Mapping and Assessing Commercial Fisheries Services in the Lithuanian Part of the Curonian Lagoon

The spatial distribution of biomass of main commercial fish species was mapped to estimate the supply of a provisioning fishery service in the Curonian lagoon. Catch per unit effort (CPUE) was used as a proxy to estimate the efficiency of commercial fishing and, subsequently, the potential biomass of fishes. The relationship between distinctive characteristics of the fishing areas and corresponding commercial catches and CPUE was analyzed using multivariate analysis. The total catch values and CPUE used in the analyses were derived from the official commercial fishery records. RDE analysis was used to assess the variation of both catch and CPUE of commercial fish species, while the percentages of bottom sediment type coverage, average depth, annual salinity, and water residence time in each of the fishing squares were used as explanatory variables. This distance e-based redundancy analysis allowed for the use of non-Euclidean dissimilarity indices. Fisheries data spatial distribution map indicated the lack of coherence between the spatial patterns of commercial catches and CPUE distribution in the northern part of the lagoon. Highest CPUE values were estimated in the central-eastern part of the lagoon as compared to the western part of the lagoon where CPUE values were substantially lower. Both total catch and CPUE appeared not to be related to the type of bottom habitats statistically while being spatially correlated in-between. However, the impact of salinity and water residence time calculated using the 3D hydraulic circulation model on the distribution of both CPUE and commercial catches was statistically significant.

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Spatial distribution, partitioning, ecological risk and source apportionment of potential toxic elements in water and sediments of the Hoor Al-Azim wetland and their bioaccumulation in selected commercial fish species

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2021.112875 ◽

2021 ◽

Vol 172 ◽

pp. 112875

Author(s):

Sara Sheikh Fakhradini ◽

Farid Moore ◽

Behnam Keshavarzi ◽

Ravi Naidu ◽

Ayanka Wijayawardena ◽

...

Keyword(s):

Spatial Distribution ◽

Source Apportionment ◽

Ecological Risk ◽

Fish Species ◽

Toxic Elements ◽

Commercial Fish ◽

Potential Toxic Elements

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Effect of hook and bait type on catch per unit effort in the Aegean Sea demersal longline fishery

Ege Journal of Fisheries and Aquatic Sciences ◽

10.12714/egejfas.38.2.07 ◽

2021 ◽

Vol 38 (2) ◽

pp. 181-188

Author(s):

Ozan Soykan ◽

Cemil Sağlam ◽

İlker Aydın ◽

Hasan Tuncay Kınacıgil

Keyword(s):

Sparus Aurata ◽

Length Distribution ◽

Aegean Sea ◽

Fishing Effort ◽

Longline Fishery ◽

Total Catch ◽

Catch Per Unit Effort ◽

Unit Effort ◽

Catch Composition ◽

The Impact

This study aimed to determine the impact of hook and bait type on the catch composition and catch per unit effort. Effects of hook and bait types on catch composition, catch per unit effort (CPUE), length and weight distributions in demersal longline fishery were determined by experimental surveys on demersal longline sets in the Aegean Sea. A total of 12 samplings corresponding to 4800 hook fishing effort were performed between April 2014 and September 2014. Two bait types; sardine (Sardina pilchardus) and grooved razor shell (Solen marginatus) and two hook types; J-hook and C-hook were tested. CPUE values were calculated for each species and assessed between different hook-bait combinations. A total of 623 individuals were captured belonging to 3 families and 9 species. It was found that more than 60% of total catch was captured by grooved razor shell and more than 50% of the total catch was caught with J type hook. J hook was found to be close to significant (p=0.06) and grooved razor shell was found significant (p=0.02) for CPUE. The effect of bait type was found to be more significant than that of hook type for CPUE and length distribution. Hook-bait combination differed according to species and C hook baited with sardine was determined to be the best combination for Sparus aurata as the most targeted fish in the study area. Discard ratio was calculated to be 34% in terms of weight and 42.5% in terms of total number of individuals for pooled data. The condition value (K) of the species ranged from 1.05 to 1.68 and differed according to bait type. Most of the high commercial value species caught with any hook-bait combination experimented within this study are larger than minimum fishing length according to minimum landing size regulations of Turkish fishery and maturity studies.

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Effects of Groundwater Inputs to the Hydraulic Circulation, Water Residence Time, and Salinity in a Moroccan Atlantic Lagoon

Journal of Marine Science and Engineering ◽

10.3390/jmse10010069 ◽

2022 ◽

Vol 10 (1) ◽

pp. 69

Author(s):

Soukaina Elyaagoubi ◽

Georg Umgiesser ◽

Mehdi Maanan ◽

Francesco Maicu ◽

Jovita Mėžinė ◽

...

Keyword(s):

Spatial Distribution ◽

Water Level ◽

Residence Time ◽

Meteorological Data ◽

Atlantic Coast ◽

Local Population ◽

Element Model ◽

Small Scale ◽

Water Residence Time ◽

Ramsar Convention

The finite element model SHYFEM was used to study the hydrodynamics and variability of water level, salinity, temperature, and water residence time (WRT) in the Oualidia lagoon located on the Moroccan Atlantic coast. The lagoon hosts a RAMSAR convention-protected area and also offers a set of valuable ecosystem services providing the source of income for the local population. To assess the effects of submarine groundwater discharge (SGD) inputs in the study area, four simulations were set up using different SGD inputs estimates in addition to tidal forcing, bathymetry, meteorological data including solar radiation, rain, and wind, in addition to boundary conditions in the Atlantic such as salinity, water level, and water temperature. The model was calibrated and validated using hydrodynamic measurements of previous studies in 2012 and 2013. The final results from the model are in good agreement with measured data. The simulation with SGD input ~0.05 m3 s−1 produced salinity values closest to the observed ones. Calculated spatial distribution of WRT, temperature, and salinity reduced to coordinates in two PCA axes is consistent with lagoon zones developed earlier using the benthic macroinvertebrate distribution. The calculated spatial distribution of WRT allowed us to evaluate the placement of oyster aquaculture farms and small-scale fisheries in relation to water quality issues existing in the lagoon.

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Biological Effects of Oil Pollution

Water Science & Technology ◽

10.2166/wst.1982.0152 ◽

1982 ◽

Vol 14 (9-11) ◽

pp. 1185-1194 ◽

Cited By ~ 2

Author(s):

R B Clark

Keyword(s):

Fish Species ◽

Deleterious Effect ◽

Oil Pollution ◽

Biological Effects ◽

Detectable Effect ◽

Commercial Catch ◽

Commercial Fish ◽

The Impact ◽

Biological Context ◽

Heavy Mortality

Pollution is defined as environmental contamination which has a deleterious effect, and in a biological context it is only mortality which has some impact at the level of the population or community that is important. Thus, very heavy mortality of the eggs and fry of commercial fish species may have no detectable effect on the commercial catch in future years. A reduction in the population of a species which is dominant in its community, on the other hand is likely to result in major ecological adjustment. Oil pollution does not appear to have reduced populations of commercial fish species or seabirds, the two groups of animals about which most fears have been expressed. The marine environment is subject to wide and erratic fluctuations which make it difficult to detect the impact of oil pollution unless the cause is obvious, even then some caution is necessary before attributing environmental change to pollution.

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Trends in cpue and related changes in spatial distribution of demersal fish species in the Kattegat and Skagerrak, eastern North Sea, between 1981 and 2003

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2004.12.018 ◽

2005 ◽

Vol 62 (4) ◽

pp. 671-682 ◽

Cited By ~ 20

Author(s):

Michele Casini ◽

Massimiliano Cardinale ◽

Joakim Hjelm ◽

Francesca Vitale

Keyword(s):

Spatial Distribution ◽

Fish Species ◽

General Pattern ◽

Demersal Fish ◽

Average Weight ◽

Trawl Survey ◽

Catch Per Unit Effort ◽

Distribution Maps ◽

Increasing Trend ◽

Commercial Species

Abstract We explored the trends in ln-transformed catch per unit effort, defined as average weight (kg) per 1 h trawling, and the spatial distribution of 32 demersal fish species in the Kattegat and Skagerrak using International Bottom Trawl Survey data collected between 1981 and 2003. As in other areas, the biomass of roundfish species such as cod, pollack, hake, and ling drastically decreased during this period most likely owing to fishing pressure. However, other commercially important fish species, e.g. haddock, whiting, and some flatfish, showed a constant or increasing trend during the same period. Non-commercial species showed no or an increasing trend in ln-cpue, by as much as 40 times in hagfish. Furthermore, analyses of the spatial distribution of 14 selected fish species by means of distribution maps of ln-cpue suggested that fish stocks contracted and expanded in response to decrease and increase of the stock biomass, respectively, with some flatfish species (i.e. plaice and flounder) and hagfish representing the exceptions to this general pattern.

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Comparative assessment of amateur fishing influence on water bioresources of Lake Tsatsa in Volgograd region

VESTNIK OF ASTRAKHAN STATE TECHNICAL UNIVERSITY SERIES FISHING INDUSTRY ◽

10.24143/2073-5529-2021-4-57-62 ◽

2021 ◽

Vol 0 (4) ◽

pp. 57-62

Author(s):

Nikolai Vladimirovich Kutsenko ◽

Yulia Nikolaevna Grozesku ◽

Anton Alexeyevich Filipenko

Keyword(s):

Fish Species ◽

Field Studies ◽

Quantitative Composition ◽

Production Volume ◽

Total Allowable Catch ◽

Commercial Fish ◽

Volgograd Region ◽

The Impact ◽

Total Stock ◽

Observation Period

The paper presents the results of research conducted in 2020 on the impact of amateur fishing on the aquatic bioresources of Lake Tsatsa, which is part of the Sarpin Lakes located in the Volgograd region. On the basis of field studies (direct accounting), the number of amateur fishermen who visited the lake, as well as the qualitative and quantitative composition of their catches, was established. According to the data obtained, the total catch of fish by amateur fishermen, as well as the average catch per fisherman, was estimated. The size and weight composition of amateur fishing catches was determined based on the analysis of 2912 fish species. During the observation period 9 fish species were marked as part of amateur fishermen’s catches. The assessment of compliance of aquatic biological resources catch by amateur fishermen with the norms of the current Fishing Regulations was carried out. An assessment of the scale of amateur fishing impact on the aquatic bioresources of Lake Tsatsa is given, according to the analysis of the collected data. The catch of amateur fishermen in 2020 in Lake Tsatsa is amounted to 8.8232 tons, which can account for up to 15% (about 65-70 tons) of the total stock of commercial fish species in the lake. The forecast values of the production volume for industrial fisheries, for which the total allowable catch (TAC) is established and the species for which the recommended catch is determined, are 5.9 and 18.6 tons, respectively. Out of the forecast volumes amateur fishermen additionally catch fish species for which the total allowable catch (TAC) is established (carp, bream, pike) in the amount of 2.858 tons, and species for which the recommended catch value is determined as 5.643 tons.

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A novel approach to quantifying trophic interaction strengths and impact of invasive species in food webs

Biological Invasions ◽

10.1007/s10530-021-02490-y ◽

2021 ◽

Author(s):

Edoardo Calizza ◽

Loreto Rossi ◽

Giulio Careddu ◽

Simona Sporta Caputi ◽

Maria Letizia Costantini

Keyword(s):

Invasive Species ◽

Food Web ◽

Food Webs ◽

Fish Species ◽

Trophic Interaction ◽

Coregonus Lavaretus ◽

Commercial Fish ◽

Novel Approach ◽

Allochthonous Species ◽

The Impact

AbstractMeasuring ecological and economic impacts of invasive species is necessary for managing invaded food webs. Based on abundance, biomass and diet data of autochthonous and allochthonous fish species, we proposed a novel approach to quantifying trophic interaction strengths in terms of number of individuals and biomass that each species subtract to the others in the food web. This allowed to estimate the economic loss associated to the impact of an invasive species on commercial fish stocks, as well as the resilience of invaded food webs to further perturbations. As case study, we measured the impact of the invasive bass Micropterus salmoides in two lake communities differing in food web complexity and species richness, as well as the biotic resistance of autochthonous and allochthonous fish species against the invader. Resistance to the invader was higher, while its ecological and economic impact was lower, in the more complex and species-rich food web. The percid Perca fluviatilis and the whitefish Coregonus lavaretus were the two species that most limited the invader, representing meaningful targets for conservation biological control strategies. In both food webs, the limiting effect of allochthonous species against M. salmoides was higher than the effect of autochthonous ones. Simulations predicted that the eradication of the invader would increase food web resilience, while that an increase in fish diversity would preserve resilience also at high abundances of M. salmoides. Our results support the conservation of biodiverse food webs as a way to mitigate the impact of bass invasion in lake ecosystems. Notably, the proposed approach could be applied to any habitat and animal species whenever biomass and diet data can be obtained.

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