Maps of estimated likelihood of occurrence generated by nonparametric multiplicative regression were consistent with observations from fishermen. Dissolved oxygen levels were bimodal, between 3.0-4.5 ml L-1 and 6.0-7.0 ml L-1 at 30 m depth.
We combined annual occurrences noted by fishermen with fisheries- dependent and fisheries-independent data between 2002-11 from 42.0080 degrees N, 131.0000 degrees W to 46.7008 degrees N, 131.0000 degrees W Humboldt squid more frequently occurred at a sea surface temperature range of 10.5 degrees-13.0 degrees C, sea surface height anomalies from -4.0-1.0 m, 0.26-3.00 mg m(-3) hlorophyll a, and sea surface salinity range of 32.2-32.8 psu. Interannual variability in Humboldt squid occurrence is largely undocumented north of California. I do not wish to be over-snarky, though, because there's always a chance I've missed some genuine scientific information.Previous studies have shown that oceanographic conditions influence the distribution of range-expanding Humboldt squid (Dosidicus gigas), but broad-scale temporal and spatial distribution analyses are limited. California researchers expect die-offs of squid in February or March." That is interesting! I, a California researcher, did not know that! Squid beachings in SoCal have generally occurred in the summer, so that would seem to be a counterexample. Item Three: "Usually, squid die in the winter. I suspect that Ken was simply using pH as an example of another water condition (in addition to salinity) to which squid are known to be sensitive, not suggesting that it is a factor in this squid beaching. (Orange juice has an acidic pH of about 4 bleach is basic at about 12.) I don't know anything about the pH of the Strait. (The salinity of truly fresh water is zero the average salinity of the ocean is 35.) Yes, pH is in fact a measure of "acidity or basicity," or, put differently, a measure of hydrogen ions dissolved in the water. Salinity is a measure of how much salt is dissolved in the water. Again, I do see that the concepts here are not the easiest to communicate, but this reads to me like a conflation of salinity and pH. “Squid are highly sensitive to water conditions, very sensitive to pH” - a measure of the acidity or basicity of a solution - he said, pointing out that water in the Strait is generally more diluted by freshwater and has more sediment than that in open ocean. Kent Baltz, a National Oceanic and Atmospheric Administration oceanographer in Santa Cruz, Calif., suspects that the lower salinity of the water in the Strait could be hard on the squid. A comparable vertical migration on land would be hiking to Yosemite's Upper Cathedral Lake and back. So, the squid do live in deep water, but they also live in very shallow water, and they go back and forth between the two.
Here in our mostly two-dimensional terrestrial world, we're much more familiar with the idea of horizontal migration. Vertical migration is a rather bizarre concept. Item One: It's not strictly true to say that Humboldt squid "generally keep to deep water," but I understand where the confusion comes in. I didn't want to be a diva by association.īut this article is the most thorough I've seen yet, including all the interviews and topics that have been covered piecemeal in earlier articles, so it seemed like a good time to jump in and clarify a few items. gigas is still not a giant squid.) I haven't been covering all of these articles here because, well. It seems like every other day there's a news story on Humboldt squid, jumbo squid, or (my favorite!) giant squid. I'm starting to suspect that my study organism, Dosidicus gigas, is a bit of a diva.
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