Category Sea/Ocean

What makes the sailfish special?

Sailfish, marlins and swordfish are part of the billfish family – all apex saltwater predators. Like marlins, the sailfish is one of the fastest fish in the ocean, reaching speeds of about 112 km/h!

It gets its name from its huge sail-like dorsal fin that allows it great manoeuvrability and speed in the water. It is able to retract this sail when required (much like the sail on a real ship!) and uses this fin as a shield to trap small prey and prevent them from escaping. Additionally, like the marlin, it uses its elongated bill to pierce and slash its prey! Its bill also allows it to cleave through the water and contributes to its streamlined shape.

It feeds on sardines, anchovies, squid and octopus. Females are much larger than the males. They can reach a length of about 3 metres and weigh up to 100 kg. They breed in large numbers and are not under much threat in the ocean from predators or humans. They are listed under ‘Least Concern’ in the IUCN List.

Sailfish are capable of changing their colour in order to communicate or while hunting prey. Often they will sneak up on unsuspecting fish before the prey sees it.

They are valued as game fish and are often caught for sport, not meat. They are often very difficult to reel in as they put up a fierce fight that may last for hours! One could say that these are one of the most redoubtable opponents that humans face in the ocean.

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Is the black marlin faster than the cheetah?

Did you know that the activity of fishing is not just a livelihood but also a sport? Recreational anglers catch fish not just to consume, but for the thrill of the chase and the challenge of fighting against heavy weight fish that test their abilities to the fullest.

High on every angler’s dream ‘game fish’ list is the black marlin. These fish grow up to 5 m in length and can weigh up to 750 kg! In fishermen’s language a marlin that weighs more than 450 kg is called a ‘grander’. Also, any marlin heavier than 200 kg is usually a female.

But don’t let all that bulk fool you. A black marlin is possibly the fastest creature on earth (except for the peregrine falcon). It reaches an astonishing speed of more than 125 km/h! That’s faster than a cheetah! It is able to reach such speeds due to its spindle-shaped body, which is wider in the middle and tapered at the ends. It has a highly rigid crescent-shaped tail which acts like a motor powering it through the water. It also has a spear-like snout or bill that helps it cleave through the water.

One of the top predators of the seas, this fish feeds on tuna, cuttlefish, squid, mackerel and octopus. The black marlin is an elusive fish and is found only in the warm waters of the Indian and Pacific oceans. These speedsters are hard to hook and even harder to reel in. Usually epic battles are fought by the marlin and the angler till one wins; and it’s not always the angler! The black marlin is yet to be evaluated by the IUCN as there is little data regarding them.

Picture Credit : Google

HOW DOES SEAWEED GROW IN INDIA?

Seaweed is being hailed as a miracle crop that absorbs more carbon dioxide than trees. For women in coastal villages in Tamil Nadu, cultivating seaweed has empowered them with a source of income.

India is the world’s third-largest carbon polluter, behind China and the U.S. Authorities are looking to seaweed farming to help reduce the impact of greenhouse gas emissions, reverse ocean acidification, improve the marine environment, and provide a sustainable livelihood for coastal communities.

Marine scientist M. Ganesan says that seaweed provides a possible way forward as coastal habitats and wetlands absorb five times more carbon than terrestrial forests. “It is a miracle crop in many ways, it is eco-friendly, it doesn’t use land or fresh water. It absorbs carbon dioxide dissolved in water during photosynthesis and oxygenates the entire marine ecosystem.” Seaweed absorbs an estimated 173 million metric tons of carbon annually.

When seaweed dies and drops to the seafloor, its carbon is locked up in the sediment. As a result, seaweed cultivation has been identified as a carbon sink that could help alleviate climate change.

Lakshmi Murgesan is part of a team of women who cultivate seaweed on bamboo rafts; one raft yields upto 200 kilos in 45 days, of which 50 kg is used to cultivate the next raft. She makes Rs 20,000 each month farming seaweed, and says, “I would not have been able to educate my children but after doing this, I could send to college.” my children

The product is sold in markets nationwide as well as the U.S. and Australia through AquAgri, a private company. India, which has an 8,000 km coastline, aims to boost production from the current 30,000 tons to more than 1 million tons each year by 2025.

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What is an albatross?

Have you heard the term ‘albatross’? It means an unwanted burden in English. Did you know the term is coined after a giant seabird of the same name?

An albatross is the largest seabird in the world. It has an incredible wingspan that can reach up to 3.35 metres – the longest of any bird. This graceful sentinel of the sky spends most of its life soaring high above the oceans in the southern hemisphere. An albatross lives most of its life out in the open Oceans and may touch land after 5 or 6 years only for the purpose of breeding!

While at sea, they eat krill, fish and rubbish from shipping vessels and sometimes follow ships for many days eating from its discarded waste.

It is this habit that caused it to be immortalized in ST Coleridge’s ‘The Rime of the Ancient Mariner’. Here a sailor shoots an albatross that follows his ship and dooms the crew with bad luck. He is forced to wear the dead albatross around his neck as punishment by the rest of the crew. Hence, an albatross around the neck signifies great problem.

The albatross is probably the most loyal bird in the world. It mates for life and its ‘divorce rate’ is zero! If its mate dies it will not search for another partner. It also has an extremely low reproductive rate, laying just one egg in a year or two!

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Which is the largest fish?

We now know that the blue whale is the largest sea creature, but it is not a fish. It is a mammal. So, you might ask -which is the biggest fish in the ocean? The answer is the ‘whale shark’. You might further ask – is it a whale or a shark? To answer, the whale shark is not a whale, but a shark. However, owing to its massive size (it is known to reach lengths of more than 12 metres), it has earned the name ‘whale’ shark.

Like many whales and unlike most sharks, it is a filter feeder. In another deviation from sharks, its mouth is located at the front of its head rather than on the underside of its head. However, like all true sharks it breathes with the help of gills, unlike whales which breathe air like humans do. Also, as with all sharks, its skeleton is made of cartilage.

Larger whale sharks may weigh up to 54,400 kg. It would follow that such enormous sharks would be top predators in the ocean, but the whale shark is a harmless fish. It feeds on tiny organisms called plankton that float in the ocean. It uses its massive mouth, which can stretch up to 1 metre wide; to take in the plankton-rich waters using sieve-like structures called filter pads to separate the food from water.

Picture Credit : Google 

Which is the largest reptile?

When it comes to reptiles, there is none deadlier than the saltwater crocodile. Reaching lengths of 2 metres and weights of 1,000 kgs, this apex water predator is the largest of all reptiles found on Earth. Saltwater crocodiles are hyper-carnivorous, opportunistic predators that will eat anything that they can get their jaws on!

They appear lethargic as they bask on riverbanks or float motionless in the water but are capable of lightning-fast strikes at unsuspecting victims. They usually drag their prey into the water. Armed with a lethal bite which is among one of the most powerful in the world, there is no escaping once a ‘saltie’ latches onto a hapless victim.

Unlike other crocodiles who are confined to river systems, this crocodile fares very well in the open seas as well. They are able to travel long distances on ocean currents and learn to track the migratory route of their prey with very little prior conditioning. They are known to be very aggressive towards humans and are more likely than other types of crocodile to treat humans as prey.

Picture Credit : Google