Long-term sublethal exposure to polyethylene and tire wear particles: Effects on risk-taking behaviour in invasive and native fish

Anthropogenic polymeric particles pollute even the most remote ecosystems and may compromise organisms' behaviour and movement skills. It is expected that invasive species cope better with pollutants than native species (i.e., pollution resistance hypothesis). In this study, invasive gibel carp (Carassius gibelio) and native crucian carp (Carassius carassius) were used as model organisms. Specimens were fed daily with food pellets (1 % body weight) added with 0.1 % polyethylene (PE), tire wear particles (TWPs) and control. Their behavioural parameters were compared before and after 14 and 60 days of exposure. Additionally, we evaluated burst swimming capacity after 60 days of exposure to the treatments. The fishes exposed to the PE and TWPs treatments showed significant trends toward increased boldness scores and, in the PE treatment, higher utilization of the open field, and both behavioural changes are associated with higher risk-taking. Invasive gibel carp had substantially better swimming performance than crucian carp, but the expected trend in relation to the treatments was not found. Fish exposed to sublethal doses of PE and TWPs showed signs of behavioural changes after two months of exposure that may affect risk-taking behaviour, which might impact species interactions with predators

Isotopic niches reveal the impact of topmouth gudgeon and gibel carp on native crucian carp

Invasive species pose a major threat to natural ecosystems and directly outcompete many native species, placing them at imminent threat of extinction. The topmouth gudgeon (Pseudorasbora parva) is on the EU’s blacklist of invasive freshwater species and threatens biodiversity, especially in wetland and floodplain ecosystems, aquacultures and village ponds. The crucian carp (Carassius carassius) is native to Europe and its populations have declined in large part of its native range, with invasive gibel carp (C. gibelio) suspected as a major cause of its decline. Invasions by topmouth gudgeon have been implicated in the decline of crucian carp populations but this still needs to be verified. The aim of this study was to evaluate by the experimental approach the competitive interaction between the two species, topmouth gudgeon and crucian carp, focusing on isotopic niche sizes and their overlap in syntopy. A four-month mesocosm experiment was performed to determine the isotopic niche of crucian carp and topmouth gudgeon living alone and in syntopy. Additionally, stable isotope data were collected at the sites where the two species co-occur to compare niche sizes and overlaps. Experimental data showed that the isotopic space of topmouth gudgeon responded more flexibly (reducing niche size at syntopy) than that of the crucian carp and confirmed a high isotopic niche overlap between the species. Field studies have shown that topmouth gudgeon has invaded the isotopic niche of the crucian carp, especially when another invasive species, the gibel carp, lived in the community (25% at 40% ellipse area and 50% at 95% ellipse area). When only the topmouth gudgeon and crucian carp were present in the field, the overlap was lower (3% and 48%, respectively) and directional overlap modelling showed that the crucian carp was more likely to invade the isotopic niche of topmouth gudgeon than vice versa. The data indicated that competition between crucian carp and topmouth gudgeon is likely, especially in syntopy with other invasive species. This study shows that the feeding plasticity of topmouth gudgeon likely facilitates its establishment outside its native range and, due to high isotopic niche overlap, threatens native fish with similar feeding ecology with competitive displacement

Mechanisms of invasive gibel carp (Carassius gibelio) competitive dominance over native crucian carp (Carassius carassius)

This thesis explores the reasons behind the decline of the native crucian carp (Carassius carassius) in European waters, emphasizing the critical endangerment due to resource competition with invasive gibel carp (Carassius gibelio). Through a combination of field studies (Czech and Swedish water bodies) and controlled laboratory experiments, the research compares growth patterns, fish condition, and resource utilization between native and invasive species. The findings reveal that C. gibelio exhibits significantly greater growth increments and more efficient to use of food resources. Additionally, trophic niche utilization and stable isotope analysis show how C. gibelio gains a competitive advantage by exploiting plant material unused by C. carassius. The thesis also explores the impacts of eutrophication on native species, focusing on how nutrient enrichment affects growth rate and competitive interaction between the species. This research supports the hypothesis that the introduction and spread of invasive C. gibelio contribute to the decline of C. carassius in European waters and highlights the need to address eutrophication and invasive species mitigation in freshwater conservation strategies

A Study of Geographical Indication (GI) System for Food Stuffs in India

India being known for its oldest civilization with its rich culture and tradition with special emphasis toward food and culture. We find much diverse food and culture in its gastronomical study. Although, food stuff contributing only 3.9% of registered GIs. Special attention need to be given by the stake holders (public and private). The present research paper attempts to look into the status and system of GI and trade practices in food stuff. This is to highlight the role of GIs to protect the importance of origin of food stuffs and its culture and tradition. Further these GI food tags are pride of Indian cultural diets, extensively followed by the world. The majorities of food stuffs are unidentified and legally unprotected and the consumers are also not aware of the same. This is to give brief indication about how GI considerations of pursuing and protecting Indian Food stuff is essential and we must give attention to register maximum food stuffs to protect originality of the food and culture which is necessary to do so.</jats:p

Assessing the sustainability of lepidophagous catfish, Pachypterus khavalchor (Kulkarni, 1952), from a tropical river Panchaganga, Maharashtra, India

Abstract Background The Western Ghats of India, one of the global biodiversity hotspots and freshwater eco-regions, harbors several fish species which not just form the important part of the world’s freshwater biodiversity yet in addition are the vital segment of livelihood of the neighborhood population. The rate of fish decline in the Western Ghats is alarming. The absence of organized study and data scarcity on basic biology and life history traits of several species could be one reason behind the decline, and thus it is difficult to execute conservation action/s. This is especially true, particularly for data-deficient species for which definite data related to distribution, population size, and trend is not available. The present study deals with the detailed investigation of population dynamics of catfish species, Pachypterus khavalchor, which is data-deficient species inhabiting the Western Ghats of India and forms an important component of freshwater inland fishery, providing nutritional and financial security to the local community. Methods Specimens for the present study were collected monthly for a period of 1 year from the River Panchaganga and length–frequency data were analyzed using FiSAT II software. Results Length–weight analysis of pooled (male + female) data suggested the fish exhibited higher exponent than expected under isometry, indicating the positive allometric growth of P. khavalchor in the Panchaganga River. The asymptotic length (L∞) and the growth rate (K) were estimated as 149.63 mm and 0.71 year−1 respectively. Potential longevity (t max) and length at first capture (Lc) were estimated as 4.22 years and 73 mm respectively. The total (Z), natural (M), and fishing mortality (F) were estimated as 2.23 year−1, 0.88 year−1, and 1.35 year−1 respectively. The current exploitation rate (E cur = 0.60) was found to be almost 90% that gives the maximum relative yield per recruit (E max = 0.67). Recruitment pattern revealed two peaks, suggesting the fish have two spawning bouts each year. Conclusions The stock of P. khavalchor in the Panchaganga River may be in near full exploitation under the current harvesting strategy, with a high chance of recruitment failure in the future. Additional studies on the reproductive biology of P. khavalchor would be particularly welcome for the imposition of the seasonal closure for effective conservation of stock

&lt;b&gt;Effects of the invasive Tilapia on the Common Spiny Loach (Cypriniformes: Cobitidae: &lt;I&gt;Lepidocephalichthys thermalis&lt;/I&gt;) - implications for conservation&lt;/b&gt;

 The introduction of invasive species leading to decline of freshwater fauna is a major concern for conservation biologists.  In this study we examined the effect of introduced Tilapia on the survival of the loach Lepidocephalichthys thermalis via predation experiments with Tilapia and a native predator, the Snakehead fish Channa gachua.  Examining the chemoecology of prey-predator interactions, we found that L. thermalis failed to detect water-borne cues from Tilapia but did recognize cues from C. gachua, indicating innate predator recognition.  We also observed that L. thermalis can learn to associate kairomones with Tilapia when conditioned with kairomones and injured conspecific cues.  Trained L. thermalis showed higher survival during Tilapia predation trials.  Thus under experimental conditions the vulnerability of L. thermalis to Tilapia predation due to failure to detect chemical cues can be reduced via associative training.  It remains to be determined how useful this behavioral plasticity can be in wild L. thermalis populations exposed to introduced Tilapia. </jats:p