Biological Effects of Oil Pollution

1982 ◽  
Vol 14 (9-11) ◽  
pp. 1185-1194 ◽  
Author(s):  
R B Clark

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.

Fishes ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Edgaras Ivanauskas ◽  
Andrius Skersonas ◽  
Vaidotas Andrašūnas ◽  
Soukaina Elyaagoubi ◽  
Artūras Razinkovas-Baziukas

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.


Author(s):  
Nikolai Vladimirovich Kutsenko ◽  
Yulia Nikolaevna Grozesku ◽  
Anton Alexeyevich Filipenko

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.


2014 ◽  
Vol 15 (2) ◽  
pp. 380 ◽  
Author(s):  
E. YEMISKEN ◽  
C. DALYAN ◽  
L. ERYILMAZ

Fish species in catch and discard of trawl fisheries in and around Iskenderun Bay were examined within the fishing closure period and fishingperiod.The sampling was performed from May 2010 to January 2011 by a commercial trawl vessel.Chondricthyan species composed 49 % of discard catch biomass whileGymnura altavela and Dasyatis pastinacawere dominant in hauls. 27 lessepsian fish species were captured during the study,nine of them beingtarget species for trawl fisheries. In total, 14 of the lessepsian fish species were determined as discard species.In both sampling periods, Equulites klunzingeriand Citharus linguatula contributed to discard fish catch dissimilarity among depth ranges (deeper and shallower than 60 m). E. klunzingerishowed high abundance in discard catch.There were no significant differences in the distribution of the discard fish biomass between the sampling periods (ANOVA test, p>0.05). However, depth range pointed out significantdifferences in discard fish catch composition (p<0.05).Among major commercial fish species of trawl fisheries, Mullus surmuletus and Sparus aurata were not separated as discard in anyhaul by fishermen. Any size of these two species  were included in commercial catch (Total length ranged from 61 to 721 mm).


Author(s):  
Edoardo Calizza ◽  
Loreto Rossi ◽  
Giulio Careddu ◽  
Simona Sporta Caputi ◽  
Maria Letizia Costantini

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.


AMBIO ◽  
2004 ◽  
Vol 33 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Gennady G. Matishov ◽  
Vladimir V. Denisov ◽  
Sergey L. Dzhenyuk ◽  
Oleg V. Karamushko ◽  
Dag Daler

Author(s):  
Vitaliy Victorovich Barabanov ◽  
Veronica Nikolaevna Tkach ◽  
Sergey Viktorovich Shipulin

The work presents the assessment of unaccounted withdrawal of fluvial anadromous and river fish species in the inland fisheries of the Astrakhan region, which is composed of despoliations of commercial catches, poaching and amateur fishing. Methodology decisions that are developed at the CaspNIRKh were the calculation basis of the unaccounted fishing withdrawal and assessment of the impact of amateur fishing on the aquatic bio-resources. The article shows the evaluation method of volumes of poaching fish withdrawal. It is found that the main objects of the unaccounted withdrawal were more valuable fishing species (roach, pike perch, catfish, carp, bream, and pike). The despoliation of commercial catches made 28% on the average. One year minimum poaching fish withdrawal in the region, using the example of 2015, was 7.94 thousands of tones and 19% from commercial catch, and 20-30% of fish catching, harvested by the amateur fishing. The work presents the pressing of unaccounted withdrawal of fluvial anadromous and river fish species on stocks. On the back of decrease of stocks and commercial catches of fluvial anadromous and river fish species, development scales of all directions of unaccounted withdrawal in the Astrakhan region disturb all preconditions for reconstruction and growth of fish number.


Author(s):  
Edward Vladimirovich Nikitin

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.


2019 ◽  
Vol 14 (11) ◽  
pp. 1705-1713
Author(s):  
Anna Grigoriadi ◽  
◽  
Yuliya Sotnikova ◽  
Еvdokiya Novoselova ◽  
Liliya Sattarova ◽  
...  

Author(s):  
Mayara P. Neves ◽  
Pavel Kratina ◽  
Rosilene L. Delariva ◽  
J. Iwan Jones ◽  
Clarice B. Fialho

AbstractCoexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal variation in resource availability influences the consumption and assimilation of resources by two syntopic fish species, Psalidodon aff. gymnodontus and P. bifasciatus, in the Lower Iguaçu basin. We also tested the impact of seasonality on trophic niche breadth and diet overlap of these two dominant omnivores. Seasonal changes in resource availability strongly influenced the consumption and assimilation of resources by the two fish species. Both species exhibited high levels of omnivory, characterized by high diversity of allochthonous resources in the wet season. Terrestrial invertebrates were the main component of diet during this season. However, in the dry season, both species reduced their isotopic niches, indicating diet specialization. High diet overlap was observed in both seasons, but the isotopic niche overlap was smaller in the dry season. Substantial reduction in the isotopic niche of P. bifascistus and a shift toward aquatic invertebrates can facilitate coexistence during this season of resource shortage. Feeding plasticity allows omnivorous fish to adjust their trophic niches according to seasonality, promoting the exploitation of different resources during periods of greater resource diversity. This seasonal variation could be an important mechanism that contributes to the resource partitioning and coexistence of dominant omnivores in Neotropical streams.


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