It’s time to announce our Habitat Highlight and our Species of the Month! In July we are exploring the Open Oceans of the Northern seas!
Open oceans are found away from land and above the seabed. The habitat consists of 5 zones, epipelagic, mesopelagic, bathypelagic, abyssopelagic and hadalpelagic (orcas dive for their food in the shallow epipelagic zone!).
Despite the size of the habitat it does not have high organism density in comparison to other ocean habitats. This is due to many factors: the lack or absence of light in the deeper zones mean that plants are unable to grow on the ocean floor therefore, the waters are very nutrient poor. However, some organisms thrive in this habitat! Crustaceans have adapted a red colour, due to the lack of light at depths the red colour becomes invisible, meaning they are invisible to predators.
Even though this habitat is far away from land it is still attacked by humans as a result of overfishing. A shocking 90% of pelagic fish are removed by fishing. This has a detrimental impact on the ecosystem of the habitat, fishes from lower zones move to a higher zone , this is called fishing down the marine food web.
July’s Species of the Month is Orcinus orca, the killer whale. Orcas are one of the most widely distributed animals on the planet and are found in all oceans around the earth, however, most commonly found in northern cold waters.
For years humans have kept orcas captive for human entertainment. These orcas undergo great stress, they are incredibly social animals but can spend their whole lives swimming in the same tank with no stimulating activities. It is shocking that this is still going on! If you want to help please follow these links! http://savedolphins.eii.org/campaigns/fwd https://www.dolphinproject.com And if you're on holiday, please don’t visit any parks that support the captivity of wild animals!! #dontbuyaticket #thanksbutnotanks
As a result of COVID-19 and travel restrictions there has been an increase in whale sightings - even a pod off the coast of Thurso back in April.
Orca’s (Orcinus orca) are large carnivorous mammals from the odontocete (toothed whale) family. They are around 23-32 feet long (around the size of a bus), and weigh up to 6 tonnes, making them the largest member of the cetacean family. The largest recorded male was measured at 32 feet, and weighed 10,000kg! The largest female recorded was 8.5m long, and weighed 7,500kg!
Their diet ranges from fish, penguins, seals and in some cases other whales! They hunt in their pods and use echolocation and form intricate formations for capturing their prey.
There are different ecotypes of killer whales all having different and unique physical differences. 5 forms in the Antarctic sea, some in the North Pacfic ocean, and 2 forms in the North Atlantic.
They are the most distinct members because of their black and white colouration. The dorsal side and pectoral flippers are black. The ventral surface, lower jaw eye spot, and rail flukes are white. Male and female orcas have different colouration patterns on their genital areas which is one method for distinguishing between sexes. Their colour pattern is known as disruptive colouration. This means that the colour pattern obscures the outline of the animal by contradicting the animals body shape. This helps the animal to become a successful predator as prey may not recognise them. Additionally, they are countershaded (meaning that the dorsal surface is darker than the ventral surface). The orca can then blend in with the limited light of deeper depth when seen from above, and the lighter ventral surface is camouflaged by the sea surface when viewed below.
“Why are they known as killer whales when they are actually dolphins?” I hear you ask. Well, they were once observed hunting larger whales by ancient sailors and given the name of ‘aesina ballenas’, roughly translated to whale killer. However, overtime this was then turned to killer whale. Their latin name also translates to kingdom of the dead, unfortunately not giving them a great reputation. They were branded as vicious pests and as a result heavily persecuted by fishermen, whalers and government agencies.
After being used for marine shows in captivity the public began to grow some form of affection towards the animals. There has been evidence that orcas kept in captivity live a much shorter life span, and over a quarter of them have significant damage to their teeth, as a result of grinding teeth to enclosure walls. Additionally, captive male orcas only reach 6.6m, and for females 5.5m, comparatively shorter than their wild counterparts. The status of orcas are rather unknown.
Like many marine creatures they are facing threats such as lack of food from overfishing and habitat loss, being poisoned with contaminants from wastewater treatments, plastic pollution, oil spills, and echolocation disturbance due to ships and military activities.
Orcas are magnificent, intelligent creatures. They do not belong in captivity, they do not deserve to be persecuted. Their unfortunate nickname ‘Killer Whale’ really has not given them the best chance. We, as a new generation, have a right to help protect these stunning creatures by either not paying to see them perform, and instead go and watch wild whales on land, by choosing sustainably sourced fish, or simply by reducing the amount of plastic we use.
Every little helps. Let’s do what we can.