This paper focuses on how the declining population of Anguilla anguilla (European Eels) negatively affects the ecological impact on the Mediterranean Sea. Throughout this paper, research has shown that because of human-made barriers, climate change, and pollutants the population of A. anguilla has decreased. In conclusion, there have been many conservation implementations that have had a positive effect on the population of A. anguilla but, there are always other ways and/or tactics to stabilize the critically endangered A. anguilla.
Introduction:
Anguilla anguilla (European Eels) is generally localized to Europe and Northern Africa. The species is under the family of Anguillidae, which falls under a family of ray-finned fish (freshwater eels). In addition, A. anguilla relies on migrations which impacts their population due to many man-made machineries created in the bodies of water.
The now-Mediterranean Sea, located in between Europe, Asia, and Africa, first began to flood with water in the Mediterranean basin, approximately five million years ago. The Mediterranean Sea is described as having hot and dry air during the summer and damp, cold air during the winter, which creates ideal conditions for human civilization. This paper will discuss the effect of A. anguilla in the Mediterranean Sea. In addition to A. anguilla existing in the sea, other species that occupy the Mediterranean Sea includes the Mediterranean monk seal and the Loggerhead turtle.
The populations of Anguilla anguilla (European Eels) have been on the decline throughout the recent years, especially in the Mediterranean Sea. This is important because A. anguilla circulate the freshwater organisms in the sea by eating organisms for their food source. In addition, A. anguilla is classified as critically endangered based on the IUCN Red List due to the impact of human activities and climate changes. Anguilla anguilla has been on the IUCN Red List as critically endangered since 2008. Previous to beginning this project, I was aware of the declining population of A. anguilla. In addition, I was also aware of the fact that these eels have an effect on the Mediterranean Sea in regards to eating organisms living in the sea. A possible hypothesis that would cleared up as the paper continues would state that a declining population of A. anguilla has a negative impact on the environment of the Mediterranean Sea, specifically. Due to the recent changes in the climate and the excessive use of sea machinery for human economic profits, the A. anguilla species is decreasing.
DISCUSSION:
European Eels:
The habitat of A. anguilla consists of a variety of habitats, from small streams to coastal waters. The species is catadromous, living in fresh, salty and coastal waters but roving to pelagic oceanic waters to breed. Anguilla anguilla becomes bigger due to temperature and the species’ growth rate is usually faster in saline water than fresh. During development, reliant on size, A. anguilla’s diet consists off an array of creatures including fish and crustaceans. In muddy habitats, A. anguilla feed on freshwater mollusks, shrimp and worms. The diet of A. anguilla helps regulate the lifecycle in the sea life.
Anguilla anguilla is a species that is harvested and traded on an international level for consumption, cultural views, and stocking purposes. The Asians markets, such as China and Japan, are the countries with the highest demand for A. anguilla species. An alarming configuration of exploitation is predominately seen. When the population of Anguilla anguilla declines or a new species suddenly becomes in demand and force exploitation levels, the economic industry carries on to the next species to fulfil demand (Crook and Nakamura 2013).
Traditionally, A. anguilla was consumed within its European and North African range States. Although still consumed in Europe, through the recent years, A. anguilla became a delicacy in East Asia (Ringuet et al. 2002). In addition to harvesting, the eels, A. anguilla farming is quite popular. Although, raising Anguilla anguilla larvae to become adult eels or glass eels have been difficult to achieve.
Additionally, between the years 2009 to 2011, over 360 tons of Anguilla species were allegedly exported from multiple countries. These exporting countries include Algeria, Belgium, Croatia, Denmark, France, Greece, Morocco, Norway, Spain, Switzerland, Tunisia and the UK, and importers included Armenia, China, Denmark, France, Hong Kong, Italy, Macedonia. On the other hand, the countries that imported Anguilla species include Netherlands, Republic of Korea, Russia, Spain, Sweden, Tunisia and Ukraine. From 2009 to 2011, approximately 30,000 tons of A. anguilla meat and bodies were exported and imported for skins and leather products (UNEP-WCMC 2013). Illegal trade of A. anguilla has created distress for ecologists and scientists and therefore establishments have detained many A. anguilla shipments intended for Asian eel farms (Crook in litt, 2013).
The causes of the declining rates of A. anguilla are still not fully comprehended (Dekker 2007), but some actions that contributed to the process of decreasing the population include, barriers to migration including the damage produced by hydropower turbines (Winter et al. 2006), pollutants existent in the Mediterranean Sea (Robinet and Feunteun 2002), and climate change (Castonguay et al. 1994). A main threat to the A. anguilla population, are the barriers that exist in the upstream path and downstream path of A. anguilla migrations. Throughout Europe, there are approximately over 24,000 hydropower plants and the amount of plants are set to increase over the coming years (van der Meer 2012). For example, Netherlands has over 4,000 hydropower plants which hinder the reproducing migrations of A. anguilla. In addition, degradation of habitat is exacerbated by human development, flood control with the building of dams, water-level management, and the use water for domestic or commercial blueprints. In another example, the decreasing level of catches of A. anguilla have been accredited to over-exploitation, dam construction, and pollution of water for domestic use in North Africa is present (Azeroual 2010).
Pollutants that contaminate the body of water have the ability to negatively affect A. anguilla. These pollutants contain many toxic substances that doesn’t allow A. anguilla to reach a mature stage or reproduce viable offspring. These chemicals are stored and then released when fat is reduced while migration which could consequently limit the spawning migrations of A. anguilla because of metabolic disturbance (Robinet and Feunteun 2002, Palstra et al. 2006). With this said, the pollutants that exist in the waters enter A. anguilla and as the species is attempting to migrate and reproduce, the chemicals now existent within the body of A. anguilla hinders the ability to reproduce viable offspring.
Climate change has been another main factor in the decreasing rate of A. anguilla. An important hypothesis states that over time the changes in climate that now affect A. anguilla were and are associated with the changing oceanic conditions. According to The North Atlantic Oscillation (NAO), natural changes in climate have been influencing A. anguilla populations for millions of years (Minegishi et al 2005) throughout times of upsurge and regression.
Conservation Actions:
In order to offer protection, promote recovery, increase the populations of A. anguilla, and enhance the sustainable management of A. anguilla. EMPs, an electromagnetic pulse that provides a small rupture of electromagnetic energy, have been implemented. The main objective of these EMPs are to decrease the amount of human-caused mortalities, and hypothesize that about 40% of A. anguilla will escape to the sea, away from anthropogenic influences, as if there were no human-caused influences placed in the body of water in the first place. Member States are liable for executing these measures in addition to understanding and increasing the populations of A. anguilla. These measures include, reducing commercial and recreational fisheries, altering habitats, creating passable rivers, transporting A. anguilla species that have drifting away from the sea back to the sea, changing hydro-power plants to decrease the rate of mortality for A. anguilla, and developing a specific section of water for A. anguilla farming, in order to build the population. Per the 2013 ICES WKEPEMP report, the conservation actions mentioned above have usually been for commercial and recreational fisheries. Actions that have secondary effects to A. anguilla, such as placing monitoring programs, are also common within fisheries. Statistics state that 756 conservation actions that were suggested in the EMPs have been implemented (ICES WKEPEMP 2013).
Besides utilizing EMPs, in 2007, A. anguilla was included in the CITES Appendix II to provide security for trading this species and to make sure that A. anguilla was sustainable. The Parties to the Convention had to provide permits for all exports and imports of A. anguilla. In order to obtain a permit, the species, A. anguilla, would have to have been collected legally and proved that when the species is ultimately exported there would be no disadvantageous or harmful consequences to the longevity of the species. On an international scale, A. anguilla was added to the OSPAR List of Threatened and/or Declining Species in the Northeast Atlantic (OSPAR 2010).
Across Europe there are many programs that are aimed to provide A. anguilla with upstream and downstream passage from the barriers created in the sea. In addition, access to the species original habitat, that has been lost through the manufacture of migratory obstacles, is open. Some of these actions/programs include catching A. anguilla and taking them through relatively small distances past barriers. These programs have a hope that by moving the species outside of the barriers it can allay against the loss of habitat and in the end and have a positive contribution to allowing A. anguilla escapement. However, in the near future there is a need to reduce the amount of direct human interference by providing more cost-effective paths for A. anguilla to navigate through (IUCN). The goal that is wanted to achieve with these actions and programs is to help the spawning or reproduction rate of the A. anguilla species.
Constant monitoring of A. anguilla escape on either a national or international scale is rare and highly unlikely as of right now. Therefore, in addition to localized monitoring, estimates of the amount of A. anguilla that escape in smaller subpopulations are recorded. There is a model dynamic that helps determine the reproduction rate of A. anguilla. The German Eel Model determines the levels of how many A. anguilla that escape from the Schwentine River system. The results showed that the rates were lower than those shown by the German EMP (Prigge et al. 2013). Indeed a report for the European Commission by Walker et al. (2011) review a number of assessment models (namely the Demographic model of the Camargue (DemCam); Eel Density Analysis 2.0 (EDA); German Eel Model (GEM); and, Scenario-based Model of Eel Production II (SMEP II)) using time series eel data sets from a variety of locations across Europe. In conclusion, all four of these dynamic models were and are qualified to predict escapement of A. anguilla to a certain amount of precision (Walker et al. 2011).
Conclusion:
In conclusion, A. anguilla, which is native to the Mediterranean Sea has been on the decline officially since 2008. The major causes of the species decline includes the human-made barriers, climate change, and pollutants that exist inside the species and therefore limits the amount of offspring. There is still a perilous need for improvement in the ways and tactics to save the critically endangered population of A. anguilla. It is imperative to note that while management actions that were instilled throughout the past couple years have been proven to be effective, A. anguilla still requires a lot more conservation tactics. The apparent rise in recruitment and restoration of this species has began since 2008 and have continued to this day. In addition, because plans have already been implements that should not be a sufficient reason to end all improvements in the future or for the future. It was suggested that reevaluation of A. anguilla will be necessary in in the upcoming years, most likely within the next 5 years. This time frame is suggested because ecologists and scientist believe that the amount of A. anguilla data will become more accessible.
The fate of A. anguilla severely depends on the how human’s treat the Mediterranean Sea. Humans have added edge effects and barriers for their own personal economic growth and international economic growth. Anguilla anguilla has been recognized as a delicacy in many countries, especially in East Asia. Instances where, people have the ability to put a specie in extinction because they provide a uniqueness is what is really detrimental to the A. anguilla. In order to save this species from becomes extinct, citizens need to become knowledgeable about the species, their impact on their lives, and how these species are critical to the balance of the Mediterranean Sea.