亚洲免费av电影一区二区三区,日韩爱爱视频,51精品视频一区二区三区,91视频爱爱,日韩欧美在线播放视频,中文字幕少妇AV,亚洲电影中文字幕,久久久久亚洲av成人网址,久久综合视频网站,国产在线不卡免费播放

        ?

        古老魚種重返伊利諾伊州水域

        2020-12-29 12:04吳冬梅
        瘋狂英語·愛英語 2020年12期
        關(guān)鍵詞:伊利諾伊州魚種水域

        吳冬梅

        The Illinois Department of Natural Resources is returning a fish called the alligator gar to the states rivers. Some people call the fish a “l(fā)iving fossil”. Experts believe the fish first appeared during the Early Cretaceous period more than 100 million years ago.

        Randy Sauer is an Illinois state fisheries biologist. He says the fish disappeared from the states rivers in the 1990s, although they have continued to do well in southern states. “Biologists want to bring the fish back to northern rivers because it is important to have top predators(捕食性動(dòng)物) to balance the species below them,” he said.

        Sport fishermen like to try to catch the alligator gar. Alligator gars are the second?largest freshwater fish in North America. They can grow as large as 2.7 meters and weigh more than 136 kilograms. Sauer says their large size is one reason why they disappeared in the 1990s. Experts say alligator gars are“opportunistic feeders”. This means they will eat almost anything—including small turtles or ducks. They also eat invasive species such as Asian silver carp. Sauer hopes the reintroduction of the alligator gar will help the states efforts to control the carp. Because alligator gars can live up to 60 years, the program will continue to increase for many years.

        Sauer notes that female alligator gars do not sexually mature until 11 years, and the male not till 6 or 7 years. That means the biologists will try to raise and release a lot of fish early in the program to reintroduce them. “Were probably going to stock (貯備) more heavily than 10 or 20 years down the road when hopefully these fish will find each other and start doing the job on their own,” Sauer says.

        Small devices have been placed in 7,000 of the fish so they can be observed after they are released into the waterways of Illinois. As it rains and floods, biologists expect some of the fish will follow the rivers into the states of Louisiana and Texas.

        1. Why do people call the alligator gar a “l(fā)iving fossil”?

        A. It can grow up to 2.7 meters.

        B. Its fossil can be found on earth.

        C. It can grow up to 136 kilograms.

        D. It has existed for over 100 million years.

        2. Why will biologists reintroduce the alligator gar to northern rivers?

        A. To keep the species balance.

        B. To help people make more money.

        C. To help to protect the environment.

        D. To increase the number of the alligator gars.

        猜你喜歡
        伊利諾伊州魚種水域
        我來講故事
        美伊利諾伊州強(qiáng)制要求公立學(xué)校講授亞裔歷史
        江蘇:出臺辦法 對五類重要水域?qū)嵭刑貏e保護(hù)
        魚種優(yōu)劣鑒別方法
        冬放魚種技術(shù)
        美國伊利諾伊州學(xué)術(shù)圖書館聯(lián)盟研究
        魚種深秋管理四要點(diǎn)
        中文字幕日韩精品美一区二区三区 | 四川老熟妇乱子xx性bbw| 在线综合网| 中国老熟女重囗味hdxx| 宝贝把腿张开我要添你下边动态图 | 996久久国产精品线观看| 亚洲综合久久1区2区3区| 日本一区二区三区清视频| 十四以下岁毛片带血a级| 亚洲国产精品久久亚洲精品| av人摸人人人澡人人超碰小说| 91福利精品老师国产自产在线| 中文字幕精品人妻av在线| 手机在线播放av网址| 人妻体内射精一区二区三四| 午夜家庭影院| 青青手机在线视频观看| 噜噜中文字幕一区二区| 最爽无遮挡行房视频| 1769国产精品短视频| 色综合色综合久久综合频道| 日本二区三区视频免费观看| 白嫩少妇高潮喷水av| 人妻在卧室被老板疯狂进入| 国产精品久久久久久妇女6080| 免费国产调教视频在线观看| 亚洲高清国产成人精品久久| 国产av一区二区三区传媒| 一级二级中文字幕在线视频| 中文字幕亚洲精品一二三区| 国产欧美精品aaaaaa片| 男女猛烈xx00免费视频试看| 久久国产精品波多野结衣av| 亚洲国产精品免费一区| 亚洲久悠悠色悠在线播放| 国产不卡视频一区二区三区| 人妻av一区二区三区精品| 婷婷成人亚洲综合国产| 亚洲成av人片极品少妇| 亚洲av午夜成人片精品电影 | 人妻精品久久中文字幕|