A small pod of s***m whales passing ever so slowly by me. these creatures tend to be a bit more shy, unless they are socializing.⠀
the s***m whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. females and young males live together in groups while mature males live solitary lives outside of the mating season. the females cooperate to protect and nurse their young. females give birth every four to twenty years, and care for the calves for more than a decade. a mature s***m whale has few natural predators, although calves and weakened adults are sometimes killed by pods of orcas.⠀
taken under government permit. ⠀
photo by @nadia.aly.photo⠀
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credit to : @nadia.aly.photo
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In the animal kingdom, communication behaviors between members of the same species happens for different reasons: to request food from parents, threaten opponents during conflict, keep predators away, warn others of danger, attract members of the opposite sex, etc. (dugatkin & reeve, 1998).
during the winter months in hawaii, male humpback whales are often seen performing these behaviors during mating season, acting aggressively towards others around the same area while competing for sexually mature females. (c. scott baker and, louis m. herman 1984). these mating strategies have been described as male dominance polygyny (clapham, 1996). the “competition” between two or more males for females usually begins with a behavior called “broadside displays” where the principal escort swims horizontally across the challenging male, blocking its path towards the female, (walther, 1984) but sometimes when it gets more aggressive they use other behaviors like head lunging, underwater blows, and sometimes they will release air from the mouth so that the bubbles may disorientate the other whale. (baker & herman, 1984).
image by @darrenjew of a heat run in tonga 🐋🐋🐋
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Awesome information via @queenofmantas on the impact of #microplastics on marine megafauna including whale sharks and manta rays. check out the link at the bottom of this post to read more and to access a recently published and very well written paper titled “microplastics: no small problem for filter-feeding megafauna” #plasticistherealkiller
repost @queenofmantas@everydayextinction ・・・
repost from a contribution i made to @everydayextinction surrounded by plastic pollution and other human waste, a reef manta ray (mobula alfredi) struggles to feed at a critical feeding site within the bird’s head seascape. despite being one of indonesia’s flagship marine protected areas, strong throughflow currents, which transport over 15 million cubic meters of water per second through the archipelago, circulate plastic pollution to even the farthest reaches of the nation’s archipelago. once ingested, plastic pollution, which is impossibly slow to break down, can build up in the stomachs of filter feeding organisms, like whales, sharks and rays, causing blockages and malabsorbtion of food. an incredible adherent of toxins and persistent organic pollutants like pcbs, plastics can also have other cryptic long-term effects on animals as they accumulate dangerous levels of these toxins and pollutants in their bodies. long-term exposure can even alter hormone levels, which regulate growth, development and reproductive functions, posing serious threats to the health of individuals and their offspring. the short and long-term effects of microplastic ingestion on marine animals is only slowly being understood but are likely to have grave impacts on whale sharks and manta rays, which are currently are listed as endangered and vulnerable to extinction respectively. read more about this dangerous anthropogenic threat to marine filter feeders in this newly published review by @marinemegafauna researchers and our collaborators https://marinemegafaunafoundation.org/blog/microplastics-no-small-problem/
It might look silly to watch a shark come up and take a big gulp of air as if they were a person submerged for more than a minute, but that’s what sand tiger sharks do! though, they are not surfacing for the same reason a person would need to surface- they swallow the air to maintain buoyancy. sand tiger sharks do not have a swim bladder, and frequently surface to swallow in air, which they store in their stomach. the retention of the air allows them to attain near- neutral buoyancy, which is very helpful and efficient in terms of the sand tigers hunting style. since the sand tiger has the same average density as the water in their neutrally buoyant state, they do not have to expend a lot of energy in order to swim, as they are able to suspend themselves in the water and move almost motionlessly. (perrine, 1999) due to their lazier lifestyle, sand tiger sharks are able to actively ventilate and hang out in the currents in order to move. (smith et. al. 2004) since sand tiger sharks are relatively inactive compared to some other species, along with their rugged and intense shark looks, they are also sought after for aquariums. in the transport process, handlers remove some of the air being held in their stomach so that the shark is at a state of negative buoyancy, and is easier to transport in the container. it can be harmful to the health of any species to go to a captive environment, and while sand tigers are present in many large scale aquariums, transport and adjustment pose a large threat to their natural process of maintaining buoyancy. after the air is forcefully taken out of the shark for transport and reintroduced into an aquatic environment, the sand tiger must frequently gulp air at the surface to get back to their optimal neutral buoyancy. if this is not done, or is not achievable for the shark in the stressful environment, the shark will need to be introduced to a tube in order to artificially get air into the stomach. (smith et.al. 2004) come out with us to learn more about sharks and observe them in the wild on their own terms on a pelagic research dive!
post by @kberry122
epic photo by @uw_photography_
In one of yesterday’s posts we discussed where galapagos sharks got their name, but have you ever wondered where sandbar sharks (another species seen on our tours) get their name? the #sandbarshark is commonly found over muddy or sandy bottoms in shallow coastal waters such as bays, estuaries, harbors, or the mouths of rivers, but it also swims in deeper waters as well. sandbar sharks are found in tropical to temperate waters world wide and are a part of the carcharhinidae family, native to the atlantic ocean and the indo-pacific. it is distinguishable by its very high first dorsal fin and inter-dorsal ridge. it is not to be confused with its similarly named shark cousin, the sand tiger shark. the sandbar shark is also called the thick skin shark or brown shark.it is one of the biggest coastal sharks in the world, and is closely related to the dusky shark, the big nose shark, and the bull shark. its dorsal fin is triangular and very high and it has very long pectoral fins. sandbar sharks usually have heavy-set bodies and rounded snouts that are shorter than the average shark's snout. their upper teeth have broadly uneven cusps with sharp edges (allen). its second dorsal fin and a**l fin are close to the same height. females reach s****l maturity around the age of 13 with an average fork-length of 154.9 cm (stevens). while males tend to reach maturity around age 12 females have been found to exhibit both biennial and triennial reproductive cycles, ovulate in early summer, and give birth to an average of 8 pups, which they carry for 1 year before giving birth (baremore). this species is long lived and takes over a decade to reach s****l maturity making it extremely difficult for them to rebound after heavy fishing pressure. we are grateful to still have relatively healthy populations of this species here in hawaii whereas the atlantic population has been depleted by 85-97% (iucn, musick et al. 2009). post by @brian_marrocco
photo by @ambermozo
Because no trip to the bahamas is complete without a hairy-nosed swimming pig 🐷 i know there's been a lot of discussion about the swimming pigs recently and i'm not sure anyone knows why so many died on the beach there. it's true for them that the island isn't quite the paradise humans perceive it to be, i'd guess they're hungry & thirsty a lot of the time 😔 in saying that it's still a universe apart from (better than) the conditions millions of pigs endure in our intensive farming industries. the pigs on big majors aren't going anywhere any time soon so personally i'd rather see these guys on the beach and give them some fresh water and food than sail straight past....
credit to : @lauracorbe
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