Menu

Ireland's sailing, boating & maritime magazine

Displaying items by tag: Dolphins

20th January 2011

Aerial Survey of Whales Begins

The first ever Air Corps survey of whale and dolphin activity in Irish waters is set to begin today, the Irish Times reports.
A survey team accompanied by members of the Irish Whale and Dolphin Group (IWDG) were scheduled to take off from Casement Aerodrome this morning headed for the southeast coast, where humpback whales have recently been sighted near Curracloe and Hook Head.
According to the IWDG, 19 whale and dolphin species have been recorded in Irish waters since 1948, the most common sightings being harbour porpoises.
The Irish Times has more on the story HERE.

The first ever Air Corps marine animal survey of whale and dolphin activity in Irish waters is set to begin today, the Irish Times reports.

A survey team accompanied by members of the Irish Whale and Dolphin Group (IWDG) were scheduled to take off from Casement Aerodrome this morning headed for the southeast coast, where humpback whales have recently been sighted near Curracloe and Hook Head.

According to the IWDG, 19 whale and dolphin species have been recorded in Irish waters since 1948, the most common sightings being harbour porpoises.

The Irish Times has more on the story HERE.

Published in Marine Wildlife
The Irish Whale and Dolphin Group's (IWDG) recent workshop on the post-mortem examination of stranded dolphins and whales is hoped to encourage the building of much needed experience for Ireland's vets.
More than 20 veterinarians from across the country attended the workshop in Athlone, where they were shown how to carry out a post-mortem from a research perspective and taken through the post-mortem protocol, as well as the collection of samples for various parameters from bacteriology to genetics.
"The IWDG have long advocated that the post-mortem examination of stranded cetaceans should be carried out by veterinary pathologists to determine their cause of death and provide samples for life-history studies," said the group's Dr Simon Berrow.

The Irish Whale and Dolphin Group's (IWDG) recent workshop on the post-mortem examination of stranded dolphins and whales is hoped to encourage the building of much needed experience for Ireland's vets dealing with marine animals.

More than 20 veterinarians from across the country attended the workshop in Athlone, where they were shown how to carry out a post-mortem from a research perspective and taken through the post-mortem protocol, as well as the collection of samples for various parameters from bacteriology to genetics. 

"The IWDG have long advocated that the post-mortem examination of stranded cetaceans should be carried out by veterinary pathologists to determine their cause of death and provide samples for life-history studies," said the group's Dr Simon Berrow.

Published in Marine Wildlife
A new pontoon intended to refloat beached whales and dolphins along the Atlantic seaboard was demonstrated at the weekend ahead of the Galway Science & Technology Festival.
The Irish Times reports that divers, scientists and local volunteers were among those participating in the training exercise on Gurteen beach, near Roundstone, which involved rescuing and refloating a dummy pilot whale.
Dr Simon Berrow of the Irish Whale and Dolphin Group (IWDG) which ran the exercise said he hoped other coastal communities would follow the example with their own training sessions, given the growing number of strandings along Ireland's west coast.
The new pontoon - which was put on display in the festival exhibition at NUI Galway on Sunday - was purchased with funds raised by the local community and a BBC television team producing the latest series by popular adventurer Monty Halls.

A new pontoon intended to refloat marine animals such as beached whales and dolphins along the Atlantic seaboard was demonstrated at the weekend ahead of the Galway Science & Technology Festival.

The Irish Times reports that divers, scientists and local volunteers were among those participating in the training exercise on Gurteen beach, near Roundstone, which involved rescuing and refloating a dummy pilot whale.

Dr Simon Berrow of the Irish Whale and Dolphin Group (IWDG) which ran the exercise said he hoped other coastal communities would follow the example with their own training sessions, given the growing number of strandings along Ireland's west coast.

The new pontoon - which was put on display in the festival exhibition at NUI Galway on Sunday - was purchased with funds raised by the local community and a BBC television team producing the latest series by popular adventurer Monty Halls.

Published in Marine Wildlife

Renowned diver Monty Halls is set to present a public talk on his marine animal work filming whales, sharks and dolphins around the world tomorrow night (7 October).

Halls, who has been in Ireland since April making his latest documentary series for the BBC, has been assisting the Irish Whale and Dolphin group (IWDG) with its research on whales, dolphins and basking sharks in Irish waters.

The diver, filmmaker and former Royal Marine, who is also a popular motivational speaker and performance coach, will talk on his experiences filming and diving with marine mammals around the world, and will surely provide some great entertainment.

The talk, part of the Tales of the Whales Lecture Series organised by the IWDG and the Galway-Mayo Institute of Technology (GMIT), begins at 8pm on Thursday 7 October in Lecture Room 1000 at GMIT, Dublin Road, Galway. The event is free and all are welcome to attend.

Published in Marine Wildlife

Pictures of Dolphins jumping off Roches Point in Cork harbour have been captured for youtube viewers courtesy of a Cork fishing trip this week. The three harbour dolphins jump clean out of the water in the clip below from about 2:20 on the timeline.  A Lovely marine animal sight on a summers evening! 

Published in Marine Wildlife

 

Atlantic Dolphins choose to eat high-energy fish to suit their energetic lifestyles, scientists have found.
A study of dolphins off the French coast shows that dolphins shy away from less calorie-dense prey in favour of high-energy food. This dispels a myth that dophins are opportunistic feeders that take any food that comes their way.
The study was carried out by Dr Jerome Spitz and other scientist at the University of La Rochelle in France, who looked at the eating habits of short-beaked common dolphins ( Delphinus delphis ).
This species are the most common type of dolphin in nearby Atlantic waters. The team studied the stomach contents of dolphins caught accidentally in tuna drift nets to see what they ate. They then compared what they found in the dolphins' stomachs with what surveys of trawling fish catches indicated as plentiful in the same waters.
What they found was that dolphins actively select their prey based on its energy density, preferring deep-sea species like lanternfish instead of fish that have lower energy densities.
The dolphins studied turned their noses up at fish with under 5kJ of energy per gram, and sought out rarer breeds of fish that had a higher energy rate.
Two favourites were less common species of  lantern fish, the Kroyer's lanternfish  and the Glacier lanternfish  which have 7.9kJ and 5.9kJ per gram respectively.

Atlantic Dolphins choose to eat high-energy fish to suit their energetic lifestyles, scientists have found.

A study of dolphins off the French coast shows that dolphins shy away from less calorie-dense prey in favour of high-energy food. This dispels a myth that dophins are opportunistic feeders that take any food that comes their way. 


The study was carried out by Dr Jerome Spitz and other scientist at the University of La Rochelle in France, who looked at the eating habits of short-beaked common dolphins.

This species are the most common type of dolphin in nearby Atlantic waters. The team studied the stomach contents of dolphins caught accidentally in tuna drift nets to see what they ate. They then compared what they found in the dolphins' stomachs with what surveys of trawling fish catches indicated as plentiful in the same waters.


What they found was that dolphins actively select their prey based on its energy density, preferring deep-sea species like lanternfish instead of fish that have lower energy densities.
The dolphins studied turned their noses up at fish with under 5kJ of energy per gram, and sought out rarer breeds of fish that had a higher energy rate.


Two favourites were less common species of  lantern fish, the Kroyer's lanternfish  and the Glacier lanternfish  which have 7.9kJ and 5.9kJ per gram respectively. Other less energetic predators, like sharks, are less fussy and take anything that's going.

 

Published in Marine Wildlife

Irish Whale and Dolphin Group (IWDG) Sightings Co-ordinator Pádraig Whooley will be presenting at this weekend's TEDX event in the West Cork Hotel, Skibereen, Co. Cork tomorrow which will be streamed live on the internet and can be viewed here.

 

Published in Marine Wildlife
Tagged under
Page 10 of 10

Sharks in Irish waters

Irish waters are home to 71 species of shark, skates and rays, 58 of which have been studied in detail and listed on the Ireland Red List of Cartilaginous fish. Irish sharks range from small Sleeper sharks, Dogfish and Catsharks, to larger species like Frilled, Mackerel and Cow sharks, all the way to the second largest shark in the world, the Basking shark. 

Irish waters provide a refuge for an array of shark species. Tralee Bay, Co. Kerry provides a habitat for several rare and endangered sharks and their relatives, including the migratory tope shark, angel shark and undulate ray. This area is also the last European refuge for the extremely rare white skate. Through a European Maritime and Fisheries Fund (EMFF) project, Marine Institute scientists have been working with fishermen to assess the distribution, diversity, and monthly relative abundance of skates and rays in Tralee, Brandon and Dingle Bays.

“These areas off the southwest coast of Ireland are important internationally as they hold some of the last remaining refuges for angel shark and white skate,” said Dr Maurice Clarke of the Marine Institute. “This EMFF project has provided data confirming the critically endangered status of some species and provides up-to-date information for the development of fishery measures to eliminate by-catch.” 

Irish waters are also home to the Black Mouthed Catshark, Galeus melastomus, one of Ireland’s smallest shark species which can be found in the deep sea along the continental shelf. In 2018, Irish scientists discovered a very rare shark-nursery 200 nautical miles off the west coast by the Marine Institute’s ROV Holland 1 on a shelf sloping to 750 metres deep. 

There are two ways that sharks are born, either as live young or from egg casings. In the ‘case’ of Black Mouthed Catsharks, the nursery discovered in 2018, was notable by the abundance of egg casings or ‘mermaid’s purses’. Many sharks, rays and skate lay eggs, the cases of which often wash ashore. If you find an egg casing along the seashore, take a photo for Purse Search Ireland, a citizen science project focusing on monitoring the shark, ray and skate species around Ireland.

Another species also found by Irish scientists using the ROV Holland 1 in 2018 was a very rare type of dogfish, the Sail Fin Rough Shark, Oxynotus paradoxus. These sharks are named after their long fins which resemble the trailing sails of a boat, and live in the deep sea in waters up to 750m deep. Like all sharks, skates and rays, they have no bones. Their skeleton is composed of cartilage, much like what our noses and ears are made from! This material is much more flexible and lighter than bone which is perfect for these animals living without the weight of gravity.

Throughout history sharks have been portrayed as the monsters of the sea, a concept that science is continuously debunking. Basking sharks were named in 1765 as Cetorhinus maximus, roughly translated to the ‘big-nosed sea monster’. Basking sharks are filter feeders, often swimming with their mouths agape, they filter plankton from the water.

They are very slow moving and like to bask in the sun in shallow water and are often seen in Irish waters around Spring and early Summer. To help understand the migration of these animals to be better able to understand and conserve these species, the Irish Basking Shark Group have tagged and mapped their travels.

Remarkably, many sharks like the Angel Shark, Squatina squatina have the ability to sense electricity. They do this via small pores in their skin called the ‘Ampullae of Lorenzini’ which are able to detect the tiny electrical impulses of a fish breathing, moving or even its heartbeat from distances of over a kilometre! Angel sharks, often referred to as Monkfish have a distinctively angelic shape, with flattened, large fins appearing like the wings of an angel. They live on the seafloor in the coastal waters of Ireland and much like a cat are nocturnal, primarily active at night.

The intricate complexity of shark adaptations is particularly noticeable in the texture of their skin. Composed of miniscule, perfectly shaped overlapping scales, the skin of shark provides them with protection. Often shark scales have been compared to teeth due to their hard enamel structure. They are strong, but also due to their intricate shape, these scales reduce drag and allow water to glide past them so that the shark can swim more effortlessly and silently. This natural flawless design has been used as inspiration for new neoprene fabric designs to help swimmers glide through the water. Although all sharks have this feature, the Leafscale Gulper Shark, Centrophorus squamosus, found in Ireland are specifically named due to the ornate leaf-shape of their scales.