由于只有少数几个潜水员进行捕捞，而且他们会注意不造成过度捕捞的现象，所以潜水员的持续活动显然不会对公主鱼种群造成严重危害。
Since the divers limit their catch to a few individuals and take care not to overfish, the divers' continuing activities will clearly not result in serious harm to populations of princessfish.
一项行动正在展开来拯救一个鳄鱼种类使其免遭灭绝。
An operation is beginning to try to save a species of crocodile from extinction.
四齿鲀科族里共有超过90个河豚鱼种类。
There are over ninety species of pufferfish all belonging to the family Tetraodontidae.
这在导致整个鲑鱼种群灭绝的案例中最为明显。
This is most evident in cases where it results in the extinction of entire salmon populations.
事实上，大多数分析家认为某种环境退化是许多已灭绝鲑鱼种群消亡的根源。
Indeed, most analysts believe that some kind of environmental degradation underlies the demise of many extinct salmon populations.
清除淤泥，发现鱼类产卵的砾石层，找到合适的鲑鱼种类来重建种群是一项艰巨的任务。
Removing the mud, uncovering gravel beds where fish spawn, and finding suitable salmon types to rebuild the population is a daunting task.
1月在美国杂志《科学》上发表的一项研究发现，在过去8至15年间，几乎所有有记录的鲨鱼种类的数量都减少了一半。
A study, published in January in the US magazine, Science, found that almost all recorded shark species have fallen by half in the past 8 to 15 years.
这一点很重要，因为理论表明，当目标鱼种的生物量为其原始水平的50%左右时，渔场才能达到可收获的最大可持续产量。
That matters because theory suggests that the maximum sustainable yield that can be cropped from a fishery comes when the biomass of a target species is about 50% of its original levels.
有些鱼种是雌雄同体的。
东方锦鲤，拥有血统纯正的，高品质锦鲤种鱼种群。
Dongfang koi farm owns highbred and high-quality parent koi fish that all come from notable bloodlines and inherited steadily.
有时他们吃掉幼小的竞争鱼种。
三分之一的鲨鱼种群遭遇濒危。
它能在夜间穿过陆地到达没有其他鱼种繁殖的水域。
It can move across land at night, reaching water no other fish species has colonised.
潘兴说，碳信用可为恢复鱼类和鲸鱼种群提供额外奖励。
Carbon credits could provide additional incentive to rebuild fish and whale populations, Pershing says.
相对于只管理目标鱼种，海洋生态系统的管理需要以下几点。
The management of ecosystems as opposed to managing only target species entails.
特别美丽的青枪鱼是最大的大西洋的马林鱼，是世界上最大的鱼种之一。
The strikingly beautiful blue marlin is the largest of the Atlantic marlins and one of the biggest fish in the world.
每年人类从海洋中捕捞约5千万吨的鱼类，但这并未导致任何鱼种的灭绝。
Every year humans take more than 50 million tons of fish from the oceans without critically depleting the population of any species.
现在，每当捕获新的鱼种，他们都会拿来给我看，我们会拍照和记录下名称。
Now when they catch something new they come to show me, and we photograph the fish and log the name for it.
那里是位于巴布亚新几内亚的一个原始的珊瑚礁生态环境，是许多鱼种的家园。
This striking blue fish was found in the waters of Milne Bay Papua New Guinea a region of pristine reef environments and home to a huge number of fish species.
那里是位于巴布亚新几内亚的一个原始的珊瑚礁生态环境，是许多鱼种的家园。
This striking blue fish was found in the waters of Milne Bay, Papua New Guinea, a region of pristine reef environments and home to a huge number of fish species.
几年后，当他们把一片海域的珍贵鱼种全都吸光之后，就会转移到一片新的海域。
They move into a new area, within a few years they have cleaned out all these live, valuable fish, then they move on to another area.
这种鱼（假设我们可以真正称它为鱼）使我们之前见过的鱼种长相最奇特的一种。
This fish (if "fish" we can really call it) is the weirdest looking sea creature we've ever seen.
许多日本人，如果不让他们把这做寿司和生鱼片的珍贵鱼种吃到绝灭可是会生气的。
Many Japanese, it seems, would be angry if they were not allowed to eat a prized source of sushi and sashimi to extinction.
如果人类继续这样的捕杀行为，那么这些鲨鱼种群在几十年内灭绝的风险将相当高。
If we carry on the way that we are, we're looking at a really high risk of extinction for some of these shark species within the next few decades.
过度捕捞不仅引起个别鱼种的消耗，而且还引起海洋中整个生态系统和食物网的崩溃。
Overfishing not only causes depletion in individual fish stocks, but also disruption to entire ecosystems and food webs in the ocean.
研究鲨鱼的科学家艾莉森·科克说，它可能是一条大白鲨，该地区最常见的鲨鱼种类。
Shark scientist Alison Kock said it was probably a great white, the most commonly spotted shark in the area.
意外发生时，考察队伍正在南非开普海岸莫塞尔湾海豹岛附近进行鲨鱼种群数量研究。
The incident occurred while the research team was conducting a shark population study off Seal Island, near Mossel Bay, on South Africa's Cape coast.
意外发生时，考察队伍正在南非开普海岸莫塞尔湾海豹岛附近进行鲨鱼种群数量研究。
The incident occurred while the research team was conducting a shark population study off Seal Island, near Mossel Bay, on South Africa's Cape coast.
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