M. Ordeix, N. Franch, F. Vidal, Miquel Rafa, K. Andree, E. Gisbert
: The aim of this project is to promote the recovery of ecological connectivity within 10–20 years in the lower Ebre River and Delta, and a healthy and sustainable population of di-adromous fish, including European sturgeon ( Acipenser sturio ), European eel ( Anguilla anguilla ), twaite shad ( Alosa fallax ) and sea lamprey ( Petromyzon marinus ), among other aquatic native species. It is focused on long-term sustainable investments, adapting all present river obstacles to allow fish migration, increasing the river spawning habitat availability and the distribution and growth areas of migrating fish. The main activities of the LIFE MIGRATOEBRE Project (LIFE13 NAT/ES/000237) are: This European sturgeon, twaite shad lamprey identified cartographed. the target population of the lower Ebre river (2000 fish tags). and fish ( Chelon labrosus , Mugil cephalus , Alosa fallax and Anguilla anguilla ) were monitored by acoustic telemetry (using 47 Vemco receivers located along the river and at in the lagoons of the Ebre delta). Obtained results indicate that the Ebre is optimal for the recovery of the target species of this project, but at the same time it would be very important to carry out a control of invasive species. This LIFE project started on 1 July 2014 and, after several extensions, it will finish on 30 June 2024. More information can be found at: www.migratoebre.eu.
{"title":"LIFE MIGRATOEBRE: Migratory Fish Recovery and Improved Management in the Final Stretch of the Ebre River (Catalonia, NE Iberian Peninsula)","authors":"M. Ordeix, N. Franch, F. Vidal, Miquel Rafa, K. Andree, E. Gisbert","doi":"10.3390/blsf2022013135","DOIUrl":"https://doi.org/10.3390/blsf2022013135","url":null,"abstract":": The aim of this project is to promote the recovery of ecological connectivity within 10–20 years in the lower Ebre River and Delta, and a healthy and sustainable population of di-adromous fish, including European sturgeon ( Acipenser sturio ), European eel ( Anguilla anguilla ), twaite shad ( Alosa fallax ) and sea lamprey ( Petromyzon marinus ), among other aquatic native species. It is focused on long-term sustainable investments, adapting all present river obstacles to allow fish migration, increasing the river spawning habitat availability and the distribution and growth areas of migrating fish. The main activities of the LIFE MIGRATOEBRE Project (LIFE13 NAT/ES/000237) are: This European sturgeon, twaite shad lamprey identified cartographed. the target population of the lower Ebre river (2000 fish tags). and fish ( Chelon labrosus , Mugil cephalus , Alosa fallax and Anguilla anguilla ) were monitored by acoustic telemetry (using 47 Vemco receivers located along the river and at in the lagoons of the Ebre delta). Obtained results indicate that the Ebre is optimal for the recovery of the target species of this project, but at the same time it would be very important to carry out a control of invasive species. This LIFE project started on 1 July 2014 and, after several extensions, it will finish on 30 June 2024. More information can be found at: www.migratoebre.eu.","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124459133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: An increasing number of reef fish species have been shown to form spawning aggregations. These aggregations occur at predictable times and places, with participants utilizing single or mixed mating systems. In a lek-like mating system, males establish temporary courtship territories that they defend against rival males while attracting females to spawn. The location of these territories often contributes to differential mating success. The males holding territories deemed “desirable” by females because of the physical attributes of their location attract more females and secure greater mating opportunities compared to those males that defend territories elsewhere within the spawning aggregation site. Presumably, females favor locations where newly spawned eggs may be carried away from potential predators more effectively. Thus, males holding territories located at the outer edge of the site in an area exposed to water currents running parallel to the reef face have far greater mating success than those males that hold territories found on inner or middle sections of the site where currents are less pronounced. This pattern is consistent across a range of taxa within the family Labridae, co-occurring at a multispecies spawning aggregation site on a coral reef in Guam, Western Pacific.
{"title":"Mating Territory Location Drives Mating Success by Male Wrasses (Labridae) at a Resident Spawning Aggregation Site","authors":"T. Donaldson","doi":"10.3390/blsf2022013137","DOIUrl":"https://doi.org/10.3390/blsf2022013137","url":null,"abstract":": An increasing number of reef fish species have been shown to form spawning aggregations. These aggregations occur at predictable times and places, with participants utilizing single or mixed mating systems. In a lek-like mating system, males establish temporary courtship territories that they defend against rival males while attracting females to spawn. The location of these territories often contributes to differential mating success. The males holding territories deemed “desirable” by females because of the physical attributes of their location attract more females and secure greater mating opportunities compared to those males that defend territories elsewhere within the spawning aggregation site. Presumably, females favor locations where newly spawned eggs may be carried away from potential predators more effectively. Thus, males holding territories located at the outer edge of the site in an area exposed to water currents running parallel to the reef face have far greater mating success than those males that hold territories found on inner or middle sections of the site where currents are less pronounced. This pattern is consistent across a range of taxa within the family Labridae, co-occurring at a multispecies spawning aggregation site on a coral reef in Guam, Western Pacific.","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127202247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ana Hernández, Fátima Gil, C. Sousa‐Santos, E. Cabrita, P. Guerreiro, V. Gallego
{"title":"Assessment of the Reproductive Status of Captive Populations of Endangered Leuciscid Species from the Iberian Peninsula: A. hispanica, I. lusitanicum and A. occidentale","authors":"Ana Hernández, Fátima Gil, C. Sousa‐Santos, E. Cabrita, P. Guerreiro, V. Gallego","doi":"10.3390/blsf2022013139","DOIUrl":"https://doi.org/10.3390/blsf2022013139","url":null,"abstract":"","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123730596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
André Moreira, Joana Boavida-Portugal, P. Almeida, Sara Silva, C. Alexandre
: The conservation of fish biodiversity requires reliable information on their distribution and habitat use, especially of endemic species that generally occur in restricted geographic areas and specific habitats. This is the case of threespine stickleback ( G. aculeatus L.), that is a small freshwater fish listed as Endangered (EN) in Portugal, which represents the southern limit of the species global distribution. The monitoring and conservation of populations placed near to the species distribution limits is very important because in these places, small environmental changes can lead to the significant decline of local populations. However, due to the lack of knowledge about its regional distribution, ecology, and macrohabitat preferences, few measures have been proposed aiming the conservation of this species. This project aimed to identify which macro-scale environmental factors determine regional distribution of G. aculeatus , to predict their potential distribution and, therefore, define the most important areas for their protection and conservation. The occurrence data, from existing databases and specific sampling campaigns, together with 15 environmental macrohabitat predictors, were used to model the potential distribution of sticklebacks in Portugal, through an ensemble of species distributions models (SDM). Through the results of our ensemble model, we found that threespine stickleback may occur predominantly at lower stretches of river systems, where sandy substrate is dominant, and flow is higher. Sticklebacks are also more likely to occur in sites with high levels of rainfall in the driest month, thus avoiding locations with high potential for drying during summer, which tend to be common in the Iberian Peninsula. The species also tends to avoid steep slope areas, with high levels of annual precipitation. Based on our results, a probability map of occurrence was generated; from this, some river stretches were categorized into levels according to their importance for the conservation of the species. With the results obtained, it was also possible to identify some atypical populations, occurring in areas with low or null habitat suitability, which need to be further studied, because they must have developed physiological characteristics that allow them to subsist in places that are not conducive to their survival.
{"title":"Habitat Suitability of Threespine Stickleback (Gasterosteus aculeatus L.) in the Southern Limit of Its Global Distribution: Implications for Species Management and Conservation","authors":"André Moreira, Joana Boavida-Portugal, P. Almeida, Sara Silva, C. Alexandre","doi":"10.3390/blsf2022013129","DOIUrl":"https://doi.org/10.3390/blsf2022013129","url":null,"abstract":": The conservation of fish biodiversity requires reliable information on their distribution and habitat use, especially of endemic species that generally occur in restricted geographic areas and specific habitats. This is the case of threespine stickleback ( G. aculeatus L.), that is a small freshwater fish listed as Endangered (EN) in Portugal, which represents the southern limit of the species global distribution. The monitoring and conservation of populations placed near to the species distribution limits is very important because in these places, small environmental changes can lead to the significant decline of local populations. However, due to the lack of knowledge about its regional distribution, ecology, and macrohabitat preferences, few measures have been proposed aiming the conservation of this species. This project aimed to identify which macro-scale environmental factors determine regional distribution of G. aculeatus , to predict their potential distribution and, therefore, define the most important areas for their protection and conservation. The occurrence data, from existing databases and specific sampling campaigns, together with 15 environmental macrohabitat predictors, were used to model the potential distribution of sticklebacks in Portugal, through an ensemble of species distributions models (SDM). Through the results of our ensemble model, we found that threespine stickleback may occur predominantly at lower stretches of river systems, where sandy substrate is dominant, and flow is higher. Sticklebacks are also more likely to occur in sites with high levels of rainfall in the driest month, thus avoiding locations with high potential for drying during summer, which tend to be common in the Iberian Peninsula. The species also tends to avoid steep slope areas, with high levels of annual precipitation. Based on our results, a probability map of occurrence was generated; from this, some river stretches were categorized into levels according to their importance for the conservation of the species. With the results obtained, it was also possible to identify some atypical populations, occurring in areas with low or null habitat suitability, which need to be further studied, because they must have developed physiological characteristics that allow them to subsist in places that are not conducive to their survival.","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132921024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sara Silva, C. Alexandre, A. Ribeiro, Andre C. Domingues, A. S. Rato, Joana Pereira, C. Mateus, B. Quintella, P. Almeida
: The trout Salmo trutta L. is an iconic fish species very well studied across most of its range. However, there is a lack of information about the biology and ecology of S. trutta populations from southern European rivers, which coincide with the southern limit of its global distribution. This study aims to analyse the movement patterns and habitat use of S. trutta in the Mondego River basin, Central Portugal, and relate them with the environmental factors to which the species is exposed. Biotelemetry represents an important tool to obtain temporal and spatial specific details about the behaviour of target species and, in this work, we used a set of complementary techniques, namely acoustics, radio and PIT telemetry. A total of 114 trout specimens were tagged with PIT-tags, to be identified in future recaptures or detected at an antenna installed at Coimbra dam fish pass. From these, 18 were also tagged with Dual Mode transmitters, that include radio and acoustic telemetry signals, allowing to track the species’ movements from the estuary to the upstream freshwater sections. Results show the existence of a migratory peak between November and January that coincides with the reproduction season, while reinforcing the importance of Alva River to spawning S. trutta , one of the main tributaries in the study area. River fragmentation in the study area, particularly in the tributaries, is still limiting the vital area of the tracked individuals, although recent restoration actions provided easier access to some important areas in this river for distinct trout life-stages. This study aims to improve the knowledge of southern European trout populations, contributing to enhancing efforts for restoring and managing these populations inhabiting areas under severe climate change effects. S.S., A.S.R., and A.D.; resources, C.M.A. and P.R.A.; data curation, S.S., A.D.,
{"title":"Migration Patterns and Behaviour of Trout (Salmo trutta L.) in the Southern Limit of the Species Distribution","authors":"Sara Silva, C. Alexandre, A. Ribeiro, Andre C. Domingues, A. S. Rato, Joana Pereira, C. Mateus, B. Quintella, P. Almeida","doi":"10.3390/blsf2022013121","DOIUrl":"https://doi.org/10.3390/blsf2022013121","url":null,"abstract":": The trout Salmo trutta L. is an iconic fish species very well studied across most of its range. However, there is a lack of information about the biology and ecology of S. trutta populations from southern European rivers, which coincide with the southern limit of its global distribution. This study aims to analyse the movement patterns and habitat use of S. trutta in the Mondego River basin, Central Portugal, and relate them with the environmental factors to which the species is exposed. Biotelemetry represents an important tool to obtain temporal and spatial specific details about the behaviour of target species and, in this work, we used a set of complementary techniques, namely acoustics, radio and PIT telemetry. A total of 114 trout specimens were tagged with PIT-tags, to be identified in future recaptures or detected at an antenna installed at Coimbra dam fish pass. From these, 18 were also tagged with Dual Mode transmitters, that include radio and acoustic telemetry signals, allowing to track the species’ movements from the estuary to the upstream freshwater sections. Results show the existence of a migratory peak between November and January that coincides with the reproduction season, while reinforcing the importance of Alva River to spawning S. trutta , one of the main tributaries in the study area. River fragmentation in the study area, particularly in the tributaries, is still limiting the vital area of the tracked individuals, although recent restoration actions provided easier access to some important areas in this river for distinct trout life-stages. This study aims to improve the knowledge of southern European trout populations, contributing to enhancing efforts for restoring and managing these populations inhabiting areas under severe climate change effects. S.S., A.S.R., and A.D.; resources, C.M.A. and P.R.A.; data curation, S.S., A.D.,","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121215803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. F. Belo, C. Mateus, B. Quintella, E. Pereira, André Moreira, R. Oliveira, C. Batista, P. Almeida
: Allis shad ( Alosa alosa L.) populations have suffered declines and even regional extinction across their distribution range, mainly due to river impoundment, overexploitation, and pollution. In Portugal, the species is classified as Endangered (EN). This fish is regarded as a valuable delicacy, and commercial fisheries dedicated to this species in Portugal are found in rivers in Minho, Lima, C á vado, Douro, Vouga, Mondego, Tagus, and Guadiana. Official landings state that, in the last 10 years, around 10 t of allis shad were sold annually at the Figueira da Foz fish market. Fisheries are selective since the allowed mesh size for the nets employed does not capture smaller fish. Moreover, larger fish are more desirable, attaining higher prices per kg at fish auctions and thus generating higher revenue for the fishermen. The fishing pressure on this threatened resource in the Mondego is significant and bound to impact its population structure. With the present work, we assess the impact of fishing pressure and gear selectivity on the dimensional structure of the Mondego’s shad spawning population, one of the last strongholds for allis shads, and identify possible consequences for the future of the species. The dimensional structure and gender proportion of over 800 shads sampled at Figueira da Foz fish auction from 2015 to 2019 was analyzed. All shads sampled were between 400 mm and 745 mm in total length, with an average of 592 mm. Simultaneously, we used images recorded in the monitoring window at Açude-Ponte Dam’s fishway in Coimbra to study the shads reaching the upstream spawning areas in order to check for differences in the dimensional structure possibly related to fishing pressure. The results obtained aim to increase the existing biological knowledge of this population and the human pressure it is subjected to, thus contributing to future management efforts.
Allis shahad (Alosa Alosa L.)在其分布范围内种群数量下降甚至区域灭绝，主要原因是河流蓄水、过度开发和污染。在葡萄牙，该物种被列为濒危物种。这种鱼被认为是一种珍贵的美味，在葡萄牙的米尼奥、利马、瓦多、杜罗、沃加、蒙台戈、塔古斯和瓜迪亚纳的河流中都可以找到专门捕捞这种鱼的商业渔场。官方发布的数据显示，在过去10年里，菲盖拉达福斯鱼市场每年售出约10吨鲱鱼。渔业是有选择性的，因为所使用的网的允许网目尺寸不能捕获较小的鱼。此外，更大的鱼更受欢迎，在鱼类拍卖中每公斤的价格更高，从而为渔民带来更高的收入。在蒙台哥，这种受威胁的资源面临着巨大的捕捞压力，势必会影响其种群结构。通过目前的工作，我们评估了捕捞压力和渔具选择对蒙台哥鱼产卵种群的维度结构的影响，蒙台哥鱼产卵种群是allis阴影的最后据点之一，并确定了该物种未来可能产生的后果。分析了2015年至2019年Figueira da Foz鱼拍卖中800多个鱼片的尺寸结构和性别比例。所有取样的树影长度在400 - 745毫米之间，平均为592毫米。同时，我们利用科英布拉阿帕拉德-庞特大坝鱼道监测窗口记录的图像，研究到达上游产卵区的阴影，以检查可能与捕捞压力有关的尺寸结构差异。获得的结果旨在增加对这一种群的现有生物学知识和它所受到的人类压力，从而有助于未来的管理工作。
{"title":"Impact of Fisheries on Allis Shad’s (Alosa alosa L.) Spawning Population Structure in the Mondego River","authors":"A. F. Belo, C. Mateus, B. Quintella, E. Pereira, André Moreira, R. Oliveira, C. Batista, P. Almeida","doi":"10.3390/blsf2022013126","DOIUrl":"https://doi.org/10.3390/blsf2022013126","url":null,"abstract":": Allis shad ( Alosa alosa L.) populations have suffered declines and even regional extinction across their distribution range, mainly due to river impoundment, overexploitation, and pollution. In Portugal, the species is classified as Endangered (EN). This fish is regarded as a valuable delicacy, and commercial fisheries dedicated to this species in Portugal are found in rivers in Minho, Lima, C á vado, Douro, Vouga, Mondego, Tagus, and Guadiana. Official landings state that, in the last 10 years, around 10 t of allis shad were sold annually at the Figueira da Foz fish market. Fisheries are selective since the allowed mesh size for the nets employed does not capture smaller fish. Moreover, larger fish are more desirable, attaining higher prices per kg at fish auctions and thus generating higher revenue for the fishermen. The fishing pressure on this threatened resource in the Mondego is significant and bound to impact its population structure. With the present work, we assess the impact of fishing pressure and gear selectivity on the dimensional structure of the Mondego’s shad spawning population, one of the last strongholds for allis shads, and identify possible consequences for the future of the species. The dimensional structure and gender proportion of over 800 shads sampled at Figueira da Foz fish auction from 2015 to 2019 was analyzed. All shads sampled were between 400 mm and 745 mm in total length, with an average of 592 mm. Simultaneously, we used images recorded in the monitoring window at Açude-Ponte Dam’s fishway in Coimbra to study the shads reaching the upstream spawning areas in order to check for differences in the dimensional structure possibly related to fishing pressure. The results obtained aim to increase the existing biological knowledge of this population and the human pressure it is subjected to, thus contributing to future management efforts.","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124097149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Comparison of Olfactory Sensitivity in Seawater- and Freshwater-Adapted Bass, Dicentrarchus labrax","authors":"Z. Velez, P. Hubbard, P. Guerreiro","doi":"10.3390/blsf2022013125","DOIUrl":"https://doi.org/10.3390/blsf2022013125","url":null,"abstract":"","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129403186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
África Oliver-Blanco, A. Rodríguez-Ruiz, L. Encina, Juan Ramón Cid-Quintero, C. Orduna
{"title":"Seasonal Comparison of Length-Weight Ratio of Sea Bass (Dicentrarchus labrax), in Two Types of Aquaculture Facilities","authors":"África Oliver-Blanco, A. Rodríguez-Ruiz, L. Encina, Juan Ramón Cid-Quintero, C. Orduna","doi":"10.3390/blsf2022013124","DOIUrl":"https://doi.org/10.3390/blsf2022013124","url":null,"abstract":"","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127438337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Oliveira, C. Alexandre, B. Quintella, A. S. Rato, S. Pedro, P. Almeida
{"title":"Assessment of Fish Passage and Behaviour through a Tidal Weir Using an Underwater Sonar","authors":"R. Oliveira, C. Alexandre, B. Quintella, A. S. Rato, S. Pedro, P. Almeida","doi":"10.3390/blsf2022013123","DOIUrl":"https://doi.org/10.3390/blsf2022013123","url":null,"abstract":"","PeriodicalId":142804,"journal":{"name":"The IX Iberian Congress of Ichthyology","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117012080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Orduna, A. Rodríguez-Ruiz, África Oliver-Blanco, Juan Ramón Cid-Quintero, L. Encina
: The introduction of exotic fish species is a global ecological and conservation problem that has caused the reduction and extinction of numerous native species. In Spain, the introduction of exotic freshwater fish is one of the main factors threatening the survival of their native fish species. One such species that recently arrived in Spanish freshwaters is the catfish ( Silurus glanis ). This study was conducted from 2010 until 2021 in the Torrej ó n reservoir in the Tagus basin. The results obtained show that the introduction of catfish has led to a significant decrease in the abundance of fish in the reservoir, as well as a clear alteration in the fish assemblage, causing changes in the proportion of species and their biomass. The common barbel ( Luciobarbus bocagei ), the only native species that still maintained an abundant population in the reservoir, has clearly been the most disadvantaged species. The size structure of the species present in the reservoir allows us to differentiate adult catfish specimens from the rest of the species using hydroacoustic methods and thus be able to estimate their density, biomass, and spatio-temporal distribution. Based on the results obtained, we can affirm that the species is active in the reservoir throughout the year and that, despite its fame as a “bottom dweller”, catfish use surface habitats more than previously thought. It has shown a great capacity of adaptation to exploit the new environments and resources, together with a great tolerance against adverse conditions, such as low oxygen concentration (even anoxia) or high concentrations of ammonium, that are characteristic of the hypolimnion of Torrej ó n during the stratification period. The insights are an important contribution both to proving the effect of the introduction of catfish in native fish populations and to the implementation of alternative tools, such as hydroacoustic methodologies, in future management programs for this exotic species in our freshwater ecosystems. .O.-B.
外来鱼类的引进是一个全球性的生态和保育问题，它已导致许多本地物种的减少和灭绝。在西班牙，外来淡水鱼的引进是威胁本地鱼类生存的主要因素之一。最近来到西班牙淡水的一个这样的物种是鲶鱼(Silurus glanis)。该研究于2010年至2021年在塔古斯盆地的Torrej ó n水库进行。结果表明，鲶鱼的引入导致水库鱼类丰度明显下降，鱼类组合发生明显变化，导致物种比例和生物量发生变化。作为唯一在水库中仍保持丰富种群的本地物种，普通刺柏显然是最不利的物种。水库中存在的物种的大小结构使我们能够使用水声方法区分成年鲶鱼标本和其他物种，从而能够估计它们的密度、生物量和时空分布。根据所获得的结果，我们可以肯定，该物种全年都在水库中活跃，尽管鲶鱼以“海底居民”而闻名，但它比以前想象的更多地使用水面栖息地。它对新环境和新资源的开发具有很强的适应能力，对分层时期Torrej ó n低铁离子所特有的低氧(甚至缺氧)或高浓度铵等不利条件具有很强的耐受性。这些见解对于证明鲶鱼在本地鱼类种群中引入的影响以及在未来淡水生态系统中对这种外来物种的管理计划中实施替代工具(如水声方法)都是重要的贡献。
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