relatives. These animals represent more, proportionally, of the tree of life than other species, meaning they are top priority for conservation campaigns. The EDGE of Existence Programme is a conservation effort that attempts to help conserve endangered animals that represent large portions of their evolutionary trees. The U.S. government has listed the vaquita as endangered under the Endangered Species Act. It is also listed by the IUCN and the CITES in the category at most critical risk of extinction.
Population decline Edit
A vaquita swims in the foreground while fishing boats ply their trade in the distance.
Vaquitas have never been hunted directly, but their population is declining, largely due to animals becoming trapped in illegal gillnets intended for capturing the totoaba, a large critically endangered fish of the drum family endemic to the Gulf. A trade in totoaba swim bladders has arisen, driven by demand from China (where they are used in soup, being considered a delicacy and also thought to have medicinal value), which is greatly exacerbating the problem.[2][3]
Estimates placed the vaquita population at 567 in 1997. Estimates in the 2000s ranged between 150[19][20] to 300.
With their population dropping as low as 85 individuals in 2014, inbreeding depression has probably begun to affect the fitness of the species, potentially contributing to the population's further decline.
In 2014, estimates of the species' abundance dropped below 100 individuals. An international vaquita recovery team concluded that the population is decreasing at a rate of 18.5% per year, and "the species will soon be extinct unless drastic steps are taken immediately." Their report recommended that a ban on gillnet fishing be enforced throughout the range of the vaquita, that action be taken to eliminate the illegal fishery for the totoaba, and that with help from the U.S. and China, trade in totoaba swim bladders be halted.
On 16 April 2015, Enrique Peña Nieto, President of Mexico, announced a program to conserve and protect the vaquita and the similar-sized totoaba, including a two-year ban on gillnet fishing in the area, patrols by the Mexican navy and financial support to fishermen impacted by the plan. However, some commentators believe the measures fall short of what is needed to ensure the species' survival.
Primary threats
Primary threats Edit
Studies performed in El Golfo de Santa Clara, one of the three major ports in which vaquitas live, indicated that gillnet fishing causes about 39 vaquita deaths a year. This is close to 17% of the whole vaquita population within this port. While these results were not taken from the entire range of habitat in which vaquitas live, it is reasonable to assume that these results can be applied to the whole vaquita population, and in fact may even be a little low.[26] Even with a gillnet ban throughout the vaquita refuge area, which contains 50% of the vaquita's habitat, the population is still in decline, which suggests a complete ban of gillnet use may be the only solution to saving the vaquita population.[27]
Other potential threats to the vaquita population include habitat alterations and pollutants. The habitat of the vaquita is small and the food supply in marine environments is affected by water quality and nutrient levels. The damming of the upper Colorado River has reduced the flow of fresh water into the gulf, potentially affecting the vaquita.[14] In addition, the use of chlorinated pesticides may also have a detrimental effect. Despite these possible problems, most of the recovered bodies of vaquitas show no signs of emaciation or environmental stressors,[14] implying that the decline is due almost solely to bycatch. However, these additional hazards may pose a long-term threat.
relatives. These animals represent more, proportionally, of the tree of life than other species, meaning they are top priority for conservation campaigns. The EDGE of Existence Programme is a conservation effort that attempts to help conserve endangered animals that represent large portions of their evolutionary trees. The U.S. government has listed the vaquita as endangered under the Endangered Species Act. It is also listed by the IUCN and the CITES in the category at most critical risk of extinction.Population decline EditA vaquita swims in the foreground while fishing boats ply their trade in the distance.Vaquitas have never been hunted directly, but their population is declining, largely due to animals becoming trapped in illegal gillnets intended for capturing the totoaba, a large critically endangered fish of the drum family endemic to the Gulf. A trade in totoaba swim bladders has arisen, driven by demand from China (where they are used in soup, being considered a delicacy and also thought to have medicinal value), which is greatly exacerbating the problem.[2][3]Estimates placed the vaquita population at 567 in 1997. Estimates in the 2000s ranged between 150[19][20] to 300.With their population dropping as low as 85 individuals in 2014, inbreeding depression has probably begun to affect the fitness of the species, potentially contributing to the population's further decline.ในปี 2014 ประเมินความอุดมสมบูรณ์ของพันธุ์ลดลงต่ำกว่า 100 คน ทีมงานกู้คืน vaquita นานาชาติมีข้อสรุปว่า ประชากรจะลดลงในอัตราร้อยละ 18.5 ต่อปี และ "สายพันธุ์จะเร็ว ๆ นี้จะสูญพันธุ์ยกเว้นขั้นตอนรุนแรงดำเนินการทันที" รายงานของพวกเขาแนะนำว่า ห้ามมา gillnet ตกปลาบังคับใช้ทุกช่วงของ vaquita ว่า ดำเนินการเพื่อขจัดการทำประมงที่ผิดกฎหมายสำหรับการ totoaba และว่า ด้วยความช่วยเหลือจากสหรัฐอเมริกาและจีน การค้า totoaba ว่ายน้ำขวถูกหยุดไว้วันที่ 16 2558 เมษายน แนท Peña ลา ประธานาธิบดีเม็กซิโก ประกาศโปรแกรมเพื่อการอนุรักษ์ และป้องกัน vaquita การ totoaba การที่คล้ายกันขนาด รวมบ้านสองปี gillnet ตกปลาในพื้นที่ ลาดตระเวนกองทัพเรือเม็กซิกัน และเงินสนับสนุนการประมงผลกระทบจากแผนการ อย่างไรก็ตาม นักวิจารณ์บางส่วนเชื่อว่า มาตรการขาดสิ่งที่จำเป็นเพื่อความอยู่รอดของสายพันธุ์ภัยคุกคามหลักภัยคุกคามหลักแก้ไขStudies performed in El Golfo de Santa Clara, one of the three major ports in which vaquitas live, indicated that gillnet fishing causes about 39 vaquita deaths a year. This is close to 17% of the whole vaquita population within this port. While these results were not taken from the entire range of habitat in which vaquitas live, it is reasonable to assume that these results can be applied to the whole vaquita population, and in fact may even be a little low.[26] Even with a gillnet ban throughout the vaquita refuge area, which contains 50% of the vaquita's habitat, the population is still in decline, which suggests a complete ban of gillnet use may be the only solution to saving the vaquita population.[27]Other potential threats to the vaquita population include habitat alterations and pollutants. The habitat of the vaquita is small and the food supply in marine environments is affected by water quality and nutrient levels. The damming of the upper Colorado River has reduced the flow of fresh water into the gulf, potentially affecting the vaquita.[14] In addition, the use of chlorinated pesticides may also have a detrimental effect. Despite these possible problems, most of the recovered bodies of vaquitas show no signs of emaciation or environmental stressors,[14] implying that the decline is due almost solely to bycatch. However, these additional hazards may pose a long-term threat.
การแปล กรุณารอสักครู่..
