In 1997, the commercially-oriented California Abalone Association shot underwater video tape of various dive sites in and around San Miguel Island, Pt. Conception, and the Farallons. Their intent at the time was to demonstrate that sufficiently healthy populations of abalone existed to justify continued commercial harvest. The Pipeline in Cojo Bay, near Pt. Conception and south of the range of California's sea otters, was one of the locations they filmed. Then, in the winter of 1998, it was discovered that 101 sea otters had taken up residence in Cojo Bay. Subsequently, the commercial abalone harvesters returned to Cojo Bay and refilmed the same area covered in their taping of the year before. The resulting 3:42 composite video illustrates the impact sea otters have on shellfish resources.
It's been widely reported that sea otter numbers are declining. It's also been acknowledged that sea otters are also expanding their range (152 sea otters were surveyed between Pt. Conception and Santa Barbara harbor in Febuary, 1999). Because of their status as a threatened species, it's also been widely asserted that sea otters should be allowed to increase their range without interference by humans. What is usually left out of this story is that sea otters are expanding into the range of California's severely depleted abalone populations; an area where, just last year, human harvesting of abalone was closed indefinitely in recognition that continued harvesting would doom any future recovery. White abalone are already classified as a Candidate Species under the Endangered Species Act and black abalone are likely to soon follow suit. The current expansion of the sea otter range is occurring only at the expense of this other, less charismatic species.
I personally share very little in common with the agendas of
commercial abalone harvesters. I do, however, share their concern about
allowing sea otters to expand unimpeded. In the interests of having a more
complete picture of what's at stake as sea otters expand into southern
California and north of the Golden Gate, the California Abalone Association
video tape is being made available here in RealPlayer digitized form. A free copy of
RealPlayer is available at
.
Two condensed versions of the same video tape are available (the uncondensed version, at 284 Meg, is too large to post on my puny web account). The best quality match is the 6 Meg version. For those with a high speed internet connection (T1, ISDN, DSL, ...), it can be downloaded in a few minutes; that same file takes more than an hour to download over my modem connection at home. For those who'd rather not wait that long, there's a 1 Meg version. Just be forewarned that the audio and video quality suffers quite a bit at times. My experience has been that it's more reliable to download large internet files to disk rather than attempting to stream them directly to the screen.
Favored foods of sea otters include abalone and sea urchin. As an assist for those who haven't developed an eye for discerning details under water, the "before" shots along the pipeline show:
- High densities of sea urchins (the black "pin cushion" looking animals on the tops and sides of the pipelines). The vast majority are under the minimum size limits to be commercially harvested.
- Lots of abalone (the gray-green "hubcap" animals mostly seen along the undersides of the pipelines) that were under the size limits for commercial and recreational harvesting.
- Occasional Chestnut Cowries, Bat Sea Stars, and Leather Sea Stars useful for size comparisons.
The "after" shots show:
- A noticably more barren environment in general due largely to the effects of El Nino induced weather patterns on the the underwater vegetation. The gray/green hues of these later underwater shots are most likely attributable to differences in ambient light conditions.
- Most of the abalone from the "before" shots are now empty shells laying alongside the pipeline. Closeups show that the shells are "holed" on top, a demonstration of sea otter predation (exposed abalone are pounded by a rock toting sea otter until the portion of the shell where the abalone attaches has broken away).
- Broken sea urchin testes (shells) are scattered about the bottom. Appearing white in color, sea urchin testes are very fragile and don't remain recognizable for long in winter ocean conditions. Some of the testes still have the black spines attached to the white teste indicating VERY recent predation.
- Wide angle shots show that the pipe lines have been almost completely stripped of sea urchins.
- Only a few of the abalone seen in the "before" shots have survived and are shown tucked under the pipeline in (very) small groups.
- Very little difference in the quantity and density of less desirable otter food (Chestnut Cowries and Sea Stars).
Video shot by Bob
Hay
Digitization work contributed by
Misha Petrenko
Last Modified: January 10, 2006
