It may be hardest of all to care about something unseen. A single glass of seawater drawn from the surf in Newport or Brookings might look clear but in fact would roil with at least 75 million organisms called phytoplankton.
And we vitally depend upon such creatures. Out in the ocean, infinite numbers of them produce half the world’s oxygen and form the base of the marine food chain. For what it’s worth, phytoplankton eat crazy amounts of carbon dioxide, a greenhouse gas.
But their numbers are down 40 percent worldwide since the 1950s and may be headed down further. The culprit appears to be rising ocean temperatures associated with climate change. The sea’s warming top layer of water, where phytoplankton do their job, increasingly lacks life-sustaining nutrients from the cold deep.
Thacher’s Woe and Avery’s Fall… see the story 1635 Hurricane
The Bermuda High pressure system sits over the Atlantic during summer. Acting as a block that hurricanes cannot penetrate, the size and location of this system can determine where hurricanes go. A normal Bermuda High often leads to hurricanes moving up the east coast and out to sea. During summer 2004 and 2005, the Bermuda High expanded to the south and west, which steered hurricanes into the Gulf of Mexico rather than up the east coast or curving out to sea. Once in the Gulf, most hurricane paths will involve landfall at some location.The Bermuda High pressure system sits over the Atlantic during summer. This visualization first shows a typical Bermuda High system. Then, it expands the Bermuda High to show what happened in the summer of 2004 and 2005.
An updated 2005 shark taxonomy list, has established 34 families, and 453 species of sharks worldwide. That’s an increase from the previous 28 families and 370 species categorized in 1984. Since 2005 several more species have been discovered.That would put today’s total around 460 shark species.
There was an incredible lack of knowledge about shark species until the 1940s, when the navies and air forces of the world got interested in sharks, because of survivors at sea during World War II. The 1975 movie “Jaws ,” spurred the public’s interest in sharks; especially the white shark, Carcharodon carcharias.
The good news is that in most areas of the world you only have to be knowledgeable about a dozen or so shark species. In the United States, on the East coast and Gulf of Mexico from Maine to Texas there are about 33 species of sharks. There are about 15 shark species in the New England area, and only a half dozen species that you are likely to encounter. So with a little effort and interest, you can learn about those species, and how to identify the sharks that ply the coastal New England waters.
Staring in awe, Skomal mouthed an expletive. “It wasn’t a report. It wasn’t a rumor, you know?” Skomal says today. “It wasn’t a mystery fish . . . it was a
.” The estuary was an ideal place for an up-close glimpse of the free-swimming female great white, which stayed until scientists coaxed her into open waters on October 4 of that year. Now, Skomal thought, every great white sighting was worth investigating.
Side-Effects of Increase in Seal Population: Shark Increase, Fish Parasites, Water Pollution…
The other thing is the effect of an expanding seal population on fish stocks. One concern is the spread of fish-eating parasitic worms found in seal waste. As a commercial fisherman, who fished for codfish 20 years ago in the Gulf of Maine, which had more seals than the Cape did at that time, we knew when the cod we caught were from “up north”. These codfish more often than not had these parasitic “worms” in their flesh. When we brought these fish home to the ports of the Cape, the fish buyers would know as soon as they filleted a few where they were caught. Years ago these worms were rarely found in the codfish off Chatham. These worms are in nearly all the codfish caught now in inshore waters. Last winter we saw that the bellies and livers of many of the monkfish we caught 60 miles south of M/V Nantucket are now loaded with these parasitic worms.
Again–Young great whites attacking–in packs?
“The only other species that gathers in abundance out there (FLORIDA) in the winter are the juvenile great white sharks,” Gilmore said. They eat their way through a migrating parade of 3- to 4-foot sharpnose sharks that travel south from New England waters to Florida.
DR. DOMEIER: Well, there were, within a pretty short time, three sea lions killed off Santa Barbara, and I think that just – they’re just being cautious. This time of year adult, mature pregnant white sharks come into the shallow waters to give birth and at least that’s a hypothesis that I’ve been working on. And it seems pretty clear from incidental gill net captures of young of the year white sharks that that is, in fact, the case, that from about April to August we’re getting baby white sharks dropped off here and then the females turn around and take off again.
DR. DOMEIER: You know, I probably not. I mean, it is a possibility but Southern California is not a – it’s not a favorite habitat for adult white sharks. It seems that they just pass through here or they come here to give birth and then they leave. The adult white sharks really prefer that area around the Farallon Islands and Guadalupe Island. And what I actually believe is that what they really want to be is out in the middle of the ocean. That is their preferred habitat, that they are really an oceanic shark and they come to shore only to give birth and to mate. Of course, this – I’m talking to you very freely about an hypothesis I have, and you’ll find other scientists that will probably disagree with me.
Why So Cal for breeding?
DR. DOMEIER: Well, it happens to be the habitat that the young need to survive. They need the shallow coastal waters and there’s probably some element of temperature that’s just right for them. So the females travel a long ways, you know, they’ll probably come 1500 miles from offshore to give birth in a specific location before they’re just turning around and going back offshore.
(Where do Great Whites Breed in Atlantic?)
… in CA it’s not smaller Great Whites that attack… but in Australia and South Africa it is??!
DR. DOMEIER: Not as juveniles but, you know, when they start to transition to sub-adults they can be a threat. In fact, it’s interesting. In February, I held an international white shark symposium in Hawaii and pretty much all my colleagues from around the world came. And it was interesting for me to learn that in South Africa and Australia, where you often hear about white shark attacks, those are all a result of sub-adults. They don’t even know where their adult white sharks are. They rarely see adults in those two locations. So they’re talking about sharks that are in the 9 to 12 foot range.
Juveniles rely especially on Grunion runs:
As newborns and yearlings, White Shark energy reserves, which are concentrated in their livers, are minimal at best so it is necessary that they begin to feed immediately. It is not surprising that juvenile White Sharks are frequently observed close inshore off Southern California beaches from April to September, the same months coincidentally that Grunion spawns occur. Thousands of egg-laden Grunion provides a bountiful supply of protein twice monthly for the young White Shark, a necessity for the newborn sharks if they are to survive their first year of life. In addition to Grunion, the young sharks also feed on other fishes that are attracted to these spawns.
Over the preceding four decades, captures or strandings of White Sharks have provided valuable insights into their biology — including dietary preferences. A brief description of a stranding and a capture are presented below.In late September 1977 a local air taxi operator sighted a large shark stranded on a beach 16 miles southwest of Ketchikan, Alaska. Fisheries biologist Robert Larson examined the shark on 30 September 1977. The adult male White Shark was 15 feet 4 inches in total length. Upon dissection of the shark’s stomach about 100 opaque circular objects were discovered, each about 0.25 inches in diameter. John E. Fitch, Research Director, California Department of Fish & Game, Long Beach, subsequently identified them as lenses from fish eyes, most probably salmonids. The number of lenses present in the shark’s stomach suggests that fish might provide a larger percentage of adult White Shark nutritional requirements than previously thought. Although White Sharks appear to prefer pinnipeds seals and sea lions as their main staple after attaining maturity, they still consume fish. This fact has been overtly omitted, or frequently understated, over the last two or three decades by some White Shark researchers. The irrefutable evidence from this stranding tells us that adult White Sharks are apparently opportunistic predators and will readily take any prey species that is available.