Dialogue

Source: https://en.wikipedia.org/wiki/Seafood#Types_of_seafood  

Jack: I’m starving. Let’s go and get something to eat.

July: Okay. What do you like to have? 

Jack: How about seafood? Do you like seafood?

July: Sure. I’ve heard white meat is healthier than red meat, and it is also a good  source of protein in our diets.

Jack: Do you know aquaculture, that is, fish farming is popular in Taiwan?

July: Really? I thought all the seafood we eat was wild seafood that were  harvested from the sea.

Jack: No, not exactly, especially when the world´s fisheries were over-exploited and  wild seafood has been dramatically depleting. By the way, do you know how seafood is classified?

July: Not exactly. How is it classified?

Jack: Well, basically seafood can be either animals or edible plants. According to the ISSCAAP classification (International Standard Statistical Classification of Aquatic Animals and Plants) used by the FAO (The Food and Agriculture Organization of the United Nations), seafood can be divided into 5 groups: fish, molluscs, crustaceans, other aquatic animals, and aquatic plants and microphytes.

July: Interesting! Tell me more.

Jack: Fish are aquatic vertebrates, and they can be further divided into 4 subgroups:pelagic fish,demersal fish, diadromous fish, and freshwater fish.  July: I didn’t know there were so many kinds of fish. How are they classified?

Jack: They are classified according to the place they live. For example, pelagic fish are those which live and feed near the surface or in the water column of the sea, but not on the bottom of the sea. Those that live and feed on or near the bottom of the sea are called demersal fish. Those that migrate between the sea and fresh       water are diadromous fish. And of course those that live in rivers, lakes, reservoirs, and ponds are called freshwater fish. 

July: Can you give me some examples of the fish in each category?

Jack: No problem. Pelagic fish can be larger predator fish like sharks, tuna, marlin, swordfish, mackerel; and smaller forage fish like herring, sardines, sprats, anchovies, and menhaden. In the demersal fish group, there are cod, flatfish, grouper and stingrays. Salmon, shad, eels and lampreys are on the other hand are diadromous fish. Common freshwater fish are carp, tilapia, catfish, bass, and trout.

July: Impressive! How about the other groups of seafood?

Jack: Molluscs are invertebrates with soft bodies. They can be further divided into subgroups of bivalves, gastropods, which are protected by a calcareous shell, and cephalopods, which are not protected by a shell. Bivalves, sometimes referred to as clams, have a protective shell in two hinged parts. Important seafood bivalves include oysters, scallops, mussels and cockles. Aquatic gastropods, also known as sea snails, are univalves which means they have a protective shell that is in a single piece. Gastropod literally means stomach-foot, because they appear to crawl on their stomachs. Common seafood groups are abalone, conch, and limpets. Unlike bivalves and gastropods, cephalopods are not protected with a shell. Cephalopod literally means head-foots, because they have limbs which appear to tissue from their head. Examples of cephalopods are octopus, squid and cuttlefish. 

July: How about shrimps, my favorite kind of seafood?

Jack: Shrimps are crustaceans, another group of seafood. Like molluscs, crustaceans       are invertebrates, but with segmented bodies protected by hard crusts. Shrimps,       crabs, lobsters and krill are subgroups of crustaceans. 

July: How about turtles?

Jack: They belong to the group of other aquatic animals, in which there are aquatic mammals, like whales and dolphins; aquatic reptiles, like turtles and crocodiles; echinoderms, which are headless invertebrates like sea cucumbers and sea urchins; and jellyfish. 

July: Is seaweed a kind of seafood?

Jack: Yes, seaweed is macroscopic forms of algae and is popular in China, Japan, and Korea. In contrast, there are microscopic forms of aquatic plants called microphytes, which are microscopic organisms, and can be algal, bacterial or fungal.  

July: Well, I’ve had enough of all the scientific names. Should we eat now?

文法

    被動式

在學術英文中經常使用被動式，尤其在描述研究的過程和結果或材料應用上。被動式的型態為  be + 過去分詞。

例如:

Fish are aquatic vertebrates, and they can be further divided into 4 subgroups.

    名詞定義

–  A is/are B which/that …

Fish are aquatic vertebrates which lack limbs with digits, use gills to breathe, and have heads protected by hard bone or cartilage skulls.

Aquatic gastropods, also known as sea snails, are univalves which means they have a protective shell that is in a single piece.