Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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0024 The US Department of Agriculture has estimated

that biohydrogenation in ruminants accounts for up

to 20% of the trans fatty acids in the US diet, with the

remaining 80% being derived from food products

formulated with partially hydrogenated fats like

margarine, shortening, shortened baked goods

(cake, cookies, pastry) and deep-fried snacks (corn

and potato chips, French fries, doughnuts, extruded

products). In the USA, the average per capita intake

of trans fatty acids has been estimated at about 12.5 g

day

1

or between about 5 and 8% of the total fat in

the diet. In Canada, hydrogenated margarine is the

main source of trans fatty acids, but other foods,

particularly cookies, crackers, doughnuts, potato

chips, and French fries, also contribute substantially

to trans fatty acid intake because they are made with

hydrogenated shortening.

0025 The primary concern about trans fatty acids in the

diet is their adverse effects on blood lipids. The results

of clinical trials indicate that moderate and high levels

of dietary trans fatty acids raise blood total and LDL

cholesterol; their effect on blood HDL cholesterol

concentrations has been variable. Several comprehen-

sive reviews of the literature report an emerging con-

sensus: when substituted for polyunsaturated fats in

the diet, trans fatty acids tend to act like saturated

fatty acids in their effects on blood lipids and thus are

likely to increase the risk of CHD. However, when

substituted for animal fats and vegetable oils high in

saturated fats, trans fatty acids have been shown to

lower blood total and LDL cholesterol concentra-

tions. Because trans fatty acids are typically found in

high-fat foods, a prudent approach to reducing CHD

risk is to reduce total fat intake in general and satur-

ated fat intake in particular. By choosing foods low in

fat and saturated fat, consumers will also reduce their

trans fatty acid intake.

Plant Sterols and Stanols

0026 It has been known since the 1950s that plant sterols

lower blood cholesterol levels. Plant sterols are

analogs of cholesterol, differing structurally from

cholesterol in their side-chain configuration. Sitos-

terol, campesterol and stigmasterol are the most

important plant sterols from a nutritional standpoint

and comprise up to 98% of the total sterols in certain

seed and vegetable oils. Plant sterols can be hydrogen-

ated to form plant stanol esters (e.g., sitostanol, cam-

pestanol, stigmastanol), a process that improves their

solubility in margarine.

0027 In studies conducted in the 1980s and 1990s, mar-

garine was chosen as the vehicle for supplementing

the diet with plant sterols because it is widely con-

sumed and easily incorporated into usual dietary pat-

terns. Recent studies show that daily consumption of

a margarine enriched with 1–3 g plant sterols or plant

stanols is sufficient to lower blood total cholesterol

levels by 10% and LDL cholesterol levels by 10–

15%. Blood concentrations of HDL cholesterol and

triacylglycerols are not affected by plant sterol or

plant stanol esters. Consumption of more than

about 3 g plant stanol esters per day does not appear

to increase its effectiveness.

0028The strength of these findings led the US Food and

Drug Administration to authorize a claim on food

labels and in food labeling that plant sterol/stanol

esters reduce risk of CHD. The health claim, which

became effective in September 2000, was designed

to inform the general public that plant sterol/stanol

esters should be consumed as part of a diet low in

saturated fat and cholesterol. This followed the lead

of some European countries, where plant sterol/

stanol-enriched margarines were already available.

The Raisio Group in Finland, for example, intro-

duced Benecol in 1995; the multinational company

Unilever/Lipton introduced a similar product, Take

Control, into the US market in 1999.

0029One potential threat to the widespread adoption of

margarines enriched with plant sterols and stanols is

the reported adverse effect of these compounds on the

absorption of nutrients such as fat-soluble vitamins

and carotenoids. In some studies, consumption of

about 1–3 g plant sterols daily for 3.5 weeks resulted

in 20% reductions in plasma a- and b-carotene, lyco-

pene, and a-tocopherol concentrations. It remains

to be determined whether this adverse effect is clinic-

ally significant and whether plant sterol- or stanol-

enriched margarines should or could be modified to

compensate for the effect.

Emerging Health Issues

0030Although margarine consumption appears to benefit

patients with hypercholesterolemia, who are advised

to reduce their dietary intake of saturated fat and

cholesterol, and may help the general public achieve

healthy dietary patterns to reduce the risk of CHD,

questions about a possible link between margarine

consumption and risk of certain types of cancer

have begun to emerge. For example, in a study of

472 women diagnosed with early-stage breast cancer

in 1982–84, the reported baseline total consumption

of butter, margarine, and lard (measured as times

per day) was associated with an increased risk of

recurrence of the cancer. Consumption of butter,

margarine, and lard appeared to increase the risk

of recurrence by 30% for each time they were con-

sumed per day. Unfortunately, the study analysis

did not attempt to separate the effects of margarine

from butter and lard. In a study of 320 men with

3724 MARGARINE/Dietary Importance

histologically confirmed prostate cancer and 246 men

without prostate cancer or a history of the disease,

added lipids such as butter on bread, butter for

cooking, margarine on bread and for cooking, and

seed oils were positively associated with increased

risk of prostate cancer. When adjustments were

made in the statistical analysis for other food groups,

butter, margarine, and seed oils were all positively

associated with prostate cancer risk, although the

effect was only significant for seed oils.

003 1 These findings are suggestive but far from conclu-

sive. Both breast and prostate cancer are hormone-

sensitive cancers, meaning that in the early stages of

tumor development, tumor growth is influenced by

the sex hormones. Thus, hormonal status and lifetime

exposure to phytoestrogens (plant compounds that

exhibit weak hormone-like activity in the human

body) are confounding factors in these studies. Other

factors such as family history, age, and diet, particu-

larly the intake of total fat, animal fat, polyunsatur-

ated fatty acids, vitamins, and antioxidants, are

known to influence cancer processes. Indeed, the

type of dietary pattern adopted over the course of a

lifetime appears to be an indicator of cancer risk.

Western-type diets high in fat, red meat, protein,

fast food, refined grains and sugar, and low in fruits

and vegetables are linked with increased risk of

cancer, while so-called prudent diets high in fruits,

vegetables, and whole-grain cereals and low in fat

are associated with low cancer risk. For colon cancer

risk, consumers who substitute margarine for butter,

whole grains for refined grains, low-fat dairy prod-

ucts for high-fat dairy products, and poultry for red

meat have a lower risk than those who eat a typical

western diet. In the final analysis, dietary fats have

significant effects on cancer processes through their

biologic roles in regulating cell growth and immune

responses, and a prudent approach to reducing cancer

risk is to reduce intake of all fats.

Role of Margarine in the Diet

0032 Margarine is recognized by health professionals and

consumers alike as a healthy table spread and a

cheaper alternative to butter for use in cooking and

in food preparation. Margarine makes an important

nutritional contribution to the diet by being a source

of one or more essential fat-soluble vitamins such as

vitamins A and/or D and by being low in saturated

fat. Margarine is cholesterol-free. Newer margarine

products are also low in trans fatty acids and in some

cases are reduced in fat and energy. Some margarines

can also be classified as a functional food, because

they are enriched with plant sterol or stanol esters

that have been shown to lower blood cholesterol

levels. Its price, taste, spreadability, and convenience

have made margarine a dietary staple in many coun-

tries around the world.

Seealso: Butter:PropertiesandAnalysis; Cancer:Dietin

CancerPrevention; Cholesterol:FactorsDetermining

BloodCholesterolLevels;RoleofCholesterolinHeart

Disease; Coronary Heart Disease:EtiologyandRisk

Factor; Margarine:TypesandProperties;Methodsof

Manufacture;CompositionandAnalysis; Sensory

Evaluation:Appearance;Texture;Aroma;Taste; Fatty

Acids:Trans-fattyAcids:HealthEffects

Further Reading

Chrysam M (1985) Tablespreads and shortenings. In:

Applewhite TH (ed.) Bailey’s Industrial Oils and Fats,

vol. 3, pp. 41–127. New York: Wiley.

Food and Drug Administration (2000) Interim final rule:

food labeling: health claims; plant sterol/stanol esters

and coronary heart disease. Federal Register 65: 54686–

54739 available at www.access.gpo.gov/su_docs/aces/

aces140.html.

Harvard Center for Cancer Prevention (1996) Harvard

report on cancer prevention. Cancer Causes and Con-

trol, vol. 7, available at www.hsph.harvard.edu/cancer.

Institute of Shortening and Edible Oils (1999) Food Fats

and Oils, 8th edn. Washington, DC: ISEO available at

www.iseo.org.

Jonnalagadda SS, Mustad VA, Champagne C and Kris-

Etherton PM (1995) Margarine and plasma cholesterol

– a perspective for dietitians on trans fatty acids in the

diet. Perspectives in Applied Nutrition 2: 9–16.

Krauss RM, Eckel RH, Howard B et al. (2000) AHA dietary

guidelines: revision 2000: a statement for healthcare pro-

fessionals from the Nutrition Committee of the American

Heart Association. Circulation 102: 2296–2311.

Ling WH and Jones PJH (1995) Dietary phytosterols: a

review of metabolism, benefits and side effects. Life

Sciences 57: 195–206.

Piggott JR (2000) Dynamism in flavour science and sensory

methodology. Food Research International 33: 191–197.

Ratnayake WMN, Hollywood R, O’Grady E and Pelletier

G (1993) Fatty acids in some common food items in

Canada. Journal of the American College of Nutrition

12: 651–660.

Tuorila H, Matuszewska I, Helleman U and Lampi A-M

(1989) Sensory and chemical characterization of fats

used as spreads on bread. Food Quality and Preference

1: 157–162.

Vaisey-Genser M and Vane BK (1995) Sensory evaluation

of margarine. In: Warner K and Eskin NAM (eds)

Methods to Assess Quality and Stability of Oils and

Fat-Containing Foods, pp. 76–106. Champaign, IL:

AOCS Press.

Van Alphen J (1969) Hippolyte Me

ge Mourie

s. In: van

Stuyvenberg JH (ed.) Margarine, an Economic, Social

and Scientific History, 1869–1969, pp. 5–7. Liverpool,

UK: University Press.

MARGARINE/Dietary Importance 3725

MARINE FOODS

Contents

Production and Uses of Marine Algae

Edible Animals Found in the Sea

Marine Mammals as Meat Sources

Production and Uses of Marine

Algae

P A Cordero, Jr., Sultan Qaboos University, Al-Khod,

Omen

This article is reproduced from Encyclopaedia of Food Science,

Background

0001 The introduction and subsequent improvement of

mariculture (i.e., managed cultivation for farming of

seaweeds) techniques explains the increased produc-

tion of certain useful green, brown, and red seaweed

species. However, the commercial production of sea-

weeds greatly depends on the demand for certain

products and on the pre- and postharvesting and

processing costs. The international market obtains

its supply of seaweed materials both from natural

vegetation and from sites cultivated by humans.

0002 In addition to consuming seaweeds directly as food,

humans have found far-reaching uses for its extracts as

food additives and as raw materials for making vari-

ous household products and other biomedical items.

Species of Importance as Food

0003 Edible seaweeds, or sea vegetables, are mainly com-

posed of green (Chlorophyta), brown (Phaeophyta)

and red (Rhodophyta) algae. The predominance of

pigments manifested externally has been the basis for

their conventional classification. However, in the case

of the red alga, e.g., Eucheuma growing in the shal-

lower intertidal zone, overlying green coloration is

visible owing to the destruction of the characteristic

red pigment, phycoerythrin.

0004 Some sea vegetables simulate the gross morphology

of terrestrial plants in having leaf-like, stem-like, and

root-like parts. The latter part, however, is mainly for

anchorage, while the functions of nutrition extraction

and the assimilation and conversion of inorganic

substances into organic ones are performed by the

leaf-like fronds or blades.

0005 The species composition of seaweeds eaten as food

varies according to the consumer groups. Thus, the

orientals such as the Chinese, Japanese, Malays, and

Filipinos include the following species among the

common sea vegetables: the green algae, Enteromor-

pha, Ulva, Monostroma, Codium, and Caulerpa; the

brown algae, Hydroclathrus, Hizikia, Cladosiphon,

Sargassum,andLaminaria; and the red algae, Por-

phyra, Gelidiella, Gracilaria, Halymenia, Hypnea,

and Laurencia. Popular among the occidentals are

the green alga, Ulva, the brown algae, Macrocystis,

Ascophyllum, Laminaria, and Undaria, and the red

algae, Porphyra, Gelidium, Palmaria palmata (Rho-

dymenia palmata), and Chondrus crispus.

0006In an attempt to popularize the eating of sea vege-

tables, several seaweed recipes were developed,

catering to the South-east Asian cuisine. Of the 80

sea vegetable recipes developed by Cordero and his

research team, 63 proved to be acceptable to selected

food tasters using the Hedonic Rating Scale, a meas-

urement to determine the acceptability of food, in

which a rating of 9 means highly acceptable and

1 least acceptable.

Harvesting and Use of Natural Floras

0007The methods of harvesting seaweeds have been revo-

lutionized through the years. The more primitive

method involved grabbing the seaweed with bare

hands, or cutting it with sharp knife or sickle while

wading in the shallow intertidal zone. This method,

while still considered economical, defies the principle

of conservation as the standing crop of wild seaweeds

in a given area is easily depleted. An improved version

finds a gatherer on-board a paddle-driven banca

(boat), later to be substituted with motorized ones,

from which the gatherer uses a ‘grabber’ pole with

curved knife on one end to cut the seaweeds from

the stem.

0008In northern Luzon, the Philippines, natural stands

of Porphyra marcosii and P. suborbiculata are

scraped from the rough surfaces of infratidal rocky

ledges.

0009Two of the more recent methods of harvesting

naturally grown seaweeds are an air-lift vacuum

cleaner system, and a mechanized harvester device

used in Europe and the USA. The former system was

3726 MARINE FOODS/Production and Uses of Marine Algae

developed to collect drift Chondrus crispus materials,

and the latter for harvesting Macrocystis pyrifera off

the coast of California. The latter device is mounted

on a specially crafted boat so that the machine

mechanically cuts, gathers, and loads the seaweed

materials into the vessel.

Farming Techniques

0010 The history of seaweed farming or mariculture is well

recorded among oriental farmers. The technology has

advanced considerably from the use of ‘Hibi’ (see

below) to the present culture nets made popular for

Porphyra, Monostroma, and Ulva. For Eucheuma

farming, the use of the monoline system, in which

ropes are tied to poles on both ends, has been adopted

in Asia.

0011 The use of Hibi was introduced by the Japanese

fishermen long before any other farming methods

were known. It utilized an artificial substrate com-

posed of cut bundles of bamboo or brushwood, af-

fixed in shallow areas where spores of wild Porphyra,

once released, became attached to the Hibi. After

sometime, the Hibi setups were gathered and trans-

ported to a 0.9–1.5 m deep growing area where the

spores germinated into sporelings and then into har-

vestable plants. An innovation of the Hibi method is

the use of rope or synthetic twine as an artificial

substrate. A rope or synthetic twine is knitted to

form a culture net with a 15 15 cm mesh size. In

autumn, nets measuring 20–40 m by 1–2 m are set

up in the natural habitats of Porphyra. The nets are

suspended afloat by ropes moored on the sea bottom,

or the ends of the nets are tied to wooden poles.

Porphyra spores, once released, settle on the nets

and are allowed to grow until harvest time.

0012 The Taiwanese experience of mariculture adopts

the polyculture system, whereby seaweed cuttings,

e.g., Eucheuma and Gracilaria, are stocked in

floating and moored cages together with other fish

and shellfish stocks.

0013 Other conventional, usually broadcast methods are

actually modified systems of vegetative propagation.

They can involve tying stocks of Eucheuma, Graci-

laria,orGelidiella to pieces of rock and then randomly

broadcasting them in the rocky or corally bottom of

the intertidal zone. Similarly, Caulerpa cuttings are

scattered inside abandoned fishponds and allowed to

grow under the prevailing natural conditions as seen

in Mactan Island, Central Phillippines.

Marketing and/or Preservation

0014 Seaweeds are marketed either in semiprocessed or

processed forms. Fresh materials, after being cleaned

of dirt, epiphytes, and invertebrates adhered to or

mixed with them, are sun- or kiln-dried, or pickled

for export or for household consumption. Those

intended for export may be dried, or they may be

processed in the form of algal extracts, such as carra-

geenan, agar, alginate, and algin. These and other

phycocolloidal extracts are used as components in

the manufacture of industrial products from dairy,

pharmaceutical, and surgical items to plastic wares

and paints, among others. The papery Porphyra and

Monostroma are dried on bamboo slats so that the

seaweeds can be molded into circular and rectangular

shapes as sold in Philippine markets. In Japan,

the same dried seaweeds are mechanically cut into

desired strips and marketed in polythene packs.

0015In the Americas and parts of Europe, live Palmaria

and Chondrus are impounded for days in specially

designed tanks allowing water movement, sufficient

nutrient exchange and entrance of sunlight. This

method of preservation and storage helps to prolong

the palatability of the sea vegetables. These are then

dried using a mechanically operated dehydrating

device and marketed. Indeed, the seaweed industry,

a potential dollar-earning enterprise, faces a bright

future. The world market needs a steady supply of

seaweeds for its wide spectrum of industrial products.

The Third World nations located within the Pacific

Basin are favored with a rich variety of tropical sea-

weed species, which, if judiciously tapped, could

plough back much-needed money to improve their

economy.

0016The recently relaxed seaweed importation scheme

by the USA, specially for Eucheuma, is a boost for the

Asian sea-farmers. The Philippines ranks seaweeds

such as Eucheuma among its top five fishery export

items. The high production of the carrageenan-

yielding Eucheuma in the Philippines is attributed to

the simplified and less capital-intensive mariculture

method introduced to the Filipino sea-farmers living

along the coastal areas of the Visayas and Mindanao

Islands. Moreover, this has given birth to the small-

scale family business in Eucheuma farming. Similarly,

Cordero (1982) has found the mariculture of Por-

phyra to be financially feasible for the Philippines,

and this author has projected a modest increase

in net income of 38% per hectare per year for the

first 5 years using P. marcosii stock.

Role of Some Species in the Diet of

Selected Societies

0017Edible seaweeds come from the green, brown, and

red groups of algae. These protein- and iodine-rich

marine plants, found in both cold and warm seas,

have been known for their contemporary food

MARINE FOODS/Production and Uses of Marine Algae 3727

preparations as salad, soup, pickles, jam, etc. The

Chinese and Japanese are among the prolific sea-

weed-eating people, and are accredited with recogniz-

ing its food value. The Hawaiians were known to

keep ‘Limu’ gardens containing choice edible sea-

weeds for the consumption of their noble families.

Green Sea Vegetables

0018 Species of Caulerpa and Codium, known in the Phil-

ippines as ‘lato’ (Visayan) and ‘pok-poklo’ (Ilokano),

respectively, are the most common edible green algae

among the South-east Asians. These, like the other

brown and red seaweeds, are simply prepared as a

salad with vinegar and a dash of salt. Some people

add slices of green unripe mango and crushed toma-

toes to enhance the salad preparation.

0019 The low incidence of goiter cases among the coastal

dwellers in Asia is attributed to the high iodine intake

derived from the edible seaweeds.

Brown Sea Vegetables

0020 Representing the more popular edible brown sea-

weeds are Hizikia, Hydroclathrus, Laminaria, and

Undaria. Aside from their food use, the Japanese

have made and marketed ‘Kombu-Cha’–a kind of

tea made out of processed Laminaria. The tender

tops of Sargassum and Hormophysa are cooked with

vegetables; Cladosiphon and Laminaria are relished

as soup preparations.

Red Sea Vegetables

0021 The red sea vegetables include the greatest number of

known edible species. The orientals prefer Porphyra,

Gracilaria, and Eucheuma; the occidentals have

Palmaria or ‘Dulse,’ Chondrus or ‘Irish Moss,’ and

Porphyra or ‘Laver,’ to cite the more popular ones.

Their food preparations vary among European and

American consumers, although salads, soups, pickles,

jellies, etc. are among the favored ones.

0022 It is no wonder that sea vegetable is now known as

the poor man’s source of cheap protein and iodine,

and has an export potential for tropical countries.

See also: Iodine: Physiology; Single-cell Protein: Algae

Further Reading

Cordero JM (1982) A Feasibility Study on Sea-farming of

the Seaweed Porphyra. MBA thesis, Philippine Christian

University, Graduate School of Business Administration.

Cordero Jr. PA (1980) Morphological Study, Recipe Prepar-

ation and Sensory Evaluation of the Sea Vegetables from

the Philippines. Terminal Report of the National Re-

search Council of the Philippines, Project I-E 98.

Madlener JC (1977) The Sea Vegetable Book. New York:

Clark N. Potter Inc. Publishers.

Marine Colloids of FMC Corporation (1977) Carrageenan.

Marine Colloids of FMC Corporation. Monograph

No. 1. Rockland, ME: FMC Corporation.

Robertson DL, Smith GJ and Alberte RS (2001) Glutamine

synthetase in marine algae: New surprises from an old

enzyme. Journal of Phycology 37(5): 793–795.

Viejo RM and Aberg P (2001) Effects of density on the vital

rates of a modular seaweed. Marine Ecology-Progress

Series 221: 105–115.

Edible Animals Found in the Sea

R D M Nash and J P Thorpe, University of Liverpool,

Isle of Man, UK

Current consumption

0001In western society the main marine invertebrates con-

sumed are those groups conventionally termed shell-

fish; that is, various crustaceans (mainly decapods)

and bivalve and gastropod molluscs. However other

marine invertebrates are widely, if not extensively,

consumed in Europe and North America, whilst else-

where in the world patterns of consumption vary

considerably. In various areas, particularly in the

tropics, artisanal fisheries for unusual invertebrates

can be locally important and in the Far East there is a

great demand for food species not commonly eaten in

the west. One group in particular, the cephalopod

molluscs (octopus, squid, and cuttlefish), are cur-

rently important in terms of world catches and also

offer potentially highly important fisheries if the

technology to exploit them can be developed.

Cephalopods

0002Of the two extant subclasses of cephalopods (phylum

Mollusca, class Cephalopoda), only the Coleoidea are

important as food for humans. The other subclass,

the Nautiloidea, contains a small number of species,

all in the single genus Nautilus and all confined to the

tropical Indo-Pacific. These support local artisanal

food fisheries only, although the very attractive shells

are more widely traded. The Coleoidea include

the three orders Sepioidea (cuttlefish), Teuthoidea

(squids), and Octopoda (octopuses), all of which

include species eaten by humans.

Sepioidea (Cuttlefish)

0003Cuttlefish are almost absent from the Americas,

although a few species of Semirossia occur along

3728 MARINE FOODS/Edible Animals Found in the Sea

the west Atlantic coast and are fished off Argentina

and in the Gulf of Mexico. Elsewhere both large

(mainly Sepia) and small (Sepiolidae) cuttlefish are

fished in the coastal waters of most temperate and

tropical latitudes. Total world annual catch is around

200 000 tonnes, with the most important areas being

the eastern central Atlantic (Spain, Morocco), north-

west Pacific (Korea, Taiwan, Japan), and western

central Pacific (Thailand, Vietnam, Malaysia).

Cuttlefish are caught in most areas as a bycatch of

other fisheries, but in some areas they are specifically

fished with trawls or other nets, dredges, pots, or jigs

(lures). The major species fished are Sepia officionalis

(which occurs down the eastern Atlantic from north-

ern Europe to South Africa and throughout the Medi-

terranean and Baltic seas), S. pharoensis (found from

the Red Sea to Japan and south to Australia), Sepiella

inermis (which occurs from the Persian Gulf to

eastern Asia, fished mainly in India and Sri Lanka)

and S. japonica (Japan and China), but numerous

other species are caught in smaller quantities. The

tiny Sepiola rondeleti, which occurs from northern

Europe to west Africa, is extensively eaten in many

Mediterranean countries.

0004 In the larger species the muscular mantle and

tentacles are mainly eaten, but in many areas sepio-

lids are consumed whole. Major markets, even for

Atlantic- and Mediterranean-caught cuttlefish, are

in Japan and Korea and large quantities are exported

frozen. In Japan larger cuttlefish are commonly eaten

raw, cut into thin strips (sashimi) and smaller animals

are packed and frozen ready for cooking. Some

species are mainly eaten dried (surume).

Teuthoidea (Squids)

0005 There are two suborders of squids, the Myopsida

which are inshore, mainly demersal, squids, generally

confined to shallower waters near shores or on con-

tinental shelves, and the Oegopsida, which are mainly

pelagic offshore squids of deep oceanic waters, al-

though these may come on to the continental shelves

to spawn.

0006 All the myopsid squids currently eaten are confined

to the family Loliginidae and most are from the very

large genus Loligo, species of which are found on

continental shelves worldwide. Inaccurate and inad-

equate statistical data make it difficult to assess

annual world catches, but the total for all loliginid

species may be around 200 000 tonnes. Major fishery

species are Loligo bleekeri (fished in the Sea of

Japan), L. chinensis (which occurs from China south

to eastern Australia), L. duvauceli (fished extensively

in coastal waters throughout most of Asia and north-

east Africa), L. edulis (China to northern Australia),

L. forbesi (coastal waters from Sweden to Senegal,

Mediterranean, Red Sea, south-east Africa), L. gahi

(southern South America, Falkland Islands), L. ja-

ponica (Japan, China), L. opalescens (Pacific coast

of North America), L. pealii (Newfoundland to

northern Brazil), L. reynaudi (South Africa), L. vul-

garis (northern Europe to South Africa, Mediterra-

nean), Sepioteuthis lessoniana (Red Sea to Japan and

Australia), Alloteuthis media (occurs from the UK to

North Africa and Mediterranean, trawled in western

Mediterranean). Capture methods for loliginid squids

are mainly with nets (purse seines, otter trawls, pair

trawls) and at night with lights. Some occur as

bycatches in finfish fisheries.

0007Oceanic (oegopsid) squids form well over half of

the total world cephalopod catch, with an annual

total of perhaps 1 500 000 tonnes. A few species are

demersal at least at some stage of the life cycle, but

most are found in the water column, although this

may be at great depths. For obvious reasons the

species presently exploited commercially are gener-

ally only those occurring comparatively close to

the surface. Currently only about nine (Enoploteuthi-

dae, Octopoteuthidae, Onychoteuthidae, Gonatidae,

Psychroteuthidae, Lepidoteuthidae, Histioteuthidae,

Ommastrephidae, Thysanoteuthidae) of 32 recog-

nized families have any species fished by humans,

although many others have potential as food.

Exploited species of major commercial significance

are confined to only four families:

0008Enoploteuthidae, Watasenia scintillans (China,

Japan).

0009Onychoteuthidae, Onychoteuthis borealijaponica

(occurs in the northern Pacific from Japan and

USA to about 55



N, fished off Japan and north-

west USA).

0010Gonatidae, Berryteuthis magister (found in the

northern Pacific, from Japan to Canada, fished

off Japan and north-eastern Russia).

0011Ommastrephidae Illex argentinus (south-eastern

South America, Falkland Islands), I. coindetii

(eastern Atlantic, Sweden to South Africa, and

Mediterranean: fished in the western Mediterra-

nean and Atlantic, off Spain and North Africa),

I. illecebrosus (north Atlantic from USA to north-

ern Europe, north to Arctic: fished north-west

Atlantic), Todaropsis eblanae (continental shelves

Europe, Africa, Asia to Australia: fished Mediter-

ranean and north-west Africa), Todarodes pacifi-

cus (northern Pacific, China to Alaska, fished by

Japanese), T. sagittatus (eastern half of Atlantic

north of 20



S to Greenland, Mediterranean,

Arctic Ocean from Greenland east to northern

central Russia: fished Norway, Italy), Nototo-

darus gouldi (Australia), N. sloani (New Zealand),

MARINE FOODS/Edible Animals Found in the Sea 3729

Ommastrephes bartrami (circumglobal, subtrop-

ical to temperate, northern and southern hemi-

spheres, fished northern and southern Pacific),

Dosidicus gigas (eastern Pacific, Chile to Mexico).

0012 The exploitation of oegopsid squid is largely to

satisfy the demands of the Japanese and, to a lesser

extent, the Taiwanese market. Thus several of the

major fishery species are those occurring in the north-

ern Pacific, whilst others (for example Nototodarus

gouldi off Australia, N. sloani off New Zealand and

I. argentinus off the Falkland Islands) are exploited

largely or almost entirely by Japanese, Korean,

and Taiwanese vessels. Capture of oceanic squids is

mainly by special ships equipped for jigging; squid are

attracted towards the surface at night by the use of

bright lights and are caught on barbless hooks at-

tached to lures. The whole process of capture,

unhooking, and processing and freezing of the catch

is automated. In a few fisheries some of the catch is

taken by drift nets in a manner similar to the gill

netting of fish.

0013 In Japan the way in which squids are sold varies

between species, but the main methods are fresh and

raw as sashimi, cooked and processed as saliika, dried

as surume, canned, and frozen.

Octopoda (Octopuses)

0014 Only octopods of the suborder Incirrata are fished

commercially. Of these, only one (Octopodidae) of

the eight families is at all important, although small

numbers of the circumglobally distributed Argonauta

argo (Argonautidae) are occasionally marketed from

bycatches. Total world annual landings of octopods

probably vary around 200 000 tonnes. All the main

species caught are in the widely distributed genus

Octopus: O. briareus (Caribbean and northern South

America), O. conispadiceus (Japan), O. cyaneus

(widespread from East Africa to India and Australia,

throughout the Indian Ocean and western and central

Pacific), O. dofleini (coastal from China to south-

western USA), O. globosus (India), O. maya (Gulf

of Mexico), O. membranaceus (coastal waters from

India to Japan and Australia, important fishery

species in Japan and China), O. variabilis (Japan,

China), O. vulgaris (coastal distribution from north-

ern Europe around Africa, including Mediterranean

and Red Sea, and Asia east to Japan, also western

Atlantic from USA to Brazil: fished over most of this

huge range; of major importance in Japan, north-west

Africa).

0015 As with other cephalopods, much of the world

market for octopus species is in Japan, where they

are highly esteemed and are marketed fresh, frozen,

dried, and/or salted.

Barnacles (Crustacea, Cirripedia)

0016There are a variety of barnacles exploited and eaten

throughout the world. The large stalked barnacle

Polliceps polliceps is eaten particularly by the Basque

people, but is also consumed throughout Iberia and

the Atlantic Island groups (Canaries, Madeira, and

Azores). The acorn barnacles (Megabalanus spp.) are

consumed in Chile (M. psittacus) and in the Azores

(M. tintabulum). The goose barnacle Mytella mytella

is eaten in Japan.

Jellyfish (Scyphozoa)

0017At least three species of jellyfish, of which Rhopilema

esculenta is the most important, are consumed in

Japan. These are usually served raw in a vinaigrette

or similar dressing.

Sea Anemones (Anthozoa)

0018A variety of species are eaten in various countries,

including Japan, Samoa, and France. The intertidal

Actinia equina is eaten in Italy. All are usually eaten

fried.

Tunicates (Urochordata, Ascidiacea)

0019The Japanese eat at least two species of sea squirts

(Halocynthis roretzi and H. aurantium) and the

French primarily utilize just one species (Microcos-

mus claudicans). All three species are from the same

family (Cynthiidae).

Sea Urchins and Sea Cucumbers

(Echinodermata)

0020Sea urchins are increasingly becoming subject to com-

mercial fisheries, primarily to satisfy the Japanese

market. Two species (Paracentrotus lividus and

Echinus esculentus) are traditionally eaten in some

Mediterranean countries and on the west coast of

Ireland. Similar species are eaten in the Far East, par-

ticularly Japan. Sea urchins are also eaten by Maoris in

New Zealand, who eat the complete contents out of the

shell. Some North Atlantic species are exported to

Japan and Japanese boats fish sea urchins commercially

in Australian waters. In general only the roe (gonad) is

eaten and this is consumed raw. In Japan the roe is only

considered top-grade if it is a pale yellow color and the

skeins are unbroken. Darker brown or damaged roes

do not command such a high price. For prime roes

prices are very high, around £30 per kg.

0021The market for sea cucumbers is also mainly in

Japan. The very large black species Stichopus japoni-

cus is taken locally, whilst several other species are

3730 MARINE FOODS/Edible Animals Found in the Sea

exported to Japan from various Pacific Islands (where

they are locally known as be

che de mer).

Bristle Worms (Polychaeta)

0022 The main type of polychete consumed is what are

known as palolo worms, several species of which

occur in various parts of the world. A common fea-

ture of these worms is that they swarm to the surface

in very large numbers at predictable times of the year.

The large swarms are primarily for reproduction, and

are of a stage in the life cycle known as a sexual

epitoke. A number of species are eaten: the Pacific

palolo (Eunice viridis) from the areas surrounding Fiji

and Samoa, wawo (Lysidice oele) from the Ambonia

area, and the Atlantic palolo (Eunice schemacephala)

in the Dry Tortugas. The Japanese palolo (Tylor-

rhynchus heterochaetus) is known by a number of

different names in Japan.

Other Exploited Marine Invertebrates

0023 Many more species and other marine invertebrate

groups are, or are likely to be, eaten or otherwise

exploited on a limited scale somewhere in the world,

but to find and list them all is beyond the scope of this

article. Those outlined above give some indication of the

diversity of marine invertebrates consumed by humans.

0024 However, one further area which should be men-

tioned is the recent and expanding exploitation of

species of certain phyla (e.g., sponges, bryozoans,

coelenterates, ascidians, nemerteans) which contain

allelopathic (usually antipredator or anticompetitor)

or otherwise ‘useful’ biologically active chemicals of

value to the pharmaceutical industry. Many of these

biologically active natural products have been studied

and a number are likely to become medically and

commercially important. One such product is what

has been termed bryostatin, a biologically active com-

pound, which has been found to have a potent action

against various types of cancer cells. Bryostatin is

obtained from the North American bryozoan Bugula

neritina, but huge quantities of the bryozoan are

needed; for example, one group studying this com-

pound based its synthesis on a sample of 10 000

gallons (about 45 000 kg) of the bryozoan. With col-

lection on such a large scale, any small invertebrate in

pharmaceutical demand may become overexploited

unless aquaculture can take over.

Possibilities for Future Exploitation of

Marine Invertebrates as Food

0025 Many of the world’s conventional shellfish fisheries,

like those for finfish, are being overfished and are in

decline. It is unlikely therefore that there is much

potential for future expansion of fisheries for decapod

crustaceans or shelled molluscs, but as fish stocks,

which provide the great bulk of wild caught marine

animals, appear certain to continue to decline, other

resources are needed.

0026Future demand for other invertebrate food species

will presumably depend partly on the success of aqua-

culture in providing fish and shellfish and whether

untapped sources (e.g., deep-sea species) can be ex-

ploited. Marine invertebrates of many groups are

eaten little or not at all in most parts of the world.

Thus there is apparent scope for the development or

expansion of fisheries. However, most of the species

within these groups are either inedible or present in

only relatively small biomasses and therefore have

little potential. Abundant marine invertebrates for

future exploitation could be Antarctic krill (mainly

Euphausia superba) and oceanic squid, particularly

some of the deeper-living species.

0027Krill stocks are thought to be unnaturally high,

because the near elimination of their major predators,

the large whales, and the huge biomasses present in

the Antarctic Ocean offer a potentially very great

fishery resource, although of low value and palatabil-

ity. They have been used for human consumption in

Russia, but their commercial exploitation to date has

been mainly as fish meal. Large-scale exploitation of

krill could lead to ecological problems because they

are generally considered the ‘cornerstone’ species for

the whole vast Antarctic marine ecosystem and hence

major exploitation could be serious, and overfishing a

disaster.

0028Currently cephalopods and in particular squids

make a useful contribution (about 2–3%) to fisheries

on a global scale and in some areas (e.g., Japan) they

are of great importance. Squids collectively rate as the

sixth most commercially important fish species in

world fishery statistics. Their significance as food is,

for various reasons, greater than catch figures would

suggest. They have little skeletal tissue and are highly

muscular and hence, compared to most fish species, a

relatively greater proportion of the catch is edible.

Several of the fish species making the greatest contri-

bution to world catches are used for fish meal (for

fertilizer or animal feeds) and thus are not directly

eaten by humans. Consequently the amount of fish

eaten is considerably less than that caught. However,

from the human viewpoint, the most important fea-

ture of cephalopods is probably their potential to

increase world food supply.

0029Currently total world landings of fish are approxi-

mately static, at about 80 million metric tonnes

(Mmt), despite continual increases in fishing effi-

ciency and effort. This is occurring because many

MARINE FOODS/Edible Animals Found in the Sea 3731

fish stocks are being overfished and are declining, and

overall the prospects for improvement do not look

good. Since about 1970 world catches of cephalopods

(mainly squids) have increased annually by an aver-

age of about 6% and even among coastal octopus

species (probably the group with the least capacity

for expansion) there is considered to be the potential

to increase world catches greatly. Among oceanic

squids the potential is enormous. Estimates of stock

sizes are necessarily very approximate because there

has been little or no relevant scientific study of the

stocks of most squid species. Indeed, it is likely that

there are still many species which are as yet unknown.

0030 Evidence pointing to massive untapped squid

populations comes from several sources. For a few

species there are adequate scientific data for stocks to

be estimated. For example, the large (up to 150 kg)

cranchid squid Mesonychoteuthis hamiltoni is abun-

dant in Antarctic waters and the flesh is considered to

be of excellent quality and flavor. This species is not

caught commercially at all, but the stock is estimated

at about 90 Mmt (i.e., larger than the total annual

catch of fish by humans). A second example is the very

large species Architeuthis (Architeuthidae) which is

thought to be distributed throughout all the oceans

apart from continental shelves and close to the poles.

Very few have been caught by humans, but its fre-

quent consumption by whales (identified mainly from

the beaks, which remain undigested in whale stom-

achs) and occasional stranding in shallow water sug-

gest it is not rare. As individuals weigh up to about

1000 kg, the total biomass is likely to be huge. Cur-

rent direct estimates by fishery biologists of total

world squid stocks vary considerably, up to about

500 Mmt, but indirect estimates from other sources

indicate that even this figure may be conservative.

0031 Studies of the squid consumed by various predators

suggest very large populations. In the Antarctic,

penguins and elephant seals, for example, are thought

to take annually about 13 and 4.5 Mmt respectively

(neither of these, incidentally, eats any of the

estimated 90 Mmt of Mesonychoteuthis hamiltoni).

Sperm whales eat mainly squid found on or near

the bottom in depths restricted by their diving

capabilities. Sperm whale populations have been ser-

iously depleted by overexploitation, but even so they

probably eat annually a weight of squid equivalent to

about twice the entire world catch of fish by humans.

0032 From recent research it is also becoming clear that

there are great biomasses of largely unknown squid at

mesopelagic and bathypelagic depths throughout much

of the world’s oceans. Over 70% of the world surface

consists of sea deeper then 2000 m and by volume more

than 98% of the sea is off the continental shelves, with

an average depth of several thousand meters. Over

many years the work of research ships towing mid-

water trawls at these depths had indicated that

throughout most of this vast volume of water, animal

life was rather scarce. However, recent studies using

television cameras attached to the net frames reveal

considerable numbers of often quite large (up to tens

of kilos) squids present at a wide range of depths and

over huge areas. These are not generally caught simply

because, as large and highly mobile visual predators,

they easily avoid nets. Since they are distributed

through such huge volumes of the deep ocean the bio-

mass of these squid is likely to be immense.

0033Thus various sources of evidence indicate that

oceanic squids may be present in biomasses which

dwarf known stocks of exploited fish species. Since

most squid are thought to be annual and semelparous

(they grow for a year, spawn, and die) they ‘turn over’

faster than most fish species and thus, if well man-

aged, should be able to sustain higher relative rates of

exploitation. If fished in the later stages of the annual

life cycle and as long as enough adults survive to

spawn, the entire stock can be exploited because

there are no juveniles which need to be preserved for

future breeding. However, for many of the oceanic

squids, the depths at which they live present major

barriers to the development of commercial exploit-

ation. Our knowledge of their biology and behavior is

at best minimal and technological advances will be

necessary before most can be utilized.

Marine Reptiles as Food

0034Marine reptiles (turtles, saltwater crocodiles, iguanas,

and sea snakes) occur in many areas of the tropics and

subtropics and various species are exploited on a

small scale by local human populations. Turtles

were formerly exported on some scale for consump-

tion, particularly in Europe, but many of the wild

populations are now endangered and their import is

banned in most countries. Most species are, however,

good to eat and are still netted or harpooned on a

small scale by native fishermen. Turtle eggs are also

considered a delicacy in many parts of the world.

Saltwater crocodiles can grow to a length of about

10 m and are the world’s largest living reptiles. These

are occasionally killed in the Far East, although their

food value is considerably less than that of the hide.

0035There are six widespread species of marine turtle:,

loggerhead (Caretta caretta), leatherback (Dermo-

chelys coriacea), hawksbill (Eretmochelys imbricata),

Kemp’s Ridley (Lepidochelys kempii), olive Ridley

(Lepidochelys olivacea), and the green turtle (Chelo-

nia mydas). The only one currently commercially ex-

ploited on a large scale for food is the green turtle. This

is a medium-sized species growing up to about 1 m and

3732 MARINE FOODS/Edible Animals Found in the Sea

occurs naturally in the tropical Atlantic, Caribbean,

and elsewhere. The species has been severely over-

exploited and is now scarce and heavily protected in

the wild, but is the subject of a large aquaculture

enterprise in the Caribbean. Captive broodstock

adults, kept in large saltwater ponds, lay their eggs

‘naturally’ on an artificial sandy beach and the eggs

are then dug up and incubated artificially. This

method is highly successful, with nearly 90% survival

of the newly hatched young (compared with about

0.2% in the wild). The young turtles are then reared

in large tanks of sea water for 3 years before harvest-

ing. The meat is highly prized and has almost no fat

content, but more protein than prime beef or chicken.

See also: Shellfish: Characteristics of Crustacea;

Characteristics of Molluscs