When the larger fish of a species
get killed off, the gene pool changes,
the average size of the fish shrinks,
and the species become threatened.
So it was alarming news when we
  learned that the mighty whale shark,
  is suffering from a severe decline in
  size. Australian scientist Dr. Mark
  Meekan says that observation logs
  of whale sharks in Ningaloo Reef,
  Western Australia, suggest that the
  average size of the fish had shrunk
  from 23 feet in 1995 to 18 feet today,
  only 10 years later. In search of the
  ingredients for shark fin soup for
  Asian banquets, fishermen shoot,
  harpoon, or do whatever is necessary
  to slow the fish, then remove the fins,
leaving the carcass for other sharks. 
"Any fish population that is
  undergoing unsustainable mortality
  usually shows a drop in average
  size of individual fish, and a drop
  in abundance," said Meekan. "What
  we're seeing at Ningaloo is particularly
  worrying, because these waters
  are protected. If we're losing the
  adults in the population, leaving only
juvenile whale sharks, then we'll have no population there to reproduce." 
Yet some divers who spear fish
  aren't helping. In two cases that
  made the U.S. press, divers went after
  huge trophy fish, with no concern for
  the endangered nature of the species
they were pursuing. 
The St. Petersburg (FL) Times  reported in July that diver Dan
  MacMahon, had speared a 400-
  pound Warsaw grouper in 425 feet of
  water. The Warsaw grouper is listed
  as "critically endangered" by the
World Conservation Union. 
In a lurid account posted on www.spearboard.com, then criticized on
  other bulletin boards, MacMahon
  described his kill as a "mission" he'd
  spent the last year "plotting and planning"
  to "finally get the big Warsaw
  I've wanted all my life." When he
  reached a wreck on the bottom,
  MacMahon says, "There were a half
  dozen Warsaws in the 40-100 lb.
  range close to us when I spotted the
  monster facing me about 100 feet
away." 
When the fish approached him, MacMahon boasts, "I pointed my 52-
  inch SS Hornet and slammed a free
  shaft into the sweet spot." When the
  fish "started shaking back and forth,"
  says MacMahon, "I slammed shaft
  number two into his head." Then, as
  a coup de grace, he says, "I put a PH
  [power head] on my kill spike and
  slammed into his head." After wrestling
  the huge fish to the surface, it
  took four men and a block and tackle
  to get it on the boat. 
"What an awesome dive," says
  MacMahon. "There's (sic) just too
  few moments like this in ones (sic)
  life." To which we can only add,
"good thing." 
In Southern California, according
  to the San Diego Union-Tribune,
  lifeguards witnessed Navid Adibi, 22,
  driving a boat into the San Diego-La
  Jolla Ecological Reserve on April 24,
  past a bright yellow buoy marking its
  boundaries. Two men put on scuba
  gear and loaded spear guns. About
  20 minutes after they entered the
  water, the men surfaced and the
  boat operator helped them lift a
  171-pound protected giant sea bass aboard; the group celebrated with
high-fives before motoring out of the
reserve. Authorities intercepted the
boat. 
Adibi, the boat driver, an undocumented
  Iranian emigrant with a
  police record, was fined $500. The
man who speared the fish, Omid Adhami, 34, was placed on probation. 
  
    | " Atlantic swordfish used to grow to more than 1,000 pounds, but the average one
 caught in 1995 weighed just 90 pounds."
 | 
Despite these wrist slap punishments,
  trophy hunting for endangered
  species or in marine reserves
  is unconscionable in an era with so
  much pressure on fish populations.
  Terry Maas, legendary spear fisherman,
  author and video maker, points
  out that a 430-pound, slow-growing
  California giant black sea bass would
  be 75 years old. He compares that
  venerable specimen with a 400-
  pound bluefin tuna, only 11 years
  old, that he took while free diving.
  "Obviously," Maas concludes, "tuna, with their rapid growth, can replace
large adults in their population in
one-seventh the time it takes black
sea bass populations to replace a similarly
sized fish." 
John Hyde, of the National
  Marine Fisheries, adds, "It's never
  good to take exceptionally large fish."
  Females are
  usually much
  bigger than
  males. And
  larger females
  tend to produce
  more
  and higher quality eggs, "so catching
  the biggest fish depletes the female
  population," Hyde points out. With
  many groupers and other sex changing
  species, all the small fish may be
  one sex. "By catching all the big fish
  you take away all of one sex, reducing
  reproductive potential until some of
  the remaining small fish can change
  sex ... you can see how easy it would
  be to alter the average size at which
these species change sex." 
News reports of an 1,100-pound
  tiger shark being reeled in during
  a recent "monster shark derby" at Martha's Vineyard, MA, point out
  that taking trophy fish is hardly exclusive
  to spear fishermen. In fact, the
  fishing industry tactic of targeting the
  biggest members of a species is now
  being challenged by new research,
  according to an article in Science News.
  Fleets target big fish because they
  yield more marketable meat. And
  yet, the biggest species--such as tuna,
  sharks, and cod--in heavily fished
  areas tend to be the first to plummet,
  notes Ransom A. Myers of Dalhousie
  University in Halifax, Nova Scotia.
  Ensuing populations get smaller with
  the disappearance of the "big mammas"
  (which often produce the largest
  numbers of eggs and the heartiest
  offspring). For instance, Atlantic
  swordfish used to grow to more
  than 1,000 pounds, but the average
  one landed in 1995 weighed just 90
  pounds--a couple of years short of its
  first chance to reproduce.
We divers have a special relationship
  to the fish in the sea and with
  that comes a special responsibility to
  protect them. That can mean giving
  your time or money to organizations
  that work hard to protect the oceans.
  There's not a lot of time.