(C) Daily Kos This story was originally published by Daily Kos and is unaltered. . . . . . . . . . . The Daily Bucket - coming up for air off Kaua’i and Lehua [1] ['This Content Is Not Subject To Review Daily Kos Staff Prior To Publication.'] Date: 2023-10-10 My last Daily Bucket was about who I saw underwater in Hawaiian waters. Today’s is about who I saw from the boat while we were either traveling or at rest during our surface intervals between dives. Being out in the middle of the Pacific, the Hawaiian islands are visited by many large oceanic animals who come relatively close to shore for feeding or resting opportunities. Some, like turtles, hang out in fairly shallow water most of the time, while others, like whales, are more passing through. All these animals are air breathers, so they were surfacing to breathe. Honu catching a breath. Image: by Bettina Arrigoni is licensed CC Honu, aka native Hawaiian Green sea turtles, have a special place in the hearts of Hawaiians. They are huge (up to 4 feet long), gentle, and pretty numerous off Kaua’i. Honu are herbivorous, you’ll see them grazing on algae and sea grasses, and sometimes sleeping underwater. But they are airbreathers and must swim up to the surface periodically, where you’ll see them floating and sticking their heads up off and on. Honu populations are apparently localized to the different islands and don’t mix. They migrate for nesting: about 95% swim every few years to the Lalo atoll system in Papahanaumokuakea Marine National Monument about 500 miles northwest of Kaua’i (and much farther from the other main Hawaiian islands). Map of Papahānaumokuākea Marine National Monument (PMNM). Image: NOAA Status and threats: Honu like to haul out onto beaches to bask, which makes them vulnerable to human interference on the Hawaiian islands. While their numbers have stabilized now that they are protected under U.S. and Hawaii state law, threats still include poaching, entanglement in fishing gear, ocean pollution and debris, loss of nesting habitat due to sea level rise, and harassment by humans and dogs. NOAA Fisheries, U.S. Fish and Wildlife (Hawksbill turtles are far more rare in Hawaiian waters. We saw one on a dive and our dive guide took a photo to send off to researchers who are tracking individuals) Hawaiian Spinner Dolphins, aka n’aia, are also quite numerous. These dolphins have a daily migration pattern, feeding at night offshore when their prey squid, fish and shrimp rise up in the water column from deep below. Spinner dolphins forage cooperatively in large groups. During the day they come into shallow water to rest and escape sharks, their main predator. Spinner dolphins really do spin, some leaping from the water to whirl around a few times before making a big splash, thought to be a way of communicating and binding the group together although there’s no definitive explanation. These are relatively small dolphins, unlike the larger and more rare Bottlenose dolphins there who we saw only once (and just a few). Since Spinner dolphins frequent the nearshore waters during the daytime, we saw them often from the boat, sometimes riding our bow wave when we were underway. Once a group of about 150 cruised by and I was so gobsmacked I didn’t even take any pictures. Spinning Spinner dolphin. Image: by kahunapulej is licensed CC Here’s a composite of videos I took during a surface interval between dives on Sept 25. It shows a small group of Spinner dolphins and then later a couple of honu surfacing to breathe. . I never saw any dolphins while I was underwater but once they were very near — I could hear them talking amongst themselves. If the visibility had just been a little better! Status and threats: Each island has a sub population; Kaua’i/Ni’ihau dolphins number about 3000. Threats to dolphins include fishing bycatch and entanglement, marine debris, and use of sonar and boat collisions. Another major problem is the tourist attraction of “swimming with dolphins”. Companies take tourists out to spots where dolphins rest, but that disturbs them by interfering with their caring of youngsters, and the need to recover from their nightly energy expenditure while fishing. In 2021 the Federal government banned those ops operating within 2 miles of shore, under the Marine Mammal Protection Act, but a quick Google search reveals many organizations are still operating, perhaps going further out. Hawaii has a conflicted position on tourism, and as someone who both lives in a tourist destination and is a tourist when I travel (like this time), I can readily understand the mixed feelings. Tourism degrades the integrity of a place but people can’t live there without tourists. It’s a tough balance to maintain. DLNR Hawaii, NOAA Fisheries report Tourist op of snorkelers crowding dolphins who are trying to rest. Image: NOAA Fisheries Monk Seals, aka īlio holo i ka uaua, are a Hawaiian endemic and highly endangered pinniped, with only 1500 individuals remaining. Most of them live in the Northwestern Hawaiian islands, protected within the Papahānaumokuākea Marine National Monument. About 400 live in the main Hawaiian islands (MHI), mostly around Ni’ihau and Lehua, with a few coming ashore on Kauai, Maui, Oahu and Hawaii. Seal presence in the MHI is a return of the population there after they were wiped out by the colonizing Polynesians, who hunted them. As low-lying islets in the Northwestern chain get covered by sea level rise, the MHI will likely become more important to Monk seals since they must come ashore to rest, sleep, give birth and nurse. Monk seals feed on whatever prey is available, from fish to octopuses, mostly by making fairly short dives. They prefer to avoid human presence on the main islands, although around Lehua (uninhabited) and Ni’ihau (population ~50) they come ashore freely, and seem curious about divers and small boats. Monk seal swimming around our boat Looking up from below while we were diving I could see two or three seals going up and down, and hanging around the boat. The one in the pic and video was one of them. Not sure why they were doing that but they clearly weren’t feeling threatened. Very few boats come out to Lehua islet. This is a video I took of one of the Monk seals who cruised around the boat. The green algae collecting on its fur tells us this seal hasn’t gone through its annual molt yet. It’ll cast off its entire outer skin/fur revealing a fresh coat below. . Status and threats: Intensive hunting in the 19th and 20th century throughout their range reduced monk seal numbers to very few and while the population has increased since the 1950s, their genetic diversity is low due to the population bottleneck. Current threats include food scarcity (competition and changing fish populations), entanglement with derelict fishing gear, shark attacks, toxoplasmosis (from feral cats) and other diseases, and human harassment. Marine Mammal Commission, NOAA Fisheries Blainville’s Beaked Whales We encountered two of these rare whales en route from Ni’ihau to Kaua’i midway in that 20-mile wide channel. Our dive op professionals expressed amazement to see them… they’re that rare (NOAA describes them as “cryptic and evasive”). Beaked whales are deep open sea creatures, and we were just lucky to cross paths that day. They dive thousands of feet deep feeding on squid and fish by sucking them into their mouths. They have an array of physiological and behavior adaptations to make such long deep dives possible. . Status and threats: Population numbers and life span are unknown for these whales, however necropsies of those found dead indicate their main threats are entanglement in trawl nets, biocontaminant accumulation, swallowing plastic debris, and decompression sickness. Even though beaked whales can manage ascending from deep dives, they are highly vulnerable to modern naval anti-submarine exercises using sonar since they use echolocation to hunt, and the mid-frequency active sonar used since the 1950s sends whales into a panic at depth. They surface too quickly and die from hemorrhaging and embolisms. NOAA Fisheries, Wikipedia Beaked whale. Image: by whale_nerd is licensed CC Blainvilles Beaked whales have a distinctive profile, and are 15-20 feet long. We saw them surfacing long enough to positively ID these rare creatures. As an air breather myself, I’m filled with respect and admiration for the abilities of all these large oceanic air-breathers. I have to remind myself a seal or turtle napping on a ledge 50 feet underwater is holding its breath! Meanwhile I’m dependent on a tank of air I have to haul around. [END] --- [1] Url: https://www.dailykos.com/stories/2023/10/10/2196752/-The-Daily-Bucket-coming-up-for-air-off-Kaua-i-and-Lehua?pm_campaign=front_page&pm_source=more_community&pm_medium=web Published and (C) by Daily Kos Content appears here under this condition or license: Site content may be used for any purpose without permission unless otherwise specified. via Magical.Fish Gopher News Feeds: gopher://magical.fish/1/feeds/news/dailykos/