranean ◽  
The Difference

The effect of shifting from a diamond mesh codend (T0) to a 90° turned mesh codend (T90) on the size selectivity of seven commercially important species in the Mediterranean bottom trawl fishery was evaluated. During sea trials conducted in the north-western Adriatic, two experimental codends made of 54 mm nominal mesh size netting that differed only in mesh configuration were alternately mounted on the same trawl. Overall, the size selectivity was significantly improved for all the species analysed, shifting from T0 to T90. The difference in the average expected L50values between T90 and T0 was particularly marked in European hake (Merluccius merluccius, 21.26 vs 11.26 cm total length), common squid (Loligo vulgaris, 12.06 vs 7.88 cm mantle length) and mantis shrimp (Squilla mantis, 20.78 vs 13.35 mm carapace length). Both codends had an excessive size selectivity especially for red mullet (Mullus barbatus), Mediterranean horse mackerel (Trachurus mediterraneus) and whiting (Merlangius merlangus), thus involving a commercial loss. These findings demonstrate the efficiency of the T90 codend tested at excluding undersized specimens, especially of hake, whose average L50was above the minimum conservation reference size of 20 cm. The adoption of this practical and inexpensive solution could help improve the management of the demersal resources targeted by the Mediterranean bottom trawl fishery.

scholarly journals Dose-dependent effects of insoluble fibre on glucose metabolism: a stratified post hoc analysis of the Optimal Fibre Trial (OptiFiT)

2021 ◽  
Author(s):  
Stefan Kabisch ◽  
Caroline Honsek ◽  
Margrit Kemper ◽  
Christiana Gerbracht ◽  
Ayman M. Arafat ◽  
...  
Keyword(s):  
Glucose Tolerance ◽  
Dose Effect ◽  
Oral Glucose ◽  
Oat Hulls ◽  
Post Hoc Analysis ◽  
Fibre Intake ◽  
Glucose Levels ◽  
Insoluble Fibre ◽  
One Year ◽  
Post Hoc

Abstract Aims As the first long-term RCT on insoluble cereal fibre, the optimal fibre trial demonstrated glycometabolic benefits, confirming cohort studies. The combined study intervention of lifestyle recommendations and supplementation with insoluble oat hulls fibre allows to clarify, which amount of fibre is required for a beneficial effect. Methods One hundred and eighty participants with impaired glucose tolerance underwent the one-year PREDIAS lifestyle programme and received a blinded, randomized fibre or placebo supplement for two years. We conducted a regression analyses and cut-off-based tertile comparisons in subjects with full data on dietary compliance (food records and accounted supplement; n = 120) after one year, investigating effects on fasting blood parameters, oral glucose tolerance test and anthropometry. Results We found a nonlinear inverse relation between fibre intake and change in postprandial 2-h glucose levels, showing a metabolic benefit beyond 14 g and a plateau beyond 25 g of total insoluble fibre per day. 2-h glucose levels improved significantly stronger in both upper tertiles (−0.9 [−1.6;−0.2] mmol/l, p = 0.047, and −0.6 [−1.6;0.3] mmol/l, p = 0.010) compared to the lowest tertile (0.1 [−1.2;1.1] mmol/l), also when adjusted for changes in bodyweight. Subjects with the highest fibre intake showed superior effects on fasting and postprandial insulin resistance, hepatic insulin clearance, leucocyte count and fatty liver index. Conclusions Extending the knowledge on the benefits of insoluble oat hulls fibre, our post hoc analysis demonstrates a dose effect for glycaemia and associated metabolic markers. Further research is needed in order to replicate our findings in larger trials.

Selectivity experiments with escape windows in the North Sea Nephrops (Nephrops norvegicus) trawl fishery

1999 ◽  
Vol 42 (1-2) ◽  
pp. 167-181 ◽  
Author(s):  
N Madsen ◽  
T Moth-Poulsen ◽  
R Holst ◽  
D Wileman
Keyword(s):  
North Sea ◽  
Nephrops Norvegicus ◽  
Trawl Fishery ◽  
The North ◽  
The North Sea

scholarly journals Predictive framework for codend size selection of brown shrimp (Crangon crangon) in the North Sea beam-trawl fishery

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0200464 ◽  
Author(s):  
Juan Santos ◽  
Bent Herrmann ◽  
Daniel Stepputtis ◽  
Claudia Günther ◽  
Bente Limmer ◽  
...  
Keyword(s):  
North Sea ◽  
Brown Shrimp ◽  
Beam Trawl ◽  
Crangon Crangon ◽  
Size Selection ◽  
Trawl Fishery ◽  
The North ◽  
Sea Beam ◽  
The North Sea ◽  
Selection Of
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