Энциклопедия акул

Научная заметка

The grey reef shark or gray reef shark is a species of requiem shark, in the family Carcharhinidae. One of the most common reef sharks in the Indo-Pacific, it is found as far east as Easter Island and as far west as South Africa. This species is most often seen in shallow water near the drop-offs of coral reefs. It has the typical "reef shark" shape, with a broad, round snout and large eyes. It can be distinguished from similar species by the plain or white-tipped first dorsal fin, the dark tips on the other fins, the broad, black rear margin on the tail fin, and the lack of a ridge between th

Экологическая роль

An apex reef predator — it balances fish species and prevents overgrazing

Заметки

• ✦يُصدر حركة تهديد فريدة بانحناء الجcm وإنزال الزعانف الصدرية
• ✦يُهاجر بين الشعاب ويحدد منطقة سكنية بدقة
• ✦يولد أحياناً داخل "الحضانات" — مناطق ضحلة محمية

Научная заметка

The whitetip reef shark is a species of requiem shark, in the family Carcharhinidae. It is the only extant species of genus Triaenodon. A small shark that does not usually exceed 1.6 m (5.2 ft) in length, this species is easily recognizable by its slender body and short but broad head, as well as tubular skin flaps beside the nostrils, oval eyes with vertical pupils, and white-tipped dorsal and caudal fins. One of the most common sharks found on Indo-Pacific coral reefs, the whitetip reef shark occurs as far west as South Africa and as far east as Central America. It is typically found on or n

Экологическая роль

At night it removes sick and weak fishes, keeping the fish community healthy

Заметки

• ✦يستطيع ضخ الماء عبر خياشيمه وهو ساكن تماماً على الشعاب
• ✦يتذكر منطقته المفضلة ويعود إليها يومياً
• ✦يُشكّل "نوادي نوم" مع أفراد آخرين في نفس الكهف

Научная заметка

The blacktip reef shark is a species of requiem shark, in the family Carcharhinidae, which can be easily identified by the prominent black tips on its fins. Among the most abundant sharks inhabiting the tropical coral reefs of the Indian and Pacific Oceans, this species prefers shallow, inshore waters. Its exposed first dorsal fin is a common sight in the region. The blacktip reef shark is usually found over reef ledges and sandy flats, though it has also been known to enter brackish and freshwater environments. It typically attains a length of 1.6 m (5.2 ft). Like other sharks, the females are larger than the males.

Экологическая роль

A key shallow-water predator that regulates small cichlid numbers

Заметки

• ✦يُرى أحياناً في مياه تعمق 30 cm فقط
• ✦الأنثى تلد 2-4 صغار بعد حمل 10 أشهر
• ✦صغاره تستخدم المانغروف كحضانة للحماية من المفترسين

Научная заметка

The oceanic whitetip shark is a large requiem shark inhabiting the pelagic zone of tropical and warm temperate seas. It has a stocky body and iconic elongated rounded fins, with white tips. The species is typically solitary, though they may gather in large numbers at food concentrations. Bony fish and cephalopods are the main components of its diet and females give live birth.

Экологическая роль

An oceanic predator that balances open water and helps nutrient cycling

Заметки

• ✦انخفضت أعداده 98% منذ الستينيات بسبب صيد الزعانف
• ✦وثّق جاك كوستو الشهير هجوماته في the Red Sea
• ✦يُعدّ من القروش القليلة التي تهاجم الغواصين بشكل استباقي

Научная заметка

The sicklefin lemon shark or sharptooth lemon shark is a species of requiem shark belonging to the family Carcharhinidae, widely distributed in the tropical waters of the Indo-Pacific. It is closely related to the better-known lemon shark (N. brevirostris) of the Americas; the two species are almost identical in appearance, both being stout-bodied sharks with broad heads, two dorsal fins of nearly equal size, and a plain yellow-tinged coloration. As its common name suggests, the sicklefin lemon shark differs from its American counterpart in having more falcate (sickle-shaped) fins. This large species grows up to 3.8 m (12 ft) long. It generally inhabits water less than 92 m (302 ft) deep in

Экологическая роль

A coastal predator that regulates fishes in mangroves and shallows

Заметки

• ✦يمكن التعرف عليه بشكل فردي من خلال زعانفه
• ✦يُعدّ من أكثر القروش قابلية للدراسة في الأسر
• ✦الأنثى ترجع إلى نفس منطقة التكاثر كل موcm

Научная заметка

The scalloped hammerhead is a species of hammerhead shark in the family Sphyrnidae. It was originally known as Zygaena lewini. The Greek word sphyrna translates into "hammer" in English, referring to the shape of this shark's head, which is its most distinguishing characteristic. The shark's eyes and nostrils are at the tips of the extensions. It is a fairly large hammerhead, but is still smaller than both the great and smooth hammerheads.

Экологическая роль

It regulates rays and flatfishes, keeping the seafloor in balance

Заметки

• ✦شكل رأسه يعطيه مجال رؤية 360 درجة كاملاً
• ✦يجتمع بالمئات عند الجبال البحرية بشكل فريد
• ✦تعاني الإناث من ندوب عض شديدة أثناء التزاوج

Научная заметка

The great hammerhead is the largest species of hammerhead shark, belonging to the family Sphyrnidae, attaining an average length of 4.6 m (15 ft) and reaching a maximum length of 6.2 m (20 ft). It is found in tropical and warm temperate waters worldwide, inhabiting coastal areas and the continental shelf. The great hammerhead can be distinguished from other hammerheads by the shape of its "hammer", which is wide with an almost straight front margin, its tall, sickle-shaped first dorsal fin, and its strongly falcated pelvic fins. A solitary, strong-swimming apex predator, the great hammerhead feeds on a wide variety of prey ranging from crustaceans and cephalopods, to bony fish, to smaller sh

Экологическая роль

It regulates bottom rays, preventing excessive decline of reef communities

Заметки

• ✦يستخدم مطرقته لتثبيت الراي على القاع قبل أكله
• ✦الزعنفة الظهرية الأولى أعلى نسبياً من أي قرش آخر
• ✦وُثّق قطع مسافة 1,200 كم في هجرة واحدة

Научная заметка

The silvertip shark is a large species of requiem shark, in the family Carcharhinidae, with a fragmented distribution throughout the tropical Indian and Pacific Oceans. It is often encountered around offshore islands and coral reefs, and has been known to dive to a depth of 800 m (2,600 ft). The silvertip shark resembles a larger and bulkier grey reef shark, but can be easily identified by the prominent white margins on its fins. It attains a maximum length of 3 m (10 ft).

Экологическая роль

A predator on outer reef edges that eases fishing pressure on inner reefs

Заметки

• ✦نهاياته الفضية تُعطيه مظهراً فريداً يسهل التعرف عليه
• ✦يُهيمن على موقع الصيد حين يجتمع مع قروش أصغر
• ✦يُعدّ من القروش الأكثر تحدياً في سلوكه مع الغواصين

Научная заметка

The nurse shark is an elasmobranch fish in the family Ginglymostomatidae. The conservation status of the nurse shark is globally assessed as Vulnerable in the IUCN List of Threatened Species. They are considered to be a species of least concern in the United States and in The Bahamas, but considered to be near threatened in the western Atlantic Ocean because of their vulnerable status in South America and reported threats throughout many areas of Central America and the Caribbean. They are directly targeted in some fisheries and considered by-catch in others.

Экологическая роль

It clears the reef floor of crustaceans and clams, improving sediment quality

Заметки

• ✦يستطيع السكن تماماً على القاع دون ضخ ماء للسباحة
• ✦شوارب فمه تشبه شوارب القط في الحساسية
• ✦قد يُعمّر up to 25 years في الطبيعة

Научная заметка

The zebra shark is a species of carpet shark and the sole member of the family Stegostomatidae. It is found throughout the tropical Indo-Pacific, frequenting coral reefs and sandy flats to a depth of 62 m (200 ft). Zebra sharks are distinctive in appearance, with adults possessing five longitudinal ridges on a cylindrical body, a low caudal fin comprising nearly half the total length, and typically a pattern of dark spots on a pale background. Young zebra sharks under 50–90 cm (20–35 in) long have a completely different pattern, consisting of light vertical stripes on a brown background, and lack the ridges. This species attains a length of 2.5 m (8.2 ft).

Экологическая роль

It extracts clams and crustaceans from crevices other sharks cannot reach

Заметки

• ✦الصغار مخططون كالزيبرا وتتحوّل للبقع النمرية عند البلوغ
• ✦وُثّق تكاثره بكراً (دون ذكر) في عام 2016 في أستراليا
• ✦يستطيع ضخ الماء وهو ساكن تماماً على القاع

Научная заметка

The whale shark is a slow-moving, filter-feeding carpet shark and the largest known extant fish species. An individual with a length of 18.8 m (61.7 ft) has been considered the largest reliably recorded. The whale shark holds many records for size in the animal kingdom, most notably being by far the most massive living non-cetacean animal. It is the only living species of the genus Rhincodon and the only extant member of the family Rhincodontidae, which belongs to the subclass Elasmobranchii in the class Chondrichthyes. Before 1984, it was classified as Rhiniodon into Rhinodontidae. An extinct

Экологическая роль

It recycles nutrients in the water column and boosts algae and plankton at the surface

Заметки

• ✦نقاطه البيضاء فريدة لكل فرد كبصمة الأصابع تماماً
• ✦يمكنه تصفية 6,000 لتر ماء في ساعة واحدة
• ✦يُقدّر عمره up to 130 years وهو الأطول بين الأcmاك

Научная заметка

The tawny nurse shark is a species of carpet shark in the family Ginglymostomatidae, and the only extant member of the genus Nebrius.

Экологическая роль

It clears crustaceans and clams from the reef floor and contributes to nutrient cycling

Заметки

• ✦يصطاد بشفط الفريسة بقوة مضغوطة هوائية فريدة
• ✦يُشكّل أحياناً مجموعات نوم كبيرة في الكهوف
• ✦يميل للعيش في نفس منطقة من الشعاب لسنوات

Научная заметка

The bigeye thresher is a species of thresher shark, family Alopiidae, found in temperate and tropical oceans worldwide. Like the other thresher sharks, nearly half its total length consists of the elongated upper lobe of the tail fin. Its common name comes from its enormous eyes, which are placed in keyhole-shaped sockets that allow them to be rotated upward. This species can also be distinguished by a pair of deep grooves on the top of its head, from which its scientific name is derived.

Экологическая роль

It regulates schooling fishes in open water and eases pressure on marine algae

Заметки

• ✦ذيله يساوي طول جcmه وهو سلاحه للصيد
• ✦يضرب ذيله كالسوط لصعق الأcmاك قبل أكلها
• ✦عيونه الكبيرة تتكيف للرؤية في أعماق 500 m معتمة